Merge commit '3f40e65c4' into merge/geth-v1.13.1

build/checksums.txt

@@ -4,20 +4,20 @@
 24bac679f3a2d8240d8e08e7f6a70b70c2dabf673317d924cf1d1887b9fe1f81  fixtures.tar.gz
 
 # https://go.dev/dl/
-818d46ede85682dd551ad378ef37a4d247006f12ec59b5b755601d2ce114369a  go1.21.0.src.tar.gz
+bfa36bf75e9a1e9cbbdb9abcf9d1707e479bd3a07880a8ae3564caee5711cb99  go1.21.1.src.tar.gz
-b314de9f704ab122c077d2ec8e67e3670affe8865479d1f01991e7ac55d65e70  go1.21.0.darwin-amd64.tar.gz
+809f5b0ef4f7dcdd5f51e9630a5b2e5a1006f22a047126d61560cdc365678a19  go1.21.1.darwin-amd64.tar.gz
-3aca44de55c5e098de2f406e98aba328898b05d509a2e2a356416faacf2c4566  go1.21.0.darwin-arm64.tar.gz
+ffd40391a1e995855488b008ad9326ff8c2e81803a6e80894401003bae47fcf1  go1.21.1.darwin-arm64.tar.gz
-312a0065714a50862af714e7a5b3fbbd70fe68f905ffb9bcc56d42eadf6bffab  go1.21.0.freebsd-386.tar.gz
+9919a9a4dc82371aba3da5b7c830bcb6249fc1502cd26d959eb340a60e41ee01  go1.21.1.freebsd-386.tar.gz
-b8eaa36654625df799654f77f4af0ea7bd9e5e760ebe86e68fe7c484748ae995  go1.21.0.freebsd-amd64.tar.gz
+2571f10f6047e04d87c1f5986a05e5e8f7b511faf98803ef12b66d563845d2a1  go1.21.1.freebsd-amd64.tar.gz
-0e6f378d9b072fab0a3d9ff4d5e990d98487d47252dba8160015a61e6bd0bcba  go1.21.0.linux-386.tar.gz
+b93850666cdadbd696a986cf7b03111fe99db8c34a9aaa113d7c96d0081e1901  go1.21.1.linux-386.tar.gz
-d0398903a16ba2232b389fb31032ddf57cac34efda306a0eebac34f0965a0742  go1.21.0.linux-amd64.tar.gz
+b3075ae1ce5dab85f89bc7905d1632de23ca196bd8336afd93fa97434cfa55ae  go1.21.1.linux-amd64.tar.gz
-f3d4548edf9b22f26bbd49720350bbfe59d75b7090a1a2bff1afad8214febaf3  go1.21.0.linux-arm64.tar.gz
+7da1a3936a928fd0b2602ed4f3ef535b8cd1990f1503b8d3e1acc0fa0759c967  go1.21.1.linux-arm64.tar.gz
-e377a0004957c8c560a3ff99601bce612330a3d95ba3b0a2ae144165fc87deb1  go1.21.0.linux-armv6l.tar.gz
+f3716a43f59ae69999841d6007b42c9e286e8d8ce470656fb3e70d7be2d7ca85  go1.21.1.linux-armv6l.tar.gz
-e938ffc81d8ebe5efc179240960ba22da6a841ff05d5cab7ce2547112b14a47f  go1.21.0.linux-ppc64le.tar.gz
+eddf018206f8a5589bda75252b72716d26611efebabdca5d0083ec15e9e41ab7  go1.21.1.linux-ppc64le.tar.gz
-be7338df8e5d5472dfa307b0df2b446d85d001b0a2a3cdb1a14048d751b70481  go1.21.0.linux-s390x.tar.gz
+a83b3e8eb4dbf76294e773055eb51397510ff4d612a247bad9903560267bba6d  go1.21.1.linux-s390x.tar.gz
-af920fbb74fc3d173118dc3cc35f02a709c1de642700e92a91a7d16981df3fec  go1.21.0.windows-386.zip
+170256c820f466f29d64876f25f4dfa4029ed9902a0a9095d8bd603aecf4d83b  go1.21.1.windows-386.zip
-732121e64e0ecb07c77fdf6cc1bc5ce7b242c2d40d4ac29021ad4c64a08731f6  go1.21.0.windows-amd64.zip
+10a4f5b63215d11d1770453733dbcbf024f3f74872f84e28d7ea59f0250316c6  go1.21.1.windows-amd64.zip
-41342f5a0f8c083b14c68bde738ddcd313a4f53a5854bfdfab47f0e88247de12  go1.21.0.windows-arm64.zip
+41135ce6e0ced4bc1e459cb96bd4090c9dc2062e24179c3f337d855af9b560ef  go1.21.1.windows-arm64.zip
 
 # https://github.com/golangci/golangci-lint/releases
 fba08acc4027f69f07cef48fbff70b8a7ecdfaa1c2aba9ad3fb31d60d9f5d4bc  golangci-lint-1.51.1-darwin-amd64.tar.gz

build/ci.go

@@ -139,7 +139,7 @@ var (
 	// This is the version of Go that will be downloaded by
 	//
 	//     go run ci.go install -dlgo
-	dlgoVersion = "1.21.0"
+	dlgoVersion = "1.21.1"
 
 	// This is the version of Go that will be used to bootstrap the PPA builder.
 	//

cmd/geth/config.go

@@ -188,7 +188,7 @@ func makeFullNode(ctx *cli.Context) (*node.Node, ethapi.Backend) {
 			"arch":      runtime.GOARCH,
 			"os":        runtime.GOOS,
 			"version":   cfg.Node.Version,
-			"eth_protocols": strings.Join(protos, ","),
+			"protocols": strings.Join(protos, ","),
 		})
 	}
 

cmd/geth/main.go

@@ -251,11 +251,16 @@ func init() {
 		debug.Flags,
 		metricsFlags,
 	)
+	flags.AutoEnvVars(app.Flags, "GETH")
 
 	app.Before = func(ctx *cli.Context) error {
 		maxprocs.Set() // Automatically set GOMAXPROCS to match Linux container CPU quota.
 		flags.MigrateGlobalFlags(ctx)
-		return debug.Setup(ctx)
+		if err := debug.Setup(ctx); err != nil {
+			return err
+		}
+		flags.CheckEnvVars(ctx, app.Flags, "GETH")
+		return nil
 	}
 	app.After = func(ctx *cli.Context) error {
 		debug.Exit()

core/blockchain.go

@@ -340,6 +340,15 @@ func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, genesis *Genesis
 	// Make sure the state associated with the block is available
 	head := bc.CurrentBlock()
 	if !bc.HasState(head.Root) {
+		if head.Number.Uint64() == 0 {
+			// The genesis state is missing, which is only possible in the path-based
+			// scheme. This situation occurs when the state syncer overwrites it.
+			//
+			// The solution is to reset the state to the genesis state. Although it may not
+			// match the sync target, the state healer will later address and correct any
+			// inconsistencies.
+			bc.resetState()
+		} else {
 			// Head state is missing, before the state recovery, find out the
 			// disk layer point of snapshot(if it's enabled). Make sure the
 			// rewound point is lower than disk layer.
@@ -365,6 +374,7 @@ func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, genesis *Genesis
 				}
 			}
 		}
+	}
 	// Ensure that a previous crash in SetHead doesn't leave extra ancients
 	if frozen, err := bc.db.Ancients(); err == nil && frozen > 0 {
 		var (
@@ -620,6 +630,28 @@ func (bc *BlockChain) SetSafe(header *types.Header) {
 	}
 }
 
+// resetState resets the persistent state to genesis state if it's not present.
+func (bc *BlockChain) resetState() {
+	// Short circuit if the genesis state is already present.
+	root := bc.genesisBlock.Root()
+	if bc.HasState(root) {
+		return
+	}
+	// Reset the state database to empty for committing genesis state.
+	// Note, it should only happen in path-based scheme and Reset function
+	// is also only call-able in this mode.
+	if bc.triedb.Scheme() == rawdb.PathScheme {
+		if err := bc.triedb.Reset(types.EmptyRootHash); err != nil {
+			log.Crit("Failed to clean state", "err", err) // Shouldn't happen
+		}
+	}
+	// Write genesis state into database.
+	if err := CommitGenesisState(bc.db, bc.triedb, bc.genesisBlock.Hash()); err != nil {
+		log.Crit("Failed to commit genesis state", "err", err)
+	}
+	log.Info("Reset state to genesis", "root", root)
+}
+
 // setHeadBeyondRoot rewinds the local chain to a new head with the extra condition
 // that the rewind must pass the specified state root. This method is meant to be
 // used when rewinding with snapshots enabled to ensure that we go back further than
@@ -646,25 +678,6 @@ func (bc *BlockChain) setHeadBeyondRoot(head uint64, time uint64, root common.Ha
 	pivot := rawdb.ReadLastPivotNumber(bc.db)
 	frozen, _ := bc.db.Ancients()
 
-	// resetState resets the persistent state to genesis if it's not available.
-	resetState := func() {
-		// Short circuit if the genesis state is already present.
-		if bc.HasState(bc.genesisBlock.Root()) {
-			return
-		}
-		// Reset the state database to empty for committing genesis state.
-		// Note, it should only happen in path-based scheme and Reset function
-		// is also only call-able in this mode.
-		if bc.triedb.Scheme() == rawdb.PathScheme {
-			if err := bc.triedb.Reset(types.EmptyRootHash); err != nil {
-				log.Crit("Failed to clean state", "err", err) // Shouldn't happen
-			}
-		}
-		// Write genesis state into database.
-		if err := CommitGenesisState(bc.db, bc.triedb, bc.genesisBlock.Hash()); err != nil {
-			log.Crit("Failed to commit genesis state", "err", err)
-		}
-	}
 	updateFn := func(db ethdb.KeyValueWriter, header *types.Header) (*types.Header, bool) {
 		// Rewind the blockchain, ensuring we don't end up with a stateless head
 		// block. Note, depth equality is permitted to allow using SetHead as a
@@ -674,7 +687,7 @@ func (bc *BlockChain) setHeadBeyondRoot(head uint64, time uint64, root common.Ha
 			if newHeadBlock == nil {
 				log.Error("Gap in the chain, rewinding to genesis", "number", header.Number, "hash", header.Hash())
 				newHeadBlock = bc.genesisBlock
-				resetState()
+				bc.resetState()
 			} else {
 				// Block exists, keep rewinding until we find one with state,
 				// keeping rewinding until we exceed the optional threshold
@@ -703,7 +716,7 @@ func (bc *BlockChain) setHeadBeyondRoot(head uint64, time uint64, root common.Ha
 					}
 					if beyondRoot || newHeadBlock.NumberU64() == 0 {
 						if newHeadBlock.NumberU64() == 0 {
-							resetState()
+							bc.resetState()
 						} else if !bc.HasState(newHeadBlock.Root()) {
 							// Rewind to a block with recoverable state. If the state is
 							// missing, run the state recovery here.

core/rawdb/ancient_utils.go

@@ -88,6 +88,9 @@ func inspectFreezers(db ethdb.Database) ([]freezerInfo, error) {
 			infos = append(infos, info)
 
 		case stateFreezerName:
+			if ReadStateScheme(db) != PathScheme {
+				continue
+			}
 			datadir, err := db.AncientDatadir()
 			if err != nil {
 				return nil, err

core/state/statedb.go

@@ -987,7 +987,7 @@ func (s *StateDB) fastDeleteStorage(addrHash common.Hash, root common.Hash) (boo
 			return true, size, nil, nil, nil
 		}
 		slot := common.CopyBytes(iter.Slot())
-		if iter.Error() != nil { // error might occur after Slot function
+		if err := iter.Error(); err != nil { // error might occur after Slot function
 			return false, 0, nil, nil, err
 		}
 		size += common.StorageSize(common.HashLength + len(slot))
@@ -997,7 +997,7 @@ func (s *StateDB) fastDeleteStorage(addrHash common.Hash, root common.Hash) (boo
 			return false, 0, nil, nil, err
 		}
 	}
-	if iter.Error() != nil { // error might occur during iteration
+	if err := iter.Error(); err != nil { // error might occur during iteration
 		return false, 0, nil, nil, err
 	}
 	if stack.Hash() != root {
@@ -1075,12 +1075,10 @@ func (s *StateDB) deleteStorage(addr common.Address, addrHash common.Hash, root
 			slotDeletionSkip.Inc(1)
 		}
 		n := int64(len(slots))
-		if n > slotDeletionMaxCount.Value() {
+
-			slotDeletionMaxCount.Update(n)
+		slotDeletionMaxCount.UpdateIfGt(int64(len(slots)))
-		}
+		slotDeletionMaxSize.UpdateIfGt(int64(size))
-		if int64(size) > slotDeletionMaxSize.Value() {
+
-			slotDeletionMaxSize.Update(int64(size))
-		}
 		slotDeletionTimer.UpdateSince(start)
 		slotDeletionCount.Mark(n)
 		slotDeletionSize.Mark(int64(size))

core/types/gen_account_rlp.go

@@ -1,8 +1,5 @@
 // Code generated by rlpgen. DO NOT EDIT.
 
-//go:build !norlpgen
-// +build !norlpgen
-
 package types
 
 import "github.com/ethereum/go-ethereum/rlp"

core/types/gen_header_rlp.go

@@ -1,8 +1,5 @@
 // Code generated by rlpgen. DO NOT EDIT.
 
-//go:build !norlpgen
-// +build !norlpgen
-
 package types
 
 import "github.com/ethereum/go-ethereum/rlp"

core/types/gen_log_rlp.go

@@ -1,8 +1,5 @@
 // Code generated by rlpgen. DO NOT EDIT.
 
-//go:build !norlpgen
-// +build !norlpgen
-
 package types
 
 import "github.com/ethereum/go-ethereum/rlp"

core/types/gen_withdrawal_rlp.go

@@ -1,8 +1,5 @@
 // Code generated by rlpgen. DO NOT EDIT.
 
-//go:build !norlpgen
-// +build !norlpgen
-
 package types
 
 import "github.com/ethereum/go-ethereum/rlp"

eth/api_debug.go

@@ -362,6 +362,9 @@ func (api *DebugAPI) getModifiedAccounts(startBlock, endBlock *types.Block) ([]c
 // The (from, to) parameters are the sequence of blocks to search, which can go
 // either forwards or backwards
 func (api *DebugAPI) GetAccessibleState(from, to rpc.BlockNumber) (uint64, error) {
+	if api.eth.blockchain.TrieDB().Scheme() == rawdb.PathScheme {
+		return 0, errors.New("state history is not yet available in path-based scheme")
+	}
 	db := api.eth.ChainDb()
 	var pivot uint64
 	if p := rawdb.ReadLastPivotNumber(db); p != nil {
@@ -422,6 +425,9 @@ func (api *DebugAPI) GetAccessibleState(from, to rpc.BlockNumber) (uint64, error
 // If the value is shorter than the block generation time, or even 0 or negative,
 // the node will flush trie after processing each block (effectively archive mode).
 func (api *DebugAPI) SetTrieFlushInterval(interval string) error {
+	if api.eth.blockchain.TrieDB().Scheme() == rawdb.PathScheme {
+		return errors.New("trie flush interval is undefined for path-based scheme")
+	}
 	t, err := time.ParseDuration(interval)
 	if err != nil {
 		return err
@@ -431,6 +437,9 @@ func (api *DebugAPI) SetTrieFlushInterval(interval string) error {
 }
 
 // GetTrieFlushInterval gets the current value of in-memory trie flush interval
-func (api *DebugAPI) GetTrieFlushInterval() string {
+func (api *DebugAPI) GetTrieFlushInterval() (string, error) {
-	return api.eth.blockchain.GetTrieFlushInterval().String()
+	if api.eth.blockchain.TrieDB().Scheme() == rawdb.PathScheme {
+		return "", errors.New("trie flush interval is undefined for path-based scheme")
+	}
+	return api.eth.blockchain.GetTrieFlushInterval().String(), nil
 }

eth/catalyst/api.go

@@ -207,21 +207,21 @@ func (api *ConsensusAPI) verifyPayloadAttributes(attr *engine.PayloadAttributes)
 	c := api.eth.BlockChain().Config()
 
 	// Verify withdrawals attribute for Shanghai.
-	if err := checkAttribute(c.IsShanghai, attr.Withdrawals != nil, attr.Timestamp); err != nil {
+	if err := checkAttribute(c.IsShanghai, attr.Withdrawals != nil, c.LondonBlock, attr.Timestamp); err != nil {
 		return fmt.Errorf("invalid withdrawals: %w", err)
 	}
 	// Verify beacon root attribute for Cancun.
-	if err := checkAttribute(c.IsCancun, attr.BeaconRoot != nil, attr.Timestamp); err != nil {
+	if err := checkAttribute(c.IsCancun, attr.BeaconRoot != nil, c.LondonBlock, attr.Timestamp); err != nil {
 		return fmt.Errorf("invalid parent beacon block root: %w", err)
 	}
 	return nil
 }
 
-func checkAttribute(active func(*big.Int, uint64) bool, exists bool, time uint64) error {
+func checkAttribute(active func(*big.Int, uint64) bool, exists bool, block *big.Int, time uint64) error {
-	if active(common.Big0, time) && !exists {
+	if active(block, time) && !exists {
 		return errors.New("fork active, missing expected attribute")
 	}
-	if !active(common.Big0, time) && exists {
+	if !active(block, time) && exists {
 		return errors.New("fork inactive, unexpected attribute set")
 	}
 	return nil

eth/downloader/downloader.go

@@ -398,7 +398,14 @@ func (d *Downloader) synchronise(id string, hash common.Hash, td, ttd *big.Int,
 		log.Info("Block synchronisation started")
 	}
 	if mode == SnapSync {
-		// Snap sync uses the snapshot namespace to store potentially flakey data until
+		// Snap sync will directly modify the persistent state, making the entire
+		// trie database unusable until the state is fully synced. To prevent any
+		// subsequent state reads, explicitly disable the trie database and state
+		// syncer is responsible to address and correct any state missing.
+		if d.blockchain.TrieDB().Scheme() == rawdb.PathScheme {
+			d.blockchain.TrieDB().Reset(types.EmptyRootHash)
+		}
+		// Snap sync uses the snapshot namespace to store potentially flaky data until
 		// sync completely heals and finishes. Pause snapshot maintenance in the mean-
 		// time to prevent access.
 		if snapshots := d.blockchain.Snapshots(); snapshots != nil { // Only nil in tests
@@ -1606,17 +1613,30 @@ func (d *Downloader) processSnapSyncContent() error {
 
 	// To cater for moving pivot points, track the pivot block and subsequently
 	// accumulated download results separately.
+	//
+	// These will be nil up to the point where we reach the pivot, and will only
+	// be set temporarily if the synced blocks are piling up, but the pivot is
+	// still busy downloading. In that case, we need to occasionally check for
+	// pivot moves, so need to unblock the loop. These fields will accumulate
+	// the results in the meantime.
+	//
+	// Note, there's no issue with memory piling up since after 64 blocks the
+	// pivot will forcefully move so these accumulators will be dropped.
 	var (
 		oldPivot *fetchResult   // Locked in pivot block, might change eventually
 		oldTail  []*fetchResult // Downloaded content after the pivot
 	)
 	for {
-		// Wait for the next batch of downloaded data to be available, and if the pivot
+		// Wait for the next batch of downloaded data to be available. If we have
-		// block became stale, move the goalpost
+		// not yet reached the pivot point, wait blockingly as there's no need to
-		results := d.queue.Results(oldPivot == nil) // Block if we're not monitoring pivot staleness
+		// spin-loop check for pivot moves. If we reached the pivot but have not
+		// yet processed it, check for results async, so we might notice pivot
+		// moves while state syncing. If the pivot was passed fully, block again
+		// as there's no more reason to check for pivot moves at all.
+		results := d.queue.Results(oldPivot == nil)
 		if len(results) == 0 {
 			// If pivot sync is done, stop
-			if oldPivot == nil {
+			if d.committed.Load() {
 				d.reportSnapSyncProgress(true)
 				return sync.Cancel()
 			}
@@ -1639,21 +1659,23 @@ func (d *Downloader) processSnapSyncContent() error {
 		pivot := d.pivotHeader
 		d.pivotLock.RUnlock()
 
-		if oldPivot == nil {
+		if oldPivot == nil { // no results piling up, we can move the pivot
-			if pivot.Root != sync.root {
+			if !d.committed.Load() { // not yet passed the pivot, we can move the pivot
+				if pivot.Root != sync.root { // pivot position changed, we can move the pivot
 					sync.Cancel()
 					sync = d.syncState(pivot.Root)
 
 					go closeOnErr(sync)
 				}
-		} else {
+			}
+		} else { // results already piled up, consume before handling pivot move
 			results = append(append([]*fetchResult{oldPivot}, oldTail...), results...)
 		}
 		// Split around the pivot block and process the two sides via snap/full sync
 		if !d.committed.Load() {
 			latest := results[len(results)-1].Header
 			// If the height is above the pivot block by 2 sets, it means the pivot
-			// become stale in the network and it was garbage collected, move to a
+			// become stale in the network, and it was garbage collected, move to a
 			// new pivot.
 			//
 			// Note, we have `reorgProtHeaderDelay` number of blocks withheld, Those

go.mod

@@ -62,7 +62,7 @@ require (
 	github.com/supranational/blst v0.3.11
 	github.com/syndtr/goleveldb v1.0.1-0.20210819022825-2ae1ddf74ef7
 	github.com/tyler-smith/go-bip39 v1.1.0
-	github.com/urfave/cli/v2 v2.24.1
+	github.com/urfave/cli/v2 v2.25.7
 	go.uber.org/automaxprocs v1.5.2
 	golang.org/x/crypto v0.12.0
 	golang.org/x/exp v0.0.0-20230810033253-352e893a4cad

go.sum

@@ -39,7 +39,7 @@ github.com/Azure/azure-sdk-for-go/sdk/internal v0.8.3/go.mod h1:KLF4gFr6DcKFZwSu
 github.com/Azure/azure-sdk-for-go/sdk/storage/azblob v0.3.0 h1:Px2UA+2RvSSvv+RvJNuUB6n7rs5Wsel4dXLe90Um2n4=
 github.com/Azure/azure-sdk-for-go/sdk/storage/azblob v0.3.0/go.mod h1:tPaiy8S5bQ+S5sOiDlINkp7+Ef339+Nz5L5XO+cnOHo=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
-github.com/BurntSushi/toml v1.2.1 h1:9F2/+DoOYIOksmaJFPw1tGFy1eDnIJXg+UHjuD8lTak=
+github.com/BurntSushi/toml v1.3.2 h1:o7IhLm0Msx3BaB+n3Ag7L8EVlByGnpq14C4YWiu/gL8=
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
 github.com/CloudyKit/fastprinter v0.0.0-20170127035650-74b38d55f37a/go.mod h1:EFZQ978U7x8IRnstaskI3IysnWY5Ao3QgZUKOXlsAdw=
 github.com/CloudyKit/jet v2.1.3-0.20180809161101-62edd43e4f88+incompatible/go.mod h1:HPYO+50pSWkPoj9Q/eq0aRGByCL6ScRlUmiEX5Zgm+w=
@@ -553,8 +553,8 @@ github.com/tyler-smith/go-bip39 v1.1.0/go.mod h1:gUYDtqQw1JS3ZJ8UWVcGTGqqr6YIN3C
 github.com/ugorji/go v1.1.4/go.mod h1:uQMGLiO92mf5W77hV/PUCpI3pbzQx3CRekS0kk+RGrc=
 github.com/ugorji/go/codec v0.0.0-20181204163529-d75b2dcb6bc8/go.mod h1:VFNgLljTbGfSG7qAOspJ7OScBnGdDN/yBr0sguwnwf0=
 github.com/urfave/cli/v2 v2.3.0/go.mod h1:LJmUH05zAU44vOAcrfzZQKsZbVcdbOG8rtL3/XcUArI=
-github.com/urfave/cli/v2 v2.24.1 h1:/QYYr7g0EhwXEML8jO+8OYt5trPnLHS0p3mrgExJ5NU=
+github.com/urfave/cli/v2 v2.25.7 h1:VAzn5oq403l5pHjc4OhD54+XGO9cdKVL/7lDjF+iKUs=
-github.com/urfave/cli/v2 v2.24.1/go.mod h1:GHupkWPMM0M/sj1a2b4wUrWBPzazNrIjouW6fmdJLxc=
+github.com/urfave/cli/v2 v2.25.7/go.mod h1:8qnjx1vcq5s2/wpsqoZFndg2CE5tNFyrTvS6SinrnYQ=
 github.com/urfave/negroni v1.0.0/go.mod h1:Meg73S6kFm/4PpbYdq35yYWoCZ9mS/YSx+lKnmiohz4=
 github.com/valyala/bytebufferpool v1.0.0/go.mod h1:6bBcMArwyJ5K/AmCkWv1jt77kVWyCJ6HpOuEn7z0Csc=
 github.com/valyala/fasthttp v1.6.0/go.mod h1:FstJa9V+Pj9vQ7OJie2qMHdwemEDaDiSdBnvPM1Su9w=

graphql/graphql.go

@@ -272,8 +272,6 @@ func (t *Transaction) GasPrice(ctx context.Context) hexutil.Big {
 		return hexutil.Big{}
 	}
 	switch tx.Type() {
-	case types.AccessListTxType:
-		return hexutil.Big(*tx.GasPrice())
 	case types.DynamicFeeTxType:
 		if block != nil {
 			if baseFee, _ := block.BaseFeePerGas(ctx); baseFee != nil {
@@ -312,9 +310,7 @@ func (t *Transaction) MaxFeePerGas(ctx context.Context) *hexutil.Big {
 		return nil
 	}
 	switch tx.Type() {
-	case types.AccessListTxType:
+	case types.DynamicFeeTxType, types.BlobTxType:
-		return nil
-	case types.DynamicFeeTxType:
 		return (*hexutil.Big)(tx.GasFeeCap())
 	default:
 		return nil
@@ -327,15 +323,33 @@ func (t *Transaction) MaxPriorityFeePerGas(ctx context.Context) *hexutil.Big {
 		return nil
 	}
 	switch tx.Type() {
-	case types.AccessListTxType:
+	case types.DynamicFeeTxType, types.BlobTxType:
-		return nil
-	case types.DynamicFeeTxType:
 		return (*hexutil.Big)(tx.GasTipCap())
 	default:
 		return nil
 	}
 }
 
+func (t *Transaction) MaxFeePerBlobGas(ctx context.Context) *hexutil.Big {
+	tx, _ := t.resolve(ctx)
+	if tx == nil {
+		return nil
+	}
+	return (*hexutil.Big)(tx.BlobGasFeeCap())
+}
+
+func (t *Transaction) BlobVersionedHashes(ctx context.Context) *[]common.Hash {
+	tx, _ := t.resolve(ctx)
+	if tx == nil {
+		return nil
+	}
+	if tx.Type() != types.BlobTxType {
+		return nil
+	}
+	blobHashes := tx.BlobHashes()
+	return &blobHashes
+}
+
 func (t *Transaction) EffectiveTip(ctx context.Context) (*hexutil.Big, error) {
 	tx, block := t.resolve(ctx)
 	if tx == nil {
@@ -468,6 +482,40 @@ func (t *Transaction) CumulativeGasUsed(ctx context.Context) (*hexutil.Uint64, e
 	return &ret, nil
 }
 
+func (t *Transaction) BlobGasUsed(ctx context.Context) (*hexutil.Uint64, error) {
+	tx, _ := t.resolve(ctx)
+	if tx == nil {
+		return nil, nil
+	}
+	if tx.Type() != types.BlobTxType {
+		return nil, nil
+	}
+
+	receipt, err := t.getReceipt(ctx)
+	if err != nil || receipt == nil {
+		return nil, err
+	}
+	ret := hexutil.Uint64(receipt.BlobGasUsed)
+	return &ret, nil
+}
+
+func (t *Transaction) BlobGasPrice(ctx context.Context) (*hexutil.Big, error) {
+	tx, _ := t.resolve(ctx)
+	if tx == nil {
+		return nil, nil
+	}
+	if tx.Type() != types.BlobTxType {
+		return nil, nil
+	}
+
+	receipt, err := t.getReceipt(ctx)
+	if err != nil || receipt == nil {
+		return nil, err
+	}
+	ret := (*hexutil.Big)(receipt.BlobGasPrice)
+	return ret, nil
+}
+
 func (t *Transaction) CreatedContract(ctx context.Context, args BlockNumberArgs) (*Account, error) {
 	receipt, err := t.getReceipt(ctx)
 	if err != nil || receipt == nil || receipt.ContractAddress == (common.Address{}) {
@@ -1019,6 +1067,30 @@ func (b *Block) Withdrawals(ctx context.Context) (*[]*Withdrawal, error) {
 	return &ret, nil
 }
 
+func (b *Block) BlobGasUsed(ctx context.Context) (*hexutil.Uint64, error) {
+	header, err := b.resolveHeader(ctx)
+	if err != nil {
+		return nil, err
+	}
+	if header.BlobGasUsed == nil {
+		return nil, nil
+	}
+	ret := hexutil.Uint64(*header.BlobGasUsed)
+	return &ret, nil
+}
+
+func (b *Block) ExcessBlobGas(ctx context.Context) (*hexutil.Uint64, error) {
+	header, err := b.resolveHeader(ctx)
+	if err != nil {
+		return nil, err
+	}
+	if header.ExcessBlobGas == nil {
+		return nil, nil
+	}
+	ret := hexutil.Uint64(*header.ExcessBlobGas)
+	return &ret, nil
+}
+
 // BlockFilterCriteria encapsulates criteria passed to a `logs` accessor inside
 // a block.
 type BlockFilterCriteria struct {

graphql/schema.go

@@ -71,8 +71,8 @@ const schema string = `
         transaction: Transaction!
     }
 
-    #EIP-2718
+    # EIP-2718
-    type AccessTuple{
+    type AccessTuple {
         address: Address!
         storageKeys : [Bytes32!]!
     }
@@ -112,6 +112,8 @@ const schema string = `
         maxFeePerGas: BigInt
         # MaxPriorityFeePerGas is the maximum miner tip per gas offered to include a transaction, in wei.
         maxPriorityFeePerGas: BigInt
+        # MaxFeePerBlobGas is the maximum blob gas fee cap per blob the sender is willing to pay for blob transaction, in wei.
+        maxFeePerBlobGas: BigInt
         # EffectiveTip is the actual amount of reward going to miner after considering the max fee cap.
         effectiveTip: BigInt
         # Gas is the maximum amount of gas this transaction can consume.
@@ -141,6 +143,10 @@ const schema string = `
         # coerced into the EIP-1559 format by setting both maxFeePerGas and
         # maxPriorityFeePerGas as the transaction's gas price.
         effectiveGasPrice: BigInt
+        # BlobGasUsed is the amount of blob gas used by this transaction.
+        blobGasUsed: Long
+        # blobGasPrice is the actual value per blob gas deducted from the senders account.
+        blobGasPrice: BigInt
         # CreatedContract is the account that was created by a contract creation
         # transaction. If the transaction was not a contract creation transaction,
         # or it has not yet been mined, this field will be null.
@@ -162,6 +168,8 @@ const schema string = `
         # RawReceipt is the canonical encoding of the receipt. For post EIP-2718 typed transactions
         # this is equivalent to TxType || ReceiptEncoding.
         rawReceipt: Bytes!
+        # BlobVersionedHashes is a set of hash outputs from the blobs in the transaction.
+        blobVersionedHashes: [Bytes32!]
     }
 
     # BlockFilterCriteria encapsulates log filter criteria for a filter applied
@@ -267,6 +275,10 @@ const schema string = `
         # Withdrawals is a list of withdrawals associated with this block. If
         # withdrawals are unavailable for this block, this field will be null.
         withdrawals: [Withdrawal!]
+        # BlobGasUsed is the total amount of gas used by the transactions.
+        blobGasUsed: Long
+        # ExcessBlobGas is a running total of blob gas consumed in excess of the target, prior to the block.
+        excessBlobGas: Long
     }
 
     # CallData represents the data associated with a local contract call.
@@ -326,7 +338,7 @@ const schema string = `
     }
 
     # SyncState contains the current synchronisation state of the client.
-    type SyncState{
+    type SyncState {
         # StartingBlock is the block number at which synchronisation started.
         startingBlock: Long!
         # CurrentBlock is the point at which synchronisation has presently reached.

internal/debug/loudpanic.go

@@ -14,9 +14,6 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
 
-//go:build go1.6
-// +build go1.6
-
 package debug
 
 import "runtime/debug"

internal/debug/loudpanic_fallback.go

@@ -1,25 +0,0 @@
-// Copyright 2016 The go-ethereum Authors
-// This file is part of the go-ethereum library.
-//
-// The go-ethereum library is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Lesser General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// The go-ethereum library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public License
-// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
-
-//go:build !go1.6
-// +build !go1.6
-
-package debug
-
-// LoudPanic panics in a way that gets all goroutine stacks printed on stderr.
-func LoudPanic(x interface{}) {
-	panic(x)
-}

internal/debug/trace.go

@@ -14,9 +14,6 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
 
-//go:build go1.5
-// +build go1.5
-
 package debug
 
 import (

internal/debug/trace_fallback.go

@@ -1,32 +0,0 @@
-// Copyright 2016 The go-ethereum Authors
-// This file is part of the go-ethereum library.
-//
-// The go-ethereum library is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Lesser General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// The go-ethereum library is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU Lesser General Public License for more details.
-//
-// You should have received a copy of the GNU Lesser General Public License
-// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
-
-//go:build !go1.5
-// +build !go1.5
-
-// no-op implementation of tracing methods for Go < 1.5.
-
-package debug
-
-import "errors"
-
-func (*HandlerT) StartGoTrace(string) error {
-	return errors.New("tracing is not supported on Go < 1.5")
-}
-
-func (*HandlerT) StopGoTrace() error {
-	return errors.New("tracing is not supported on Go < 1.5")
-}

internal/ethapi/api.go

@@ -1520,8 +1520,8 @@ func newRPCTransaction(tx *types.Transaction, blockHash common.Hash, blockNumber
 func effectiveGasPrice(tx *types.Transaction, baseFee *big.Int) *big.Int {
 	fee := tx.GasTipCap()
 	fee = fee.Add(fee, baseFee)
-	if tx.GasTipCapIntCmp(fee) < 0 {
+	if tx.GasFeeCapIntCmp(fee) < 0 {
-		return tx.GasTipCap()
+		return tx.GasFeeCap()
 	}
 	return fee
 }

internal/flags/flags.go

@@ -20,11 +20,13 @@ import (
 	"encoding"
 	"errors"
 	"flag"
+	"fmt"
 	"math/big"
 	"os"
 	"os/user"
 	"path/filepath"
 	"strings"
+	"syscall"
 
 	"github.com/ethereum/go-ethereum/common/math"
 	"github.com/urfave/cli/v2"
@@ -68,6 +70,7 @@ type DirectoryFlag struct {
 	Value DirectoryString
 
 	Aliases []string
+	EnvVars []string
 }
 
 // For cli.Flag:
@@ -79,6 +82,14 @@ func (f *DirectoryFlag) String() string  { return cli.FlagStringer(f) }
 // Apply called by cli library, grabs variable from environment (if in env)
 // and adds variable to flag set for parsing.
 func (f *DirectoryFlag) Apply(set *flag.FlagSet) error {
+	for _, envVar := range f.EnvVars {
+		envVar = strings.TrimSpace(envVar)
+		if value, found := syscall.Getenv(envVar); found {
+			f.Value.Set(value)
+			f.HasBeenSet = true
+			break
+		}
+	}
 	eachName(f, func(name string) {
 		set.Var(&f.Value, f.Name, f.Usage)
 	})
@@ -102,7 +113,7 @@ func (f *DirectoryFlag) GetCategory() string { return f.Category }
 func (f *DirectoryFlag) TakesValue() bool     { return true }
 func (f *DirectoryFlag) GetUsage() string     { return f.Usage }
 func (f *DirectoryFlag) GetValue() string     { return f.Value.String() }
-func (f *DirectoryFlag) GetEnvVars() []string { return nil } // env not supported
+func (f *DirectoryFlag) GetEnvVars() []string { return f.EnvVars }
 
 func (f *DirectoryFlag) GetDefaultText() string {
 	if f.DefaultText != "" {
@@ -156,6 +167,7 @@ type TextMarshalerFlag struct {
 	Value TextMarshaler
 
 	Aliases []string
+	EnvVars []string
 }
 
 // For cli.Flag:
@@ -165,6 +177,16 @@ func (f *TextMarshalerFlag) IsSet() bool     { return f.HasBeenSet }
 func (f *TextMarshalerFlag) String() string  { return cli.FlagStringer(f) }
 
 func (f *TextMarshalerFlag) Apply(set *flag.FlagSet) error {
+	for _, envVar := range f.EnvVars {
+		envVar = strings.TrimSpace(envVar)
+		if value, found := syscall.Getenv(envVar); found {
+			if err := f.Value.UnmarshalText([]byte(value)); err != nil {
+				return fmt.Errorf("could not parse %q from environment variable %q for flag %s: %s", value, envVar, f.Name, err)
+			}
+			f.HasBeenSet = true
+			break
+		}
+	}
 	eachName(f, func(name string) {
 		set.Var(textMarshalerVal{f.Value}, f.Name, f.Usage)
 	})
@@ -187,7 +209,7 @@ func (f *TextMarshalerFlag) GetCategory() string { return f.Category }
 
 func (f *TextMarshalerFlag) TakesValue() bool     { return true }
 func (f *TextMarshalerFlag) GetUsage() string     { return f.Usage }
-func (f *TextMarshalerFlag) GetEnvVars() []string { return nil } // env not supported
+func (f *TextMarshalerFlag) GetEnvVars() []string { return f.EnvVars }
 
 func (f *TextMarshalerFlag) GetValue() string {
 	t, err := f.Value.MarshalText()
@@ -237,6 +259,7 @@ type BigFlag struct {
 	Value *big.Int
 
 	Aliases []string
+	EnvVars []string
 }
 
 // For cli.Flag:
@@ -246,6 +269,16 @@ func (f *BigFlag) IsSet() bool     { return f.HasBeenSet }
 func (f *BigFlag) String() string  { return cli.FlagStringer(f) }
 
 func (f *BigFlag) Apply(set *flag.FlagSet) error {
+	for _, envVar := range f.EnvVars {
+		envVar = strings.TrimSpace(envVar)
+		if value, found := syscall.Getenv(envVar); found {
+			if _, ok := f.Value.SetString(value, 10); !ok {
+				return fmt.Errorf("could not parse %q from environment variable %q for flag %s", value, envVar, f.Name)
+			}
+			f.HasBeenSet = true
+			break
+		}
+	}
 	eachName(f, func(name string) {
 		f.Value = new(big.Int)
 		set.Var((*bigValue)(f.Value), f.Name, f.Usage)
@@ -271,7 +304,7 @@ func (f *BigFlag) GetCategory() string { return f.Category }
 func (f *BigFlag) TakesValue() bool     { return true }
 func (f *BigFlag) GetUsage() string     { return f.Usage }
 func (f *BigFlag) GetValue() string     { return f.Value.String() }
-func (f *BigFlag) GetEnvVars() []string { return nil } // env not supported
+func (f *BigFlag) GetEnvVars() []string { return f.EnvVars }
 
 func (f *BigFlag) GetDefaultText() string {
 	if f.DefaultText != "" {

internal/flags/helpers.go

@@ -18,13 +18,22 @@ package flags
 
 import (
 	"fmt"
+	"os"
+	"regexp"
+	"sort"
 	"strings"
 
 	"github.com/ethereum/go-ethereum/internal/version"
+	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/params"
+	"github.com/mattn/go-isatty"
 	"github.com/urfave/cli/v2"
 )
 
+// usecolor defines whether the CLI help should use colored output or normal dumb
+// colorless terminal formatting.
+var usecolor = (isatty.IsTerminal(os.Stdout.Fd()) || isatty.IsCygwinTerminal(os.Stdout.Fd())) && os.Getenv("TERM") != "dumb"
+
 // NewApp creates an app with sane defaults.
 func NewApp(usage string) *cli.App {
 	git, _ := version.VCS()
@@ -129,6 +138,14 @@ func doMigrateFlags(ctx *cli.Context) {
 }
 
 func init() {
+	if usecolor {
+		// Annotate all help categories with colors
+		cli.AppHelpTemplate = regexp.MustCompile("[A-Z ]+:").ReplaceAllString(cli.AppHelpTemplate, "\u001B[33m$0\u001B[0m")
+
+		// Annotate flag categories with colors (private template, so need to
+		// copy-paste the entire thing here...)
+		cli.AppHelpTemplate = strings.ReplaceAll(cli.AppHelpTemplate, "{{template \"visibleFlagCategoryTemplate\" .}}", "{{range .VisibleFlagCategories}}\n   {{if .Name}}\u001B[33m{{.Name}}\u001B[0m\n\n   {{end}}{{$flglen := len .Flags}}{{range $i, $e := .Flags}}{{if eq (subtract $flglen $i) 1}}{{$e}}\n{{else}}{{$e}}\n   {{end}}{{end}}{{end}}")
+	}
 	cli.FlagStringer = FlagString
 }
 
@@ -138,37 +155,31 @@ func FlagString(f cli.Flag) string {
 	if !ok {
 		return ""
 	}
-
 	needsPlaceholder := df.TakesValue()
 	placeholder := ""
 	if needsPlaceholder {
 		placeholder = "value"
 	}
 
-	namesText := pad(cli.FlagNamePrefixer(df.Names(), placeholder), 30)
+	namesText := cli.FlagNamePrefixer(df.Names(), placeholder)
 
 	defaultValueString := ""
 	if s := df.GetDefaultText(); s != "" {
 		defaultValueString = " (default: " + s + ")"
 	}
-
-	usage := strings.TrimSpace(df.GetUsage())
 	envHint := strings.TrimSpace(cli.FlagEnvHinter(df.GetEnvVars(), ""))
-	if len(envHint) > 0 {
+	if envHint != "" {
-		usage += " " + envHint
+		envHint = " (" + envHint[1:len(envHint)-1] + ")"
 	}
-
+	usage := strings.TrimSpace(df.GetUsage())
 	usage = wordWrap(usage, 80)
 	usage = indent(usage, 10)
 
-	return fmt.Sprintf("\n    %s%s\n%s", namesText, defaultValueString, usage)
+	if usecolor {
-}
+		return fmt.Sprintf("\n    \u001B[32m%-35s%-35s\u001B[0m%s\n%s", namesText, defaultValueString, envHint, usage)
-
+	} else {
-func pad(s string, length int) string {
+		return fmt.Sprintf("\n    %-35s%-35s%s\n%s", namesText, defaultValueString, envHint, usage)
-	if len(s) < length {
-		s += strings.Repeat(" ", length-len(s))
 	}
-	return s
 }
 
 func indent(s string, nspace int) string {
@@ -213,3 +224,78 @@ func wordWrap(s string, width int) string {
 
 	return output.String()
 }
+
+// AutoEnvVars extends all the specific CLI flags with automatically generated
+// env vars by capitalizing the flag, replacing . with _ and prefixing it with
+// the specified string.
+//
+// Note, the prefix should *not* contain the separator underscore, that will be
+// added automatically.
+func AutoEnvVars(flags []cli.Flag, prefix string) {
+	for _, flag := range flags {
+		envvar := strings.ToUpper(prefix + "_" + strings.ReplaceAll(strings.ReplaceAll(flag.Names()[0], ".", "_"), "-", "_"))
+
+		switch flag := flag.(type) {
+		case *cli.StringFlag:
+			flag.EnvVars = append(flag.EnvVars, envvar)
+
+		case *cli.BoolFlag:
+			flag.EnvVars = append(flag.EnvVars, envvar)
+
+		case *cli.IntFlag:
+			flag.EnvVars = append(flag.EnvVars, envvar)
+
+		case *cli.Uint64Flag:
+			flag.EnvVars = append(flag.EnvVars, envvar)
+
+		case *cli.DurationFlag:
+			flag.EnvVars = append(flag.EnvVars, envvar)
+
+		case *cli.PathFlag:
+			flag.EnvVars = append(flag.EnvVars, envvar)
+
+		case *BigFlag:
+			flag.EnvVars = append(flag.EnvVars, envvar)
+
+		case *TextMarshalerFlag:
+			flag.EnvVars = append(flag.EnvVars, envvar)
+
+		case *DirectoryFlag:
+			flag.EnvVars = append(flag.EnvVars, envvar)
+		}
+	}
+}
+
+// CheckEnvVars iterates over all the environment variables and checks if any of
+// them look like a CLI flag but is not consumed. This can be used to detect old
+// or mistyped names.
+func CheckEnvVars(ctx *cli.Context, flags []cli.Flag, prefix string) {
+	known := make(map[string]string)
+	for _, flag := range flags {
+		docflag, ok := flag.(cli.DocGenerationFlag)
+		if !ok {
+			continue
+		}
+		for _, envvar := range docflag.GetEnvVars() {
+			known[envvar] = flag.Names()[0]
+		}
+	}
+	keyvals := os.Environ()
+	sort.Strings(keyvals)
+
+	for _, keyval := range keyvals {
+		key := strings.Split(keyval, "=")[0]
+		if !strings.HasPrefix(key, prefix) {
+			continue
+		}
+		if flag, ok := known[key]; ok {
+			if ctx.Count(flag) > 0 {
+				log.Info("Config environment variable found", "envvar", key, "shadowedby", "--"+flag)
+			} else {
+				log.Info("Config environment variable found", "envvar", key)
+			}
+		} else {
+			log.Warn("Unknown config environment variable", "envvar", key)
+		}
+	}
+}

log/handler.go

@@ -7,6 +7,7 @@ import (
 	"os"
 	"reflect"
 	"sync"
+	"sync/atomic"
 
 	"github.com/go-stack/stack"
 )
@@ -354,3 +355,21 @@ func (m muster) FileHandler(path string, fmtr Format) Handler {
 func (m muster) NetHandler(network, addr string, fmtr Format) Handler {
 	return must(NetHandler(network, addr, fmtr))
 }
+
+// swapHandler wraps another handler that may be swapped out
+// dynamically at runtime in a thread-safe fashion.
+type swapHandler struct {
+	handler atomic.Value
+}
+
+func (h *swapHandler) Log(r *Record) error {
+	return (*h.handler.Load().(*Handler)).Log(r)
+}
+
+func (h *swapHandler) Swap(newHandler Handler) {
+	h.handler.Store(&newHandler)
+}
+
+func (h *swapHandler) Get() Handler {
+	return *h.handler.Load().(*Handler)
+}

log/handler_go13.go

@@ -1,27 +0,0 @@
-//go:build !go1.4
-// +build !go1.4
-
-package log
-
-import (
-	"sync/atomic"
-	"unsafe"
-)
-
-// swapHandler wraps another handler that may be swapped out
-// dynamically at runtime in a thread-safe fashion.
-type swapHandler struct {
-	handler unsafe.Pointer
-}
-
-func (h *swapHandler) Log(r *Record) error {
-	return h.Get().Log(r)
-}
-
-func (h *swapHandler) Get() Handler {
-	return *(*Handler)(atomic.LoadPointer(&h.handler))
-}
-
-func (h *swapHandler) Swap(newHandler Handler) {
-	atomic.StorePointer(&h.handler, unsafe.Pointer(&newHandler))
-}

log/handler_go14.go

@@ -1,24 +0,0 @@
-//go:build go1.4
-// +build go1.4
-
-package log
-
-import "sync/atomic"
-
-// swapHandler wraps another handler that may be swapped out
-// dynamically at runtime in a thread-safe fashion.
-type swapHandler struct {
-	handler atomic.Value
-}
-
-func (h *swapHandler) Log(r *Record) error {
-	return (*h.handler.Load().(*Handler)).Log(r)
-}
-
-func (h *swapHandler) Swap(newHandler Handler) {
-	h.handler.Store(&newHandler)
-}
-
-func (h *swapHandler) Get() Handler {
-	return *h.handler.Load().(*Handler)
-}

metrics/counter.go

@@ -4,13 +4,16 @@ import (
 	"sync/atomic"
 )
 
+type CounterSnapshot interface {
+	Count() int64
+}
+
 // Counters hold an int64 value that can be incremented and decremented.
 type Counter interface {
 	Clear()
-	Count() int64
 	Dec(int64)
 	Inc(int64)
-	Snapshot() Counter
+	Snapshot() CounterSnapshot
 }
 
 // GetOrRegisterCounter returns an existing Counter or constructs and registers
@@ -38,13 +41,13 @@ func NewCounter() Counter {
 	if !Enabled {
 		return NilCounter{}
 	}
-	return &StandardCounter{}
+	return new(StandardCounter)
 }
 
 // NewCounterForced constructs a new StandardCounter and returns it no matter if
 // the global switch is enabled or not.
 func NewCounterForced() Counter {
-	return &StandardCounter{}
+	return new(StandardCounter)
 }
 
 // NewRegisteredCounter constructs and registers a new StandardCounter.
@@ -70,75 +73,40 @@ func NewRegisteredCounterForced(name string, r Registry) Counter {
 	return c
 }
 
-// CounterSnapshot is a read-only copy of another Counter.
+// counterSnapshot is a read-only copy of another Counter.
-type CounterSnapshot int64
+type counterSnapshot int64
-
-// Clear panics.
-func (CounterSnapshot) Clear() {
-	panic("Clear called on a CounterSnapshot")
-}
 
 // Count returns the count at the time the snapshot was taken.
-func (c CounterSnapshot) Count() int64 { return int64(c) }
+func (c counterSnapshot) Count() int64 { return int64(c) }
-
-// Dec panics.
-func (CounterSnapshot) Dec(int64) {
-	panic("Dec called on a CounterSnapshot")
-}
-
-// Inc panics.
-func (CounterSnapshot) Inc(int64) {
-	panic("Inc called on a CounterSnapshot")
-}
-
-// Snapshot returns the snapshot.
-func (c CounterSnapshot) Snapshot() Counter { return c }
 
 // NilCounter is a no-op Counter.
 type NilCounter struct{}
 
-// Clear is a no-op.
 func (NilCounter) Clear()                    {}
-
-// Count is a no-op.
-func (NilCounter) Count() int64 { return 0 }
-
-// Dec is a no-op.
 func (NilCounter) Dec(i int64)               {}
-
-// Inc is a no-op.
 func (NilCounter) Inc(i int64)               {}
-
+func (NilCounter) Snapshot() CounterSnapshot { return (*emptySnapshot)(nil) }
-// Snapshot is a no-op.
-func (NilCounter) Snapshot() Counter { return NilCounter{} }
 
 // StandardCounter is the standard implementation of a Counter and uses the
 // sync/atomic package to manage a single int64 value.
-type StandardCounter struct {
+type StandardCounter atomic.Int64
-	count atomic.Int64
-}
 
 // Clear sets the counter to zero.
 func (c *StandardCounter) Clear() {
-	c.count.Store(0)
+	(*atomic.Int64)(c).Store(0)
-}
-
-// Count returns the current count.
-func (c *StandardCounter) Count() int64 {
-	return c.count.Load()
 }
 
 // Dec decrements the counter by the given amount.
 func (c *StandardCounter) Dec(i int64) {
-	c.count.Add(-i)
+	(*atomic.Int64)(c).Add(-i)
 }
 
 // Inc increments the counter by the given amount.
 func (c *StandardCounter) Inc(i int64) {
-	c.count.Add(i)
+	(*atomic.Int64)(c).Add(i)
 }
 
 // Snapshot returns a read-only copy of the counter.
-func (c *StandardCounter) Snapshot() Counter {
+func (c *StandardCounter) Snapshot() CounterSnapshot {
-	return CounterSnapshot(c.Count())
+	return counterSnapshot((*atomic.Int64)(c).Load())
 }

metrics/counter_float64.go

@@ -5,13 +5,16 @@ import (
 	"sync/atomic"
 )
 
+type CounterFloat64Snapshot interface {
+	Count() float64
+}
+
 // CounterFloat64 holds a float64 value that can be incremented and decremented.
 type CounterFloat64 interface {
 	Clear()
-	Count() float64
 	Dec(float64)
 	Inc(float64)
-	Snapshot() CounterFloat64
+	Snapshot() CounterFloat64Snapshot
 }
 
 // GetOrRegisterCounterFloat64 returns an existing CounterFloat64 or constructs and registers
@@ -71,47 +74,19 @@ func NewRegisteredCounterFloat64Forced(name string, r Registry) CounterFloat64 {
 	return c
 }
 
-// CounterFloat64Snapshot is a read-only copy of another CounterFloat64.
+// counterFloat64Snapshot is a read-only copy of another CounterFloat64.
-type CounterFloat64Snapshot float64
+type counterFloat64Snapshot float64
-
-// Clear panics.
-func (CounterFloat64Snapshot) Clear() {
-	panic("Clear called on a CounterFloat64Snapshot")
-}
 
 // Count returns the value at the time the snapshot was taken.
-func (c CounterFloat64Snapshot) Count() float64 { return float64(c) }
+func (c counterFloat64Snapshot) Count() float64 { return float64(c) }
 
-// Dec panics.
-func (CounterFloat64Snapshot) Dec(float64) {
-	panic("Dec called on a CounterFloat64Snapshot")
-}
-
-// Inc panics.
-func (CounterFloat64Snapshot) Inc(float64) {
-	panic("Inc called on a CounterFloat64Snapshot")
-}
-
-// Snapshot returns the snapshot.
-func (c CounterFloat64Snapshot) Snapshot() CounterFloat64 { return c }
-
-// NilCounterFloat64 is a no-op CounterFloat64.
 type NilCounterFloat64 struct{}
 
-// Clear is a no-op.
 func (NilCounterFloat64) Clear()                           {}
-
-// Count is a no-op.
 func (NilCounterFloat64) Count() float64                   { return 0.0 }
-
-// Dec is a no-op.
 func (NilCounterFloat64) Dec(i float64)                    {}
-
-// Inc is a no-op.
 func (NilCounterFloat64) Inc(i float64)                    {}
-
+func (NilCounterFloat64) Snapshot() CounterFloat64Snapshot { return NilCounterFloat64{} }
-// Snapshot is a no-op.
-func (NilCounterFloat64) Snapshot() CounterFloat64 { return NilCounterFloat64{} }
 
 // StandardCounterFloat64 is the standard implementation of a CounterFloat64 and uses the
 // atomic to manage a single float64 value.
@@ -124,11 +99,6 @@ func (c *StandardCounterFloat64) Clear() {
 	c.floatBits.Store(0)
 }
 
-// Count returns the current value.
-func (c *StandardCounterFloat64) Count() float64 {
-	return math.Float64frombits(c.floatBits.Load())
-}
-
 // Dec decrements the counter by the given amount.
 func (c *StandardCounterFloat64) Dec(v float64) {
 	atomicAddFloat(&c.floatBits, -v)
@@ -140,8 +110,9 @@ func (c *StandardCounterFloat64) Inc(v float64) {
 }
 
 // Snapshot returns a read-only copy of the counter.
-func (c *StandardCounterFloat64) Snapshot() CounterFloat64 {
+func (c *StandardCounterFloat64) Snapshot() CounterFloat64Snapshot {
-	return CounterFloat64Snapshot(c.Count())
+	v := math.Float64frombits(c.floatBits.Load())
+	return counterFloat64Snapshot(v)
 }
 
 func atomicAddFloat(fbits *atomic.Uint64, v float64) {

metrics/counter_float_64_test.go

@@ -27,7 +27,7 @@ func BenchmarkCounterFloat64Parallel(b *testing.B) {
 		}()
 	}
 	wg.Wait()
-	if have, want := c.Count(), 10.0*float64(b.N); have != want {
+	if have, want := c.Snapshot().Count(), 10.0*float64(b.N); have != want {
 		b.Fatalf("have %f want %f", have, want)
 	}
 }
@@ -36,7 +36,7 @@ func TestCounterFloat64Clear(t *testing.T) {
 	c := NewCounterFloat64()
 	c.Inc(1.0)
 	c.Clear()
-	if count := c.Count(); count != 0 {
+	if count := c.Snapshot().Count(); count != 0 {
 		t.Errorf("c.Count(): 0 != %v\n", count)
 	}
 }
@@ -44,7 +44,7 @@ func TestCounterFloat64Clear(t *testing.T) {
 func TestCounterFloat64Dec1(t *testing.T) {
 	c := NewCounterFloat64()
 	c.Dec(1.0)
-	if count := c.Count(); count != -1.0 {
+	if count := c.Snapshot().Count(); count != -1.0 {
 		t.Errorf("c.Count(): -1.0 != %v\n", count)
 	}
 }
@@ -52,7 +52,7 @@ func TestCounterFloat64Dec1(t *testing.T) {
 func TestCounterFloat64Dec2(t *testing.T) {
 	c := NewCounterFloat64()
 	c.Dec(2.0)
-	if count := c.Count(); count != -2.0 {
+	if count := c.Snapshot().Count(); count != -2.0 {
 		t.Errorf("c.Count(): -2.0 != %v\n", count)
 	}
 }
@@ -60,7 +60,7 @@ func TestCounterFloat64Dec2(t *testing.T) {
 func TestCounterFloat64Inc1(t *testing.T) {
 	c := NewCounterFloat64()
 	c.Inc(1.0)
-	if count := c.Count(); count != 1.0 {
+	if count := c.Snapshot().Count(); count != 1.0 {
 		t.Errorf("c.Count(): 1.0 != %v\n", count)
 	}
 }
@@ -68,7 +68,7 @@ func TestCounterFloat64Inc1(t *testing.T) {
 func TestCounterFloat64Inc2(t *testing.T) {
 	c := NewCounterFloat64()
 	c.Inc(2.0)
-	if count := c.Count(); count != 2.0 {
+	if count := c.Snapshot().Count(); count != 2.0 {
 		t.Errorf("c.Count(): 2.0 != %v\n", count)
 	}
 }
@@ -85,7 +85,7 @@ func TestCounterFloat64Snapshot(t *testing.T) {
 
 func TestCounterFloat64Zero(t *testing.T) {
 	c := NewCounterFloat64()
-	if count := c.Count(); count != 0 {
+	if count := c.Snapshot().Count(); count != 0 {
 		t.Errorf("c.Count(): 0 != %v\n", count)
 	}
 }
@@ -93,7 +93,7 @@ func TestCounterFloat64Zero(t *testing.T) {
 func TestGetOrRegisterCounterFloat64(t *testing.T) {
 	r := NewRegistry()
 	NewRegisteredCounterFloat64("foo", r).Inc(47.0)
-	if c := GetOrRegisterCounterFloat64("foo", r); c.Count() != 47.0 {
+	if c := GetOrRegisterCounterFloat64("foo", r).Snapshot(); c.Count() != 47.0 {
 		t.Fatal(c)
 	}
 }

metrics/counter_test.go

@@ -14,7 +14,7 @@ func TestCounterClear(t *testing.T) {
 	c := NewCounter()
 	c.Inc(1)
 	c.Clear()
-	if count := c.Count(); count != 0 {
+	if count := c.Snapshot().Count(); count != 0 {
 		t.Errorf("c.Count(): 0 != %v\n", count)
 	}
 }
@@ -22,7 +22,7 @@ func TestCounterClear(t *testing.T) {
 func TestCounterDec1(t *testing.T) {
 	c := NewCounter()
 	c.Dec(1)
-	if count := c.Count(); count != -1 {
+	if count := c.Snapshot().Count(); count != -1 {
 		t.Errorf("c.Count(): -1 != %v\n", count)
 	}
 }
@@ -30,7 +30,7 @@ func TestCounterDec1(t *testing.T) {
 func TestCounterDec2(t *testing.T) {
 	c := NewCounter()
 	c.Dec(2)
-	if count := c.Count(); count != -2 {
+	if count := c.Snapshot().Count(); count != -2 {
 		t.Errorf("c.Count(): -2 != %v\n", count)
 	}
 }
@@ -38,7 +38,7 @@ func TestCounterDec2(t *testing.T) {
 func TestCounterInc1(t *testing.T) {
 	c := NewCounter()
 	c.Inc(1)
-	if count := c.Count(); count != 1 {
+	if count := c.Snapshot().Count(); count != 1 {
 		t.Errorf("c.Count(): 1 != %v\n", count)
 	}
 }
@@ -46,7 +46,7 @@ func TestCounterInc1(t *testing.T) {
 func TestCounterInc2(t *testing.T) {
 	c := NewCounter()
 	c.Inc(2)
-	if count := c.Count(); count != 2 {
+	if count := c.Snapshot().Count(); count != 2 {
 		t.Errorf("c.Count(): 2 != %v\n", count)
 	}
 }
@@ -63,7 +63,7 @@ func TestCounterSnapshot(t *testing.T) {
 
 func TestCounterZero(t *testing.T) {
 	c := NewCounter()
-	if count := c.Count(); count != 0 {
+	if count := c.Snapshot().Count(); count != 0 {
 		t.Errorf("c.Count(): 0 != %v\n", count)
 	}
 }
@@ -71,7 +71,7 @@ func TestCounterZero(t *testing.T) {
 func TestGetOrRegisterCounter(t *testing.T) {
 	r := NewRegistry()
 	NewRegisteredCounter("foo", r).Inc(47)
-	if c := GetOrRegisterCounter("foo", r); c.Count() != 47 {
+	if c := GetOrRegisterCounter("foo", r).Snapshot(); c.Count() != 47 {
 		t.Fatal(c)
 	}
 }

metrics/doc.go

@@ -1,4 +0,0 @@
-package metrics
-
-const epsilon = 0.0000000000000001
-const epsilonPercentile = .00000000001

metrics/ewma.go

@@ -7,11 +7,14 @@ import (
 	"time"
 )
 
+type EWMASnapshot interface {
+	Rate() float64
+}
+
 // EWMAs continuously calculate an exponentially-weighted moving average
 // based on an outside source of clock ticks.
 type EWMA interface {
-	Rate() float64
+	Snapshot() EWMASnapshot
-	Snapshot() EWMA
 	Tick()
 	Update(int64)
 }
@@ -36,39 +39,18 @@ func NewEWMA15() EWMA {
 	return NewEWMA(1 - math.Exp(-5.0/60.0/15))
 }
 
-// EWMASnapshot is a read-only copy of another EWMA.
+// ewmaSnapshot is a read-only copy of another EWMA.
-type EWMASnapshot float64
+type ewmaSnapshot float64
 
 // Rate returns the rate of events per second at the time the snapshot was
 // taken.
-func (a EWMASnapshot) Rate() float64 { return float64(a) }
+func (a ewmaSnapshot) Rate() float64 { return float64(a) }
-
-// Snapshot returns the snapshot.
-func (a EWMASnapshot) Snapshot() EWMA { return a }
-
-// Tick panics.
-func (EWMASnapshot) Tick() {
-	panic("Tick called on an EWMASnapshot")
-}
-
-// Update panics.
-func (EWMASnapshot) Update(int64) {
-	panic("Update called on an EWMASnapshot")
-}
 
 // NilEWMA is a no-op EWMA.
 type NilEWMA struct{}
 
-// Rate is a no-op.
+func (NilEWMA) Snapshot() EWMASnapshot { return (*emptySnapshot)(nil) }
-func (NilEWMA) Rate() float64 { return 0.0 }
-
-// Snapshot is a no-op.
-func (NilEWMA) Snapshot() EWMA { return NilEWMA{} }
-
-// Tick is a no-op.
 func (NilEWMA) Tick()                  {}
-
-// Update is a no-op.
 func (NilEWMA) Update(n int64)         {}
 
 // StandardEWMA is the standard implementation of an EWMA and tracks the number
@@ -77,37 +59,50 @@ func (NilEWMA) Update(n int64) {}
 type StandardEWMA struct {
 	uncounted atomic.Int64
 	alpha     float64
-	rate      float64
+	rate      atomic.Uint64
-	init      bool
+	init      atomic.Bool
 	mutex     sync.Mutex
 }
 
-// Rate returns the moving average rate of events per second.
-func (a *StandardEWMA) Rate() float64 {
-	a.mutex.Lock()
-	defer a.mutex.Unlock()
-	return a.rate * float64(time.Second)
-}
-
 // Snapshot returns a read-only copy of the EWMA.
-func (a *StandardEWMA) Snapshot() EWMA {
+func (a *StandardEWMA) Snapshot() EWMASnapshot {
-	return EWMASnapshot(a.Rate())
+	r := math.Float64frombits(a.rate.Load()) * float64(time.Second)
+	return ewmaSnapshot(r)
 }
 
 // Tick ticks the clock to update the moving average.  It assumes it is called
 // every five seconds.
 func (a *StandardEWMA) Tick() {
-	count := a.uncounted.Load()
+	// Optimization to avoid mutex locking in the hot-path.
-	a.uncounted.Add(-count)
+	if a.init.Load() {
-	instantRate := float64(count) / float64(5*time.Second)
+		a.updateRate(a.fetchInstantRate())
-	a.mutex.Lock()
+		return
-	defer a.mutex.Unlock()
-	if a.init {
-		a.rate += a.alpha * (instantRate - a.rate)
-	} else {
-		a.init = true
-		a.rate = instantRate
 	}
+	// Slow-path: this is only needed on the first Tick() and preserves transactional updating
+	// of init and rate in the else block. The first conditional is needed below because
+	// a different thread could have set a.init = 1 between the time of the first atomic load and when
+	// the lock was acquired.
+	a.mutex.Lock()
+	if a.init.Load() {
+		// The fetchInstantRate() uses atomic loading, which is unnecessary in this critical section
+		// but again, this section is only invoked on the first successful Tick() operation.
+		a.updateRate(a.fetchInstantRate())
+	} else {
+		a.init.Store(true)
+		a.rate.Store(math.Float64bits(a.fetchInstantRate()))
+	}
+	a.mutex.Unlock()
+}
+
+func (a *StandardEWMA) fetchInstantRate() float64 {
+	count := a.uncounted.Swap(0)
+	return float64(count) / float64(5*time.Second)
+}
+
+func (a *StandardEWMA) updateRate(instantRate float64) {
+	currentRate := math.Float64frombits(a.rate.Load())
+	currentRate += a.alpha * (instantRate - currentRate)
+	a.rate.Store(math.Float64bits(currentRate))
 }
 
 // Update adds n uncounted events.

metrics/ewma_test.go

@@ -5,6 +5,8 @@ import (
 	"testing"
 )
 
+const epsilon = 0.0000000000000001
+
 func BenchmarkEWMA(b *testing.B) {
 	a := NewEWMA1()
 	b.ResetTimer()
@@ -14,72 +16,33 @@ func BenchmarkEWMA(b *testing.B) {
 	}
 }
 
+func BenchmarkEWMAParallel(b *testing.B) {
+	a := NewEWMA1()
+	b.ResetTimer()
+
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			a.Update(1)
+			a.Tick()
+		}
+	})
+}
+
 func TestEWMA1(t *testing.T) {
 	a := NewEWMA1()
 	a.Update(3)
 	a.Tick()
-	if rate := a.Rate(); math.Abs(0.6-rate) > epsilon {
+	for i, want := range []float64{0.6,
-		t.Errorf("initial a.Rate(): 0.6 != %v\n", rate)
+		0.22072766470286553, 0.08120116994196772, 0.029872241020718428,
+		0.01098938333324054, 0.004042768199451294, 0.0014872513059998212,
+		0.0005471291793327122, 0.00020127757674150815, 7.404588245200814e-05,
+		2.7239957857491083e-05, 1.0021020474147462e-05, 3.6865274119969525e-06,
+		1.3561976441886433e-06, 4.989172314621449e-07, 1.8354139230109722e-07,
+	} {
+		if rate := a.Snapshot().Rate(); math.Abs(want-rate) > epsilon {
+			t.Errorf("%d minute a.Snapshot().Rate(): %f != %v\n", i, want, rate)
 		}
 		elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.22072766470286553-rate) > epsilon {
-		t.Errorf("1 minute a.Rate(): 0.22072766470286553 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.08120116994196772-rate) > epsilon {
-		t.Errorf("2 minute a.Rate(): 0.08120116994196772 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.029872241020718428-rate) > epsilon {
-		t.Errorf("3 minute a.Rate(): 0.029872241020718428 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.01098938333324054-rate) > epsilon {
-		t.Errorf("4 minute a.Rate(): 0.01098938333324054 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.004042768199451294-rate) > epsilon {
-		t.Errorf("5 minute a.Rate(): 0.004042768199451294 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.0014872513059998212-rate) > epsilon {
-		t.Errorf("6 minute a.Rate(): 0.0014872513059998212 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.0005471291793327122-rate) > epsilon {
-		t.Errorf("7 minute a.Rate(): 0.0005471291793327122 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.00020127757674150815-rate) > epsilon {
-		t.Errorf("8 minute a.Rate(): 0.00020127757674150815 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(7.404588245200814e-05-rate) > epsilon {
-		t.Errorf("9 minute a.Rate(): 7.404588245200814e-05 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(2.7239957857491083e-05-rate) > epsilon {
-		t.Errorf("10 minute a.Rate(): 2.7239957857491083e-05 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(1.0021020474147462e-05-rate) > epsilon {
-		t.Errorf("11 minute a.Rate(): 1.0021020474147462e-05 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(3.6865274119969525e-06-rate) > epsilon {
-		t.Errorf("12 minute a.Rate(): 3.6865274119969525e-06 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(1.3561976441886433e-06-rate) > epsilon {
-		t.Errorf("13 minute a.Rate(): 1.3561976441886433e-06 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(4.989172314621449e-07-rate) > epsilon {
-		t.Errorf("14 minute a.Rate(): 4.989172314621449e-07 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(1.8354139230109722e-07-rate) > epsilon {
-		t.Errorf("15 minute a.Rate(): 1.8354139230109722e-07 != %v\n", rate)
 	}
 }
 
@@ -87,68 +50,17 @@ func TestEWMA5(t *testing.T) {
 	a := NewEWMA5()
 	a.Update(3)
 	a.Tick()
-	if rate := a.Rate(); math.Abs(0.6-rate) > epsilon {
+	for i, want := range []float64{
-		t.Errorf("initial a.Rate(): 0.6 != %v\n", rate)
+		0.6, 0.49123845184678905, 0.4021920276213837, 0.32928698165641596,
+		0.269597378470333, 0.2207276647028654, 0.18071652714732128,
+		0.14795817836496392, 0.12113791079679326, 0.09917933293295193,
+		0.08120116994196763, 0.06648189501740036, 0.05443077197364752,
+		0.04456414692860035, 0.03648603757513079, 0.0298722410207183831020718428,
+	} {
+		if rate := a.Snapshot().Rate(); math.Abs(want-rate) > epsilon {
+			t.Errorf("%d minute a.Snapshot().Rate(): %f != %v\n", i, want, rate)
 		}
 		elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.49123845184678905-rate) > epsilon {
-		t.Errorf("1 minute a.Rate(): 0.49123845184678905 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.4021920276213837-rate) > epsilon {
-		t.Errorf("2 minute a.Rate(): 0.4021920276213837 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.32928698165641596-rate) > epsilon {
-		t.Errorf("3 minute a.Rate(): 0.32928698165641596 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.269597378470333-rate) > epsilon {
-		t.Errorf("4 minute a.Rate(): 0.269597378470333 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.2207276647028654-rate) > epsilon {
-		t.Errorf("5 minute a.Rate(): 0.2207276647028654 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.18071652714732128-rate) > epsilon {
-		t.Errorf("6 minute a.Rate(): 0.18071652714732128 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.14795817836496392-rate) > epsilon {
-		t.Errorf("7 minute a.Rate(): 0.14795817836496392 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.12113791079679326-rate) > epsilon {
-		t.Errorf("8 minute a.Rate(): 0.12113791079679326 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.09917933293295193-rate) > epsilon {
-		t.Errorf("9 minute a.Rate(): 0.09917933293295193 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.08120116994196763-rate) > epsilon {
-		t.Errorf("10 minute a.Rate(): 0.08120116994196763 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.06648189501740036-rate) > epsilon {
-		t.Errorf("11 minute a.Rate(): 0.06648189501740036 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.05443077197364752-rate) > epsilon {
-		t.Errorf("12 minute a.Rate(): 0.05443077197364752 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.04456414692860035-rate) > epsilon {
-		t.Errorf("13 minute a.Rate(): 0.04456414692860035 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.03648603757513079-rate) > epsilon {
-		t.Errorf("14 minute a.Rate(): 0.03648603757513079 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.0298722410207183831020718428-rate) > epsilon {
-		t.Errorf("15 minute a.Rate(): 0.0298722410207183831020718428 != %v\n", rate)
 	}
 }
 
@@ -156,68 +68,17 @@ func TestEWMA15(t *testing.T) {
 	a := NewEWMA15()
 	a.Update(3)
 	a.Tick()
-	if rate := a.Rate(); math.Abs(0.6-rate) > epsilon {
+	for i, want := range []float64{
-		t.Errorf("initial a.Rate(): 0.6 != %v\n", rate)
+		0.6, 0.5613041910189706, 0.5251039914257684, 0.4912384518467888184678905,
+		0.459557003018789, 0.4299187863442732, 0.4021920276213831,
+		0.37625345116383313, 0.3519877317060185, 0.3292869816564153165641596,
+		0.3080502714195546, 0.2881831806538789, 0.26959737847033216,
+		0.2522102307052083, 0.23594443252115815, 0.2207276647028646247028654470286553,
+	} {
+		if rate := a.Snapshot().Rate(); math.Abs(want-rate) > epsilon {
+			t.Errorf("%d minute a.Snapshot().Rate(): %f != %v\n", i, want, rate)
 		}
 		elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.5613041910189706-rate) > epsilon {
-		t.Errorf("1 minute a.Rate(): 0.5613041910189706 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.5251039914257684-rate) > epsilon {
-		t.Errorf("2 minute a.Rate(): 0.5251039914257684 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.4912384518467888184678905-rate) > epsilon {
-		t.Errorf("3 minute a.Rate(): 0.4912384518467888184678905 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.459557003018789-rate) > epsilon {
-		t.Errorf("4 minute a.Rate(): 0.459557003018789 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.4299187863442732-rate) > epsilon {
-		t.Errorf("5 minute a.Rate(): 0.4299187863442732 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.4021920276213831-rate) > epsilon {
-		t.Errorf("6 minute a.Rate(): 0.4021920276213831 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.37625345116383313-rate) > epsilon {
-		t.Errorf("7 minute a.Rate(): 0.37625345116383313 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.3519877317060185-rate) > epsilon {
-		t.Errorf("8 minute a.Rate(): 0.3519877317060185 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.3292869816564153165641596-rate) > epsilon {
-		t.Errorf("9 minute a.Rate(): 0.3292869816564153165641596 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.3080502714195546-rate) > epsilon {
-		t.Errorf("10 minute a.Rate(): 0.3080502714195546 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.2881831806538789-rate) > epsilon {
-		t.Errorf("11 minute a.Rate(): 0.2881831806538789 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.26959737847033216-rate) > epsilon {
-		t.Errorf("12 minute a.Rate(): 0.26959737847033216 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.2522102307052083-rate) > epsilon {
-		t.Errorf("13 minute a.Rate(): 0.2522102307052083 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.23594443252115815-rate) > epsilon {
-		t.Errorf("14 minute a.Rate(): 0.23594443252115815 != %v\n", rate)
-	}
-	elapseMinute(a)
-	if rate := a.Rate(); math.Abs(0.2207276647028646247028654470286553-rate) > epsilon {
-		t.Errorf("15 minute a.Rate(): 0.2207276647028646247028654470286553 != %v\n", rate)
 	}
 }
 

metrics/exp/exp.go

@@ -109,25 +109,25 @@ func (exp *exp) getInfo(name string) *expvar.String {
 	return v
 }
 
-func (exp *exp) publishCounter(name string, metric metrics.Counter) {
+func (exp *exp) publishCounter(name string, metric metrics.CounterSnapshot) {
 	v := exp.getInt(name)
 	v.Set(metric.Count())
 }
 
-func (exp *exp) publishCounterFloat64(name string, metric metrics.CounterFloat64) {
+func (exp *exp) publishCounterFloat64(name string, metric metrics.CounterFloat64Snapshot) {
 	v := exp.getFloat(name)
 	v.Set(metric.Count())
 }
 
-func (exp *exp) publishGauge(name string, metric metrics.Gauge) {
+func (exp *exp) publishGauge(name string, metric metrics.GaugeSnapshot) {
 	v := exp.getInt(name)
 	v.Set(metric.Value())
 }
-func (exp *exp) publishGaugeFloat64(name string, metric metrics.GaugeFloat64) {
+func (exp *exp) publishGaugeFloat64(name string, metric metrics.GaugeFloat64Snapshot) {
 	exp.getFloat(name).Set(metric.Value())
 }
 
-func (exp *exp) publishGaugeInfo(name string, metric metrics.GaugeInfo) {
+func (exp *exp) publishGaugeInfo(name string, metric metrics.GaugeInfoSnapshot) {
 	exp.getInfo(name).Set(metric.Value().String())
 }
 
@@ -176,28 +176,28 @@ func (exp *exp) publishTimer(name string, metric metrics.Timer) {
 
 func (exp *exp) publishResettingTimer(name string, metric metrics.ResettingTimer) {
 	t := metric.Snapshot()
-	ps := t.Percentiles([]float64{50, 75, 95, 99})
+	ps := t.Percentiles([]float64{0.50, 0.75, 0.95, 0.99})
-	exp.getInt(name + ".count").Set(int64(len(t.Values())))
+	exp.getInt(name + ".count").Set(int64(t.Count()))
 	exp.getFloat(name + ".mean").Set(t.Mean())
-	exp.getInt(name + ".50-percentile").Set(ps[0])
+	exp.getFloat(name + ".50-percentile").Set(ps[0])
-	exp.getInt(name + ".75-percentile").Set(ps[1])
+	exp.getFloat(name + ".75-percentile").Set(ps[1])
-	exp.getInt(name + ".95-percentile").Set(ps[2])
+	exp.getFloat(name + ".95-percentile").Set(ps[2])
-	exp.getInt(name + ".99-percentile").Set(ps[3])
+	exp.getFloat(name + ".99-percentile").Set(ps[3])
 }
 
 func (exp *exp) syncToExpvar() {
 	exp.registry.Each(func(name string, i interface{}) {
 		switch i := i.(type) {
 		case metrics.Counter:
-			exp.publishCounter(name, i)
+			exp.publishCounter(name, i.Snapshot())
 		case metrics.CounterFloat64:
-			exp.publishCounterFloat64(name, i)
+			exp.publishCounterFloat64(name, i.Snapshot())
 		case metrics.Gauge:
-			exp.publishGauge(name, i)
+			exp.publishGauge(name, i.Snapshot())
 		case metrics.GaugeFloat64:
-			exp.publishGaugeFloat64(name, i)
+			exp.publishGaugeFloat64(name, i.Snapshot())
 		case metrics.GaugeInfo:
-			exp.publishGaugeInfo(name, i)
+			exp.publishGaugeInfo(name, i.Snapshot())
 		case metrics.Histogram:
 			exp.publishHistogram(name, i)
 		case metrics.Meter:

metrics/gauge.go

@@ -2,13 +2,18 @@ package metrics
 
 import "sync/atomic"
 
+// gaugeSnapshot contains a readonly int64.
+type GaugeSnapshot interface {
+	Value() int64
+}
+
 // Gauges hold an int64 value that can be set arbitrarily.
 type Gauge interface {
-	Snapshot() Gauge
+	Snapshot() GaugeSnapshot
 	Update(int64)
+	UpdateIfGt(int64)
 	Dec(int64)
 	Inc(int64)
-	Value() int64
 }
 
 // GetOrRegisterGauge returns an existing Gauge or constructs and registers a
@@ -38,66 +43,21 @@ func NewRegisteredGauge(name string, r Registry) Gauge {
 	return c
 }
 
-// NewFunctionalGauge constructs a new FunctionalGauge.
+// gaugeSnapshot is a read-only copy of another Gauge.
-func NewFunctionalGauge(f func() int64) Gauge {
+type gaugeSnapshot int64
-	if !Enabled {
-		return NilGauge{}
-	}
-	return &FunctionalGauge{value: f}
-}
-
-// NewRegisteredFunctionalGauge constructs and registers a new StandardGauge.
-func NewRegisteredFunctionalGauge(name string, r Registry, f func() int64) Gauge {
-	c := NewFunctionalGauge(f)
-	if nil == r {
-		r = DefaultRegistry
-	}
-	r.Register(name, c)
-	return c
-}
-
-// GaugeSnapshot is a read-only copy of another Gauge.
-type GaugeSnapshot int64
-
-// Snapshot returns the snapshot.
-func (g GaugeSnapshot) Snapshot() Gauge { return g }
-
-// Update panics.
-func (GaugeSnapshot) Update(int64) {
-	panic("Update called on a GaugeSnapshot")
-}
-
-// Dec panics.
-func (GaugeSnapshot) Dec(int64) {
-	panic("Dec called on a GaugeSnapshot")
-}
-
-// Inc panics.
-func (GaugeSnapshot) Inc(int64) {
-	panic("Inc called on a GaugeSnapshot")
-}
 
 // Value returns the value at the time the snapshot was taken.
-func (g GaugeSnapshot) Value() int64 { return int64(g) }
+func (g gaugeSnapshot) Value() int64 { return int64(g) }
 
 // NilGauge is a no-op Gauge.
 type NilGauge struct{}
 
-// Snapshot is a no-op.
+func (NilGauge) Snapshot() GaugeSnapshot { return (*emptySnapshot)(nil) }
-func (NilGauge) Snapshot() Gauge { return NilGauge{} }
-
-// Update is a no-op.
 func (NilGauge) Update(v int64)          {}
-
+func (NilGauge) UpdateIfGt(v int64)      {}
-// Dec is a no-op.
 func (NilGauge) Dec(i int64)             {}
-
-// Inc is a no-op.
 func (NilGauge) Inc(i int64)             {}
 
-// Value is a no-op.
-func (NilGauge) Value() int64 { return 0 }
-
 // StandardGauge is the standard implementation of a Gauge and uses the
 // sync/atomic package to manage a single int64 value.
 type StandardGauge struct {
@@ -105,8 +65,8 @@ type StandardGauge struct {
 }
 
 // Snapshot returns a read-only copy of the gauge.
-func (g *StandardGauge) Snapshot() Gauge {
+func (g *StandardGauge) Snapshot() GaugeSnapshot {
-	return GaugeSnapshot(g.Value())
+	return gaugeSnapshot(g.value.Load())
 }
 
 // Update updates the gauge's value.
@@ -114,9 +74,17 @@ func (g *StandardGauge) Update(v int64) {
 	g.value.Store(v)
 }
 
-// Value returns the gauge's current value.
+// Update updates the gauge's value if v is larger then the current valie.
-func (g *StandardGauge) Value() int64 {
+func (g *StandardGauge) UpdateIfGt(v int64) {
-	return g.value.Load()
+	for {
+		exist := g.value.Load()
+		if exist >= v {
+			break
+		}
+		if g.value.CompareAndSwap(exist, v) {
+			break
+		}
+	}
 }
 
 // Dec decrements the gauge's current value by the given amount.
@@ -128,31 +96,3 @@ func (g *StandardGauge) Dec(i int64) {
 func (g *StandardGauge) Inc(i int64) {
 	g.value.Add(i)
 }
-
-// FunctionalGauge returns value from given function
-type FunctionalGauge struct {
-	value func() int64
-}
-
-// Value returns the gauge's current value.
-func (g FunctionalGauge) Value() int64 {
-	return g.value()
-}
-
-// Snapshot returns the snapshot.
-func (g FunctionalGauge) Snapshot() Gauge { return GaugeSnapshot(g.Value()) }
-
-// Update panics.
-func (FunctionalGauge) Update(int64) {
-	panic("Update called on a FunctionalGauge")
-}
-
-// Dec panics.
-func (FunctionalGauge) Dec(int64) {
-	panic("Dec called on a FunctionalGauge")
-}
-
-// Inc panics.
-func (FunctionalGauge) Inc(int64) {
-	panic("Inc called on a FunctionalGauge")
-}

metrics/gauge_float64.go

@@ -5,13 +5,16 @@ import (
 	"sync/atomic"
 )
 
-// GaugeFloat64s hold a float64 value that can be set arbitrarily.
+type GaugeFloat64Snapshot interface {
-type GaugeFloat64 interface {
-	Snapshot() GaugeFloat64
-	Update(float64)
 	Value() float64
 }
 
+// GaugeFloat64 hold a float64 value that can be set arbitrarily.
+type GaugeFloat64 interface {
+	Snapshot() GaugeFloat64Snapshot
+	Update(float64)
+}
+
 // GetOrRegisterGaugeFloat64 returns an existing GaugeFloat64 or constructs and registers a
 // new StandardGaugeFloat64.
 func GetOrRegisterGaugeFloat64(name string, r Registry) GaugeFloat64 {
@@ -39,48 +42,17 @@ func NewRegisteredGaugeFloat64(name string, r Registry) GaugeFloat64 {
 	return c
 }
 
-// NewFunctionalGauge constructs a new FunctionalGauge.
+// gaugeFloat64Snapshot is a read-only copy of another GaugeFloat64.
-func NewFunctionalGaugeFloat64(f func() float64) GaugeFloat64 {
+type gaugeFloat64Snapshot float64
-	if !Enabled {
-		return NilGaugeFloat64{}
-	}
-	return &FunctionalGaugeFloat64{value: f}
-}
-
-// NewRegisteredFunctionalGauge constructs and registers a new StandardGauge.
-func NewRegisteredFunctionalGaugeFloat64(name string, r Registry, f func() float64) GaugeFloat64 {
-	c := NewFunctionalGaugeFloat64(f)
-	if nil == r {
-		r = DefaultRegistry
-	}
-	r.Register(name, c)
-	return c
-}
-
-// GaugeFloat64Snapshot is a read-only copy of another GaugeFloat64.
-type GaugeFloat64Snapshot float64
-
-// Snapshot returns the snapshot.
-func (g GaugeFloat64Snapshot) Snapshot() GaugeFloat64 { return g }
-
-// Update panics.
-func (GaugeFloat64Snapshot) Update(float64) {
-	panic("Update called on a GaugeFloat64Snapshot")
-}
 
 // Value returns the value at the time the snapshot was taken.
-func (g GaugeFloat64Snapshot) Value() float64 { return float64(g) }
+func (g gaugeFloat64Snapshot) Value() float64 { return float64(g) }
 
 // NilGauge is a no-op Gauge.
 type NilGaugeFloat64 struct{}
 
-// Snapshot is a no-op.
+func (NilGaugeFloat64) Snapshot() GaugeFloat64Snapshot { return NilGaugeFloat64{} }
-func (NilGaugeFloat64) Snapshot() GaugeFloat64 { return NilGaugeFloat64{} }
-
-// Update is a no-op.
 func (NilGaugeFloat64) Update(v float64)               {}
-
-// Value is a no-op.
 func (NilGaugeFloat64) Value() float64                 { return 0.0 }
 
 // StandardGaugeFloat64 is the standard implementation of a GaugeFloat64 and uses
@@ -90,34 +62,12 @@ type StandardGaugeFloat64 struct {
 }
 
 // Snapshot returns a read-only copy of the gauge.
-func (g *StandardGaugeFloat64) Snapshot() GaugeFloat64 {
+func (g *StandardGaugeFloat64) Snapshot() GaugeFloat64Snapshot {
-	return GaugeFloat64Snapshot(g.Value())
+	v := math.Float64frombits(g.floatBits.Load())
+	return gaugeFloat64Snapshot(v)
 }
 
 // Update updates the gauge's value.
 func (g *StandardGaugeFloat64) Update(v float64) {
 	g.floatBits.Store(math.Float64bits(v))
 }
-
-// Value returns the gauge's current value.
-func (g *StandardGaugeFloat64) Value() float64 {
-	return math.Float64frombits(g.floatBits.Load())
-}
-
-// FunctionalGaugeFloat64 returns value from given function
-type FunctionalGaugeFloat64 struct {
-	value func() float64
-}
-
-// Value returns the gauge's current value.
-func (g FunctionalGaugeFloat64) Value() float64 {
-	return g.value()
-}
-
-// Snapshot returns the snapshot.
-func (g FunctionalGaugeFloat64) Snapshot() GaugeFloat64 { return GaugeFloat64Snapshot(g.Value()) }
-
-// Update panics.
-func (FunctionalGaugeFloat64) Update(float64) {
-	panic("Update called on a FunctionalGaugeFloat64")
-}

metrics/gauge_float64_test.go

@@ -26,19 +26,11 @@ func BenchmarkGaugeFloat64Parallel(b *testing.B) {
 		}()
 	}
 	wg.Wait()
-	if have, want := c.Value(), float64(b.N-1); have != want {
+	if have, want := c.Snapshot().Value(), float64(b.N-1); have != want {
 		b.Fatalf("have %f want %f", have, want)
 	}
 }
 
-func TestGaugeFloat64(t *testing.T) {
-	g := NewGaugeFloat64()
-	g.Update(47.0)
-	if v := g.Value(); 47.0 != v {
-		t.Errorf("g.Value(): 47.0 != %v\n", v)
-	}
-}
-
 func TestGaugeFloat64Snapshot(t *testing.T) {
 	g := NewGaugeFloat64()
 	g.Update(47.0)
@@ -53,28 +45,7 @@ func TestGetOrRegisterGaugeFloat64(t *testing.T) {
 	r := NewRegistry()
 	NewRegisteredGaugeFloat64("foo", r).Update(47.0)
 	t.Logf("registry: %v", r)
-	if g := GetOrRegisterGaugeFloat64("foo", r); 47.0 != g.Value() {
+	if g := GetOrRegisterGaugeFloat64("foo", r).Snapshot(); 47.0 != g.Value() {
-		t.Fatal(g)
-	}
-}
-
-func TestFunctionalGaugeFloat64(t *testing.T) {
-	var counter float64
-	fg := NewFunctionalGaugeFloat64(func() float64 {
-		counter++
-		return counter
-	})
-	fg.Value()
-	fg.Value()
-	if counter != 2 {
-		t.Error("counter != 2")
-	}
-}
-
-func TestGetOrRegisterFunctionalGaugeFloat64(t *testing.T) {
-	r := NewRegistry()
-	NewRegisteredFunctionalGaugeFloat64("foo", r, func() float64 { return 47 })
-	if g := GetOrRegisterGaugeFloat64("foo", r); g.Value() != 47 {
 		t.Fatal(g)
 	}
 }

metrics/gauge_info.go

@@ -5,14 +5,17 @@ import (
 	"sync"
 )
 
-// GaugeInfos hold a GaugeInfoValue value that can be set arbitrarily.
+type GaugeInfoSnapshot interface {
-type GaugeInfo interface {
-	Snapshot() GaugeInfo
-	Update(GaugeInfoValue)
 	Value() GaugeInfoValue
 }
 
-// GaugeInfoValue is a mappng of (string) keys to (string) values
+// GaugeInfos hold a GaugeInfoValue value that can be set arbitrarily.
+type GaugeInfo interface {
+	Update(GaugeInfoValue)
+	Snapshot() GaugeInfoSnapshot
+}
+
+// GaugeInfoValue is a mapping of keys to values
 type GaugeInfoValue map[string]string
 
 func (val GaugeInfoValue) String() string {
@@ -49,48 +52,16 @@ func NewRegisteredGaugeInfo(name string, r Registry) GaugeInfo {
 	return c
 }
 
-// NewFunctionalGauge constructs a new FunctionalGauge.
+// gaugeInfoSnapshot is a read-only copy of another GaugeInfo.
-func NewFunctionalGaugeInfo(f func() GaugeInfoValue) GaugeInfo {
+type gaugeInfoSnapshot GaugeInfoValue
-	if !Enabled {
-		return NilGaugeInfo{}
-	}
-	return &FunctionalGaugeInfo{value: f}
-}
-
-// NewRegisteredFunctionalGauge constructs and registers a new StandardGauge.
-func NewRegisteredFunctionalGaugeInfo(name string, r Registry, f func() GaugeInfoValue) GaugeInfo {
-	c := NewFunctionalGaugeInfo(f)
-	if nil == r {
-		r = DefaultRegistry
-	}
-	r.Register(name, c)
-	return c
-}
-
-// GaugeInfoSnapshot is a read-only copy of another GaugeInfo.
-type GaugeInfoSnapshot GaugeInfoValue
-
-// Snapshot returns the snapshot.
-func (g GaugeInfoSnapshot) Snapshot() GaugeInfo { return g }
-
-// Update panics.
-func (GaugeInfoSnapshot) Update(GaugeInfoValue) {
-	panic("Update called on a GaugeInfoSnapshot")
-}
 
 // Value returns the value at the time the snapshot was taken.
-func (g GaugeInfoSnapshot) Value() GaugeInfoValue { return GaugeInfoValue(g) }
+func (g gaugeInfoSnapshot) Value() GaugeInfoValue { return GaugeInfoValue(g) }
 
-// NilGauge is a no-op Gauge.
 type NilGaugeInfo struct{}
 
-// Snapshot is a no-op.
+func (NilGaugeInfo) Snapshot() GaugeInfoSnapshot { return NilGaugeInfo{} }
-func (NilGaugeInfo) Snapshot() GaugeInfo { return NilGaugeInfo{} }
-
-// Update is a no-op.
 func (NilGaugeInfo) Update(v GaugeInfoValue)     {}
-
-// Value is a no-op.
 func (NilGaugeInfo) Value() GaugeInfoValue       { return GaugeInfoValue{} }
 
 // StandardGaugeInfo is the standard implementation of a GaugeInfo and uses
@@ -101,8 +72,8 @@ type StandardGaugeInfo struct {
 }
 
 // Snapshot returns a read-only copy of the gauge.
-func (g *StandardGaugeInfo) Snapshot() GaugeInfo {
+func (g *StandardGaugeInfo) Snapshot() GaugeInfoSnapshot {
-	return GaugeInfoSnapshot(g.Value())
+	return gaugeInfoSnapshot(g.value)
 }
 
 // Update updates the gauge's value.
@@ -111,34 +82,3 @@ func (g *StandardGaugeInfo) Update(v GaugeInfoValue) {
 	defer g.mutex.Unlock()
 	g.value = v
 }
-
-// Value returns the gauge's current value.
-func (g *StandardGaugeInfo) Value() GaugeInfoValue {
-	g.mutex.Lock()
-	defer g.mutex.Unlock()
-	return g.value
-}
-
-// FunctionalGaugeInfo returns value from given function
-type FunctionalGaugeInfo struct {
-	value func() GaugeInfoValue
-}
-
-// Value returns the gauge's current value.
-func (g FunctionalGaugeInfo) Value() GaugeInfoValue {
-	return g.value()
-}
-
-// Value returns the gauge's current value in JSON string format
-func (g FunctionalGaugeInfo) ValueJsonString() string {
-	data, _ := json.Marshal(g.value())
-	return string(data)
-}
-
-// Snapshot returns the snapshot.
-func (g FunctionalGaugeInfo) Snapshot() GaugeInfo { return GaugeInfoSnapshot(g.Value()) }
-
-// Update panics.
-func (FunctionalGaugeInfo) Update(GaugeInfoValue) {
-	panic("Update called on a FunctionalGaugeInfo")
-}

metrics/gauge_info_test.go

@@ -1,7 +1,6 @@
 package metrics
 
 import (
-	"strconv"
 	"testing"
 )
 
@@ -14,22 +13,14 @@ func TestGaugeInfoJsonString(t *testing.T) {
 	},
 	)
 	want := `{"anotherKey":"any_string_value","chain_id":"5","third_key":"anything"}`
-	if have := g.Value().String(); have != want {
-		t.Errorf("\nhave: %v\nwant: %v\n", have, want)
-	}
-}
 
-func TestGaugeInfoSnapshot(t *testing.T) {
+	original := g.Snapshot()
-	g := NewGaugeInfo()
-	g.Update(GaugeInfoValue{"value": "original"})
-	snapshot := g.Snapshot() // Snapshot @chainid 5
 	g.Update(GaugeInfoValue{"value": "updated"})
-	// The 'g' should be updated
+
-	if have, want := g.Value().String(), `{"value":"updated"}`; have != want {
+	if have := original.Value().String(); have != want {
 		t.Errorf("\nhave: %v\nwant: %v\n", have, want)
 	}
-	// Snapshot should be unupdated
+	if have, want := g.Snapshot().Value().String(), `{"value":"updated"}`; have != want {
-	if have, want := snapshot.Value().String(), `{"value":"original"}`; have != want {
 		t.Errorf("\nhave: %v\nwant: %v\n", have, want)
 	}
 }
@@ -38,38 +29,8 @@ func TestGetOrRegisterGaugeInfo(t *testing.T) {
 	r := NewRegistry()
 	NewRegisteredGaugeInfo("foo", r).Update(
 		GaugeInfoValue{"chain_id": "5"})
-	g := GetOrRegisterGaugeInfo("foo", r)
+	g := GetOrRegisterGaugeInfo("foo", r).Snapshot()
 	if have, want := g.Value().String(), `{"chain_id":"5"}`; have != want {
 		t.Errorf("have\n%v\nwant\n%v\n", have, want)
 	}
 }
-
-func TestFunctionalGaugeInfo(t *testing.T) {
-	info := GaugeInfoValue{"chain_id": "0"}
-	counter := 1
-	// A "functional" gauge invokes the method to obtain the value
-	fg := NewFunctionalGaugeInfo(func() GaugeInfoValue {
-		info["chain_id"] = strconv.Itoa(counter)
-		counter++
-		return info
-	})
-	fg.Value()
-	fg.Value()
-	if have, want := info["chain_id"], "2"; have != want {
-		t.Errorf("have %v want %v", have, want)
-	}
-}
-
-func TestGetOrRegisterFunctionalGaugeInfo(t *testing.T) {
-	r := NewRegistry()
-	NewRegisteredFunctionalGaugeInfo("foo", r, func() GaugeInfoValue {
-		return GaugeInfoValue{
-			"chain_id": "5",
-		}
-	})
-	want := `{"chain_id":"5"}`
-	have := GetOrRegisterGaugeInfo("foo", r).Value().String()
-	if have != want {
-		t.Errorf("have\n%v\nwant\n%v\n", have, want)
-	}
-}

metrics/gauge_test.go

@@ -1,7 +1,6 @@
 package metrics
 
 import (
-	"fmt"
 	"testing"
 )
 
@@ -13,14 +12,6 @@ func BenchmarkGauge(b *testing.B) {
 	}
 }
 
-func TestGauge(t *testing.T) {
-	g := NewGauge()
-	g.Update(int64(47))
-	if v := g.Value(); v != 47 {
-		t.Errorf("g.Value(): 47 != %v\n", v)
-	}
-}
-
 func TestGaugeSnapshot(t *testing.T) {
 	g := NewGauge()
 	g.Update(int64(47))
@@ -34,35 +25,7 @@ func TestGaugeSnapshot(t *testing.T) {
 func TestGetOrRegisterGauge(t *testing.T) {
 	r := NewRegistry()
 	NewRegisteredGauge("foo", r).Update(47)
-	if g := GetOrRegisterGauge("foo", r); g.Value() != 47 {
+	if g := GetOrRegisterGauge("foo", r); g.Snapshot().Value() != 47 {
 		t.Fatal(g)
 	}
 }
-
-func TestFunctionalGauge(t *testing.T) {
-	var counter int64
-	fg := NewFunctionalGauge(func() int64 {
-		counter++
-		return counter
-	})
-	fg.Value()
-	fg.Value()
-	if counter != 2 {
-		t.Error("counter != 2")
-	}
-}
-
-func TestGetOrRegisterFunctionalGauge(t *testing.T) {
-	r := NewRegistry()
-	NewRegisteredFunctionalGauge("foo", r, func() int64 { return 47 })
-	if g := GetOrRegisterGauge("foo", r); g.Value() != 47 {
-		t.Fatal(g)
-	}
-}
-
-func ExampleGetOrRegisterGauge() {
-	m := "server.bytes_sent"
-	g := GetOrRegisterGauge(m, nil)
-	g.Update(47)
-	fmt.Println(g.Value()) // Output: 47
-}

metrics/graphite.go

@@ -66,15 +66,15 @@ func graphite(c *GraphiteConfig) error {
 	c.Registry.Each(func(name string, i interface{}) {
 		switch metric := i.(type) {
 		case Counter:
-			fmt.Fprintf(w, "%s.%s.count %d %d\n", c.Prefix, name, metric.Count(), now)
+			fmt.Fprintf(w, "%s.%s.count %d %d\n", c.Prefix, name, metric.Snapshot().Count(), now)
 		case CounterFloat64:
-			fmt.Fprintf(w, "%s.%s.count %f %d\n", c.Prefix, name, metric.Count(), now)
+			fmt.Fprintf(w, "%s.%s.count %f %d\n", c.Prefix, name, metric.Snapshot().Count(), now)
 		case Gauge:
-			fmt.Fprintf(w, "%s.%s.value %d %d\n", c.Prefix, name, metric.Value(), now)
+			fmt.Fprintf(w, "%s.%s.value %d %d\n", c.Prefix, name, metric.Snapshot().Value(), now)
 		case GaugeFloat64:
-			fmt.Fprintf(w, "%s.%s.value %f %d\n", c.Prefix, name, metric.Value(), now)
+			fmt.Fprintf(w, "%s.%s.value %f %d\n", c.Prefix, name, metric.Snapshot().Value(), now)
 		case GaugeInfo:
-			fmt.Fprintf(w, "%s.%s.value %s %d\n", c.Prefix, name, metric.Value().String(), now)
+			fmt.Fprintf(w, "%s.%s.value %s %d\n", c.Prefix, name, metric.Snapshot().Value().String(), now)
 		case Histogram:
 			h := metric.Snapshot()
 			ps := h.Percentiles(c.Percentiles)

metrics/histogram.go

@@ -1,20 +1,14 @@
 package metrics
 
+type HistogramSnapshot interface {
+	SampleSnapshot
+}
+
 // Histograms calculate distribution statistics from a series of int64 values.
 type Histogram interface {
 	Clear()
-	Count() int64
-	Max() int64
-	Mean() float64
-	Min() int64
-	Percentile(float64) float64
-	Percentiles([]float64) []float64
-	Sample() Sample
-	Snapshot() Histogram
-	StdDev() float64
-	Sum() int64
 	Update(int64)
-	Variance() float64
+	Snapshot() HistogramSnapshot
 }
 
 // GetOrRegisterHistogram returns an existing Histogram or constructs and
@@ -54,109 +48,13 @@ func NewRegisteredHistogram(name string, r Registry, s Sample) Histogram {
 	return c
 }
 
-// HistogramSnapshot is a read-only copy of another Histogram.
-type HistogramSnapshot struct {
-	sample *SampleSnapshot
-}
-
-// Clear panics.
-func (*HistogramSnapshot) Clear() {
-	panic("Clear called on a HistogramSnapshot")
-}
-
-// Count returns the number of samples recorded at the time the snapshot was
-// taken.
-func (h *HistogramSnapshot) Count() int64 { return h.sample.Count() }
-
-// Max returns the maximum value in the sample at the time the snapshot was
-// taken.
-func (h *HistogramSnapshot) Max() int64 { return h.sample.Max() }
-
-// Mean returns the mean of the values in the sample at the time the snapshot
-// was taken.
-func (h *HistogramSnapshot) Mean() float64 { return h.sample.Mean() }
-
-// Min returns the minimum value in the sample at the time the snapshot was
-// taken.
-func (h *HistogramSnapshot) Min() int64 { return h.sample.Min() }
-
-// Percentile returns an arbitrary percentile of values in the sample at the
-// time the snapshot was taken.
-func (h *HistogramSnapshot) Percentile(p float64) float64 {
-	return h.sample.Percentile(p)
-}
-
-// Percentiles returns a slice of arbitrary percentiles of values in the sample
-// at the time the snapshot was taken.
-func (h *HistogramSnapshot) Percentiles(ps []float64) []float64 {
-	return h.sample.Percentiles(ps)
-}
-
-// Sample returns the Sample underlying the histogram.
-func (h *HistogramSnapshot) Sample() Sample { return h.sample }
-
-// Snapshot returns the snapshot.
-func (h *HistogramSnapshot) Snapshot() Histogram { return h }
-
-// StdDev returns the standard deviation of the values in the sample at the
-// time the snapshot was taken.
-func (h *HistogramSnapshot) StdDev() float64 { return h.sample.StdDev() }
-
-// Sum returns the sum in the sample at the time the snapshot was taken.
-func (h *HistogramSnapshot) Sum() int64 { return h.sample.Sum() }
-
-// Update panics.
-func (*HistogramSnapshot) Update(int64) {
-	panic("Update called on a HistogramSnapshot")
-}
-
-// Variance returns the variance of inputs at the time the snapshot was taken.
-func (h *HistogramSnapshot) Variance() float64 { return h.sample.Variance() }
-
 // NilHistogram is a no-op Histogram.
 type NilHistogram struct{}
 
-// Clear is a no-op.
 func (NilHistogram) Clear()                      {}
-
+func (NilHistogram) Snapshot() HistogramSnapshot { return (*emptySnapshot)(nil) }
-// Count is a no-op.
-func (NilHistogram) Count() int64 { return 0 }
-
-// Max is a no-op.
-func (NilHistogram) Max() int64 { return 0 }
-
-// Mean is a no-op.
-func (NilHistogram) Mean() float64 { return 0.0 }
-
-// Min is a no-op.
-func (NilHistogram) Min() int64 { return 0 }
-
-// Percentile is a no-op.
-func (NilHistogram) Percentile(p float64) float64 { return 0.0 }
-
-// Percentiles is a no-op.
-func (NilHistogram) Percentiles(ps []float64) []float64 {
-	return make([]float64, len(ps))
-}
-
-// Sample is a no-op.
-func (NilHistogram) Sample() Sample { return NilSample{} }
-
-// Snapshot is a no-op.
-func (NilHistogram) Snapshot() Histogram { return NilHistogram{} }
-
-// StdDev is a no-op.
-func (NilHistogram) StdDev() float64 { return 0.0 }
-
-// Sum is a no-op.
-func (NilHistogram) Sum() int64 { return 0 }
-
-// Update is a no-op.
 func (NilHistogram) Update(v int64)              {}
 
-// Variance is a no-op.
-func (NilHistogram) Variance() float64 { return 0.0 }
-
 // StandardHistogram is the standard implementation of a Histogram and uses a
 // Sample to bound its memory use.
 type StandardHistogram struct {
@@ -166,46 +64,10 @@ type StandardHistogram struct {
 // Clear clears the histogram and its sample.
 func (h *StandardHistogram) Clear() { h.sample.Clear() }
 
-// Count returns the number of samples recorded since the histogram was last
-// cleared.
-func (h *StandardHistogram) Count() int64 { return h.sample.Count() }
-
-// Max returns the maximum value in the sample.
-func (h *StandardHistogram) Max() int64 { return h.sample.Max() }
-
-// Mean returns the mean of the values in the sample.
-func (h *StandardHistogram) Mean() float64 { return h.sample.Mean() }
-
-// Min returns the minimum value in the sample.
-func (h *StandardHistogram) Min() int64 { return h.sample.Min() }
-
-// Percentile returns an arbitrary percentile of the values in the sample.
-func (h *StandardHistogram) Percentile(p float64) float64 {
-	return h.sample.Percentile(p)
-}
-
-// Percentiles returns a slice of arbitrary percentiles of the values in the
-// sample.
-func (h *StandardHistogram) Percentiles(ps []float64) []float64 {
-	return h.sample.Percentiles(ps)
-}
-
-// Sample returns the Sample underlying the histogram.
-func (h *StandardHistogram) Sample() Sample { return h.sample }
-
 // Snapshot returns a read-only copy of the histogram.
-func (h *StandardHistogram) Snapshot() Histogram {
+func (h *StandardHistogram) Snapshot() HistogramSnapshot {
-	return &HistogramSnapshot{sample: h.sample.Snapshot().(*SampleSnapshot)}
+	return h.sample.Snapshot()
 }
 
-// StdDev returns the standard deviation of the values in the sample.
-func (h *StandardHistogram) StdDev() float64 { return h.sample.StdDev() }
-
-// Sum returns the sum in the sample.
-func (h *StandardHistogram) Sum() int64 { return h.sample.Sum() }
-
 // Update samples a new value.
 func (h *StandardHistogram) Update(v int64) { h.sample.Update(v) }
-
-// Variance returns the variance of the values in the sample.
-func (h *StandardHistogram) Variance() float64 { return h.sample.Variance() }

metrics/histogram_test.go

@@ -14,7 +14,7 @@ func TestGetOrRegisterHistogram(t *testing.T) {
 	r := NewRegistry()
 	s := NewUniformSample(100)
 	NewRegisteredHistogram("foo", r, s).Update(47)
-	if h := GetOrRegisterHistogram("foo", r, s); h.Count() != 1 {
+	if h := GetOrRegisterHistogram("foo", r, s).Snapshot(); h.Count() != 1 {
 		t.Fatal(h)
 	}
 }
@@ -24,11 +24,11 @@ func TestHistogram10000(t *testing.T) {
 	for i := 1; i <= 10000; i++ {
 		h.Update(int64(i))
 	}
-	testHistogram10000(t, h)
+	testHistogram10000(t, h.Snapshot())
 }
 
 func TestHistogramEmpty(t *testing.T) {
-	h := NewHistogram(NewUniformSample(100))
+	h := NewHistogram(NewUniformSample(100)).Snapshot()
 	if count := h.Count(); count != 0 {
 		t.Errorf("h.Count(): 0 != %v\n", count)
 	}
@@ -66,7 +66,7 @@ func TestHistogramSnapshot(t *testing.T) {
 	testHistogram10000(t, snapshot)
 }
 
-func testHistogram10000(t *testing.T, h Histogram) {
+func testHistogram10000(t *testing.T, h HistogramSnapshot) {
 	if count := h.Count(); count != 10000 {
 		t.Errorf("h.Count(): 10000 != %v\n", count)
 	}

metrics/inactive.go

@@ -0,0 +1,48 @@
+// Copyright 2023 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package metrics
+
+// compile-time checks that interfaces are implemented.
+var (
+	_ SampleSnapshot    = (*emptySnapshot)(nil)
+	_ HistogramSnapshot = (*emptySnapshot)(nil)
+	_ CounterSnapshot   = (*emptySnapshot)(nil)
+	_ GaugeSnapshot     = (*emptySnapshot)(nil)
+	_ MeterSnapshot     = (*emptySnapshot)(nil)
+	_ EWMASnapshot      = (*emptySnapshot)(nil)
+	_ TimerSnapshot     = (*emptySnapshot)(nil)
+)
+
+type emptySnapshot struct{}
+
+func (*emptySnapshot) Count() int64                       { return 0 }
+func (*emptySnapshot) Max() int64                         { return 0 }
+func (*emptySnapshot) Mean() float64                      { return 0.0 }
+func (*emptySnapshot) Min() int64                         { return 0 }
+func (*emptySnapshot) Percentile(p float64) float64       { return 0.0 }
+func (*emptySnapshot) Percentiles(ps []float64) []float64 { return make([]float64, len(ps)) }
+func (*emptySnapshot) Size() int                          { return 0 }
+func (*emptySnapshot) StdDev() float64                    { return 0.0 }
+func (*emptySnapshot) Sum() int64                         { return 0 }
+func (*emptySnapshot) Values() []int64                    { return []int64{} }
+func (*emptySnapshot) Variance() float64                  { return 0.0 }
+func (*emptySnapshot) Value() int64                       { return 0 }
+func (*emptySnapshot) Rate() float64                      { return 0.0 }
+func (*emptySnapshot) Rate1() float64                     { return 0.0 }
+func (*emptySnapshot) Rate5() float64                     { return 0.0 }
+func (*emptySnapshot) Rate15() float64                    { return 0.0 }
+func (*emptySnapshot) RateMean() float64                  { return 0.0 }

metrics/influxdb/influxdb.go

@@ -11,13 +11,13 @@ func readMeter(namespace, name string, i interface{}) (string, map[string]interf
 	case metrics.Counter:
 		measurement := fmt.Sprintf("%s%s.count", namespace, name)
 		fields := map[string]interface{}{
-			"value": metric.Count(),
+			"value": metric.Snapshot().Count(),
 		}
 		return measurement, fields
 	case metrics.CounterFloat64:
 		measurement := fmt.Sprintf("%s%s.count", namespace, name)
 		fields := map[string]interface{}{
-			"value": metric.Count(),
+			"value": metric.Snapshot().Count(),
 		}
 		return measurement, fields
 	case metrics.Gauge:
@@ -99,20 +99,19 @@ func readMeter(namespace, name string, i interface{}) (string, map[string]interf
 		return measurement, fields
 	case metrics.ResettingTimer:
 		t := metric.Snapshot()
-		if len(t.Values()) == 0 {
+		if t.Count() == 0 {
 			break
 		}
-		ps := t.Percentiles([]float64{50, 95, 99})
+		ps := t.Percentiles([]float64{0.50, 0.95, 0.99})
-		val := t.Values()
 		measurement := fmt.Sprintf("%s%s.span", namespace, name)
 		fields := map[string]interface{}{
-			"count": len(val),
+			"count": t.Count(),
-			"max":   val[len(val)-1],
+			"max":   t.Max(),
 			"mean":  t.Mean(),
-			"min":   val[0],
+			"min":   t.Min(),
-			"p50":   ps[0],
+			"p50":   int(ps[0]),
-			"p95":   ps[1],
+			"p95":   int(ps[1]),
-			"p99":   ps[2],
+			"p99":   int(ps[2]),
 		}
 		return measurement, fields
 	}

metrics/influxdb/influxdb_test.go

@@ -96,7 +96,7 @@ func TestExampleV2(t *testing.T) {
 	}
 	if have != want {
 		t.Errorf("\nhave:\n%v\nwant:\n%v\n", have, want)
-		t.Logf("have vs want:\n %v", findFirstDiffPos(have, want))
+		t.Logf("have vs want:\n%v", findFirstDiffPos(have, want))
 	}
 }
 

metrics/influxdb/testdata/influxdbv1.want

@@ -1,3 +1,5 @@
+goth.system/cpu/schedlatency.histogram count=5645i,max=41943040i,mean=1819544.0410983171,min=0i,p25=0,p50=0,p75=7168,p95=16777216,p99=29360128,p999=33554432,p9999=33554432,stddev=6393570.217198883,variance=40877740122252.57 978307200000000000
+goth.system/memory/pauses.histogram count=14i,max=229376i,mean=50066.28571428572,min=5120i,p25=10240,p50=32768,p75=57344,p95=196608,p99=196608,p999=196608,p9999=196608,stddev=54726.062410783874,variance=2994941906.9890113 978307200000000000
 goth.test/counter.count value=12345 978307200000000000
 goth.test/counter_float64.count value=54321.98 978307200000000000
 goth.test/gauge.gauge value=23456i 978307200000000000
@@ -5,5 +7,5 @@ goth.test/gauge_float64.gauge value=34567.89 978307200000000000
 goth.test/gauge_info.gauge value="{\"arch\":\"amd64\",\"commit\":\"7caa2d8163ae3132c1c2d6978c76610caee2d949\",\"os\":\"linux\",\"protocol_versions\":\"64 65 66\",\"version\":\"1.10.18-unstable\"}" 978307200000000000
 goth.test/histogram.histogram count=3i,max=3i,mean=2,min=1i,p25=1,p50=2,p75=3,p95=3,p99=3,p999=3,p9999=3,stddev=0.816496580927726,variance=0.6666666666666666 978307200000000000
 goth.test/meter.meter count=0i,m1=0,m15=0,m5=0,mean=0 978307200000000000
-goth.test/resetting_timer.span count=6i,max=120000000i,mean=30000000,min=10000000i,p50=12000000i,p95=120000000i,p99=120000000i 978307200000000000
+goth.test/resetting_timer.span count=6i,max=120000000i,mean=30000000,min=10000000i,p50=12500000i,p95=120000000i,p99=120000000i 978307200000000000
 goth.test/timer.timer count=6i,m1=0,m15=0,m5=0,max=120000000i,mean=38333333.333333336,meanrate=0,min=20000000i,p50=22500000,p75=48000000,p95=120000000,p99=120000000,p999=120000000,p9999=120000000,stddev=36545253.529775314,variance=1335555555555555.2 978307200000000000

metrics/influxdb/testdata/influxdbv2.want

@@ -1,3 +1,5 @@
+goth.system/cpu/schedlatency.histogram count=5645i,max=41943040i,mean=1819544.0410983171,min=0i,p25=0,p50=0,p75=7168,p95=16777216,p99=29360128,p999=33554432,p9999=33554432,stddev=6393570.217198883,variance=40877740122252.57 978307200000000000
+goth.system/memory/pauses.histogram count=14i,max=229376i,mean=50066.28571428572,min=5120i,p25=10240,p50=32768,p75=57344,p95=196608,p99=196608,p999=196608,p9999=196608,stddev=54726.062410783874,variance=2994941906.9890113 978307200000000000
 goth.test/counter.count value=12345 978307200000000000
 goth.test/counter_float64.count value=54321.98 978307200000000000
 goth.test/gauge.gauge value=23456i 978307200000000000
@@ -5,5 +7,5 @@ goth.test/gauge_float64.gauge value=34567.89 978307200000000000
 goth.test/gauge_info.gauge value="{\"arch\":\"amd64\",\"commit\":\"7caa2d8163ae3132c1c2d6978c76610caee2d949\",\"os\":\"linux\",\"protocol_versions\":\"64 65 66\",\"version\":\"1.10.18-unstable\"}" 978307200000000000
 goth.test/histogram.histogram count=3i,max=3i,mean=2,min=1i,p25=1,p50=2,p75=3,p95=3,p99=3,p999=3,p9999=3,stddev=0.816496580927726,variance=0.6666666666666666 978307200000000000
 goth.test/meter.meter count=0i,m1=0,m15=0,m5=0,mean=0 978307200000000000
-goth.test/resetting_timer.span count=6i,max=120000000i,mean=30000000,min=10000000i,p50=12000000i,p95=120000000i,p99=120000000i 978307200000000000
+goth.test/resetting_timer.span count=6i,max=120000000i,mean=30000000,min=10000000i,p50=12500000i,p95=120000000i,p99=120000000i 978307200000000000
 goth.test/timer.timer count=6i,m1=0,m15=0,m5=0,max=120000000i,mean=38333333.333333336,meanrate=0,min=20000000i,p50=22500000,p75=48000000,p95=120000000,p99=120000000,p999=120000000,p9999=120000000,stddev=36545253.529775314,variance=1335555555555555.2 978307200000000000

metrics/internal/sampledata.go

@@ -17,6 +17,9 @@
 package internal
 
 import (
+	"bytes"
+	"encoding/gob"
+	metrics2 "runtime/metrics"
 	"time"
 
 	"github.com/ethereum/go-ethereum/metrics"
@@ -38,7 +41,15 @@ func ExampleMetrics() metrics.Registry {
 			"commit":            "7caa2d8163ae3132c1c2d6978c76610caee2d949",
 			"protocol_versions": "64 65 66",
 		})
-	metrics.NewRegisteredHistogram("test/histogram", registry, metrics.NewSampleSnapshot(3, []int64{1, 2, 3}))
+
+	{
+		s := metrics.NewUniformSample(3)
+		s.Update(1)
+		s.Update(2)
+		s.Update(3)
+		//metrics.NewRegisteredHistogram("test/histogram", registry, metrics.NewSampleSnapshot(3, []int64{1, 2, 3}))
+		metrics.NewRegisteredHistogram("test/histogram", registry, s)
+	}
 	registry.Register("test/meter", metrics.NewInactiveMeter())
 	{
 		timer := metrics.NewRegisteredResettingTimer("test/resetting_timer", registry)
@@ -60,5 +71,25 @@ func ExampleMetrics() metrics.Registry {
 		timer.Stop()
 	}
 	registry.Register("test/empty_resetting_timer", metrics.NewResettingTimer().Snapshot())
+
+	{ // go runtime metrics
+		var sLatency = "7\xff\x81\x03\x01\x01\x10Float64Histogram\x01\xff\x82\x00\x01\x02\x01\x06Counts\x01\xff\x84\x00\x01\aBuckets\x01\xff\x86\x00\x00\x00\x16\xff\x83\x02\x01\x01\b[]uint64\x01\xff\x84\x00\x01\x06\x00\x00\x17\xff\x85\x02\x01\x01\t[]float64\x01\xff\x86\x00\x01\b\x00\x00\xfe\x06T\xff\x82\x01\xff\xa2\x00\xfe\r\xef\x00\x01\x02\x02\x04\x05\x04\b\x15\x17 B?6.L;$!2) \x1a? \x190aH7FY6#\x190\x1d\x14\x10\x1b\r\t\x04\x03\x01\x01\x00\x03\x02\x00\x03\x05\x05\x02\x02\x06\x04\v\x06\n\x15\x18\x13'&.\x12=H/L&\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\xff\xa3\xfe\xf0\xff\x00\xf8\x95\xd6&\xe8\v.q>\xf8\x95\xd6&\xe8\v.\x81>\xf8\xdfA:\xdc\x11ʼn>\xf8\x95\xd6&\xe8\v.\x91>\xf8:\x8c0\xe2\x8ey\x95>\xf8\xdfA:\xdc\x11ř>\xf8\x84\xf7C֔\x10\x9e>\xf8\x95\xd6&\xe8\v.\xa1>\xf8:\x8c0\xe2\x8ey\xa5>\xf8\xdfA:\xdc\x11ũ>\xf8\x84\xf7C֔\x10\xae>\xf8\x95\xd6&\xe8\v.\xb1>\xf8:\x8c0\xe2\x8ey\xb5>\xf8\xdfA:\xdc\x11Ź>\xf8\x84\xf7C֔\x10\xbe>\xf8\x95\xd6&\xe8\v.\xc1>\xf8:\x8c0\xe2\x8ey\xc5>\xf8\xdfA:\xdc\x11\xc5\xc9>\xf8\x84\xf7C֔\x10\xce>\xf8\x95\xd6&\xe8\v.\xd1>\xf8:\x8c0\xe2\x8ey\xd5>\xf8\xdfA:\xdc\x11\xc5\xd9>\xf8\x84\xf7C֔\x10\xde>\xf8\x95\xd6&\xe8\v.\xe1>\xf8:\x8c0\xe2\x8ey\xe5>\xf8\xdfA:\xdc\x11\xc5\xe9>\xf8\x84\xf7C֔\x10\xee>\xf8\x95\xd6&\xe8\v.\xf1>\xf8:\x8c0\xe2\x8ey\xf5>\xf8\xdfA:\xdc\x11\xc5\xf9>\xf8\x84\xf7C֔\x10\xfe>\xf8\x95\xd6&\xe8\v.\x01?\xf8:\x8c0\xe2\x8ey\x05?\xf8\xdfA:\xdc\x11\xc5\t?\xf8\x84\xf7C֔\x10\x0e?\xf8\x95\xd6&\xe8\v.\x11?\xf8:\x8c0\xe2\x8ey\x15?\xf8\xdfA:\xdc\x11\xc5\x19?\xf8\x84\xf7C֔\x10\x1e?\xf8\x95\xd6&\xe8\v.!?\xf8:\x8c0\xe2\x8ey%?\xf8\xdfA:\xdc\x11\xc5)?\xf8\x84\xf7C֔\x10.?\xf8\x95\xd6&\xe8\v.1?\xf8:\x8c0\xe2\x8ey5?\xf8\xdfA:\xdc\x11\xc59?\xf8\x84\xf7C֔\x10>?\xf8\x95\xd6&\xe8\v.A?\xf8:\x8c0\xe2\x8eyE?\xf8\xdfA:\xdc\x11\xc5I?\xf8\x84\xf7C֔\x10N?\xf8\x95\xd6&\xe8\v.Q?\xf8:\x8c0\xe2\x8eyU?\xf8\xdfA:\xdc\x11\xc5Y?\xf8\x84\xf7C֔\x10^?\xf8\x95\xd6&\xe8\v.a?\xf8:\x8c0\xe2\x8eye?\xf8\xdfA:\xdc\x11\xc5i?\xf8\x84\xf7C֔\x10n?\xf8\x95\xd6&\xe8\v.q?\xf8:\x8c0\xe2\x8eyu?\xf8\xdfA:\xdc\x11\xc5y?\xf8\x84\xf7C֔\x10~?\xf8\x95\xd6&\xe8\v.\x81?\xf8:\x8c0\xe2\x8ey\x85?\xf8\xdfA:\xdc\x11ʼn?\xf8\x84\xf7C֔\x10\x8e?\xf8\x95\xd6&\xe8\v.\x91?\xf8:\x8c0\xe2\x8ey\x95?\xf8\xdfA:\xdc\x11ř?\xf8\x84\xf7C֔\x10\x9e?\xf8\x95\xd6&\xe8\v.\xa1?\xf8:\x8c0\xe2\x8ey\xa5?\xf8\xdfA:\xdc\x11ũ?\xf8\x84\xf7C֔\x10\xae?\xf8\x95\xd6&\xe8\v.\xb1?\xf8:\x8c0\xe2\x8ey\xb5?\xf8\xdfA:\xdc\x11Ź?\xf8\x84\xf7C֔\x10\xbe?\xf8\x95\xd6&\xe8\v.\xc1?\xf8:\x8c0\xe2\x8ey\xc5?\xf8\xdfA:\xdc\x11\xc5\xc9?\xf8\x84\xf7C֔\x10\xce?\xf8\x95\xd6&\xe8\v.\xd1?\xf8:\x8c0\xe2\x8ey\xd5?\xf8\xdfA:\xdc\x11\xc5\xd9?\xf8\x84\xf7C֔\x10\xde?\xf8\x95\xd6&\xe8\v.\xe1?\xf8:\x8c0\xe2\x8ey\xe5?\xf8\xdfA:\xdc\x11\xc5\xe9?\xf8\x84\xf7C֔\x10\xee?\xf8\x95\xd6&\xe8\v.\xf1?\xf8:\x8c0\xe2\x8ey\xf5?\xf8\xdfA:\xdc\x11\xc5\xf9?\xf8\x84\xf7C֔\x10\xfe?\xf8\x95\xd6&\xe8\v.\x01@\xf8:\x8c0\xe2\x8ey\x05@\xf8\xdfA:\xdc\x11\xc5\t@\xf8\x84\xf7C֔\x10\x0e@\xf8\x95\xd6&\xe8\v.\x11@\xf8:\x8c0\xe2\x8ey\x15@\xf8\xdfA:\xdc\x11\xc5\x19@\xf8\x84\xf7C֔\x10\x1e@\xf8\x95\xd6&\xe8\v.!@\xf8:\x8c0\xe2\x8ey%@\xf8\xdfA:\xdc\x11\xc5)@\xf8\x84\xf7C֔\x10.@\xf8\x95\xd6&\xe8\v.1@\xf8:\x8c0\xe2\x8ey5@\xf8\xdfA:\xdc\x11\xc59@\xf8\x84\xf7C֔\x10>@\xf8\x95\xd6&\xe8\v.A@\xf8:\x8c0\xe2\x8eyE@\xf8\xdfA:\xdc\x11\xc5I@\xf8\x84\xf7C֔\x10N@\xf8\x95\xd6&\xe8\v.Q@\xf8:\x8c0\xe2\x8eyU@\xf8\xdfA:\xdc\x11\xc5Y@\xf8\x84\xf7C֔\x10^@\xf8\x95\xd6&\xe8\v.a@\xf8:\x8c0\xe2\x8eye@\xf8\xdfA:\xdc\x11\xc5i@\xf8\x84\xf7C֔\x10n@\xf8\x95\xd6&\xe8\v.q@\xf8:\x8c0\xe2\x8eyu@\xf8\xdfA:\xdc\x11\xc5y@\xf8\x84\xf7C֔\x10~@\xf8\x95\xd6&\xe8\v.\x81@\xf8:\x8c0\xe2\x8ey\x85@\xf8\xdfA:\xdc\x11ʼn@\xf8\x84\xf7C֔\x10\x8e@\xf8\x95\xd6&\xe8\v.\x91@\xf8:\x8c0\xe2\x8ey\x95@\xf8\xdfA:\xdc\x11ř@\xf8\x84\xf7C֔\x10\x9e@\xf8\x95\xd6&\xe8\v.\xa1@\xf8:\x8c0\xe2\x8ey\xa5@\xf8\xdfA:\xdc\x11ũ@\xf8\x84\xf7C֔\x10\xae@\xf8\x95\xd6&\xe8\v.\xb1@\xf8:\x8c0\xe2\x8ey\xb5@\xf8\xdfA:\xdc\x11Ź@\xf8\x84\xf7C֔\x10\xbe@\xf8\x95\xd6&\xe8\v.\xc1@\xf8:\x8c0\xe2\x8ey\xc5@\xf8\xdfA:\xdc\x11\xc5\xc9@\xf8\x84\xf7C֔\x10\xce@\xf8\x95\xd6&\xe8\v.\xd1@\xf8:\x8c0\xe2\x8ey\xd5@\xf8\xdfA:\xdc\x11\xc5\xd9@\xf8\x84\xf7C֔\x10\xde@\xf8\x95\xd6&\xe8\v.\xe1@\xf8:\x8c0\xe2\x8ey\xe5@\xf8\xdfA:\xdc\x11\xc5\xe9@\xf8\x84\xf7C֔\x10\xee@\xf8\x95\xd6&\xe8\v.\xf1@\xf8:\x8c0\xe2\x8ey\xf5@\xf8\xdfA:\xdc\x11\xc5\xf9@\xf8\x84\xf7C֔\x10\xfe@\xf8\x95\xd6&\xe8\v.\x01A\xfe\xf0\x7f\x00"
+		var gcPauses = "7\xff\x81\x03\x01\x01\x10Float64Histogram\x01\xff\x82\x00\x01\x02\x01\x06Counts\x01\xff\x84\x00\x01\aBuckets\x01\xff\x86\x00\x00\x00\x16\xff\x83\x02\x01\x01\b[]uint64\x01\xff\x84\x00\x01\x06\x00\x00\x17\xff\x85\x02\x01\x01\t[]float64\x01\xff\x86\x00\x01\b\x00\x00\xfe\x06R\xff\x82\x01\xff\xa2\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x01\x01\x00\x01\x00\x00\x00\x01\x01\x01\x01\x01\x01\x01\x00\x02\x00\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\xff\xa3\xfe\xf0\xff\x00\xf8\x95\xd6&\xe8\v.q>\xf8\x95\xd6&\xe8\v.\x81>\xf8\xdfA:\xdc\x11ʼn>\xf8\x95\xd6&\xe8\v.\x91>\xf8:\x8c0\xe2\x8ey\x95>\xf8\xdfA:\xdc\x11ř>\xf8\x84\xf7C֔\x10\x9e>\xf8\x95\xd6&\xe8\v.\xa1>\xf8:\x8c0\xe2\x8ey\xa5>\xf8\xdfA:\xdc\x11ũ>\xf8\x84\xf7C֔\x10\xae>\xf8\x95\xd6&\xe8\v.\xb1>\xf8:\x8c0\xe2\x8ey\xb5>\xf8\xdfA:\xdc\x11Ź>\xf8\x84\xf7C֔\x10\xbe>\xf8\x95\xd6&\xe8\v.\xc1>\xf8:\x8c0\xe2\x8ey\xc5>\xf8\xdfA:\xdc\x11\xc5\xc9>\xf8\x84\xf7C֔\x10\xce>\xf8\x95\xd6&\xe8\v.\xd1>\xf8:\x8c0\xe2\x8ey\xd5>\xf8\xdfA:\xdc\x11\xc5\xd9>\xf8\x84\xf7C֔\x10\xde>\xf8\x95\xd6&\xe8\v.\xe1>\xf8:\x8c0\xe2\x8ey\xe5>\xf8\xdfA:\xdc\x11\xc5\xe9>\xf8\x84\xf7C֔\x10\xee>\xf8\x95\xd6&\xe8\v.\xf1>\xf8:\x8c0\xe2\x8ey\xf5>\xf8\xdfA:\xdc\x11\xc5\xf9>\xf8\x84\xf7C֔\x10\xfe>\xf8\x95\xd6&\xe8\v.\x01?\xf8:\x8c0\xe2\x8ey\x05?\xf8\xdfA:\xdc\x11\xc5\t?\xf8\x84\xf7C֔\x10\x0e?\xf8\x95\xd6&\xe8\v.\x11?\xf8:\x8c0\xe2\x8ey\x15?\xf8\xdfA:\xdc\x11\xc5\x19?\xf8\x84\xf7C֔\x10\x1e?\xf8\x95\xd6&\xe8\v.!?\xf8:\x8c0\xe2\x8ey%?\xf8\xdfA:\xdc\x11\xc5)?\xf8\x84\xf7C֔\x10.?\xf8\x95\xd6&\xe8\v.1?\xf8:\x8c0\xe2\x8ey5?\xf8\xdfA:\xdc\x11\xc59?\xf8\x84\xf7C֔\x10>?\xf8\x95\xd6&\xe8\v.A?\xf8:\x8c0\xe2\x8eyE?\xf8\xdfA:\xdc\x11\xc5I?\xf8\x84\xf7C֔\x10N?\xf8\x95\xd6&\xe8\v.Q?\xf8:\x8c0\xe2\x8eyU?\xf8\xdfA:\xdc\x11\xc5Y?\xf8\x84\xf7C֔\x10^?\xf8\x95\xd6&\xe8\v.a?\xf8:\x8c0\xe2\x8eye?\xf8\xdfA:\xdc\x11\xc5i?\xf8\x84\xf7C֔\x10n?\xf8\x95\xd6&\xe8\v.q?\xf8:\x8c0\xe2\x8eyu?\xf8\xdfA:\xdc\x11\xc5y?\xf8\x84\xf7C֔\x10~?\xf8\x95\xd6&\xe8\v.\x81?\xf8:\x8c0\xe2\x8ey\x85?\xf8\xdfA:\xdc\x11ʼn?\xf8\x84\xf7C֔\x10\x8e?\xf8\x95\xd6&\xe8\v.\x91?\xf8:\x8c0\xe2\x8ey\x95?\xf8\xdfA:\xdc\x11ř?\xf8\x84\xf7C֔\x10\x9e?\xf8\x95\xd6&\xe8\v.\xa1?\xf8:\x8c0\xe2\x8ey\xa5?\xf8\xdfA:\xdc\x11ũ?\xf8\x84\xf7C֔\x10\xae?\xf8\x95\xd6&\xe8\v.\xb1?\xf8:\x8c0\xe2\x8ey\xb5?\xf8\xdfA:\xdc\x11Ź?\xf8\x84\xf7C֔\x10\xbe?\xf8\x95\xd6&\xe8\v.\xc1?\xf8:\x8c0\xe2\x8ey\xc5?\xf8\xdfA:\xdc\x11\xc5\xc9?\xf8\x84\xf7C֔\x10\xce?\xf8\x95\xd6&\xe8\v.\xd1?\xf8:\x8c0\xe2\x8ey\xd5?\xf8\xdfA:\xdc\x11\xc5\xd9?\xf8\x84\xf7C֔\x10\xde?\xf8\x95\xd6&\xe8\v.\xe1?\xf8:\x8c0\xe2\x8ey\xe5?\xf8\xdfA:\xdc\x11\xc5\xe9?\xf8\x84\xf7C֔\x10\xee?\xf8\x95\xd6&\xe8\v.\xf1?\xf8:\x8c0\xe2\x8ey\xf5?\xf8\xdfA:\xdc\x11\xc5\xf9?\xf8\x84\xf7C֔\x10\xfe?\xf8\x95\xd6&\xe8\v.\x01@\xf8:\x8c0\xe2\x8ey\x05@\xf8\xdfA:\xdc\x11\xc5\t@\xf8\x84\xf7C֔\x10\x0e@\xf8\x95\xd6&\xe8\v.\x11@\xf8:\x8c0\xe2\x8ey\x15@\xf8\xdfA:\xdc\x11\xc5\x19@\xf8\x84\xf7C֔\x10\x1e@\xf8\x95\xd6&\xe8\v.!@\xf8:\x8c0\xe2\x8ey%@\xf8\xdfA:\xdc\x11\xc5)@\xf8\x84\xf7C֔\x10.@\xf8\x95\xd6&\xe8\v.1@\xf8:\x8c0\xe2\x8ey5@\xf8\xdfA:\xdc\x11\xc59@\xf8\x84\xf7C֔\x10>@\xf8\x95\xd6&\xe8\v.A@\xf8:\x8c0\xe2\x8eyE@\xf8\xdfA:\xdc\x11\xc5I@\xf8\x84\xf7C֔\x10N@\xf8\x95\xd6&\xe8\v.Q@\xf8:\x8c0\xe2\x8eyU@\xf8\xdfA:\xdc\x11\xc5Y@\xf8\x84\xf7C֔\x10^@\xf8\x95\xd6&\xe8\v.a@\xf8:\x8c0\xe2\x8eye@\xf8\xdfA:\xdc\x11\xc5i@\xf8\x84\xf7C֔\x10n@\xf8\x95\xd6&\xe8\v.q@\xf8:\x8c0\xe2\x8eyu@\xf8\xdfA:\xdc\x11\xc5y@\xf8\x84\xf7C֔\x10~@\xf8\x95\xd6&\xe8\v.\x81@\xf8:\x8c0\xe2\x8ey\x85@\xf8\xdfA:\xdc\x11ʼn@\xf8\x84\xf7C֔\x10\x8e@\xf8\x95\xd6&\xe8\v.\x91@\xf8:\x8c0\xe2\x8ey\x95@\xf8\xdfA:\xdc\x11ř@\xf8\x84\xf7C֔\x10\x9e@\xf8\x95\xd6&\xe8\v.\xa1@\xf8:\x8c0\xe2\x8ey\xa5@\xf8\xdfA:\xdc\x11ũ@\xf8\x84\xf7C֔\x10\xae@\xf8\x95\xd6&\xe8\v.\xb1@\xf8:\x8c0\xe2\x8ey\xb5@\xf8\xdfA:\xdc\x11Ź@\xf8\x84\xf7C֔\x10\xbe@\xf8\x95\xd6&\xe8\v.\xc1@\xf8:\x8c0\xe2\x8ey\xc5@\xf8\xdfA:\xdc\x11\xc5\xc9@\xf8\x84\xf7C֔\x10\xce@\xf8\x95\xd6&\xe8\v.\xd1@\xf8:\x8c0\xe2\x8ey\xd5@\xf8\xdfA:\xdc\x11\xc5\xd9@\xf8\x84\xf7C֔\x10\xde@\xf8\x95\xd6&\xe8\v.\xe1@\xf8:\x8c0\xe2\x8ey\xe5@\xf8\xdfA:\xdc\x11\xc5\xe9@\xf8\x84\xf7C֔\x10\xee@\xf8\x95\xd6&\xe8\v.\xf1@\xf8:\x8c0\xe2\x8ey\xf5@\xf8\xdfA:\xdc\x11\xc5\xf9@\xf8\x84\xf7C֔\x10\xfe@\xf8\x95\xd6&\xe8\v.\x01A\xfe\xf0\x7f\x00"
+
+		var secondsToNs = float64(time.Second)
+
+		dserialize := func(data string) *metrics2.Float64Histogram {
+			var res metrics2.Float64Histogram
+			if err := gob.NewDecoder(bytes.NewReader([]byte(data))).Decode(&res); err != nil {
+				panic(err)
+			}
+			return &res
+		}
+		cpuSchedLatency := metrics.RuntimeHistogramFromData(secondsToNs, dserialize(sLatency))
+		registry.Register("system/cpu/schedlatency", cpuSchedLatency)
+
+		memPauses := metrics.RuntimeHistogramFromData(secondsToNs, dserialize(gcPauses))
+		registry.Register("system/memory/pauses", memPauses)
+	}
 	return registry
 }

metrics/internal/sampledata_test.go

@@ -0,0 +1,27 @@
+package internal
+
+import (
+	"bytes"
+	"encoding/gob"
+	"fmt"
+	metrics2 "runtime/metrics"
+	"testing"
+	"time"
+
+	"github.com/ethereum/go-ethereum/metrics"
+)
+
+func TestCollectRuntimeMetrics(t *testing.T) {
+	t.Skip("Only used for generating testdata")
+	serialize := func(path string, histogram *metrics2.Float64Histogram) {
+		var f = new(bytes.Buffer)
+		if err := gob.NewEncoder(f).Encode(histogram); err != nil {
+			panic(err)
+		}
+		fmt.Printf("var %v = %q\n", path, f.Bytes())
+	}
+	time.Sleep(2 * time.Second)
+	stats := metrics.ReadRuntimeStats()
+	serialize("schedlatency", stats.SchedLatency)
+	serialize("gcpauses", stats.GCPauses)
+}

metrics/librato/librato.go

@@ -61,16 +61,16 @@ func (rep *Reporter) Run() {
 
 // calculate sum of squares from data provided by metrics.Histogram
 // see http://en.wikipedia.org/wiki/Standard_deviation#Rapid_calculation_methods
-func sumSquares(s metrics.Sample) float64 {
+func sumSquares(icount int64, mean, stDev float64) float64 {
-	count := float64(s.Count())
+	count := float64(icount)
-	sumSquared := math.Pow(count*s.Mean(), 2)
+	sumSquared := math.Pow(count*mean, 2)
-	sumSquares := math.Pow(count*s.StdDev(), 2) + sumSquared/count
+	sumSquares := math.Pow(count*stDev, 2) + sumSquared/count
 	if math.IsNaN(sumSquares) {
 		return 0.0
 	}
 	return sumSquares
 }
-func sumSquaresTimer(t metrics.Timer) float64 {
+func sumSquaresTimer(t metrics.TimerSnapshot) float64 {
 	count := float64(t.Count())
 	sumSquared := math.Pow(count*t.Mean(), 2)
 	sumSquares := math.Pow(count*t.StdDev(), 2) + sumSquared/count
@@ -97,9 +97,10 @@ func (rep *Reporter) BuildRequest(now time.Time, r metrics.Registry) (snapshot B
 		measurement[Period] = rep.Interval.Seconds()
 		switch m := metric.(type) {
 		case metrics.Counter:
-			if m.Count() > 0 {
+			ms := m.Snapshot()
+			if ms.Count() > 0 {
 				measurement[Name] = fmt.Sprintf("%s.%s", name, "count")
-				measurement[Value] = float64(m.Count())
+				measurement[Value] = float64(ms.Count())
 				measurement[Attributes] = map[string]interface{}{
 					DisplayUnitsLong:  Operations,
 					DisplayUnitsShort: OperationsShort,
@@ -108,9 +109,9 @@ func (rep *Reporter) BuildRequest(now time.Time, r metrics.Registry) (snapshot B
 				snapshot.Counters = append(snapshot.Counters, measurement)
 			}
 		case metrics.CounterFloat64:
-			if m.Count() > 0 {
+			if count := m.Snapshot().Count(); count > 0 {
 				measurement[Name] = fmt.Sprintf("%s.%s", name, "count")
-				measurement[Value] = m.Count()
+				measurement[Value] = count
 				measurement[Attributes] = map[string]interface{}{
 					DisplayUnitsLong:  Operations,
 					DisplayUnitsShort: OperationsShort,
@@ -120,44 +121,45 @@ func (rep *Reporter) BuildRequest(now time.Time, r metrics.Registry) (snapshot B
 			}
 		case metrics.Gauge:
 			measurement[Name] = name
-			measurement[Value] = float64(m.Value())
+			measurement[Value] = float64(m.Snapshot().Value())
 			snapshot.Gauges = append(snapshot.Gauges, measurement)
 		case metrics.GaugeFloat64:
 			measurement[Name] = name
-			measurement[Value] = m.Value()
+			measurement[Value] = m.Snapshot().Value()
 			snapshot.Gauges = append(snapshot.Gauges, measurement)
 		case metrics.GaugeInfo:
 			measurement[Name] = name
-			measurement[Value] = m.Value()
+			measurement[Value] = m.Snapshot().Value()
 			snapshot.Gauges = append(snapshot.Gauges, measurement)
 		case metrics.Histogram:
-			if m.Count() > 0 {
+			ms := m.Snapshot()
+			if ms.Count() > 0 {
 				gauges := make([]Measurement, histogramGaugeCount)
-				s := m.Sample()
 				measurement[Name] = fmt.Sprintf("%s.%s", name, "hist")
-				measurement[Count] = uint64(s.Count())
+				measurement[Count] = uint64(ms.Count())
-				measurement[Max] = float64(s.Max())
+				measurement[Max] = float64(ms.Max())
-				measurement[Min] = float64(s.Min())
+				measurement[Min] = float64(ms.Min())
-				measurement[Sum] = float64(s.Sum())
+				measurement[Sum] = float64(ms.Sum())
-				measurement[SumSquares] = sumSquares(s)
+				measurement[SumSquares] = sumSquares(ms.Count(), ms.Mean(), ms.StdDev())
 				gauges[0] = measurement
 				for i, p := range rep.Percentiles {
 					gauges[i+1] = Measurement{
 						Name:   fmt.Sprintf("%s.%.2f", measurement[Name], p),
-						Value:  s.Percentile(p),
+						Value:  ms.Percentile(p),
 						Period: measurement[Period],
 					}
 				}
 				snapshot.Gauges = append(snapshot.Gauges, gauges...)
 			}
 		case metrics.Meter:
+			ms := m.Snapshot()
 			measurement[Name] = name
-			measurement[Value] = float64(m.Count())
+			measurement[Value] = float64(ms.Count())
 			snapshot.Counters = append(snapshot.Counters, measurement)
 			snapshot.Gauges = append(snapshot.Gauges,
 				Measurement{
 					Name:   fmt.Sprintf("%s.%s", name, "1min"),
-					Value:  m.Rate1(),
+					Value:  ms.Rate1(),
 					Period: int64(rep.Interval.Seconds()),
 					Attributes: map[string]interface{}{
 						DisplayUnitsLong:  Operations,
@@ -167,7 +169,7 @@ func (rep *Reporter) BuildRequest(now time.Time, r metrics.Registry) (snapshot B
 				},
 				Measurement{
 					Name:   fmt.Sprintf("%s.%s", name, "5min"),
-					Value:  m.Rate5(),
+					Value:  ms.Rate5(),
 					Period: int64(rep.Interval.Seconds()),
 					Attributes: map[string]interface{}{
 						DisplayUnitsLong:  Operations,
@@ -177,7 +179,7 @@ func (rep *Reporter) BuildRequest(now time.Time, r metrics.Registry) (snapshot B
 				},
 				Measurement{
 					Name:   fmt.Sprintf("%s.%s", name, "15min"),
-					Value:  m.Rate15(),
+					Value:  ms.Rate15(),
 					Period: int64(rep.Interval.Seconds()),
 					Attributes: map[string]interface{}{
 						DisplayUnitsLong:  Operations,
@@ -187,26 +189,27 @@ func (rep *Reporter) BuildRequest(now time.Time, r metrics.Registry) (snapshot B
 				},
 			)
 		case metrics.Timer:
+			ms := m.Snapshot()
 			measurement[Name] = name
-			measurement[Value] = float64(m.Count())
+			measurement[Value] = float64(ms.Count())
 			snapshot.Counters = append(snapshot.Counters, measurement)
-			if m.Count() > 0 {
+			if ms.Count() > 0 {
 				libratoName := fmt.Sprintf("%s.%s", name, "timer.mean")
 				gauges := make([]Measurement, histogramGaugeCount)
 				gauges[0] = Measurement{
 					Name:       libratoName,
-					Count:      uint64(m.Count()),
+					Count:      uint64(ms.Count()),
-					Sum:        m.Mean() * float64(m.Count()),
+					Sum:        ms.Mean() * float64(ms.Count()),
-					Max:        float64(m.Max()),
+					Max:        float64(ms.Max()),
-					Min:        float64(m.Min()),
+					Min:        float64(ms.Min()),
-					SumSquares: sumSquaresTimer(m),
+					SumSquares: sumSquaresTimer(ms),
 					Period:     int64(rep.Interval.Seconds()),
 					Attributes: rep.TimerAttributes,
 				}
 				for i, p := range rep.Percentiles {
 					gauges[i+1] = Measurement{
 						Name:       fmt.Sprintf("%s.timer.%2.0f", name, p*100),
-						Value:      m.Percentile(p),
+						Value:      ms.Percentile(p),
 						Period:     int64(rep.Interval.Seconds()),
 						Attributes: rep.TimerAttributes,
 					}
@@ -215,7 +218,7 @@ func (rep *Reporter) BuildRequest(now time.Time, r metrics.Registry) (snapshot B
 				snapshot.Gauges = append(snapshot.Gauges,
 					Measurement{
 						Name:   fmt.Sprintf("%s.%s", name, "rate.1min"),
-						Value:  m.Rate1(),
+						Value:  ms.Rate1(),
 						Period: int64(rep.Interval.Seconds()),
 						Attributes: map[string]interface{}{
 							DisplayUnitsLong:  Operations,
@@ -225,7 +228,7 @@ func (rep *Reporter) BuildRequest(now time.Time, r metrics.Registry) (snapshot B
 					},
 					Measurement{
 						Name:   fmt.Sprintf("%s.%s", name, "rate.5min"),
-						Value:  m.Rate5(),
+						Value:  ms.Rate5(),
 						Period: int64(rep.Interval.Seconds()),
 						Attributes: map[string]interface{}{
 							DisplayUnitsLong:  Operations,
@@ -235,7 +238,7 @@ func (rep *Reporter) BuildRequest(now time.Time, r metrics.Registry) (snapshot B
 					},
 					Measurement{
 						Name:   fmt.Sprintf("%s.%s", name, "rate.15min"),
-						Value:  m.Rate15(),
+						Value:  ms.Rate15(),
 						Period: int64(rep.Interval.Seconds()),
 						Attributes: map[string]interface{}{
 							DisplayUnitsLong:  Operations,

metrics/log.go

@@ -23,19 +23,19 @@ func LogScaled(r Registry, freq time.Duration, scale time.Duration, l Logger) {
 			switch metric := i.(type) {
 			case Counter:
 				l.Printf("counter %s\n", name)
-				l.Printf("  count:       %9d\n", metric.Count())
+				l.Printf("  count:       %9d\n", metric.Snapshot().Count())
 			case CounterFloat64:
 				l.Printf("counter %s\n", name)
-				l.Printf("  count:       %f\n", metric.Count())
+				l.Printf("  count:       %f\n", metric.Snapshot().Count())
 			case Gauge:
 				l.Printf("gauge %s\n", name)
-				l.Printf("  value:       %9d\n", metric.Value())
+				l.Printf("  value:       %9d\n", metric.Snapshot().Value())
 			case GaugeFloat64:
 				l.Printf("gauge %s\n", name)
-				l.Printf("  value:       %f\n", metric.Value())
+				l.Printf("  value:       %f\n", metric.Snapshot().Value())
 			case GaugeInfo:
 				l.Printf("gauge %s\n", name)
-				l.Printf("  value:       %s\n", metric.Value())
+				l.Printf("  value:       %s\n", metric.Snapshot().Value())
 			case Healthcheck:
 				metric.Check()
 				l.Printf("healthcheck %s\n", name)

metrics/meter.go

@@ -1,21 +1,25 @@
 package metrics
 
 import (
+	"math"
 	"sync"
 	"sync/atomic"
 	"time"
 )
 
-// Meters count events to produce exponentially-weighted moving average rates
+type MeterSnapshot interface {
-// at one-, five-, and fifteen-minutes and a mean rate.
-type Meter interface {
 	Count() int64
-	Mark(int64)
 	Rate1() float64
 	Rate5() float64
 	Rate15() float64
 	RateMean() float64
-	Snapshot() Meter
+}
+
+// Meters count events to produce exponentially-weighted moving average rates
+// at one-, five-, and fifteen-minutes and a mean rate.
+type Meter interface {
+	Mark(int64)
+	Snapshot() MeterSnapshot
 	Stop()
 }
 
@@ -30,17 +34,6 @@ func GetOrRegisterMeter(name string, r Registry) Meter {
 	return r.GetOrRegister(name, NewMeter).(Meter)
 }
 
-// GetOrRegisterMeterForced returns an existing Meter or constructs and registers a
-// new StandardMeter no matter the global switch is enabled or not.
-// Be sure to unregister the meter from the registry once it is of no use to
-// allow for garbage collection.
-func GetOrRegisterMeterForced(name string, r Registry) Meter {
-	if nil == r {
-		r = DefaultRegistry
-	}
-	return r.GetOrRegister(name, NewMeterForced).(Meter)
-}
-
 // NewMeter constructs a new StandardMeter and launches a goroutine.
 // Be sure to call Stop() once the meter is of no use to allow for garbage collection.
 func NewMeter() Meter {
@@ -68,115 +61,53 @@ func NewInactiveMeter() Meter {
 	return m
 }
 
-// NewMeterForced constructs a new StandardMeter and launches a goroutine no matter
-// the global switch is enabled or not.
-// Be sure to call Stop() once the meter is of no use to allow for garbage collection.
-func NewMeterForced() Meter {
-	m := newStandardMeter()
-	arbiter.Lock()
-	defer arbiter.Unlock()
-	arbiter.meters[m] = struct{}{}
-	if !arbiter.started {
-		arbiter.started = true
-		go arbiter.tick()
-	}
-	return m
-}
-
 // NewRegisteredMeter constructs and registers a new StandardMeter
 // and launches a goroutine.
 // Be sure to unregister the meter from the registry once it is of no use to
 // allow for garbage collection.
 func NewRegisteredMeter(name string, r Registry) Meter {
-	c := NewMeter()
+	return GetOrRegisterMeter(name, r)
-	if nil == r {
-		r = DefaultRegistry
-	}
-	r.Register(name, c)
-	return c
 }
 
-// NewRegisteredMeterForced constructs and registers a new StandardMeter
+// meterSnapshot is a read-only copy of the meter's internal values.
-// and launches a goroutine no matter the global switch is enabled or not.
+type meterSnapshot struct {
-// Be sure to unregister the meter from the registry once it is of no use to
-// allow for garbage collection.
-func NewRegisteredMeterForced(name string, r Registry) Meter {
-	c := NewMeterForced()
-	if nil == r {
-		r = DefaultRegistry
-	}
-	r.Register(name, c)
-	return c
-}
-
-// MeterSnapshot is a read-only copy of another Meter.
-type MeterSnapshot struct {
-	temp                           atomic.Int64
 	count                          int64
 	rate1, rate5, rate15, rateMean float64
 }
 
 // Count returns the count of events at the time the snapshot was taken.
-func (m *MeterSnapshot) Count() int64 { return m.count }
+func (m *meterSnapshot) Count() int64 { return m.count }
-
-// Mark panics.
-func (*MeterSnapshot) Mark(n int64) {
-	panic("Mark called on a MeterSnapshot")
-}
 
 // Rate1 returns the one-minute moving average rate of events per second at the
 // time the snapshot was taken.
-func (m *MeterSnapshot) Rate1() float64 { return m.rate1 }
+func (m *meterSnapshot) Rate1() float64 { return m.rate1 }
 
 // Rate5 returns the five-minute moving average rate of events per second at
 // the time the snapshot was taken.
-func (m *MeterSnapshot) Rate5() float64 { return m.rate5 }
+func (m *meterSnapshot) Rate5() float64 { return m.rate5 }
 
 // Rate15 returns the fifteen-minute moving average rate of events per second
 // at the time the snapshot was taken.
-func (m *MeterSnapshot) Rate15() float64 { return m.rate15 }
+func (m *meterSnapshot) Rate15() float64 { return m.rate15 }
 
 // RateMean returns the meter's mean rate of events per second at the time the
 // snapshot was taken.
-func (m *MeterSnapshot) RateMean() float64 { return m.rateMean }
+func (m *meterSnapshot) RateMean() float64 { return m.rateMean }
-
-// Snapshot returns the snapshot.
-func (m *MeterSnapshot) Snapshot() Meter { return m }
-
-// Stop is a no-op.
-func (m *MeterSnapshot) Stop() {}
 
 // NilMeter is a no-op Meter.
 type NilMeter struct{}
 
-// Count is a no-op.
 func (NilMeter) Count() int64            { return 0 }
-
-// Mark is a no-op.
 func (NilMeter) Mark(n int64)            {}
-
+func (NilMeter) Snapshot() MeterSnapshot { return (*emptySnapshot)(nil) }
-// Rate1 is a no-op.
-func (NilMeter) Rate1() float64 { return 0.0 }
-
-// Rate5 is a no-op.
-func (NilMeter) Rate5() float64 { return 0.0 }
-
-// Rate15 is a no-op.
-func (NilMeter) Rate15() float64 { return 0.0 }
-
-// RateMean is a no-op.
-func (NilMeter) RateMean() float64 { return 0.0 }
-
-// Snapshot is a no-op.
-func (NilMeter) Snapshot() Meter { return NilMeter{} }
-
-// Stop is a no-op.
 func (NilMeter) Stop()                   {}
 
 // StandardMeter is the standard implementation of a Meter.
 type StandardMeter struct {
-	lock        sync.RWMutex
+	count     atomic.Int64
-	snapshot    *MeterSnapshot
+	uncounted atomic.Int64 // not yet added to the EWMAs
+	rateMean  atomic.Uint64
+
 	a1, a5, a15 EWMA
 	startTime   time.Time
 	stopped     atomic.Bool
@@ -184,7 +115,6 @@ type StandardMeter struct {
 
 func newStandardMeter() *StandardMeter {
 	return &StandardMeter{
-		snapshot:  &MeterSnapshot{},
 		a1:        NewEWMA1(),
 		a5:        NewEWMA5(),
 		a15:       NewEWMA15(),
@@ -194,97 +124,42 @@ func newStandardMeter() *StandardMeter {
 
 // Stop stops the meter, Mark() will be a no-op if you use it after being stopped.
 func (m *StandardMeter) Stop() {
-	stopped := m.stopped.Swap(true)
+	if stopped := m.stopped.Swap(true); !stopped {
-	if !stopped {
 		arbiter.Lock()
 		delete(arbiter.meters, m)
 		arbiter.Unlock()
 	}
 }
 
-// Count returns the number of events recorded.
-// It updates the meter to be as accurate as possible
-func (m *StandardMeter) Count() int64 {
-	m.lock.Lock()
-	defer m.lock.Unlock()
-	m.updateMeter()
-	return m.snapshot.count
-}
-
 // Mark records the occurrence of n events.
 func (m *StandardMeter) Mark(n int64) {
-	m.snapshot.temp.Add(n)
+	m.uncounted.Add(n)
-}
-
-// Rate1 returns the one-minute moving average rate of events per second.
-func (m *StandardMeter) Rate1() float64 {
-	m.lock.RLock()
-	defer m.lock.RUnlock()
-	return m.snapshot.rate1
-}
-
-// Rate5 returns the five-minute moving average rate of events per second.
-func (m *StandardMeter) Rate5() float64 {
-	m.lock.RLock()
-	defer m.lock.RUnlock()
-	return m.snapshot.rate5
-}
-
-// Rate15 returns the fifteen-minute moving average rate of events per second.
-func (m *StandardMeter) Rate15() float64 {
-	m.lock.RLock()
-	defer m.lock.RUnlock()
-	return m.snapshot.rate15
-}
-
-// RateMean returns the meter's mean rate of events per second.
-func (m *StandardMeter) RateMean() float64 {
-	m.lock.RLock()
-	defer m.lock.RUnlock()
-	return m.snapshot.rateMean
 }
 
 // Snapshot returns a read-only copy of the meter.
-func (m *StandardMeter) Snapshot() Meter {
+func (m *StandardMeter) Snapshot() MeterSnapshot {
-	m.lock.RLock()
+	return &meterSnapshot{
-	snapshot := MeterSnapshot{
+		count:    m.count.Load() + m.uncounted.Load(),
-		count:    m.snapshot.count,
+		rate1:    m.a1.Snapshot().Rate(),
-		rate1:    m.snapshot.rate1,
+		rate5:    m.a5.Snapshot().Rate(),
-		rate5:    m.snapshot.rate5,
+		rate15:   m.a15.Snapshot().Rate(),
-		rate15:   m.snapshot.rate15,
+		rateMean: math.Float64frombits(m.rateMean.Load()),
-		rateMean: m.snapshot.rateMean,
 	}
-	snapshot.temp.Store(m.snapshot.temp.Load())
-	m.lock.RUnlock()
-	return &snapshot
-}
-
-func (m *StandardMeter) updateSnapshot() {
-	// should run with write lock held on m.lock
-	snapshot := m.snapshot
-	snapshot.rate1 = m.a1.Rate()
-	snapshot.rate5 = m.a5.Rate()
-	snapshot.rate15 = m.a15.Rate()
-	snapshot.rateMean = float64(snapshot.count) / time.Since(m.startTime).Seconds()
-}
-
-func (m *StandardMeter) updateMeter() {
-	// should only run with write lock held on m.lock
-	n := m.snapshot.temp.Swap(0)
-	m.snapshot.count += n
-	m.a1.Update(n)
-	m.a5.Update(n)
-	m.a15.Update(n)
 }
 
 func (m *StandardMeter) tick() {
-	m.lock.Lock()
+	// Take the uncounted values, add to count
-	defer m.lock.Unlock()
+	n := m.uncounted.Swap(0)
-	m.updateMeter()
+	count := m.count.Add(n)
+	m.rateMean.Store(math.Float64bits(float64(count) / time.Since(m.startTime).Seconds()))
+	// Update the EWMA's internal state
+	m.a1.Update(n)
+	m.a5.Update(n)
+	m.a15.Update(n)
+	// And trigger them to calculate the rates
 	m.a1.Tick()
 	m.a5.Tick()
 	m.a15.Tick()
-	m.updateSnapshot()
 }
 
 // meterArbiter ticks meters every 5s from a single goroutine.

metrics/meter_test.go

@@ -12,11 +12,17 @@ func BenchmarkMeter(b *testing.B) {
 		m.Mark(1)
 	}
 }
-
+func TestMeter(t *testing.T) {
+	m := NewMeter()
+	m.Mark(47)
+	if v := m.Snapshot().Count(); v != 47 {
+		t.Fatalf("have %d want %d", v, 47)
+	}
+}
 func TestGetOrRegisterMeter(t *testing.T) {
 	r := NewRegistry()
 	NewRegisteredMeter("foo", r).Mark(47)
-	if m := GetOrRegisterMeter("foo", r); m.Count() != 47 {
+	if m := GetOrRegisterMeter("foo", r).Snapshot(); m.Count() != 47 {
 		t.Fatal(m.Count())
 	}
 }
@@ -31,10 +37,10 @@ func TestMeterDecay(t *testing.T) {
 	ma.meters[m] = struct{}{}
 	m.Mark(1)
 	ma.tickMeters()
-	rateMean := m.RateMean()
+	rateMean := m.Snapshot().RateMean()
 	time.Sleep(100 * time.Millisecond)
 	ma.tickMeters()
-	if m.RateMean() >= rateMean {
+	if m.Snapshot().RateMean() >= rateMean {
 		t.Error("m.RateMean() didn't decrease")
 	}
 }
@@ -42,7 +48,7 @@ func TestMeterDecay(t *testing.T) {
 func TestMeterNonzero(t *testing.T) {
 	m := NewMeter()
 	m.Mark(3)
-	if count := m.Count(); count != 3 {
+	if count := m.Snapshot().Count(); count != 3 {
 		t.Errorf("m.Count(): 3 != %v\n", count)
 	}
 }
@@ -59,16 +65,8 @@ func TestMeterStop(t *testing.T) {
 	}
 }
 
-func TestMeterSnapshot(t *testing.T) {
-	m := NewMeter()
-	m.Mark(1)
-	if snapshot := m.Snapshot(); m.RateMean() != snapshot.RateMean() {
-		t.Fatal(snapshot)
-	}
-}
-
 func TestMeterZero(t *testing.T) {
-	m := NewMeter()
+	m := NewMeter().Snapshot()
 	if count := m.Count(); count != 0 {
 		t.Errorf("m.Count(): 0 != %v\n", count)
 	}
@@ -79,13 +77,13 @@ func TestMeterRepeat(t *testing.T) {
 	for i := 0; i < 101; i++ {
 		m.Mark(int64(i))
 	}
-	if count := m.Count(); count != 5050 {
+	if count := m.Snapshot().Count(); count != 5050 {
 		t.Errorf("m.Count(): 5050 != %v\n", count)
 	}
 	for i := 0; i < 101; i++ {
 		m.Mark(int64(i))
 	}
-	if count := m.Count(); count != 10100 {
+	if count := m.Snapshot().Count(); count != 10100 {
 		t.Errorf("m.Count(): 10100 != %v\n", count)
 	}
 }

metrics/metrics.go

@@ -9,7 +9,9 @@ import (
 	"os"
 	"runtime/metrics"
 	"runtime/pprof"
+	"strconv"
 	"strings"
+	"syscall"
 	"time"
 
 	"github.com/ethereum/go-ethereum/log"
@@ -30,13 +32,35 @@ var EnabledExpensive = false
 // enablerFlags is the CLI flag names to use to enable metrics collections.
 var enablerFlags = []string{"metrics"}
 
+// enablerEnvVars is the env var names to use to enable metrics collections.
+var enablerEnvVars = []string{"GETH_METRICS"}
+
 // expensiveEnablerFlags is the CLI flag names to use to enable metrics collections.
 var expensiveEnablerFlags = []string{"metrics.expensive"}
 
+// expensiveEnablerEnvVars is the env var names to use to enable metrics collections.
+var expensiveEnablerEnvVars = []string{"GETH_METRICS_EXPENSIVE"}
+
 // Init enables or disables the metrics system. Since we need this to run before
 // any other code gets to create meters and timers, we'll actually do an ugly hack
 // and peek into the command line args for the metrics flag.
 func init() {
+	for _, enabler := range enablerEnvVars {
+		if val, found := syscall.Getenv(enabler); found && !Enabled {
+			if enable, _ := strconv.ParseBool(val); enable { // ignore error, flag parser will choke on it later
+				log.Info("Enabling metrics collection")
+				Enabled = true
+			}
+		}
+	}
+	for _, enabler := range expensiveEnablerEnvVars {
+		if val, found := syscall.Getenv(enabler); found && !EnabledExpensive {
+			if enable, _ := strconv.ParseBool(val); enable { // ignore error, flag parser will choke on it later
+				log.Info("Enabling expensive metrics collection")
+				EnabledExpensive = true
+			}
+		}
+	}
 	for _, arg := range os.Args {
 		flag := strings.TrimLeft(arg, "-")
 
@@ -85,6 +109,12 @@ var runtimeSamples = []metrics.Sample{
 	{Name: "/sched/latencies:seconds"}, // histogram
 }
 
+func ReadRuntimeStats() *runtimeStats {
+	r := new(runtimeStats)
+	readRuntimeStats(r)
+	return r
+}
+
 func readRuntimeStats(v *runtimeStats) {
 	metrics.Read(runtimeSamples)
 	for _, s := range runtimeSamples {

metrics/metrics_test.go

@@ -98,8 +98,8 @@ func Example() {
 	t.Time(func() { time.Sleep(10 * time.Millisecond) })
 	t.Update(1)
 
-	fmt.Println(c.Count())
+	fmt.Println(c.Snapshot().Count())
-	fmt.Println(t.Min())
+	fmt.Println(t.Snapshot().Min())
 	// Output: 17
 	// 1
 }

metrics/opentsdb.go

@@ -65,15 +65,15 @@ func (c *OpenTSDBConfig) writeRegistry(w io.Writer, now int64, shortHostname str
 	c.Registry.Each(func(name string, i interface{}) {
 		switch metric := i.(type) {
 		case Counter:
-			fmt.Fprintf(w, "put %s.%s.count %d %d host=%s\n", c.Prefix, name, now, metric.Count(), shortHostname)
+			fmt.Fprintf(w, "put %s.%s.count %d %d host=%s\n", c.Prefix, name, now, metric.Snapshot().Count(), shortHostname)
 		case CounterFloat64:
-			fmt.Fprintf(w, "put %s.%s.count %d %f host=%s\n", c.Prefix, name, now, metric.Count(), shortHostname)
+			fmt.Fprintf(w, "put %s.%s.count %d %f host=%s\n", c.Prefix, name, now, metric.Snapshot().Count(), shortHostname)
 		case Gauge:
-			fmt.Fprintf(w, "put %s.%s.value %d %d host=%s\n", c.Prefix, name, now, metric.Value(), shortHostname)
+			fmt.Fprintf(w, "put %s.%s.value %d %d host=%s\n", c.Prefix, name, now, metric.Snapshot().Value(), shortHostname)
 		case GaugeFloat64:
-			fmt.Fprintf(w, "put %s.%s.value %d %f host=%s\n", c.Prefix, name, now, metric.Value(), shortHostname)
+			fmt.Fprintf(w, "put %s.%s.value %d %f host=%s\n", c.Prefix, name, now, metric.Snapshot().Value(), shortHostname)
 		case GaugeInfo:
-			fmt.Fprintf(w, "put %s.%s.value %d %s host=%s\n", c.Prefix, name, now, metric.Value().String(), shortHostname)
+			fmt.Fprintf(w, "put %s.%s.value %d %s host=%s\n", c.Prefix, name, now, metric.Snapshot().Value().String(), shortHostname)
 		case Histogram:
 			h := metric.Snapshot()
 			ps := h.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999})

metrics/opentsdb_test.go

@@ -1,6 +1,7 @@
 package metrics
 
 import (
+	"fmt"
 	"net"
 	"os"
 	"strings"
@@ -47,5 +48,19 @@ func TestExampleOpenTSB(t *testing.T) {
 	}
 	if have, want := w.String(), string(wantB); have != want {
 		t.Errorf("\nhave:\n%v\nwant:\n%v\n", have, want)
+		t.Logf("have vs want:\n%v", findFirstDiffPos(have, want))
 	}
 }
+
+func findFirstDiffPos(a, b string) string {
+	yy := strings.Split(b, "\n")
+	for i, x := range strings.Split(a, "\n") {
+		if i >= len(yy) {
+			return fmt.Sprintf("have:%d: %s\nwant:%d: <EOF>", i, x, i)
+		}
+		if y := yy[i]; x != y {
+			return fmt.Sprintf("have:%d: %s\nwant:%d: %s", i, x, i, y)
+		}
+	}
+	return ""
+}

metrics/prometheus/collector.go

@@ -75,27 +75,27 @@ func (c *collector) Add(name string, i any) error {
 	return nil
 }
 
-func (c *collector) addCounter(name string, m metrics.Counter) {
+func (c *collector) addCounter(name string, m metrics.CounterSnapshot) {
 	c.writeGaugeCounter(name, m.Count())
 }
 
-func (c *collector) addCounterFloat64(name string, m metrics.CounterFloat64) {
+func (c *collector) addCounterFloat64(name string, m metrics.CounterFloat64Snapshot) {
 	c.writeGaugeCounter(name, m.Count())
 }
 
-func (c *collector) addGauge(name string, m metrics.Gauge) {
+func (c *collector) addGauge(name string, m metrics.GaugeSnapshot) {
 	c.writeGaugeCounter(name, m.Value())
 }
 
-func (c *collector) addGaugeFloat64(name string, m metrics.GaugeFloat64) {
+func (c *collector) addGaugeFloat64(name string, m metrics.GaugeFloat64Snapshot) {
 	c.writeGaugeCounter(name, m.Value())
 }
 
-func (c *collector) addGaugeInfo(name string, m metrics.GaugeInfo) {
+func (c *collector) addGaugeInfo(name string, m metrics.GaugeInfoSnapshot) {
 	c.writeGaugeInfo(name, m.Value())
 }
 
-func (c *collector) addHistogram(name string, m metrics.Histogram) {
+func (c *collector) addHistogram(name string, m metrics.HistogramSnapshot) {
 	pv := []float64{0.5, 0.75, 0.95, 0.99, 0.999, 0.9999}
 	ps := m.Percentiles(pv)
 	c.writeSummaryCounter(name, m.Count())
@@ -106,11 +106,11 @@ func (c *collector) addHistogram(name string, m metrics.Histogram) {
 	c.buff.WriteRune('\n')
 }
 
-func (c *collector) addMeter(name string, m metrics.Meter) {
+func (c *collector) addMeter(name string, m metrics.MeterSnapshot) {
 	c.writeGaugeCounter(name, m.Count())
 }
 
-func (c *collector) addTimer(name string, m metrics.Timer) {
+func (c *collector) addTimer(name string, m metrics.TimerSnapshot) {
 	pv := []float64{0.5, 0.75, 0.95, 0.99, 0.999, 0.9999}
 	ps := m.Percentiles(pv)
 	c.writeSummaryCounter(name, m.Count())
@@ -121,13 +121,12 @@ func (c *collector) addTimer(name string, m metrics.Timer) {
 	c.buff.WriteRune('\n')
 }
 
-func (c *collector) addResettingTimer(name string, m metrics.ResettingTimer) {
+func (c *collector) addResettingTimer(name string, m metrics.ResettingTimerSnapshot) {
-	if len(m.Values()) <= 0 {
+	if m.Count() <= 0 {
 		return
 	}
-	ps := m.Percentiles([]float64{50, 95, 99})
+	ps := m.Percentiles([]float64{0.50, 0.95, 0.99})
-	val := m.Values()
+	c.writeSummaryCounter(name, m.Count())
-	c.writeSummaryCounter(name, len(val))
 	c.buff.WriteString(fmt.Sprintf(typeSummaryTpl, mutateKey(name)))
 	c.writeSummaryPercentile(name, "0.50", ps[0])
 	c.writeSummaryPercentile(name, "0.95", ps[1])

metrics/prometheus/collector_test.go

@@ -55,10 +55,10 @@ func findFirstDiffPos(a, b string) string {
 	yy := strings.Split(b, "\n")
 	for i, x := range strings.Split(a, "\n") {
 		if i >= len(yy) {
-			return fmt.Sprintf("a:%d: %s\nb:%d: <EOF>", i, x, i)
+			return fmt.Sprintf("have:%d: %s\nwant:%d: <EOF>", i, x, i)
 		}
 		if y := yy[i]; x != y {
-			return fmt.Sprintf("a:%d: %s\nb:%d: %s", i, x, i, y)
+			return fmt.Sprintf("have:%d: %s\nwant:%d: %s", i, x, i, y)
 		}
 	}
 	return ""

metrics/prometheus/testdata/prometheus.want

@@ -1,3 +1,25 @@
+# TYPE system_cpu_schedlatency_count counter
+system_cpu_schedlatency_count 5645
+
+# TYPE system_cpu_schedlatency summary
+system_cpu_schedlatency {quantile="0.5"} 0
+system_cpu_schedlatency {quantile="0.75"} 7168
+system_cpu_schedlatency {quantile="0.95"} 1.6777216e+07
+system_cpu_schedlatency {quantile="0.99"} 2.9360128e+07
+system_cpu_schedlatency {quantile="0.999"} 3.3554432e+07
+system_cpu_schedlatency {quantile="0.9999"} 3.3554432e+07
+
+# TYPE system_memory_pauses_count counter
+system_memory_pauses_count 14
+
+# TYPE system_memory_pauses summary
+system_memory_pauses {quantile="0.5"} 32768
+system_memory_pauses {quantile="0.75"} 57344
+system_memory_pauses {quantile="0.95"} 196608
+system_memory_pauses {quantile="0.99"} 196608
+system_memory_pauses {quantile="0.999"} 196608
+system_memory_pauses {quantile="0.9999"} 196608
+
 # TYPE test_counter gauge
 test_counter 12345
 
@@ -31,9 +53,9 @@ test_meter 0
 test_resetting_timer_count 6
 
 # TYPE test_resetting_timer summary
-test_resetting_timer {quantile="0.50"} 12000000
+test_resetting_timer {quantile="0.50"} 1.25e+07
-test_resetting_timer {quantile="0.95"} 120000000
+test_resetting_timer {quantile="0.95"} 1.2e+08
-test_resetting_timer {quantile="0.99"} 120000000
+test_resetting_timer {quantile="0.99"} 1.2e+08
 
 # TYPE test_timer_count counter
 test_timer_count 6

metrics/registry.go

@@ -150,13 +150,13 @@ func (r *StandardRegistry) GetAll() map[string]map[string]interface{} {
 		values := make(map[string]interface{})
 		switch metric := i.(type) {
 		case Counter:
-			values["count"] = metric.Count()
+			values["count"] = metric.Snapshot().Count()
 		case CounterFloat64:
-			values["count"] = metric.Count()
+			values["count"] = metric.Snapshot().Count()
 		case Gauge:
-			values["value"] = metric.Value()
+			values["value"] = metric.Snapshot().Value()
 		case GaugeFloat64:
-			values["value"] = metric.Value()
+			values["value"] = metric.Snapshot().Value()
 		case Healthcheck:
 			values["error"] = nil
 			metric.Check()

metrics/registry_test.go

@@ -85,11 +85,11 @@ func TestRegistryDuplicate(t *testing.T) {
 func TestRegistryGet(t *testing.T) {
 	r := NewRegistry()
 	r.Register("foo", NewCounter())
-	if count := r.Get("foo").(Counter).Count(); count != 0 {
+	if count := r.Get("foo").(Counter).Snapshot().Count(); count != 0 {
 		t.Fatal(count)
 	}
 	r.Get("foo").(Counter).Inc(1)
-	if count := r.Get("foo").(Counter).Count(); count != 1 {
+	if count := r.Get("foo").(Counter).Snapshot().Count(); count != 1 {
 		t.Fatal(count)
 	}
 }

metrics/resetting_sample.go

@@ -17,7 +17,7 @@ type resettingSample struct {
 }
 
 // Snapshot returns a read-only copy of the sample with the original reset.
-func (rs *resettingSample) Snapshot() Sample {
+func (rs *resettingSample) Snapshot() SampleSnapshot {
 	s := rs.Sample.Snapshot()
 	rs.Sample.Clear()
 	return s

metrics/resetting_timer.go

@@ -1,22 +1,24 @@
 package metrics
 
 import (
-	"math"
 	"sync"
 	"time"
-
-	"golang.org/x/exp/slices"
 )
 
 // Initial slice capacity for the values stored in a ResettingTimer
 const InitialResettingTimerSliceCap = 10
 
+type ResettingTimerSnapshot interface {
+	Count() int
+	Mean() float64
+	Max() int64
+	Min() int64
+	Percentiles([]float64) []float64
+}
+
 // ResettingTimer is used for storing aggregated values for timers, which are reset on every flush interval.
 type ResettingTimer interface {
-	Values() []int64
+	Snapshot() ResettingTimerSnapshot
-	Snapshot() ResettingTimer
-	Percentiles([]float64) []int64
-	Mean() float64
 	Time(func())
 	Update(time.Duration)
 	UpdateSince(time.Time)
@@ -52,70 +54,40 @@ func NewResettingTimer() ResettingTimer {
 }
 
 // NilResettingTimer is a no-op ResettingTimer.
-type NilResettingTimer struct {
+type NilResettingTimer struct{}
-}
 
-// Values is a no-op.
 func (NilResettingTimer) Values() []int64                    { return nil }
-
+func (n NilResettingTimer) Snapshot() ResettingTimerSnapshot { return n }
-// Snapshot is a no-op.
-func (NilResettingTimer) Snapshot() ResettingTimer {
-	return &ResettingTimerSnapshot{
-		values: []int64{},
-	}
-}
-
-// Time is a no-op.
 func (NilResettingTimer) Time(f func())                      { f() }
-
-// Update is a no-op.
 func (NilResettingTimer) Update(time.Duration)               {}
-
+func (NilResettingTimer) Percentiles([]float64) []float64    { return nil }
-// Percentiles panics.
+func (NilResettingTimer) Mean() float64                      { return 0.0 }
-func (NilResettingTimer) Percentiles([]float64) []int64 {
+func (NilResettingTimer) Max() int64                         { return 0 }
-	panic("Percentiles called on a NilResettingTimer")
+func (NilResettingTimer) Min() int64                         { return 0 }
-}
-
-// Mean panics.
-func (NilResettingTimer) Mean() float64 {
-	panic("Mean called on a NilResettingTimer")
-}
-
-// UpdateSince is a no-op.
 func (NilResettingTimer) UpdateSince(time.Time)              {}
+func (NilResettingTimer) Count() int                         { return 0 }
 
 // StandardResettingTimer is the standard implementation of a ResettingTimer.
 // and Meter.
 type StandardResettingTimer struct {
 	values []int64
+	sum    int64 // sum is a running count of the total sum, used later to calculate mean
+
 	mutex sync.Mutex
 }
 
-// Values returns a slice with all measurements.
-func (t *StandardResettingTimer) Values() []int64 {
-	return t.values
-}
-
 // Snapshot resets the timer and returns a read-only copy of its contents.
-func (t *StandardResettingTimer) Snapshot() ResettingTimer {
+func (t *StandardResettingTimer) Snapshot() ResettingTimerSnapshot {
 	t.mutex.Lock()
 	defer t.mutex.Unlock()
-	currentValues := t.values
+	snapshot := &resettingTimerSnapshot{}
+	if len(t.values) > 0 {
+		snapshot.mean = float64(t.sum) / float64(len(t.values))
+		snapshot.values = t.values
 		t.values = make([]int64, 0, InitialResettingTimerSliceCap)
-
-	return &ResettingTimerSnapshot{
-		values: currentValues,
 	}
-}
+	t.sum = 0
-
+	return snapshot
-// Percentiles panics.
-func (t *StandardResettingTimer) Percentiles([]float64) []int64 {
-	panic("Percentiles called on a StandardResettingTimer")
-}
-
-// Mean panics.
-func (t *StandardResettingTimer) Mean() float64 {
-	panic("Mean called on a StandardResettingTimer")
 }
 
 // Record the duration of the execution of the given function.
@@ -130,106 +102,70 @@ func (t *StandardResettingTimer) Update(d time.Duration) {
 	t.mutex.Lock()
 	defer t.mutex.Unlock()
 	t.values = append(t.values, int64(d))
+	t.sum += int64(d)
 }
 
 // Record the duration of an event that started at a time and ends now.
 func (t *StandardResettingTimer) UpdateSince(ts time.Time) {
-	t.mutex.Lock()
+	t.Update(time.Since(ts))
-	defer t.mutex.Unlock()
-	t.values = append(t.values, int64(time.Since(ts)))
 }
 
-// ResettingTimerSnapshot is a point-in-time copy of another ResettingTimer.
+// resettingTimerSnapshot is a point-in-time copy of another ResettingTimer.
-type ResettingTimerSnapshot struct {
+type resettingTimerSnapshot struct {
 	values              []int64
 	mean                float64
-	thresholdBoundaries []int64
+	max                 int64
+	min                 int64
+	thresholdBoundaries []float64
 	calculated          bool
 }
 
-// Snapshot returns the snapshot.
+// Count return the length of the values from snapshot.
-func (t *ResettingTimerSnapshot) Snapshot() ResettingTimer { return t }
+func (t *resettingTimerSnapshot) Count() int {
-
+	return len(t.values)
-// Time panics.
-func (*ResettingTimerSnapshot) Time(func()) {
-	panic("Time called on a ResettingTimerSnapshot")
-}
-
-// Update panics.
-func (*ResettingTimerSnapshot) Update(time.Duration) {
-	panic("Update called on a ResettingTimerSnapshot")
-}
-
-// UpdateSince panics.
-func (*ResettingTimerSnapshot) UpdateSince(time.Time) {
-	panic("UpdateSince called on a ResettingTimerSnapshot")
-}
-
-// Values returns all values from snapshot.
-func (t *ResettingTimerSnapshot) Values() []int64 {
-	return t.values
 }
 
 // Percentiles returns the boundaries for the input percentiles.
-func (t *ResettingTimerSnapshot) Percentiles(percentiles []float64) []int64 {
+// note: this method is not thread safe
+func (t *resettingTimerSnapshot) Percentiles(percentiles []float64) []float64 {
 	t.calc(percentiles)
-
 	return t.thresholdBoundaries
 }
 
 // Mean returns the mean of the snapshotted values
-func (t *ResettingTimerSnapshot) Mean() float64 {
+// note: this method is not thread safe
+func (t *resettingTimerSnapshot) Mean() float64 {
 	if !t.calculated {
-		t.calc([]float64{})
+		t.calc(nil)
 	}
 
 	return t.mean
 }
 
-func (t *ResettingTimerSnapshot) calc(percentiles []float64) {
+// Max returns the max of the snapshotted values
-	slices.Sort(t.values)
+// note: this method is not thread safe
-
+func (t *resettingTimerSnapshot) Max() int64 {
-	count := len(t.values)
+	if !t.calculated {
-	if count > 0 {
+		t.calc(nil)
-		min := t.values[0]
-		max := t.values[count-1]
-
-		cumulativeValues := make([]int64, count)
-		cumulativeValues[0] = min
-		for i := 1; i < count; i++ {
-			cumulativeValues[i] = t.values[i] + cumulativeValues[i-1]
 	}
-
+	return t.max
-		t.thresholdBoundaries = make([]int64, len(percentiles))
+}
-
+
-		thresholdBoundary := max
+// Min returns the min of the snapshotted values
-
+// note: this method is not thread safe
-		for i, pct := range percentiles {
+func (t *resettingTimerSnapshot) Min() int64 {
-			if count > 1 {
+	if !t.calculated {
-				var abs float64
+		t.calc(nil)
-				if pct >= 0 {
+	}
-					abs = pct
+	return t.min
-				} else {
+}
-					abs = 100 + pct
+
-				}
+func (t *resettingTimerSnapshot) calc(percentiles []float64) {
-				// poor man's math.Round(x):
+	scores := CalculatePercentiles(t.values, percentiles)
-				// math.Floor(x + 0.5)
+	t.thresholdBoundaries = scores
-				indexOfPerc := int(math.Floor(((abs / 100.0) * float64(count)) + 0.5))
+	if len(t.values) == 0 {
-				if pct >= 0 && indexOfPerc > 0 {
+		return
-					indexOfPerc -= 1 // index offset=0
+	}
-				}
+	t.min = t.values[0]
-				thresholdBoundary = t.values[indexOfPerc]
+	t.max = t.values[len(t.values)-1]
-			}
-
-			t.thresholdBoundaries[i] = thresholdBoundary
-		}
-
-		sum := cumulativeValues[count-1]
-		t.mean = float64(sum) / float64(count)
-	} else {
-		t.thresholdBoundaries = make([]int64, len(percentiles))
-		t.mean = 0
-	}
-
-	t.calculated = true
 }

metrics/resetting_timer_test.go

@@ -10,9 +10,9 @@ func TestResettingTimer(t *testing.T) {
 		values   []int64
 		start    int
 		end      int
-		wantP50  int64
+		wantP50  float64
-		wantP95  int64
+		wantP95  float64
-		wantP99  int64
+		wantP99  float64
 		wantMean float64
 		wantMin  int64
 		wantMax  int64
@@ -21,14 +21,14 @@ func TestResettingTimer(t *testing.T) {
 			values:  []int64{},
 			start:   1,
 			end:     11,
-			wantP50: 5, wantP95: 10, wantP99: 10,
+			wantP50: 5.5, wantP95: 10, wantP99: 10,
 			wantMin: 1, wantMax: 10, wantMean: 5.5,
 		},
 		{
 			values:  []int64{},
 			start:   1,
 			end:     101,
-			wantP50: 50, wantP95: 95, wantP99: 99,
+			wantP50: 50.5, wantP95: 95.94999999999999, wantP99: 99.99,
 			wantMin: 1, wantMax: 100, wantMean: 50.5,
 		},
 		{
@@ -56,11 +56,11 @@ func TestResettingTimer(t *testing.T) {
 			values:  []int64{1, 10},
 			start:   0,
 			end:     0,
-			wantP50: 1, wantP95: 10, wantP99: 10,
+			wantP50: 5.5, wantP95: 10, wantP99: 10,
 			wantMin: 1, wantMax: 10, wantMean: 5.5,
 		},
 	}
-	for ind, tt := range tests {
+	for i, tt := range tests {
 		timer := NewResettingTimer()
 
 		for i := tt.start; i < tt.end; i++ {
@@ -70,37 +70,27 @@ func TestResettingTimer(t *testing.T) {
 		for _, v := range tt.values {
 			timer.Update(time.Duration(v))
 		}
-
 		snap := timer.Snapshot()
 
-		ps := snap.Percentiles([]float64{50, 95, 99})
+		ps := snap.Percentiles([]float64{0.50, 0.95, 0.99})
 
-		val := snap.Values()
+		if have, want := snap.Min(), tt.wantMin; have != want {
-
+			t.Fatalf("%d: min: have %d, want %d", i, have, want)
-		if len(val) > 0 {
-			if tt.wantMin != val[0] {
-				t.Fatalf("%d: min: got %d, want %d", ind, val[0], tt.wantMin)
 		}
-
+		if have, want := snap.Max(), tt.wantMax; have != want {
-			if tt.wantMax != val[len(val)-1] {
+			t.Fatalf("%d: max: have %d, want %d", i, have, want)
-				t.Fatalf("%d: max: got %d, want %d", ind, val[len(val)-1], tt.wantMax)
 		}
+		if have, want := snap.Mean(), tt.wantMean; have != want {
+			t.Fatalf("%d: mean: have %v, want %v", i, have, want)
 		}
-
+		if have, want := ps[0], tt.wantP50; have != want {
-		if tt.wantMean != snap.Mean() {
+			t.Errorf("%d: p50: have %v, want %v", i, have, want)
-			t.Fatalf("%d: mean: got %.2f, want %.2f", ind, snap.Mean(), tt.wantMean)
 		}
-
+		if have, want := ps[1], tt.wantP95; have != want {
-		if tt.wantP50 != ps[0] {
+			t.Errorf("%d: p95: have %v, want %v", i, have, want)
-			t.Fatalf("%d: p50: got %d, want %d", ind, ps[0], tt.wantP50)
 		}
-
+		if have, want := ps[2], tt.wantP99; have != want {
-		if tt.wantP95 != ps[1] {
+			t.Errorf("%d: p99: have %v, want %v", i, have, want)
-			t.Fatalf("%d: p95: got %d, want %d", ind, ps[1], tt.wantP95)
-		}
-
-		if tt.wantP99 != ps[2] {
-			t.Fatalf("%d: p99: got %d, want %d", ind, ps[2], tt.wantP99)
 		}
 	}
 }
@@ -110,11 +100,11 @@ func TestResettingTimerWithFivePercentiles(t *testing.T) {
 		values   []int64
 		start    int
 		end      int
-		wantP05  int64
+		wantP05  float64
-		wantP20  int64
+		wantP20  float64
-		wantP50  int64
+		wantP50  float64
-		wantP95  int64
+		wantP95  float64
-		wantP99  int64
+		wantP99  float64
 		wantMean float64
 		wantMin  int64
 		wantMax  int64
@@ -123,14 +113,14 @@ func TestResettingTimerWithFivePercentiles(t *testing.T) {
 			values:  []int64{},
 			start:   1,
 			end:     11,
-			wantP05: 1, wantP20: 2, wantP50: 5, wantP95: 10, wantP99: 10,
+			wantP05: 1, wantP20: 2.2, wantP50: 5.5, wantP95: 10, wantP99: 10,
 			wantMin: 1, wantMax: 10, wantMean: 5.5,
 		},
 		{
 			values:  []int64{},
 			start:   1,
 			end:     101,
-			wantP05: 5, wantP20: 20, wantP50: 50, wantP95: 95, wantP99: 99,
+			wantP05: 5.050000000000001, wantP20: 20.200000000000003, wantP50: 50.5, wantP95: 95.94999999999999, wantP99: 99.99,
 			wantMin: 1, wantMax: 100, wantMean: 50.5,
 		},
 		{
@@ -158,7 +148,7 @@ func TestResettingTimerWithFivePercentiles(t *testing.T) {
 			values:  []int64{1, 10},
 			start:   0,
 			end:     0,
-			wantP05: 1, wantP20: 1, wantP50: 1, wantP95: 10, wantP99: 10,
+			wantP05: 1, wantP20: 1, wantP50: 5.5, wantP95: 10, wantP99: 10,
 			wantMin: 1, wantMax: 10, wantMean: 5.5,
 		},
 	}
@@ -175,42 +165,33 @@ func TestResettingTimerWithFivePercentiles(t *testing.T) {
 
 		snap := timer.Snapshot()
 
-		ps := snap.Percentiles([]float64{5, 20, 50, 95, 99})
+		ps := snap.Percentiles([]float64{0.05, 0.20, 0.50, 0.95, 0.99})
 
-		val := snap.Values()
+		if tt.wantMin != snap.Min() {
-
+			t.Errorf("%d: min: got %d, want %d", ind, snap.Min(), tt.wantMin)
-		if len(val) > 0 {
-			if tt.wantMin != val[0] {
-				t.Fatalf("%d: min: got %d, want %d", ind, val[0], tt.wantMin)
 		}
 
-			if tt.wantMax != val[len(val)-1] {
+		if tt.wantMax != snap.Max() {
-				t.Fatalf("%d: max: got %d, want %d", ind, val[len(val)-1], tt.wantMax)
+			t.Errorf("%d: max: got %d, want %d", ind, snap.Max(), tt.wantMax)
-			}
 		}
 
 		if tt.wantMean != snap.Mean() {
-			t.Fatalf("%d: mean: got %.2f, want %.2f", ind, snap.Mean(), tt.wantMean)
+			t.Errorf("%d: mean: got %.2f, want %.2f", ind, snap.Mean(), tt.wantMean)
 		}
-
 		if tt.wantP05 != ps[0] {
-			t.Fatalf("%d: p05: got %d, want %d", ind, ps[0], tt.wantP05)
+			t.Errorf("%d: p05: got %v, want %v", ind, ps[0], tt.wantP05)
 		}
-
 		if tt.wantP20 != ps[1] {
-			t.Fatalf("%d: p20: got %d, want %d", ind, ps[1], tt.wantP20)
+			t.Errorf("%d: p20: got %v, want %v", ind, ps[1], tt.wantP20)
 		}
-
 		if tt.wantP50 != ps[2] {
-			t.Fatalf("%d: p50: got %d, want %d", ind, ps[2], tt.wantP50)
+			t.Errorf("%d: p50: got %v, want %v", ind, ps[2], tt.wantP50)
 		}
-
 		if tt.wantP95 != ps[3] {
-			t.Fatalf("%d: p95: got %d, want %d", ind, ps[3], tt.wantP95)
+			t.Errorf("%d: p95: got %v, want %v", ind, ps[3], tt.wantP95)
 		}
-
 		if tt.wantP99 != ps[4] {
-			t.Fatalf("%d: p99: got %d, want %d", ind, ps[4], tt.wantP99)
+			t.Errorf("%d: p99: got %v, want %v", ind, ps[4], tt.wantP99)
 		}
 	}
 }

metrics/runtimehistogram.go

@@ -17,13 +17,19 @@ func getOrRegisterRuntimeHistogram(name string, scale float64, r Registry) *runt
 
 // runtimeHistogram wraps a runtime/metrics histogram.
 type runtimeHistogram struct {
-	v           atomic.Value
+	v           atomic.Value // v is a pointer to a metrics.Float64Histogram
 	scaleFactor float64
 }
 
 func newRuntimeHistogram(scale float64) *runtimeHistogram {
 	h := &runtimeHistogram{scaleFactor: scale}
-	h.update(&metrics.Float64Histogram{})
+	h.update(new(metrics.Float64Histogram))
+	return h
+}
+
+func RuntimeHistogramFromData(scale float64, hist *metrics.Float64Histogram) *runtimeHistogram {
+	h := &runtimeHistogram{scaleFactor: scale}
+	h.update(hist)
 	return h
 }
 
@@ -35,130 +41,107 @@ func (h *runtimeHistogram) update(mh *metrics.Float64Histogram) {
 		return
 	}
 
-	s := runtimeHistogramSnapshot{
+	s := metrics.Float64Histogram{
 		Counts:  make([]uint64, len(mh.Counts)),
 		Buckets: make([]float64, len(mh.Buckets)),
 	}
 	copy(s.Counts, mh.Counts)
-	copy(s.Buckets, mh.Buckets)
+	for i, b := range mh.Buckets {
-	for i, b := range s.Buckets {
 		s.Buckets[i] = b * h.scaleFactor
 	}
 	h.v.Store(&s)
 }
 
-func (h *runtimeHistogram) load() *runtimeHistogramSnapshot {
-	return h.v.Load().(*runtimeHistogramSnapshot)
-}
-
 func (h *runtimeHistogram) Clear() {
 	panic("runtimeHistogram does not support Clear")
 }
 func (h *runtimeHistogram) Update(int64) {
 	panic("runtimeHistogram does not support Update")
 }
-func (h *runtimeHistogram) Sample() Sample {
+
-	return NilSample{}
+// Snapshot returns a non-changing copy of the histogram.
+func (h *runtimeHistogram) Snapshot() HistogramSnapshot {
+	hist := h.v.Load().(*metrics.Float64Histogram)
+	return newRuntimeHistogramSnapshot(hist)
 }
 
-// Snapshot returns a non-changing cop of the histogram.
+type runtimeHistogramSnapshot struct {
-func (h *runtimeHistogram) Snapshot() Histogram {
+	internal   *metrics.Float64Histogram
-	return h.load()
+	calculated bool
+	// The following fields are (lazily) calculated based on 'internal'
+	mean     float64
+	count    int64
+	min      int64 // min is the lowest sample value.
+	max      int64 // max is the highest sample value.
+	variance float64
 }
 
-// Count returns the sample count.
+func newRuntimeHistogramSnapshot(h *metrics.Float64Histogram) *runtimeHistogramSnapshot {
-func (h *runtimeHistogram) Count() int64 {
+	return &runtimeHistogramSnapshot{
-	return h.load().Count()
+		internal: h,
+	}
 }
 
-// Mean returns an approximation of the mean.
+// calc calculates the values for the snapshot. This method is not threadsafe.
-func (h *runtimeHistogram) Mean() float64 {
+func (h *runtimeHistogramSnapshot) calc() {
-	return h.load().Mean()
+	h.calculated = true
-}
+	var (
-
+		count int64   // number of samples
-// StdDev approximates the standard deviation of the histogram.
+		sum   float64 // approx sum of all sample values
-func (h *runtimeHistogram) StdDev() float64 {
+		min   int64
-	return h.load().StdDev()
+		max   float64
-}
+	)
-
+	if len(h.internal.Counts) == 0 {
-// Variance approximates the variance of the histogram.
+		return
-func (h *runtimeHistogram) Variance() float64 {
+	}
-	return h.load().Variance()
+	for i, c := range h.internal.Counts {
-}
+		if c == 0 {
-
+			continue
-// Percentile computes the p'th percentile value.
+		}
-func (h *runtimeHistogram) Percentile(p float64) float64 {
+		if count == 0 { // Set min only first loop iteration
-	return h.load().Percentile(p)
+			min = int64(math.Floor(h.internal.Buckets[i]))
-}
+		}
-
+		count += int64(c)
-// Percentiles computes all requested percentile values.
+		sum += h.midpoint(i) * float64(c)
-func (h *runtimeHistogram) Percentiles(ps []float64) []float64 {
+		// Set max on every iteration
-	return h.load().Percentiles(ps)
+		edge := h.internal.Buckets[i+1]
-}
+		if math.IsInf(edge, 1) {
-
+			edge = h.internal.Buckets[i]
-// Max returns the highest sample value.
+		}
-func (h *runtimeHistogram) Max() int64 {
+		if edge > max {
-	return h.load().Max()
+			max = edge
-}
+		}
-
+	}
-// Min returns the lowest sample value.
+	h.min = min
-func (h *runtimeHistogram) Min() int64 {
+	h.max = int64(max)
-	return h.load().Min()
+	h.mean = sum / float64(count)
-}
+	h.count = count
-
-// Sum returns the sum of all sample values.
-func (h *runtimeHistogram) Sum() int64 {
-	return h.load().Sum()
-}
-
-type runtimeHistogramSnapshot metrics.Float64Histogram
-
-func (h *runtimeHistogramSnapshot) Clear() {
-	panic("runtimeHistogram does not support Clear")
-}
-func (h *runtimeHistogramSnapshot) Update(int64) {
-	panic("runtimeHistogram does not support Update")
-}
-func (h *runtimeHistogramSnapshot) Sample() Sample {
-	return NilSample{}
-}
-
-func (h *runtimeHistogramSnapshot) Snapshot() Histogram {
-	return h
 }
 
 // Count returns the sample count.
 func (h *runtimeHistogramSnapshot) Count() int64 {
-	var count int64
+	if !h.calculated {
-	for _, c := range h.Counts {
+		h.calc()
-		count += int64(c)
 	}
-	return count
+	return h.count
+}
+
+// Size returns the size of the sample at the time the snapshot was taken.
+func (h *runtimeHistogramSnapshot) Size() int {
+	return len(h.internal.Counts)
 }
 
 // Mean returns an approximation of the mean.
 func (h *runtimeHistogramSnapshot) Mean() float64 {
-	if len(h.Counts) == 0 {
+	if !h.calculated {
-		return 0
+		h.calc()
 	}
-	mean, _ := h.mean()
+	return h.mean
-	return mean
-}
-
-// mean computes the mean and also the total sample count.
-func (h *runtimeHistogramSnapshot) mean() (mean, totalCount float64) {
-	var sum float64
-	for i, c := range h.Counts {
-		midpoint := h.midpoint(i)
-		sum += midpoint * float64(c)
-		totalCount += float64(c)
-	}
-	return sum / totalCount, totalCount
 }
 
 func (h *runtimeHistogramSnapshot) midpoint(bucket int) float64 {
-	high := h.Buckets[bucket+1]
+	high := h.internal.Buckets[bucket+1]
-	low := h.Buckets[bucket]
+	low := h.internal.Buckets[bucket]
 	if math.IsInf(high, 1) {
 		// The edge of the highest bucket can be +Inf, and it's supposed to mean that this
 		// bucket contains all remaining samples > low. We can't get the middle of an
@@ -180,23 +163,31 @@ func (h *runtimeHistogramSnapshot) StdDev() float64 {
 
 // Variance approximates the variance of the histogram.
 func (h *runtimeHistogramSnapshot) Variance() float64 {
-	if len(h.Counts) == 0 {
+	if len(h.internal.Counts) == 0 {
 		return 0
 	}
-
+	if !h.calculated {
-	mean, totalCount := h.mean()
+		h.calc()
-	if totalCount <= 1 {
+	}
+	if h.count <= 1 {
 		// There is no variance when there are zero or one items.
 		return 0
 	}
-
+	// Variance is not calculated in 'calc', because it requires a second iteration.
+	// Therefore we calculate it lazily in this method, triggered either by
+	// a direct call to Variance or via StdDev.
+	if h.variance != 0.0 {
+		return h.variance
+	}
 	var sum float64
-	for i, c := range h.Counts {
+
+	for i, c := range h.internal.Counts {
 		midpoint := h.midpoint(i)
-		d := midpoint - mean
+		d := midpoint - h.mean
 		sum += float64(c) * (d * d)
 	}
-	return sum / (totalCount - 1)
+	h.variance = sum / float64(h.count-1)
+	return h.variance
 }
 
 // Percentile computes the p'th percentile value.
@@ -231,11 +222,11 @@ func (h *runtimeHistogramSnapshot) Percentiles(ps []float64) []float64 {
 
 func (h *runtimeHistogramSnapshot) computePercentiles(thresh []float64) {
 	var totalCount float64
-	for i, count := range h.Counts {
+	for i, count := range h.internal.Counts {
 		totalCount += float64(count)
 
 		for len(thresh) > 0 && thresh[0] < totalCount {
-			thresh[0] = h.Buckets[i]
+			thresh[0] = h.internal.Buckets[i]
 			thresh = thresh[1:]
 		}
 		if len(thresh) == 0 {
@@ -250,34 +241,25 @@ func (h *runtimeHistogramSnapshot) computePercentiles(thresh []float64) {
 
 // Max returns the highest sample value.
 func (h *runtimeHistogramSnapshot) Max() int64 {
-	for i := len(h.Counts) - 1; i >= 0; i-- {
+	if !h.calculated {
-		count := h.Counts[i]
+		h.calc()
-		if count > 0 {
-			edge := h.Buckets[i+1]
-			if math.IsInf(edge, 1) {
-				edge = h.Buckets[i]
 	}
-			return int64(math.Ceil(edge))
+	return h.max
-		}
-	}
-	return 0
 }
 
 // Min returns the lowest sample value.
 func (h *runtimeHistogramSnapshot) Min() int64 {
-	for i, count := range h.Counts {
+	if !h.calculated {
-		if count > 0 {
+		h.calc()
-			return int64(math.Floor(h.Buckets[i]))
 	}
-	}
+	return h.min
-	return 0
 }
 
 // Sum returns the sum of all sample values.
 func (h *runtimeHistogramSnapshot) Sum() int64 {
 	var sum float64
-	for i := range h.Counts {
+	for i := range h.internal.Counts {
-		sum += h.Buckets[i] * float64(h.Counts[i])
+		sum += h.internal.Buckets[i] * float64(h.internal.Counts[i])
 	}
 	return int64(math.Ceil(sum))
 }

metrics/runtimehistogram_test.go

@@ -1,11 +1,14 @@
 package metrics
 
 import (
+	"bytes"
+	"encoding/gob"
 	"fmt"
 	"math"
 	"reflect"
 	"runtime/metrics"
 	"testing"
+	"time"
 )
 
 var _ Histogram = (*runtimeHistogram)(nil)
@@ -74,7 +77,7 @@ func TestRuntimeHistogramStats(t *testing.T) {
 
 	for i, test := range tests {
 		t.Run(fmt.Sprint(i), func(t *testing.T) {
-			s := runtimeHistogramSnapshot(test.h)
+			s := RuntimeHistogramFromData(1.0, &test.h).Snapshot()
 
 			if v := s.Count(); v != test.Count {
 				t.Errorf("Count() = %v, want %v", v, test.Count)
@@ -121,13 +124,39 @@ func approxEqual(x, y, ε float64) bool {
 // This test verifies that requesting Percentiles in unsorted order
 // returns them in the requested order.
 func TestRuntimeHistogramStatsPercentileOrder(t *testing.T) {
-	p := runtimeHistogramSnapshot{
+	s := RuntimeHistogramFromData(1.0, &metrics.Float64Histogram{
 		Counts:  []uint64{1, 1, 1, 1, 1, 1, 1, 1, 1, 1},
 		Buckets: []float64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10},
-	}
+	}).Snapshot()
-	result := p.Percentiles([]float64{1, 0.2, 0.5, 0.1, 0.2})
+	result := s.Percentiles([]float64{1, 0.2, 0.5, 0.1, 0.2})
 	expected := []float64{10, 2, 5, 1, 2}
 	if !reflect.DeepEqual(result, expected) {
 		t.Fatal("wrong result:", result)
 	}
 }
+
+func BenchmarkRuntimeHistogramSnapshotRead(b *testing.B) {
+	var sLatency = "7\xff\x81\x03\x01\x01\x10Float64Histogram\x01\xff\x82\x00\x01\x02\x01\x06Counts\x01\xff\x84\x00\x01\aBuckets\x01\xff\x86\x00\x00\x00\x16\xff\x83\x02\x01\x01\b[]uint64\x01\xff\x84\x00\x01\x06\x00\x00\x17\xff\x85\x02\x01\x01\t[]float64\x01\xff\x86\x00\x01\b\x00\x00\xfe\x06T\xff\x82\x01\xff\xa2\x00\xfe\r\xef\x00\x01\x02\x02\x04\x05\x04\b\x15\x17 B?6.L;$!2) \x1a? \x190aH7FY6#\x190\x1d\x14\x10\x1b\r\t\x04\x03\x01\x01\x00\x03\x02\x00\x03\x05\x05\x02\x02\x06\x04\v\x06\n\x15\x18\x13'&.\x12=H/L&\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\xff\xa3\xfe\xf0\xff\x00\xf8\x95\xd6&\xe8\v.q>\xf8\x95\xd6&\xe8\v.\x81>\xf8\xdfA:\xdc\x11ʼn>\xf8\x95\xd6&\xe8\v.\x91>\xf8:\x8c0\xe2\x8ey\x95>\xf8\xdfA:\xdc\x11ř>\xf8\x84\xf7C֔\x10\x9e>\xf8\x95\xd6&\xe8\v.\xa1>\xf8:\x8c0\xe2\x8ey\xa5>\xf8\xdfA:\xdc\x11ũ>\xf8\x84\xf7C֔\x10\xae>\xf8\x95\xd6&\xe8\v.\xb1>\xf8:\x8c0\xe2\x8ey\xb5>\xf8\xdfA:\xdc\x11Ź>\xf8\x84\xf7C֔\x10\xbe>\xf8\x95\xd6&\xe8\v.\xc1>\xf8:\x8c0\xe2\x8ey\xc5>\xf8\xdfA:\xdc\x11\xc5\xc9>\xf8\x84\xf7C֔\x10\xce>\xf8\x95\xd6&\xe8\v.\xd1>\xf8:\x8c0\xe2\x8ey\xd5>\xf8\xdfA:\xdc\x11\xc5\xd9>\xf8\x84\xf7C֔\x10\xde>\xf8\x95\xd6&\xe8\v.\xe1>\xf8:\x8c0\xe2\x8ey\xe5>\xf8\xdfA:\xdc\x11\xc5\xe9>\xf8\x84\xf7C֔\x10\xee>\xf8\x95\xd6&\xe8\v.\xf1>\xf8:\x8c0\xe2\x8ey\xf5>\xf8\xdfA:\xdc\x11\xc5\xf9>\xf8\x84\xf7C֔\x10\xfe>\xf8\x95\xd6&\xe8\v.\x01?\xf8:\x8c0\xe2\x8ey\x05?\xf8\xdfA:\xdc\x11\xc5\t?\xf8\x84\xf7C֔\x10\x0e?\xf8\x95\xd6&\xe8\v.\x11?\xf8:\x8c0\xe2\x8ey\x15?\xf8\xdfA:\xdc\x11\xc5\x19?\xf8\x84\xf7C֔\x10\x1e?\xf8\x95\xd6&\xe8\v.!?\xf8:\x8c0\xe2\x8ey%?\xf8\xdfA:\xdc\x11\xc5)?\xf8\x84\xf7C֔\x10.?\xf8\x95\xd6&\xe8\v.1?\xf8:\x8c0\xe2\x8ey5?\xf8\xdfA:\xdc\x11\xc59?\xf8\x84\xf7C֔\x10>?\xf8\x95\xd6&\xe8\v.A?\xf8:\x8c0\xe2\x8eyE?\xf8\xdfA:\xdc\x11\xc5I?\xf8\x84\xf7C֔\x10N?\xf8\x95\xd6&\xe8\v.Q?\xf8:\x8c0\xe2\x8eyU?\xf8\xdfA:\xdc\x11\xc5Y?\xf8\x84\xf7C֔\x10^?\xf8\x95\xd6&\xe8\v.a?\xf8:\x8c0\xe2\x8eye?\xf8\xdfA:\xdc\x11\xc5i?\xf8\x84\xf7C֔\x10n?\xf8\x95\xd6&\xe8\v.q?\xf8:\x8c0\xe2\x8eyu?\xf8\xdfA:\xdc\x11\xc5y?\xf8\x84\xf7C֔\x10~?\xf8\x95\xd6&\xe8\v.\x81?\xf8:\x8c0\xe2\x8ey\x85?\xf8\xdfA:\xdc\x11ʼn?\xf8\x84\xf7C֔\x10\x8e?\xf8\x95\xd6&\xe8\v.\x91?\xf8:\x8c0\xe2\x8ey\x95?\xf8\xdfA:\xdc\x11ř?\xf8\x84\xf7C֔\x10\x9e?\xf8\x95\xd6&\xe8\v.\xa1?\xf8:\x8c0\xe2\x8ey\xa5?\xf8\xdfA:\xdc\x11ũ?\xf8\x84\xf7C֔\x10\xae?\xf8\x95\xd6&\xe8\v.\xb1?\xf8:\x8c0\xe2\x8ey\xb5?\xf8\xdfA:\xdc\x11Ź?\xf8\x84\xf7C֔\x10\xbe?\xf8\x95\xd6&\xe8\v.\xc1?\xf8:\x8c0\xe2\x8ey\xc5?\xf8\xdfA:\xdc\x11\xc5\xc9?\xf8\x84\xf7C֔\x10\xce?\xf8\x95\xd6&\xe8\v.\xd1?\xf8:\x8c0\xe2\x8ey\xd5?\xf8\xdfA:\xdc\x11\xc5\xd9?\xf8\x84\xf7C֔\x10\xde?\xf8\x95\xd6&\xe8\v.\xe1?\xf8:\x8c0\xe2\x8ey\xe5?\xf8\xdfA:\xdc\x11\xc5\xe9?\xf8\x84\xf7C֔\x10\xee?\xf8\x95\xd6&\xe8\v.\xf1?\xf8:\x8c0\xe2\x8ey\xf5?\xf8\xdfA:\xdc\x11\xc5\xf9?\xf8\x84\xf7C֔\x10\xfe?\xf8\x95\xd6&\xe8\v.\x01@\xf8:\x8c0\xe2\x8ey\x05@\xf8\xdfA:\xdc\x11\xc5\t@\xf8\x84\xf7C֔\x10\x0e@\xf8\x95\xd6&\xe8\v.\x11@\xf8:\x8c0\xe2\x8ey\x15@\xf8\xdfA:\xdc\x11\xc5\x19@\xf8\x84\xf7C֔\x10\x1e@\xf8\x95\xd6&\xe8\v.!@\xf8:\x8c0\xe2\x8ey%@\xf8\xdfA:\xdc\x11\xc5)@\xf8\x84\xf7C֔\x10.@\xf8\x95\xd6&\xe8\v.1@\xf8:\x8c0\xe2\x8ey5@\xf8\xdfA:\xdc\x11\xc59@\xf8\x84\xf7C֔\x10>@\xf8\x95\xd6&\xe8\v.A@\xf8:\x8c0\xe2\x8eyE@\xf8\xdfA:\xdc\x11\xc5I@\xf8\x84\xf7C֔\x10N@\xf8\x95\xd6&\xe8\v.Q@\xf8:\x8c0\xe2\x8eyU@\xf8\xdfA:\xdc\x11\xc5Y@\xf8\x84\xf7C֔\x10^@\xf8\x95\xd6&\xe8\v.a@\xf8:\x8c0\xe2\x8eye@\xf8\xdfA:\xdc\x11\xc5i@\xf8\x84\xf7C֔\x10n@\xf8\x95\xd6&\xe8\v.q@\xf8:\x8c0\xe2\x8eyu@\xf8\xdfA:\xdc\x11\xc5y@\xf8\x84\xf7C֔\x10~@\xf8\x95\xd6&\xe8\v.\x81@\xf8:\x8c0\xe2\x8ey\x85@\xf8\xdfA:\xdc\x11ʼn@\xf8\x84\xf7C֔\x10\x8e@\xf8\x95\xd6&\xe8\v.\x91@\xf8:\x8c0\xe2\x8ey\x95@\xf8\xdfA:\xdc\x11ř@\xf8\x84\xf7C֔\x10\x9e@\xf8\x95\xd6&\xe8\v.\xa1@\xf8:\x8c0\xe2\x8ey\xa5@\xf8\xdfA:\xdc\x11ũ@\xf8\x84\xf7C֔\x10\xae@\xf8\x95\xd6&\xe8\v.\xb1@\xf8:\x8c0\xe2\x8ey\xb5@\xf8\xdfA:\xdc\x11Ź@\xf8\x84\xf7C֔\x10\xbe@\xf8\x95\xd6&\xe8\v.\xc1@\xf8:\x8c0\xe2\x8ey\xc5@\xf8\xdfA:\xdc\x11\xc5\xc9@\xf8\x84\xf7C֔\x10\xce@\xf8\x95\xd6&\xe8\v.\xd1@\xf8:\x8c0\xe2\x8ey\xd5@\xf8\xdfA:\xdc\x11\xc5\xd9@\xf8\x84\xf7C֔\x10\xde@\xf8\x95\xd6&\xe8\v.\xe1@\xf8:\x8c0\xe2\x8ey\xe5@\xf8\xdfA:\xdc\x11\xc5\xe9@\xf8\x84\xf7C֔\x10\xee@\xf8\x95\xd6&\xe8\v.\xf1@\xf8:\x8c0\xe2\x8ey\xf5@\xf8\xdfA:\xdc\x11\xc5\xf9@\xf8\x84\xf7C֔\x10\xfe@\xf8\x95\xd6&\xe8\v.\x01A\xfe\xf0\x7f\x00"
+
+	dserialize := func(data string) *metrics.Float64Histogram {
+		var res metrics.Float64Histogram
+		if err := gob.NewDecoder(bytes.NewReader([]byte(data))).Decode(&res); err != nil {
+			panic(err)
+		}
+		return &res
+	}
+	latency := RuntimeHistogramFromData(float64(time.Second), dserialize(sLatency))
+	b.ResetTimer()
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		snap := latency.Snapshot()
+		// These are the fields that influxdb accesses
+		_ = snap.Count()
+		_ = snap.Max()
+		_ = snap.Mean()
+		_ = snap.Min()
+		_ = snap.StdDev()
+		_ = snap.Variance()
+		_ = snap.Percentiles([]float64{0.25, 0.5, 0.75, 0.95, 0.99, 0.999, 0.9999})
+	}
+}

metrics/sample.go

@@ -11,10 +11,7 @@ import (
 
 const rescaleThreshold = time.Hour
 
-// Samples maintain a statistically-significant selection of values from
+type SampleSnapshot interface {
-// a stream.
-type Sample interface {
-	Clear()
 	Count() int64
 	Max() int64
 	Mean() float64
@@ -22,14 +19,19 @@ type Sample interface {
 	Percentile(float64) float64
 	Percentiles([]float64) []float64
 	Size() int
-	Snapshot() Sample
 	StdDev() float64
 	Sum() int64
-	Update(int64)
-	Values() []int64
 	Variance() float64
 }
 
+// Samples maintain a statistically-significant selection of values from
+// a stream.
+type Sample interface {
+	Snapshot() SampleSnapshot
+	Clear()
+	Update(int64)
+}
+
 // ExpDecaySample is an exponentially-decaying sample using a forward-decaying
 // priority reservoir.  See Cormode et al's "Forward Decay: A Practical Time
 // Decay Model for Streaming Systems".
@@ -77,72 +79,29 @@ func (s *ExpDecaySample) Clear() {
 	s.values.Clear()
 }
 
-// Count returns the number of samples recorded, which may exceed the
-// reservoir size.
-func (s *ExpDecaySample) Count() int64 {
-	s.mutex.Lock()
-	defer s.mutex.Unlock()
-	return s.count
-}
-
-// Max returns the maximum value in the sample, which may not be the maximum
-// value ever to be part of the sample.
-func (s *ExpDecaySample) Max() int64 {
-	return SampleMax(s.Values())
-}
-
-// Mean returns the mean of the values in the sample.
-func (s *ExpDecaySample) Mean() float64 {
-	return SampleMean(s.Values())
-}
-
-// Min returns the minimum value in the sample, which may not be the minimum
-// value ever to be part of the sample.
-func (s *ExpDecaySample) Min() int64 {
-	return SampleMin(s.Values())
-}
-
-// Percentile returns an arbitrary percentile of values in the sample.
-func (s *ExpDecaySample) Percentile(p float64) float64 {
-	return SamplePercentile(s.Values(), p)
-}
-
-// Percentiles returns a slice of arbitrary percentiles of values in the
-// sample.
-func (s *ExpDecaySample) Percentiles(ps []float64) []float64 {
-	return SamplePercentiles(s.Values(), ps)
-}
-
-// Size returns the size of the sample, which is at most the reservoir size.
-func (s *ExpDecaySample) Size() int {
-	s.mutex.Lock()
-	defer s.mutex.Unlock()
-	return s.values.Size()
-}
-
 // Snapshot returns a read-only copy of the sample.
-func (s *ExpDecaySample) Snapshot() Sample {
+func (s *ExpDecaySample) Snapshot() SampleSnapshot {
 	s.mutex.Lock()
 	defer s.mutex.Unlock()
-	vals := s.values.Values()
+	var (
-	values := make([]int64, len(vals))
+		samples       = s.values.Values()
-	for i, v := range vals {
+		values        = make([]int64, len(samples))
-		values[i] = v.v
+		max     int64 = math.MinInt64
+		min     int64 = math.MaxInt64
+		sum     int64
+	)
+	for i, item := range samples {
+		v := item.v
+		values[i] = v
+		sum += v
+		if v > max {
+			max = v
 		}
-	return &SampleSnapshot{
+		if v < min {
-		count:  s.count,
+			min = v
-		values: values,
 		}
-}
+	}
-
+	return newSampleSnapshotPrecalculated(s.count, values, min, max, sum)
-// StdDev returns the standard deviation of the values in the sample.
-func (s *ExpDecaySample) StdDev() float64 {
-	return SampleStdDev(s.Values())
-}
-
-// Sum returns the sum of the values in the sample.
-func (s *ExpDecaySample) Sum() int64 {
-	return SampleSum(s.Values())
 }
 
 // Update samples a new value.
@@ -150,23 +109,6 @@ func (s *ExpDecaySample) Update(v int64) {
 	s.update(time.Now(), v)
 }
 
-// Values returns a copy of the values in the sample.
-func (s *ExpDecaySample) Values() []int64 {
-	s.mutex.Lock()
-	defer s.mutex.Unlock()
-	vals := s.values.Values()
-	values := make([]int64, len(vals))
-	for i, v := range vals {
-		values[i] = v.v
-	}
-	return values
-}
-
-// Variance returns the variance of the values in the sample.
-func (s *ExpDecaySample) Variance() float64 {
-	return SampleVariance(s.Values())
-}
-
 // update samples a new value at a particular timestamp.  This is a method all
 // its own to facilitate testing.
 func (s *ExpDecaySample) update(t time.Time, v int64) {
@@ -202,100 +144,31 @@ func (s *ExpDecaySample) update(t time.Time, v int64) {
 // NilSample is a no-op Sample.
 type NilSample struct{}
 
-// Clear is a no-op.
 func (NilSample) Clear()                   {}
-
+func (NilSample) Snapshot() SampleSnapshot { return (*emptySnapshot)(nil) }
-// Count is a no-op.
-func (NilSample) Count() int64 { return 0 }
-
-// Max is a no-op.
-func (NilSample) Max() int64 { return 0 }
-
-// Mean is a no-op.
-func (NilSample) Mean() float64 { return 0.0 }
-
-// Min is a no-op.
-func (NilSample) Min() int64 { return 0 }
-
-// Percentile is a no-op.
-func (NilSample) Percentile(p float64) float64 { return 0.0 }
-
-// Percentiles is a no-op.
-func (NilSample) Percentiles(ps []float64) []float64 {
-	return make([]float64, len(ps))
-}
-
-// Size is a no-op.
-func (NilSample) Size() int { return 0 }
-
-// Sample is a no-op.
-func (NilSample) Snapshot() Sample { return NilSample{} }
-
-// StdDev is a no-op.
-func (NilSample) StdDev() float64 { return 0.0 }
-
-// Sum is a no-op.
-func (NilSample) Sum() int64 { return 0 }
-
-// Update is a no-op.
 func (NilSample) Update(v int64)           {}
 
-// Values is a no-op.
-func (NilSample) Values() []int64 { return []int64{} }
-
-// Variance is a no-op.
-func (NilSample) Variance() float64 { return 0.0 }
-
-// SampleMax returns the maximum value of the slice of int64.
-func SampleMax(values []int64) int64 {
-	if len(values) == 0 {
-		return 0
-	}
-	var max int64 = math.MinInt64
-	for _, v := range values {
-		if max < v {
-			max = v
-		}
-	}
-	return max
-}
-
-// SampleMean returns the mean value of the slice of int64.
-func SampleMean(values []int64) float64 {
-	if len(values) == 0 {
-		return 0.0
-	}
-	return float64(SampleSum(values)) / float64(len(values))
-}
-
-// SampleMin returns the minimum value of the slice of int64.
-func SampleMin(values []int64) int64 {
-	if len(values) == 0 {
-		return 0
-	}
-	var min int64 = math.MaxInt64
-	for _, v := range values {
-		if min > v {
-			min = v
-		}
-	}
-	return min
-}
-
 // SamplePercentiles returns an arbitrary percentile of the slice of int64.
 func SamplePercentile(values []int64, p float64) float64 {
-	return SamplePercentiles(values, []float64{p})[0]
+	return CalculatePercentiles(values, []float64{p})[0]
 }
 
-// SamplePercentiles returns a slice of arbitrary percentiles of the slice of
+// CalculatePercentiles returns a slice of arbitrary percentiles of the slice of
-// int64.
+// int64. This method returns interpolated results, so e.g if there are only two
-func SamplePercentiles(values []int64, ps []float64) []float64 {
+// values, [0, 10], a 50% percentile will land between them.
+//
+// Note: As a side-effect, this method will also sort the slice of values.
+// Note2: The input format for percentiles is NOT percent! To express 50%, use 0.5, not 50.
+func CalculatePercentiles(values []int64, ps []float64) []float64 {
 	scores := make([]float64, len(ps))
 	size := len(values)
-	if size > 0 {
+	if size == 0 {
+		return scores
+	}
 	slices.Sort(values)
 	for i, p := range ps {
 		pos := p * float64(size+1)
+
 		if pos < 1.0 {
 			scores[i] = float64(values[0])
 		} else if pos >= float64(size) {
@@ -306,103 +179,125 @@ func SamplePercentiles(values []int64, ps []float64) []float64 {
 			scores[i] = lower + (pos-math.Floor(pos))*(upper-lower)
 		}
 	}
-	}
 	return scores
 }
 
-// SampleSnapshot is a read-only copy of another Sample.
+// sampleSnapshot is a read-only copy of another Sample.
-type SampleSnapshot struct {
+type sampleSnapshot struct {
 	count  int64
 	values []int64
+
+	max      int64
+	min      int64
+	mean     float64
+	sum      int64
+	variance float64
 }
 
-func NewSampleSnapshot(count int64, values []int64) *SampleSnapshot {
+// newSampleSnapshotPrecalculated creates a read-only sampleSnapShot, using
-	return &SampleSnapshot{
+// precalculated sums to avoid iterating the values
+func newSampleSnapshotPrecalculated(count int64, values []int64, min, max, sum int64) *sampleSnapshot {
+	if len(values) == 0 {
+		return &sampleSnapshot{
 			count:  count,
 			values: values,
 		}
+	}
+	return &sampleSnapshot{
+		count:  count,
+		values: values,
+		max:    max,
+		min:    min,
+		mean:   float64(sum) / float64(len(values)),
+		sum:    sum,
+	}
 }
 
-// Clear panics.
+// newSampleSnapshot creates a read-only sampleSnapShot, and calculates some
-func (*SampleSnapshot) Clear() {
+// numbers.
-	panic("Clear called on a SampleSnapshot")
+func newSampleSnapshot(count int64, values []int64) *sampleSnapshot {
+	var (
+		max int64 = math.MinInt64
+		min int64 = math.MaxInt64
+		sum int64
+	)
+	for _, v := range values {
+		sum += v
+		if v > max {
+			max = v
+		}
+		if v < min {
+			min = v
+		}
+	}
+	return newSampleSnapshotPrecalculated(count, values, min, max, sum)
 }
 
 // Count returns the count of inputs at the time the snapshot was taken.
-func (s *SampleSnapshot) Count() int64 { return s.count }
+func (s *sampleSnapshot) Count() int64 { return s.count }
 
 // Max returns the maximal value at the time the snapshot was taken.
-func (s *SampleSnapshot) Max() int64 { return SampleMax(s.values) }
+func (s *sampleSnapshot) Max() int64 { return s.max }
 
 // Mean returns the mean value at the time the snapshot was taken.
-func (s *SampleSnapshot) Mean() float64 { return SampleMean(s.values) }
+func (s *sampleSnapshot) Mean() float64 { return s.mean }
 
 // Min returns the minimal value at the time the snapshot was taken.
-func (s *SampleSnapshot) Min() int64 { return SampleMin(s.values) }
+func (s *sampleSnapshot) Min() int64 { return s.min }
 
 // Percentile returns an arbitrary percentile of values at the time the
 // snapshot was taken.
-func (s *SampleSnapshot) Percentile(p float64) float64 {
+func (s *sampleSnapshot) Percentile(p float64) float64 {
 	return SamplePercentile(s.values, p)
 }
 
 // Percentiles returns a slice of arbitrary percentiles of values at the time
 // the snapshot was taken.
-func (s *SampleSnapshot) Percentiles(ps []float64) []float64 {
+func (s *sampleSnapshot) Percentiles(ps []float64) []float64 {
-	return SamplePercentiles(s.values, ps)
+	return CalculatePercentiles(s.values, ps)
 }
 
 // Size returns the size of the sample at the time the snapshot was taken.
-func (s *SampleSnapshot) Size() int { return len(s.values) }
+func (s *sampleSnapshot) Size() int { return len(s.values) }
 
 // Snapshot returns the snapshot.
-func (s *SampleSnapshot) Snapshot() Sample { return s }
+func (s *sampleSnapshot) Snapshot() SampleSnapshot { return s }
 
 // StdDev returns the standard deviation of values at the time the snapshot was
 // taken.
-func (s *SampleSnapshot) StdDev() float64 { return SampleStdDev(s.values) }
+func (s *sampleSnapshot) StdDev() float64 {
-
+	if s.variance == 0.0 {
-// Sum returns the sum of values at the time the snapshot was taken.
+		s.variance = SampleVariance(s.mean, s.values)
-func (s *SampleSnapshot) Sum() int64 { return SampleSum(s.values) }
+	}
-
+	return math.Sqrt(s.variance)
-// Update panics.
-func (*SampleSnapshot) Update(int64) {
-	panic("Update called on a SampleSnapshot")
 }
 
+// Sum returns the sum of values at the time the snapshot was taken.
+func (s *sampleSnapshot) Sum() int64 { return s.sum }
+
 // Values returns a copy of the values in the sample.
-func (s *SampleSnapshot) Values() []int64 {
+func (s *sampleSnapshot) Values() []int64 {
 	values := make([]int64, len(s.values))
 	copy(values, s.values)
 	return values
 }
 
 // Variance returns the variance of values at the time the snapshot was taken.
-func (s *SampleSnapshot) Variance() float64 { return SampleVariance(s.values) }
+func (s *sampleSnapshot) Variance() float64 {
-
+	if s.variance == 0.0 {
-// SampleStdDev returns the standard deviation of the slice of int64.
+		s.variance = SampleVariance(s.mean, s.values)
-func SampleStdDev(values []int64) float64 {
-	return math.Sqrt(SampleVariance(values))
-}
-
-// SampleSum returns the sum of the slice of int64.
-func SampleSum(values []int64) int64 {
-	var sum int64
-	for _, v := range values {
-		sum += v
 	}
-	return sum
+	return s.variance
 }
 
 // SampleVariance returns the variance of the slice of int64.
-func SampleVariance(values []int64) float64 {
+func SampleVariance(mean float64, values []int64) float64 {
 	if len(values) == 0 {
 		return 0.0
 	}
-	m := SampleMean(values)
 	var sum float64
 	for _, v := range values {
-		d := float64(v) - m
+		d := float64(v) - mean
 		sum += d * d
 	}
 	return sum / float64(len(values))
@@ -445,83 +340,14 @@ func (s *UniformSample) Clear() {
 	s.values = make([]int64, 0, s.reservoirSize)
 }
 
-// Count returns the number of samples recorded, which may exceed the
-// reservoir size.
-func (s *UniformSample) Count() int64 {
-	s.mutex.Lock()
-	defer s.mutex.Unlock()
-	return s.count
-}
-
-// Max returns the maximum value in the sample, which may not be the maximum
-// value ever to be part of the sample.
-func (s *UniformSample) Max() int64 {
-	s.mutex.Lock()
-	defer s.mutex.Unlock()
-	return SampleMax(s.values)
-}
-
-// Mean returns the mean of the values in the sample.
-func (s *UniformSample) Mean() float64 {
-	s.mutex.Lock()
-	defer s.mutex.Unlock()
-	return SampleMean(s.values)
-}
-
-// Min returns the minimum value in the sample, which may not be the minimum
-// value ever to be part of the sample.
-func (s *UniformSample) Min() int64 {
-	s.mutex.Lock()
-	defer s.mutex.Unlock()
-	return SampleMin(s.values)
-}
-
-// Percentile returns an arbitrary percentile of values in the sample.
-func (s *UniformSample) Percentile(p float64) float64 {
-	s.mutex.Lock()
-	defer s.mutex.Unlock()
-	return SamplePercentile(s.values, p)
-}
-
-// Percentiles returns a slice of arbitrary percentiles of values in the
-// sample.
-func (s *UniformSample) Percentiles(ps []float64) []float64 {
-	s.mutex.Lock()
-	defer s.mutex.Unlock()
-	return SamplePercentiles(s.values, ps)
-}
-
-// Size returns the size of the sample, which is at most the reservoir size.
-func (s *UniformSample) Size() int {
-	s.mutex.Lock()
-	defer s.mutex.Unlock()
-	return len(s.values)
-}
-
 // Snapshot returns a read-only copy of the sample.
-func (s *UniformSample) Snapshot() Sample {
+func (s *UniformSample) Snapshot() SampleSnapshot {
 	s.mutex.Lock()
-	defer s.mutex.Unlock()
 	values := make([]int64, len(s.values))
 	copy(values, s.values)
-	return &SampleSnapshot{
+	count := s.count
-		count:  s.count,
+	s.mutex.Unlock()
-		values: values,
+	return newSampleSnapshot(count, values)
-	}
-}
-
-// StdDev returns the standard deviation of the values in the sample.
-func (s *UniformSample) StdDev() float64 {
-	s.mutex.Lock()
-	defer s.mutex.Unlock()
-	return SampleStdDev(s.values)
-}
-
-// Sum returns the sum of the values in the sample.
-func (s *UniformSample) Sum() int64 {
-	s.mutex.Lock()
-	defer s.mutex.Unlock()
-	return SampleSum(s.values)
 }
 
 // Update samples a new value.
@@ -544,22 +370,6 @@ func (s *UniformSample) Update(v int64) {
 	}
 }
 
-// Values returns a copy of the values in the sample.
-func (s *UniformSample) Values() []int64 {
-	s.mutex.Lock()
-	defer s.mutex.Unlock()
-	values := make([]int64, len(s.values))
-	copy(values, s.values)
-	return values
-}
-
-// Variance returns the variance of the values in the sample.
-func (s *UniformSample) Variance() float64 {
-	s.mutex.Lock()
-	defer s.mutex.Unlock()
-	return SampleVariance(s.values)
-}
-
 // expDecaySample represents an individual sample in a heap.
 type expDecaySample struct {
 	k float64

metrics/sample_test.go

@@ -8,28 +8,36 @@ import (
 	"time"
 )
 
+const epsilonPercentile = .00000000001
+
 // Benchmark{Compute,Copy}{1000,1000000} demonstrate that, even for relatively
 // expensive computations like Variance, the cost of copying the Sample, as
 // approximated by a make and copy, is much greater than the cost of the
 // computation for small samples and only slightly less for large samples.
 func BenchmarkCompute1000(b *testing.B) {
 	s := make([]int64, 1000)
+	var sum int64
 	for i := 0; i < len(s); i++ {
 		s[i] = int64(i)
+		sum += int64(i)
 	}
+	mean := float64(sum) / float64(len(s))
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		SampleVariance(s)
+		SampleVariance(mean, s)
 	}
 }
 func BenchmarkCompute1000000(b *testing.B) {
 	s := make([]int64, 1000000)
+	var sum int64
 	for i := 0; i < len(s); i++ {
 		s[i] = int64(i)
+		sum += int64(i)
 	}
+	mean := float64(sum) / float64(len(s))
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		SampleVariance(s)
+		SampleVariance(mean, s)
 	}
 }
 func BenchmarkCopy1000(b *testing.B) {
@@ -79,66 +87,43 @@ func BenchmarkUniformSample1028(b *testing.B) {
 	benchmarkSample(b, NewUniformSample(1028))
 }
 
-func TestExpDecaySample10(t *testing.T) {
+func min(a, b int) int {
-	s := NewExpDecaySample(100, 0.99)
+	if a < b {
-	for i := 0; i < 10; i++ {
+		return a
-		s.Update(int64(i))
-	}
-	if size := s.Count(); size != 10 {
-		t.Errorf("s.Count(): 10 != %v\n", size)
-	}
-	if size := s.Size(); size != 10 {
-		t.Errorf("s.Size(): 10 != %v\n", size)
-	}
-	if l := len(s.Values()); l != 10 {
-		t.Errorf("len(s.Values()): 10 != %v\n", l)
-	}
-	for _, v := range s.Values() {
-		if v > 10 || v < 0 {
-			t.Errorf("out of range [0, 10): %v\n", v)
-		}
 	}
+	return b
 }
 
-func TestExpDecaySample100(t *testing.T) {
+func TestExpDecaySample(t *testing.T) {
-	s := NewExpDecaySample(1000, 0.01)
+	for _, tc := range []struct {
-	for i := 0; i < 100; i++ {
+		reservoirSize int
-		s.Update(int64(i))
+		alpha         float64
+		updates       int
+	}{
+		{100, 0.99, 10},
+		{1000, 0.01, 100},
+		{100, 0.99, 1000},
+	} {
+		sample := NewExpDecaySample(tc.reservoirSize, tc.alpha)
+		for i := 0; i < tc.updates; i++ {
+			sample.Update(int64(i))
 		}
-	if size := s.Count(); size != 100 {
+		snap := sample.Snapshot()
-		t.Errorf("s.Count(): 100 != %v\n", size)
+		if have, want := int(snap.Count()), tc.updates; have != want {
+			t.Errorf("have %d want %d", have, want)
 		}
-	if size := s.Size(); size != 100 {
+		if have, want := snap.Size(), min(tc.updates, tc.reservoirSize); have != want {
-		t.Errorf("s.Size(): 100 != %v\n", size)
+			t.Errorf("have %d want %d", have, want)
 		}
-	if l := len(s.Values()); l != 100 {
+		values := snap.(*sampleSnapshot).values
-		t.Errorf("len(s.Values()): 100 != %v\n", l)
+		if have, want := len(values), min(tc.updates, tc.reservoirSize); have != want {
+			t.Errorf("have %d want %d", have, want)
 		}
-	for _, v := range s.Values() {
+		for _, v := range values {
-		if v > 100 || v < 0 {
+			if v > int64(tc.updates) || v < 0 {
-			t.Errorf("out of range [0, 100): %v\n", v)
+				t.Errorf("out of range [0, %d): %v", tc.updates, v)
 			}
 		}
-}
-
-func TestExpDecaySample1000(t *testing.T) {
-	s := NewExpDecaySample(100, 0.99)
-	for i := 0; i < 1000; i++ {
-		s.Update(int64(i))
-	}
-	if size := s.Count(); size != 1000 {
-		t.Errorf("s.Count(): 1000 != %v\n", size)
-	}
-	if size := s.Size(); size != 100 {
-		t.Errorf("s.Size(): 100 != %v\n", size)
-	}
-	if l := len(s.Values()); l != 100 {
-		t.Errorf("len(s.Values()): 100 != %v\n", l)
-	}
-	for _, v := range s.Values() {
-		if v > 1000 || v < 0 {
-			t.Errorf("out of range [0, 1000): %v\n", v)
-		}
 	}
 }
 
@@ -147,15 +132,16 @@ func TestExpDecaySample1000(t *testing.T) {
 // The priority becomes +Inf quickly after starting if this is done,
 // effectively freezing the set of samples until a rescale step happens.
 func TestExpDecaySampleNanosecondRegression(t *testing.T) {
-	s := NewExpDecaySample(100, 0.99)
+	sw := NewExpDecaySample(100, 0.99)
 	for i := 0; i < 100; i++ {
-		s.Update(10)
+		sw.Update(10)
 	}
 	time.Sleep(1 * time.Millisecond)
 	for i := 0; i < 100; i++ {
-		s.Update(20)
+		sw.Update(20)
 	}
-	v := s.Values()
+	s := sw.Snapshot()
+	v := s.(*sampleSnapshot).values
 	avg := float64(0)
 	for i := 0; i < len(v); i++ {
 		avg += float64(v[i])
@@ -194,24 +180,27 @@ func TestExpDecaySampleStatistics(t *testing.T) {
 	for i := 1; i <= 10000; i++ {
 		s.(*ExpDecaySample).update(now.Add(time.Duration(i)), int64(i))
 	}
-	testExpDecaySampleStatistics(t, s)
+	testExpDecaySampleStatistics(t, s.Snapshot())
 }
 
 func TestUniformSample(t *testing.T) {
-	s := NewUniformSample(100)
+	sw := NewUniformSample(100)
 	for i := 0; i < 1000; i++ {
-		s.Update(int64(i))
+		sw.Update(int64(i))
 	}
+	s := sw.Snapshot()
 	if size := s.Count(); size != 1000 {
 		t.Errorf("s.Count(): 1000 != %v\n", size)
 	}
 	if size := s.Size(); size != 100 {
 		t.Errorf("s.Size(): 100 != %v\n", size)
 	}
-	if l := len(s.Values()); l != 100 {
+	values := s.(*sampleSnapshot).values
+
+	if l := len(values); l != 100 {
 		t.Errorf("len(s.Values()): 100 != %v\n", l)
 	}
-	for _, v := range s.Values() {
+	for _, v := range values {
 		if v > 1000 || v < 0 {
 			t.Errorf("out of range [0, 100): %v\n", v)
 		}
@@ -219,12 +208,13 @@ func TestUniformSample(t *testing.T) {
 }
 
 func TestUniformSampleIncludesTail(t *testing.T) {
-	s := NewUniformSample(100)
+	sw := NewUniformSample(100)
 	max := 100
 	for i := 0; i < max; i++ {
-		s.Update(int64(i))
+		sw.Update(int64(i))
 	}
-	v := s.Values()
+	s := sw.Snapshot()
+	v := s.(*sampleSnapshot).values
 	sum := 0
 	exp := (max - 1) * max / 2
 	for i := 0; i < len(v); i++ {
@@ -250,7 +240,7 @@ func TestUniformSampleStatistics(t *testing.T) {
 	for i := 1; i <= 10000; i++ {
 		s.Update(int64(i))
 	}
-	testUniformSampleStatistics(t, s)
+	testUniformSampleStatistics(t, s.Snapshot())
 }
 
 func benchmarkSample(b *testing.B, s Sample) {
@@ -267,7 +257,7 @@ func benchmarkSample(b *testing.B, s Sample) {
 	b.Logf("GC cost: %d ns/op", int(memStats.PauseTotalNs-pauseTotalNs)/b.N)
 }
 
-func testExpDecaySampleStatistics(t *testing.T, s Sample) {
+func testExpDecaySampleStatistics(t *testing.T, s SampleSnapshot) {
 	if count := s.Count(); count != 10000 {
 		t.Errorf("s.Count(): 10000 != %v\n", count)
 	}
@@ -295,7 +285,7 @@ func testExpDecaySampleStatistics(t *testing.T, s Sample) {
 	}
 }
 
-func testUniformSampleStatistics(t *testing.T, s Sample) {
+func testUniformSampleStatistics(t *testing.T, s SampleSnapshot) {
 	if count := s.Count(); count != 10000 {
 		t.Errorf("s.Count(): 10000 != %v\n", count)
 	}
@@ -349,8 +339,22 @@ func TestUniformSampleConcurrentUpdateCount(t *testing.T) {
 		}
 	}()
 	for i := 0; i < 1000; i++ {
-		s.Count()
+		s.Snapshot().Count()
 		time.Sleep(5 * time.Millisecond)
 	}
 	quit <- struct{}{}
 }
+
+func BenchmarkCalculatePercentiles(b *testing.B) {
+	pss := []float64{0.5, 0.75, 0.95, 0.99, 0.999, 0.9999}
+	var vals []int64
+	for i := 0; i < 1000; i++ {
+		vals = append(vals, int64(rand.Int31()))
+	}
+	v := make([]int64, len(vals))
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		copy(v, vals)
+		_ = CalculatePercentiles(v, pss)
+	}
+}

metrics/syslog.go

@@ -16,15 +16,15 @@ func Syslog(r Registry, d time.Duration, w *syslog.Writer) {
 		r.Each(func(name string, i interface{}) {
 			switch metric := i.(type) {
 			case Counter:
-				w.Info(fmt.Sprintf("counter %s: count: %d", name, metric.Count()))
+				w.Info(fmt.Sprintf("counter %s: count: %d", name, metric.Snapshot().Count()))
 			case CounterFloat64:
-				w.Info(fmt.Sprintf("counter %s: count: %f", name, metric.Count()))
+				w.Info(fmt.Sprintf("counter %s: count: %f", name, metric.Snapshot().Count()))
 			case Gauge:
-				w.Info(fmt.Sprintf("gauge %s: value: %d", name, metric.Value()))
+				w.Info(fmt.Sprintf("gauge %s: value: %d", name, metric.Snapshot().Value()))
 			case GaugeFloat64:
-				w.Info(fmt.Sprintf("gauge %s: value: %f", name, metric.Value()))
+				w.Info(fmt.Sprintf("gauge %s: value: %f", name, metric.Snapshot().Value()))
 			case GaugeInfo:
-				w.Info(fmt.Sprintf("gauge %s: value: %s", name, metric.Value()))
+				w.Info(fmt.Sprintf("gauge %s: value: %s", name, metric.Snapshot().Value()))
 			case Healthcheck:
 				metric.Check()
 				w.Info(fmt.Sprintf("healthcheck %s: error: %v", name, metric.Error()))

metrics/testdata/opentsb.want

@@ -1,4 +1,4 @@
-put pre.elite.count 978307200 0 host=hal9000
+put pre.elite.count 978307200 1337 host=hal9000
 put pre.elite.one-minute 978307200 0.00 host=hal9000
 put pre.elite.five-minute 978307200 0.00 host=hal9000
 put pre.elite.fifteen-minute 978307200 0.00 host=hal9000

metrics/timer.go

@@ -5,26 +5,18 @@ import (
 	"time"
 )
 
+type TimerSnapshot interface {
+	HistogramSnapshot
+	MeterSnapshot
+}
+
 // Timers capture the duration and rate of events.
 type Timer interface {
-	Count() int64
+	Snapshot() TimerSnapshot
-	Max() int64
-	Mean() float64
-	Min() int64
-	Percentile(float64) float64
-	Percentiles([]float64) []float64
-	Rate1() float64
-	Rate5() float64
-	Rate15() float64
-	RateMean() float64
-	Snapshot() Timer
-	StdDev() float64
 	Stop()
-	Sum() int64
 	Time(func())
-	Update(time.Duration)
 	UpdateSince(time.Time)
-	Variance() float64
+	Update(time.Duration)
 }
 
 // GetOrRegisterTimer returns an existing Timer or constructs and registers a
@@ -78,62 +70,12 @@ func NewTimer() Timer {
 // NilTimer is a no-op Timer.
 type NilTimer struct{}
 
-// Count is a no-op.
+func (NilTimer) Snapshot() TimerSnapshot { return (*emptySnapshot)(nil) }
-func (NilTimer) Count() int64 { return 0 }
-
-// Max is a no-op.
-func (NilTimer) Max() int64 { return 0 }
-
-// Mean is a no-op.
-func (NilTimer) Mean() float64 { return 0.0 }
-
-// Min is a no-op.
-func (NilTimer) Min() int64 { return 0 }
-
-// Percentile is a no-op.
-func (NilTimer) Percentile(p float64) float64 { return 0.0 }
-
-// Percentiles is a no-op.
-func (NilTimer) Percentiles(ps []float64) []float64 {
-	return make([]float64, len(ps))
-}
-
-// Rate1 is a no-op.
-func (NilTimer) Rate1() float64 { return 0.0 }
-
-// Rate5 is a no-op.
-func (NilTimer) Rate5() float64 { return 0.0 }
-
-// Rate15 is a no-op.
-func (NilTimer) Rate15() float64 { return 0.0 }
-
-// RateMean is a no-op.
-func (NilTimer) RateMean() float64 { return 0.0 }
-
-// Snapshot is a no-op.
-func (NilTimer) Snapshot() Timer { return NilTimer{} }
-
-// StdDev is a no-op.
-func (NilTimer) StdDev() float64 { return 0.0 }
-
-// Stop is a no-op.
 func (NilTimer) Stop()                   {}
-
-// Sum is a no-op.
-func (NilTimer) Sum() int64 { return 0 }
-
-// Time is a no-op.
 func (NilTimer) Time(f func())           { f() }
-
-// Update is a no-op.
 func (NilTimer) Update(time.Duration)    {}
-
-// UpdateSince is a no-op.
 func (NilTimer) UpdateSince(time.Time)   {}
 
-// Variance is a no-op.
-func (NilTimer) Variance() float64 { return 0.0 }
-
 // StandardTimer is the standard implementation of a Timer and uses a Histogram
 // and Meter.
 type StandardTimer struct {
@@ -142,82 +84,21 @@ type StandardTimer struct {
 	mutex     sync.Mutex
 }
 
-// Count returns the number of events recorded.
-func (t *StandardTimer) Count() int64 {
-	return t.histogram.Count()
-}
-
-// Max returns the maximum value in the sample.
-func (t *StandardTimer) Max() int64 {
-	return t.histogram.Max()
-}
-
-// Mean returns the mean of the values in the sample.
-func (t *StandardTimer) Mean() float64 {
-	return t.histogram.Mean()
-}
-
-// Min returns the minimum value in the sample.
-func (t *StandardTimer) Min() int64 {
-	return t.histogram.Min()
-}
-
-// Percentile returns an arbitrary percentile of the values in the sample.
-func (t *StandardTimer) Percentile(p float64) float64 {
-	return t.histogram.Percentile(p)
-}
-
-// Percentiles returns a slice of arbitrary percentiles of the values in the
-// sample.
-func (t *StandardTimer) Percentiles(ps []float64) []float64 {
-	return t.histogram.Percentiles(ps)
-}
-
-// Rate1 returns the one-minute moving average rate of events per second.
-func (t *StandardTimer) Rate1() float64 {
-	return t.meter.Rate1()
-}
-
-// Rate5 returns the five-minute moving average rate of events per second.
-func (t *StandardTimer) Rate5() float64 {
-	return t.meter.Rate5()
-}
-
-// Rate15 returns the fifteen-minute moving average rate of events per second.
-func (t *StandardTimer) Rate15() float64 {
-	return t.meter.Rate15()
-}
-
-// RateMean returns the meter's mean rate of events per second.
-func (t *StandardTimer) RateMean() float64 {
-	return t.meter.RateMean()
-}
-
 // Snapshot returns a read-only copy of the timer.
-func (t *StandardTimer) Snapshot() Timer {
+func (t *StandardTimer) Snapshot() TimerSnapshot {
 	t.mutex.Lock()
 	defer t.mutex.Unlock()
-	return &TimerSnapshot{
+	return &timerSnapshot{
-		histogram: t.histogram.Snapshot().(*HistogramSnapshot),
+		histogram: t.histogram.Snapshot(),
-		meter:     t.meter.Snapshot().(*MeterSnapshot),
+		meter:     t.meter.Snapshot(),
 	}
 }
 
-// StdDev returns the standard deviation of the values in the sample.
-func (t *StandardTimer) StdDev() float64 {
-	return t.histogram.StdDev()
-}
-
 // Stop stops the meter.
 func (t *StandardTimer) Stop() {
 	t.meter.Stop()
 }
 
-// Sum returns the sum in the sample.
-func (t *StandardTimer) Sum() int64 {
-	return t.histogram.Sum()
-}
-
 // Record the duration of the execution of the given function.
 func (t *StandardTimer) Time(f func()) {
 	ts := time.Now()
@@ -241,86 +122,63 @@ func (t *StandardTimer) UpdateSince(ts time.Time) {
 	t.meter.Mark(1)
 }
 
-// Variance returns the variance of the values in the sample.
+// timerSnapshot is a read-only copy of another Timer.
-func (t *StandardTimer) Variance() float64 {
+type timerSnapshot struct {
-	return t.histogram.Variance()
+	histogram HistogramSnapshot
-}
+	meter     MeterSnapshot
-
-// TimerSnapshot is a read-only copy of another Timer.
-type TimerSnapshot struct {
-	histogram *HistogramSnapshot
-	meter     *MeterSnapshot
 }
 
 // Count returns the number of events recorded at the time the snapshot was
 // taken.
-func (t *TimerSnapshot) Count() int64 { return t.histogram.Count() }
+func (t *timerSnapshot) Count() int64 { return t.histogram.Count() }
 
 // Max returns the maximum value at the time the snapshot was taken.
-func (t *TimerSnapshot) Max() int64 { return t.histogram.Max() }
+func (t *timerSnapshot) Max() int64 { return t.histogram.Max() }
+
+// Size returns the size of the sample at the time the snapshot was taken.
+func (t *timerSnapshot) Size() int { return t.histogram.Size() }
 
 // Mean returns the mean value at the time the snapshot was taken.
-func (t *TimerSnapshot) Mean() float64 { return t.histogram.Mean() }
+func (t *timerSnapshot) Mean() float64 { return t.histogram.Mean() }
 
 // Min returns the minimum value at the time the snapshot was taken.
-func (t *TimerSnapshot) Min() int64 { return t.histogram.Min() }
+func (t *timerSnapshot) Min() int64 { return t.histogram.Min() }
 
 // Percentile returns an arbitrary percentile of sampled values at the time the
 // snapshot was taken.
-func (t *TimerSnapshot) Percentile(p float64) float64 {
+func (t *timerSnapshot) Percentile(p float64) float64 {
 	return t.histogram.Percentile(p)
 }
 
 // Percentiles returns a slice of arbitrary percentiles of sampled values at
 // the time the snapshot was taken.
-func (t *TimerSnapshot) Percentiles(ps []float64) []float64 {
+func (t *timerSnapshot) Percentiles(ps []float64) []float64 {
 	return t.histogram.Percentiles(ps)
 }
 
 // Rate1 returns the one-minute moving average rate of events per second at the
 // time the snapshot was taken.
-func (t *TimerSnapshot) Rate1() float64 { return t.meter.Rate1() }
+func (t *timerSnapshot) Rate1() float64 { return t.meter.Rate1() }
 
 // Rate5 returns the five-minute moving average rate of events per second at
 // the time the snapshot was taken.
-func (t *TimerSnapshot) Rate5() float64 { return t.meter.Rate5() }
+func (t *timerSnapshot) Rate5() float64 { return t.meter.Rate5() }
 
 // Rate15 returns the fifteen-minute moving average rate of events per second
 // at the time the snapshot was taken.
-func (t *TimerSnapshot) Rate15() float64 { return t.meter.Rate15() }
+func (t *timerSnapshot) Rate15() float64 { return t.meter.Rate15() }
 
 // RateMean returns the meter's mean rate of events per second at the time the
 // snapshot was taken.
-func (t *TimerSnapshot) RateMean() float64 { return t.meter.RateMean() }
+func (t *timerSnapshot) RateMean() float64 { return t.meter.RateMean() }
-
-// Snapshot returns the snapshot.
-func (t *TimerSnapshot) Snapshot() Timer { return t }
 
 // StdDev returns the standard deviation of the values at the time the snapshot
 // was taken.
-func (t *TimerSnapshot) StdDev() float64 { return t.histogram.StdDev() }
+func (t *timerSnapshot) StdDev() float64 { return t.histogram.StdDev() }
-
-// Stop is a no-op.
-func (t *TimerSnapshot) Stop() {}
 
 // Sum returns the sum at the time the snapshot was taken.
-func (t *TimerSnapshot) Sum() int64 { return t.histogram.Sum() }
+func (t *timerSnapshot) Sum() int64 { return t.histogram.Sum() }
-
-// Time panics.
-func (*TimerSnapshot) Time(func()) {
-	panic("Time called on a TimerSnapshot")
-}
-
-// Update panics.
-func (*TimerSnapshot) Update(time.Duration) {
-	panic("Update called on a TimerSnapshot")
-}
-
-// UpdateSince panics.
-func (*TimerSnapshot) UpdateSince(time.Time) {
-	panic("UpdateSince called on a TimerSnapshot")
-}
 
 // Variance returns the variance of the values at the time the snapshot was
 // taken.
-func (t *TimerSnapshot) Variance() float64 { return t.histogram.Variance() }
+func (t *timerSnapshot) Variance() float64 { return t.histogram.Variance() }

metrics/timer_test.go

@@ -18,7 +18,7 @@ func BenchmarkTimer(b *testing.B) {
 func TestGetOrRegisterTimer(t *testing.T) {
 	r := NewRegistry()
 	NewRegisteredTimer("foo", r).Update(47)
-	if tm := GetOrRegisterTimer("foo", r); tm.Count() != 1 {
+	if tm := GetOrRegisterTimer("foo", r).Snapshot(); tm.Count() != 1 {
 		t.Fatal(tm)
 	}
 }
@@ -27,7 +27,7 @@ func TestTimerExtremes(t *testing.T) {
 	tm := NewTimer()
 	tm.Update(math.MaxInt64)
 	tm.Update(0)
-	if stdDev := tm.StdDev(); stdDev != 4.611686018427388e+18 {
+	if stdDev := tm.Snapshot().StdDev(); stdDev != 4.611686018427388e+18 {
 		t.Errorf("tm.StdDev(): 4.611686018427388e+18 != %v\n", stdDev)
 	}
 }
@@ -56,7 +56,7 @@ func TestTimerFunc(t *testing.T) {
 	})
 	var (
 		drift    = time.Millisecond * 2
-		measured = time.Duration(tm.Max())
+		measured = time.Duration(tm.Snapshot().Max())
 		ceil     = actualTime + drift
 		floor    = actualTime - drift
 	)
@@ -66,7 +66,7 @@ func TestTimerFunc(t *testing.T) {
 }
 
 func TestTimerZero(t *testing.T) {
-	tm := NewTimer()
+	tm := NewTimer().Snapshot()
 	if count := tm.Count(); count != 0 {
 		t.Errorf("tm.Count(): 0 != %v\n", count)
 	}
@@ -110,5 +110,5 @@ func ExampleGetOrRegisterTimer() {
 	m := "account.create.latency"
 	t := GetOrRegisterTimer(m, nil)
 	t.Update(47)
-	fmt.Println(t.Max()) // Output: 47
+	fmt.Println(t.Snapshot().Max()) // Output: 47
 }

metrics/writer.go

@@ -29,19 +29,19 @@ func WriteOnce(r Registry, w io.Writer) {
 		switch metric := namedMetric.m.(type) {
 		case Counter:
 			fmt.Fprintf(w, "counter %s\n", namedMetric.name)
-			fmt.Fprintf(w, "  count:       %9d\n", metric.Count())
+			fmt.Fprintf(w, "  count:       %9d\n", metric.Snapshot().Count())
 		case CounterFloat64:
 			fmt.Fprintf(w, "counter %s\n", namedMetric.name)
-			fmt.Fprintf(w, "  count:       %f\n", metric.Count())
+			fmt.Fprintf(w, "  count:       %f\n", metric.Snapshot().Count())
 		case Gauge:
 			fmt.Fprintf(w, "gauge %s\n", namedMetric.name)
-			fmt.Fprintf(w, "  value:       %9d\n", metric.Value())
+			fmt.Fprintf(w, "  value:       %9d\n", metric.Snapshot().Value())
 		case GaugeFloat64:
 			fmt.Fprintf(w, "gauge %s\n", namedMetric.name)
-			fmt.Fprintf(w, "  value:       %f\n", metric.Value())
+			fmt.Fprintf(w, "  value:       %f\n", metric.Snapshot().Value())
 		case GaugeInfo:
 			fmt.Fprintf(w, "gauge %s\n", namedMetric.name)
-			fmt.Fprintf(w, "  value:       %s\n", metric.Value().String())
+			fmt.Fprintf(w, "  value:       %s\n", metric.Snapshot().Value().String())
 		case Healthcheck:
 			metric.Check()
 			fmt.Fprintf(w, "healthcheck %s\n", namedMetric.name)

params/config.go

@@ -358,7 +358,7 @@ func (c *CliqueConfig) String() string {
 func (c *ChainConfig) Description() string {
 	var banner string
 
-	// Create some basinc network config output
+	// Create some basic network config output
 	network := NetworkNames[c.ChainID.String()]
 	if network == "" {
 		network = "unknown"

params/version.go

@@ -23,7 +23,7 @@ import (
 const (
 	VersionMajor = 1        // Major version component of the current release
 	VersionMinor = 13       // Minor version component of the current release
-	VersionPatch = 0        // Patch version component of the current release
+	VersionPatch = 1        // Patch version component of the current release
 	VersionMeta  = "stable" // Version metadata to append to the version string
 )
 

rlp/rlpgen/main.go

@@ -73,9 +73,8 @@ type Config struct {
 func (cfg *Config) process() (code []byte, err error) {
 	// Load packages.
 	pcfg := &packages.Config{
-		Mode:       packages.NeedName | packages.NeedTypes | packages.NeedImports | packages.NeedDeps,
+		Mode: packages.NeedName | packages.NeedTypes,
 		Dir:  cfg.Dir,
-		BuildFlags: []string{"-tags", "norlpgen"},
 	}
 	ps, err := packages.Load(pcfg, pathOfPackageRLP, ".")
 	if err != nil {
@@ -117,8 +116,6 @@ func (cfg *Config) process() (code []byte, err error) {
 	// This is done here to avoid processing these lines with gofmt.
 	var header bytes.Buffer
 	fmt.Fprint(&header, "// Code generated by rlpgen. DO NOT EDIT.\n\n")
-	fmt.Fprint(&header, "//go:build !norlpgen\n")
-	fmt.Fprint(&header, "// +build !norlpgen\n\n")
 	return append(header.Bytes(), code...), nil
 }