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eth/downloader: adaptive quality of service tuning

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This commit is contained in:
Péter Szilágyi 2016-06-01 18:07:25 +03:00
parent 780bdb3e80
commit 88f174a014
3 changed files with 235 additions and 48 deletions
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144
eth/downloader/downloader.go
View File

@ -54,14 +54,15 @@ var (
blockTargetRTT = 3 * time.Second / 2 // [eth/61] Target time for completing a block retrieval request
blockTTL = 3 * blockTargetRTT // [eth/61] Maximum time allowance before a block request is considered expired
headerTargetRTT = time.Second // [eth/62] Target time for completing a header retrieval request (only for measurements for now)
headerTTL = 3 * time.Second // [eth/62] Time it takes for a header request to time out
bodyTargetRTT = 3 * time.Second / 2 // [eth/62] Target time for completing a block body retrieval request
bodyTTL = 3 * bodyTargetRTT // [eth/62] Maximum time allowance before a block body request is considered expired
receiptTargetRTT = 3 * time.Second / 2 // [eth/63] Target time for completing a receipt retrieval request
receiptTTL = 3 * receiptTargetRTT // [eth/63] Maximum time allowance before a receipt request is considered expired
stateTargetRTT = 2 * time.Second / 2 // [eth/63] Target time for completing a state trie retrieval request
stateTTL = 3 * stateTargetRTT // [eth/63] Maximum time allowance before a node data request is considered expired
rttMinEstimate = 2 * time.Second // Minimum round-trip time to target for download requests
rttMaxEstimate = 20 * time.Second // Maximum rount-trip time to target for download requests
rttMinConfidence = 0.1 // Worse confidence factor in our estimated RTT value
ttlScaling = 3 // Constant scaling factor for RTT -> TTL conversion
ttlLimit = time.Minute // Maximum TTL allowance to prevent reaching crazy timeouts
qosTuningPeers = 5 // Number of peers to tune based on (best peers)
qosConfidenceCap = 10 // Number of peers above which not to modify RTT confidence
qosTuningImpact = 0.25 // Impact that a new tuning target has on the previous value
maxQueuedHashes = 32 * 1024 // [eth/61] Maximum number of hashes to queue for import (DOS protection)
maxQueuedHeaders = 32 * 1024 // [eth/62] Maximum number of headers to queue for import (DOS protection)
@ -113,7 +114,8 @@ type Downloader struct {
fsPivotLock *types.Header // Pivot header on critical section entry (cannot change between retries)
fsPivotFails int // Number of fast sync failures in the critical section
interrupt int32 // Atomic boolean to signal termination
rttEstimate uint64 // Round trip time to target for download requests
rttConfidence uint64 // Confidence in the estimated RTT (unit: millionths to allow atomic ops)
// Statistics
syncStatsChainOrigin uint64 // Origin block number where syncing started at
@ -159,6 +161,9 @@ type Downloader struct {
cancelCh chan struct{} // Channel to cancel mid-flight syncs
cancelLock sync.RWMutex // Lock to protect the cancel channel in delivers
quitCh chan struct{} // Quit channel to signal termination
quitLock sync.RWMutex // Lock to prevent double closes
// Testing hooks
syncInitHook func(uint64, uint64) // Method to call upon initiating a new sync run
bodyFetchHook func([]*types.Header) // Method to call upon starting a block body fetch
@ -172,11 +177,13 @@ func New(stateDb ethdb.Database, mux *event.TypeMux, hasHeader headerCheckFn, ha
headFastBlock headFastBlockRetrievalFn, commitHeadBlock headBlockCommitterFn, getTd tdRetrievalFn, insertHeaders headerChainInsertFn,
insertBlocks blockChainInsertFn, insertReceipts receiptChainInsertFn, rollback chainRollbackFn, dropPeer peerDropFn) *Downloader {
return &Downloader{
dl := &Downloader{
mode: FullSync,
mux: mux,
queue: newQueue(stateDb),
peers: newPeerSet(),
rttEstimate: uint64(rttMaxEstimate),
rttConfidence: uint64(1000000),
hasHeader: hasHeader,
hasBlockAndState: hasBlockAndState,
getHeader: getHeader,
@ -203,7 +210,10 @@ func New(stateDb ethdb.Database, mux *event.TypeMux, hasHeader headerCheckFn, ha
receiptWakeCh: make(chan bool, 1),
stateWakeCh: make(chan bool, 1),
headerProcCh: make(chan []*types.Header, 1),
quitCh: make(chan struct{}),
}
go dl.qosTuner()
return dl
}
// Progress retrieves the synchronisation boundaries, specifically the origin
@ -250,6 +260,8 @@ func (d *Downloader) RegisterPeer(id string, version int, head common.Hash,
glog.V(logger.Error).Infoln("Register failed:", err)
return err
}
d.qosReduceConfidence()
return nil
}
@ -515,7 +527,16 @@ func (d *Downloader) cancel() {
// Terminate interrupts the downloader, canceling all pending operations.
// The downloader cannot be reused after calling Terminate.
func (d *Downloader) Terminate() {
atomic.StoreInt32(&d.interrupt, 1)
// Close the termination channel (make sure double close is allowed)
d.quitLock.Lock()
select {
case <-d.quitCh:
default:
close(d.quitCh)
}
d.quitLock.Unlock()
// Cancel any pending download requests
d.cancel()
}
@ -932,7 +953,7 @@ func (d *Downloader) fetchBlocks61(from uint64) error {
// Reserve a chunk of hashes for a peer. A nil can mean either that
// no more hashes are available, or that the peer is known not to
// have them.
request := d.queue.ReserveBlocks(peer, peer.BlockCapacity())
request := d.queue.ReserveBlocks(peer, peer.BlockCapacity(blockTargetRTT))
if request == nil {
continue
}
@ -973,7 +994,7 @@ func (d *Downloader) fetchHeight(p *peer) (*types.Header, error) {
// Request the advertised remote head block and wait for the response
go p.getRelHeaders(p.head, 1, 0, false)
timeout := time.After(headerTTL)
timeout := time.After(d.requestTTL())
for {
select {
case <-d.cancelCh:
@ -1041,7 +1062,7 @@ func (d *Downloader) findAncestor(p *peer, height uint64) (uint64, error) {
// Wait for the remote response to the head fetch
number, hash := uint64(0), common.Hash{}
timeout := time.After(hashTTL)
timeout := time.After(d.requestTTL())
for finished := false; !finished; {
select {
@ -1118,7 +1139,7 @@ func (d *Downloader) findAncestor(p *peer, height uint64) (uint64, error) {
// Split our chain interval in two, and request the hash to cross check
check := (start + end) / 2
timeout := time.After(hashTTL)
timeout := time.After(d.requestTTL())
go p.getAbsHeaders(uint64(check), 1, 0, false)
// Wait until a reply arrives to this request
@ -1199,7 +1220,7 @@ func (d *Downloader) fetchHeaders(p *peer, from uint64) error {
getHeaders := func(from uint64) {
request = time.Now()
timeout.Reset(headerTTL)
timeout.Reset(d.requestTTL())
if skeleton {
glog.V(logger.Detail).Infof("%v: fetching %d skeleton headers from #%d", p, MaxHeaderFetch, from)
@ -1311,13 +1332,13 @@ func (d *Downloader) fillHeaderSkeleton(from uint64, skeleton []*types.Header) (
pack := packet.(*headerPack)
return d.queue.DeliverHeaders(pack.peerId, pack.headers, d.headerProcCh)
}
expire = func() map[string]int { return d.queue.ExpireHeaders(headerTTL) }
expire = func() map[string]int { return d.queue.ExpireHeaders(d.requestTTL()) }
throttle = func() bool { return false }
reserve = func(p *peer, count int) (*fetchRequest, bool, error) {
return d.queue.ReserveHeaders(p, count), false, nil
}
fetch = func(p *peer, req *fetchRequest) error { return p.FetchHeaders(req.From, MaxHeaderFetch) }
capacity = func(p *peer) int { return p.HeaderCapacity() }
capacity = func(p *peer) int { return p.HeaderCapacity(d.requestRTT()) }
setIdle = func(p *peer, accepted int) { p.SetHeadersIdle(accepted) }
)
err := d.fetchParts(errCancelHeaderFetch, d.headerCh, deliver, d.queue.headerContCh, expire,
@ -1341,9 +1362,9 @@ func (d *Downloader) fetchBodies(from uint64) error {
pack := packet.(*bodyPack)
return d.queue.DeliverBodies(pack.peerId, pack.transactions, pack.uncles)
}
expire = func() map[string]int { return d.queue.ExpireBodies(bodyTTL) }
expire = func() map[string]int { return d.queue.ExpireBodies(d.requestTTL()) }
fetch = func(p *peer, req *fetchRequest) error { return p.FetchBodies(req) }
capacity = func(p *peer) int { return p.BlockCapacity() }
capacity = func(p *peer) int { return p.BlockCapacity(d.requestRTT()) }
setIdle = func(p *peer, accepted int) { p.SetBodiesIdle(accepted) }
)
err := d.fetchParts(errCancelBodyFetch, d.bodyCh, deliver, d.bodyWakeCh, expire,
@ -1365,9 +1386,9 @@ func (d *Downloader) fetchReceipts(from uint64) error {
pack := packet.(*receiptPack)
return d.queue.DeliverReceipts(pack.peerId, pack.receipts)
}
expire = func() map[string]int { return d.queue.ExpireReceipts(receiptTTL) }
expire = func() map[string]int { return d.queue.ExpireReceipts(d.requestTTL()) }
fetch = func(p *peer, req *fetchRequest) error { return p.FetchReceipts(req) }
capacity = func(p *peer) int { return p.ReceiptCapacity() }
capacity = func(p *peer) int { return p.ReceiptCapacity(d.requestRTT()) }
setIdle = func(p *peer, accepted int) { p.SetReceiptsIdle(accepted) }
)
err := d.fetchParts(errCancelReceiptFetch, d.receiptCh, deliver, d.receiptWakeCh, expire,
@ -1417,13 +1438,13 @@ func (d *Downloader) fetchNodeData() error {
}
})
}
expire = func() map[string]int { return d.queue.ExpireNodeData(stateTTL) }
expire = func() map[string]int { return d.queue.ExpireNodeData(d.requestTTL()) }
throttle = func() bool { return false }
reserve = func(p *peer, count int) (*fetchRequest, bool, error) {
return d.queue.ReserveNodeData(p, count), false, nil
}
fetch = func(p *peer, req *fetchRequest) error { return p.FetchNodeData(req) }
capacity = func(p *peer) int { return p.NodeDataCapacity() }
capacity = func(p *peer) int { return p.NodeDataCapacity(d.requestRTT()) }
setIdle = func(p *peer, accepted int) { p.SetNodeDataIdle(accepted) }
)
err := d.fetchParts(errCancelStateFetch, d.stateCh, deliver, d.stateWakeCh, expire,
@ -1799,8 +1820,10 @@ func (d *Downloader) processContent() error {
}
for len(results) != 0 {
// Check for any termination requests
if atomic.LoadInt32(&d.interrupt) == 1 {
select {
case <-d.quitCh:
return errCancelContentProcessing
default:
}
// Retrieve the a batch of results to import
var (
@ -1901,3 +1924,74 @@ func (d *Downloader) deliver(id string, destCh chan dataPack, packet dataPack, i
return errNoSyncActive
}
}
// qosTuner is the quality of service tuning loop that occasionally gathers the
// peer latency statistics and updates the estimated request round trip time.
func (d *Downloader) qosTuner() {
for {
// Retrieve the current median RTT and integrate into the previoust target RTT
rtt := time.Duration(float64(1-qosTuningImpact)*float64(atomic.LoadUint64(&d.rttEstimate)) + qosTuningImpact*float64(d.peers.medianRTT()))
atomic.StoreUint64(&d.rttEstimate, uint64(rtt))
// A new RTT cycle passed, increase our confidence in the estimated RTT
conf := atomic.LoadUint64(&d.rttConfidence)
conf = conf + (1000000-conf)/2
atomic.StoreUint64(&d.rttConfidence, conf)
// Log the new QoS values and sleep until the next RTT
glog.V(logger.Debug).Infof("Quality of service: rtt %v, conf %.3f, ttl %v", rtt, float64(conf)/1000000.0, d.requestTTL())
select {
case <-d.quitCh:
return
case <-time.After(rtt):
}
}
}
// qosReduceConfidence is meant to be called when a new peer joins the downloader's
// peer set, needing to reduce the confidence we have in out QoS estimates.
func (d *Downloader) qosReduceConfidence() {
// If we have a single peer, confidence is always 1
peers := uint64(d.peers.Len())
if peers == 1 {
atomic.StoreUint64(&d.rttConfidence, 1000000)
return
}
// If we have a ton of peers, don't drop confidence)
if peers >= uint64(qosConfidenceCap) {
return
}
// Otherwise drop the confidence factor
conf := atomic.LoadUint64(&d.rttConfidence) * (peers - 1) / peers
if float64(conf)/1000000 < rttMinConfidence {
conf = uint64(rttMinConfidence * 1000000)
}
atomic.StoreUint64(&d.rttConfidence, conf)
rtt := time.Duration(atomic.LoadUint64(&d.rttEstimate))
glog.V(logger.Debug).Infof("Quality of service: rtt %v, conf %.3f, ttl %v", rtt, float64(conf)/1000000.0, d.requestTTL())
}
// requestRTT returns the current target round trip time for a download request
// to complete in.
//
// Note, the returned RTT is .9 of the actually estimated RTT. The reason is that
// the downloader tries to adapt queries to the RTT, so multiple RTT values can
// be adapted to, but smaller ones are preffered (stabler download stream).
func (d *Downloader) requestRTT() time.Duration {
return time.Duration(atomic.LoadUint64(&d.rttEstimate)) * 9 / 10
}
// requestTTL returns the current timeout allowance for a single download request
// to finish under.
func (d *Downloader) requestTTL() time.Duration {
var (
rtt = time.Duration(atomic.LoadUint64(&d.rttEstimate))
conf = float64(atomic.LoadUint64(&d.rttConfidence)) / 1000000.0
)
ttl := time.Duration(ttlScaling) * time.Duration(float64(rtt)/conf)
if ttl > ttlLimit {
ttl = ttlLimit
}
return ttl
}

58
eth/downloader/downloader_test.go
View File

@ -179,6 +179,12 @@ func newTester() *downloadTester {
return tester
}
// terminate aborts any operations on the embedded downloader and releases all
// held resources.
func (dl *downloadTester) terminate() {
dl.downloader.Terminate()
}
// sync starts synchronizing with a remote peer, blocking until it completes.
func (dl *downloadTester) sync(id string, td *big.Int, mode SyncMode) error {
dl.lock.RLock()
@ -740,6 +746,8 @@ func testCanonicalSynchronisation(t *testing.T, protocol int, mode SyncMode) {
hashes, headers, blocks, receipts := makeChain(targetBlocks, 0, genesis, nil, false)
tester := newTester()
defer tester.terminate()
tester.newPeer("peer", protocol, hashes, headers, blocks, receipts)
// Synchronise with the peer and make sure all relevant data was retrieved
@ -764,6 +772,8 @@ func testThrottling(t *testing.T, protocol int, mode SyncMode) {
hashes, headers, blocks, receipts := makeChain(targetBlocks, 0, genesis, nil, false)
tester := newTester()
defer tester.terminate()
tester.newPeer("peer", protocol, hashes, headers, blocks, receipts)
// Wrap the importer to allow stepping
@ -851,6 +861,8 @@ func testForkedSync(t *testing.T, protocol int, mode SyncMode) {
hashesA, hashesB, headersA, headersB, blocksA, blocksB, receiptsA, receiptsB := makeChainFork(common+fork, fork, genesis, nil, true)
tester := newTester()
defer tester.terminate()
tester.newPeer("fork A", protocol, hashesA, headersA, blocksA, receiptsA)
tester.newPeer("fork B", protocol, hashesB, headersB, blocksB, receiptsB)
@ -885,6 +897,8 @@ func testHeavyForkedSync(t *testing.T, protocol int, mode SyncMode) {
hashesA, hashesB, headersA, headersB, blocksA, blocksB, receiptsA, receiptsB := makeChainFork(common+fork, fork, genesis, nil, false)
tester := newTester()
defer tester.terminate()
tester.newPeer("light", protocol, hashesA, headersA, blocksA, receiptsA)
tester.newPeer("heavy", protocol, hashesB[fork/2:], headersB, blocksB, receiptsB)
@ -934,6 +948,8 @@ func testBoundedForkedSync(t *testing.T, protocol int, mode SyncMode) {
hashesA, hashesB, headersA, headersB, blocksA, blocksB, receiptsA, receiptsB := makeChainFork(common+fork, fork, genesis, nil, true)
tester := newTester()
defer tester.terminate()
tester.newPeer("original", protocol, hashesA, headersA, blocksA, receiptsA)
tester.newPeer("rewriter", protocol, hashesB, headersB, blocksB, receiptsB)
@ -968,6 +984,8 @@ func testBoundedHeavyForkedSync(t *testing.T, protocol int, mode SyncMode) {
hashesA, hashesB, headersA, headersB, blocksA, blocksB, receiptsA, receiptsB := makeChainFork(common+fork, fork, genesis, nil, false)
tester := newTester()
defer tester.terminate()
tester.newPeer("original", protocol, hashesA, headersA, blocksA, receiptsA)
tester.newPeer("heavy-rewriter", protocol, hashesB[MaxForkAncestry-17:], headersB, blocksB, receiptsB) // Root the fork below the ancestor limit
@ -987,7 +1005,9 @@ func testBoundedHeavyForkedSync(t *testing.T, protocol int, mode SyncMode) {
// bodies.
func TestInactiveDownloader62(t *testing.T) {
t.Parallel()
tester := newTester()
defer tester.terminate()
// Check that neither block headers nor bodies are accepted
if err := tester.downloader.DeliverHeaders("bad peer", []*types.Header{}); err != errNoSyncActive {
@ -1002,7 +1022,9 @@ func TestInactiveDownloader62(t *testing.T) {
// bodies and receipts.
func TestInactiveDownloader63(t *testing.T) {
t.Parallel()
tester := newTester()
defer tester.terminate()
// Check that neither block headers nor bodies are accepted
if err := tester.downloader.DeliverHeaders("bad peer", []*types.Header{}); err != errNoSyncActive {
@ -1039,6 +1061,8 @@ func testCancel(t *testing.T, protocol int, mode SyncMode) {
hashes, headers, blocks, receipts := makeChain(targetBlocks, 0, genesis, nil, false)
tester := newTester()
defer tester.terminate()
tester.newPeer("peer", protocol, hashes, headers, blocks, receipts)
// Make sure canceling works with a pristine downloader
@ -1074,6 +1098,8 @@ func testMultiSynchronisation(t *testing.T, protocol int, mode SyncMode) {
hashes, headers, blocks, receipts := makeChain(targetBlocks, 0, genesis, nil, false)
tester := newTester()
defer tester.terminate()
for i := 0; i < targetPeers; i++ {
id := fmt.Sprintf("peer #%d", i)
tester.newPeer(id, protocol, hashes[i*blockCacheLimit:], headers, blocks, receipts)
@ -1103,6 +1129,8 @@ func testMultiProtoSync(t *testing.T, protocol int, mode SyncMode) {
// Create peers of every type
tester := newTester()
defer tester.terminate()
tester.newPeer("peer 61", 61, hashes, nil, blocks, nil)
tester.newPeer("peer 62", 62, hashes, headers, blocks, nil)
tester.newPeer("peer 63", 63, hashes, headers, blocks, receipts)
@ -1140,6 +1168,8 @@ func testEmptyShortCircuit(t *testing.T, protocol int, mode SyncMode) {
hashes, headers, blocks, receipts := makeChain(targetBlocks, 0, genesis, nil, false)
tester := newTester()
defer tester.terminate()
tester.newPeer("peer", protocol, hashes, headers, blocks, receipts)
// Instrument the downloader to signal body requests
@ -1193,6 +1223,7 @@ func testMissingHeaderAttack(t *testing.T, protocol int, mode SyncMode) {
hashes, headers, blocks, receipts := makeChain(targetBlocks, 0, genesis, nil, false)
tester := newTester()
defer tester.terminate()
// Attempt a full sync with an attacker feeding gapped headers
tester.newPeer("attack", protocol, hashes, headers, blocks, receipts)
@ -1225,6 +1256,7 @@ func testShiftedHeaderAttack(t *testing.T, protocol int, mode SyncMode) {
hashes, headers, blocks, receipts := makeChain(targetBlocks, 0, genesis, nil, false)
tester := newTester()
defer tester.terminate()
// Attempt a full sync with an attacker feeding shifted headers
tester.newPeer("attack", protocol, hashes, headers, blocks, receipts)
@ -1256,6 +1288,7 @@ func testInvalidHeaderRollback(t *testing.T, protocol int, mode SyncMode) {
hashes, headers, blocks, receipts := makeChain(targetBlocks, 0, genesis, nil, false)
tester := newTester()
defer tester.terminate()
// Attempt to sync with an attacker that feeds junk during the fast sync phase.
// This should result in the last fsHeaderSafetyNet headers being rolled back.
@ -1347,9 +1380,11 @@ func testHighTDStarvationAttack(t *testing.T, protocol int, mode SyncMode) {
t.Parallel()
tester := newTester()
hashes, headers, blocks, receipts := makeChain(0, 0, genesis, nil, false)
defer tester.terminate()
hashes, headers, blocks, receipts := makeChain(0, 0, genesis, nil, false)
tester.newPeer("attack", protocol, []common.Hash{hashes[0]}, headers, blocks, receipts)
if err := tester.sync("attack", big.NewInt(1000000), mode); err != errStallingPeer {
t.Fatalf("synchronisation error mismatch: have %v, want %v", err, errStallingPeer)
}
@ -1392,6 +1427,8 @@ func testBlockHeaderAttackerDropping(t *testing.T, protocol int) {
}
// Run the tests and check disconnection status
tester := newTester()
defer tester.terminate()
for i, tt := range tests {
// Register a new peer and ensure it's presence
id := fmt.Sprintf("test %d", i)
@ -1433,6 +1470,8 @@ func testSyncProgress(t *testing.T, protocol int, mode SyncMode) {
progress := make(chan struct{})
tester := newTester()
defer tester.terminate()
tester.downloader.syncInitHook = func(origin, latest uint64) {
starting <- struct{}{}
<-progress
@ -1505,6 +1544,8 @@ func testForkedSyncProgress(t *testing.T, protocol int, mode SyncMode) {
progress := make(chan struct{})
tester := newTester()
defer tester.terminate()
tester.downloader.syncInitHook = func(origin, latest uint64) {
starting <- struct{}{}
<-progress
@ -1580,6 +1621,8 @@ func testFailedSyncProgress(t *testing.T, protocol int, mode SyncMode) {
progress := make(chan struct{})
tester := newTester()
defer tester.terminate()
tester.downloader.syncInitHook = func(origin, latest uint64) {
starting <- struct{}{}
<-progress
@ -1656,6 +1699,8 @@ func testFakedSyncProgress(t *testing.T, protocol int, mode SyncMode) {
progress := make(chan struct{})
tester := newTester()
defer tester.terminate()
tester.downloader.syncInitHook = func(origin, latest uint64) {
starting <- struct{}{}
<-progress
@ -1742,7 +1787,7 @@ func testDeliverHeadersHang(t *testing.T, protocol int, mode SyncMode) {
impl := tester.peerGetAbsHeadersFn("peer", 0)
go impl(from, count, skip, reverse)
// None of the extra deliveries should block.
timeout := time.After(5 * time.Second)
timeout := time.After(15 * time.Second)
for i := 0; i < cap(deliveriesDone); i++ {
select {
case <-deliveriesDone:
@ -1755,6 +1800,7 @@ func testDeliverHeadersHang(t *testing.T, protocol int, mode SyncMode) {
if err := tester.sync("peer", nil, mode); err != nil {
t.Errorf("sync failed: %v", err)
}
tester.terminate()
}
}
@ -1772,8 +1818,9 @@ func testFastCriticalRestarts(t *testing.T, protocol int) {
// Create a tester peer with the critical section state roots missing (force failures)
tester := newTester()
tester.newPeer("peer", protocol, hashes, headers, blocks, receipts)
defer tester.terminate()
tester.newPeer("peer", protocol, hashes, headers, blocks, receipts)
for i := 0; i < fsPivotInterval; i++ {
tester.peerMissingStates["peer"][headers[hashes[fsMinFullBlocks+i]].Root] = true
}
@ -1783,11 +1830,14 @@ func testFastCriticalRestarts(t *testing.T, protocol int) {
if err := tester.sync("peer", nil, FastSync); err == nil {
t.Fatalf("failing fast sync succeeded: %v", err)
}
time.Sleep(500 * time.Millisecond) // Make sure no in-flight requests remain
// If it's the first failure, pivot should be locked => reenable all others to detect pivot changes
if i == 0 {
tester.lock.Lock()
tester.peerMissingStates["peer"] = map[common.Hash]bool{tester.downloader.fsPivotLock.Root: true}
tester.lock.Unlock()
}
time.Sleep(100 * time.Millisecond) // Make sure no in-flight requests remain
}
// Retry limit exhausted, downloader will switch to full sync, should succeed
if err := tester.sync("peer", nil, FastSync); err != nil {

81
eth/downloader/peer.go
View File

@ -23,6 +23,8 @@ import (
"errors"
"fmt"
"math"
"sort"
"strings"
"sync"
"sync/atomic"
"time"
@ -31,8 +33,8 @@ import (
)
const (
maxLackingHashes = 4096 // Maximum number of entries allowed on the list or lacking items
throughputImpact = 0.1 // The impact a single measurement has on a peer's final throughput value.
maxLackingHashes = 4096 // Maximum number of entries allowed on the list or lacking items
measurementImpact = 0.1 // The impact a single measurement has on a peer's final throughput value.
)
// Hash and block fetchers belonging to eth/61 and below
@ -68,6 +70,8 @@ type peer struct {
receiptThroughput float64 // Number of receipts measured to be retrievable per second
stateThroughput float64 // Number of node data pieces measured to be retrievable per second
rtt time.Duration // Request round trip time to track responsiveness (QoS)
headerStarted time.Time // Time instance when the last header fetch was started
blockStarted time.Time // Time instance when the last block (body) fetch was started
receiptStarted time.Time // Time instance when the last receipt fetch was started
@ -290,44 +294,47 @@ func (p *peer) setIdle(started time.Time, delivered int, throughput *float64, id
return
}
// Otherwise update the throughput with a new measurement
measured := float64(delivered) / (float64(time.Since(started)+1) / float64(time.Second)) // +1 (ns) to ensure non-zero divisor
*throughput = (1-throughputImpact)*(*throughput) + throughputImpact*measured
elapsed := time.Since(started) + 1 // +1 (ns) to ensure non-zero divisor
measured := float64(delivered) / (float64(elapsed) / float64(time.Second))
*throughput = (1-measurementImpact)*(*throughput) + measurementImpact*measured
p.rtt = time.Duration((1-measurementImpact)*float64(p.rtt) + measurementImpact*float64(elapsed))
}
// HeaderCapacity retrieves the peers header download allowance based on its
// previously discovered throughput.
func (p *peer) HeaderCapacity() int {
func (p *peer) HeaderCapacity(targetRTT time.Duration) int {
p.lock.RLock()
defer p.lock.RUnlock()
return int(math.Max(1, math.Min(p.headerThroughput*float64(headerTargetRTT)/float64(time.Second), float64(MaxHeaderFetch))))
return int(math.Min(1+math.Max(1, p.headerThroughput*float64(targetRTT)/float64(time.Second)), float64(MaxHeaderFetch)))
}
// BlockCapacity retrieves the peers block download allowance based on its
// previously discovered throughput.
func (p *peer) BlockCapacity() int {
func (p *peer) BlockCapacity(targetRTT time.Duration) int {
p.lock.RLock()
defer p.lock.RUnlock()
return int(math.Max(1, math.Min(p.blockThroughput*float64(blockTargetRTT)/float64(time.Second), float64(MaxBlockFetch))))
return int(math.Min(1+math.Max(1, p.blockThroughput*float64(targetRTT)/float64(time.Second)), float64(MaxBlockFetch)))
}
// ReceiptCapacity retrieves the peers receipt download allowance based on its
// previously discovered throughput.
func (p *peer) ReceiptCapacity() int {
func (p *peer) ReceiptCapacity(targetRTT time.Duration) int {
p.lock.RLock()
defer p.lock.RUnlock()
return int(math.Max(1, math.Min(p.receiptThroughput*float64(receiptTargetRTT)/float64(time.Second), float64(MaxReceiptFetch))))
return int(math.Min(1+math.Max(1, p.receiptThroughput*float64(targetRTT)/float64(time.Second)), float64(MaxReceiptFetch)))
}
// NodeDataCapacity retrieves the peers state download allowance based on its
// previously discovered throughput.
func (p *peer) NodeDataCapacity() int {
func (p *peer) NodeDataCapacity(targetRTT time.Duration) int {
p.lock.RLock()
defer p.lock.RUnlock()
return int(math.Max(1, math.Min(p.stateThroughput*float64(stateTargetRTT)/float64(time.Second), float64(MaxStateFetch))))
return int(math.Min(1+math.Max(1, p.stateThroughput*float64(targetRTT)/float64(time.Second)), float64(MaxStateFetch)))
}
// MarkLacking appends a new entity to the set of items (blocks, receipts, states)
@ -361,13 +368,14 @@ func (p *peer) String() string {
p.lock.RLock()
defer p.lock.RUnlock()
return fmt.Sprintf("Peer %s [%s]", p.id,
fmt.Sprintf("headers %3.2f/s, ", p.headerThroughput)+
fmt.Sprintf("blocks %3.2f/s, ", p.blockThroughput)+
fmt.Sprintf("receipts %3.2f/s, ", p.receiptThroughput)+
fmt.Sprintf("states %3.2f/s, ", p.stateThroughput)+
fmt.Sprintf("lacking %4d", len(p.lacking)),
)
return fmt.Sprintf("Peer %s [%s]", p.id, strings.Join([]string{
fmt.Sprintf("hs %3.2f/s", p.headerThroughput),
fmt.Sprintf("bs %3.2f/s", p.blockThroughput),
fmt.Sprintf("rs %3.2f/s", p.receiptThroughput),
fmt.Sprintf("ss %3.2f/s", p.stateThroughput),
fmt.Sprintf("miss %4d", len(p.lacking)),
fmt.Sprintf("rtt %v", p.rtt),
}, ", "))
}
// peerSet represents the collection of active peer participating in the chain
@ -402,6 +410,10 @@ func (ps *peerSet) Reset() {
// average of all existing peers, to give it a realistic chance of being used
// for data retrievals.
func (ps *peerSet) Register(p *peer) error {
// Retrieve the current median RTT as a sane default
p.rtt = ps.medianRTT()
// Register the new peer with some meaningful defaults
ps.lock.Lock()
defer ps.lock.Unlock()
@ -564,3 +576,34 @@ func (ps *peerSet) idlePeers(minProtocol, maxProtocol int, idleCheck func(*peer)
}
return idle, total
}
// medianRTT returns the median RTT of te peerset, considering only the tuning
// peers if there are more peers available.
func (ps *peerSet) medianRTT() time.Duration {
// Gather all the currnetly measured round trip times
ps.lock.RLock()
defer ps.lock.RUnlock()
rtts := make([]float64, 0, len(ps.peers))
for _, p := range ps.peers {
p.lock.RLock()
rtts = append(rtts, float64(p.rtt))
p.lock.RUnlock()
}
sort.Float64s(rtts)
median := rttMaxEstimate
if qosTuningPeers <= len(rtts) {
median = time.Duration(rtts[qosTuningPeers/2]) // Median of our tuning peers
} else if len(rtts) > 0 {
median = time.Duration(rtts[len(rtts)/2]) // Median of our connected peers (maintain even like this some baseline qos)
}
// Restrict the RTT into some QoS defaults, irrelevant of true RTT
if median < rttMinEstimate {
median = rttMinEstimate
}
if median > rttMaxEstimate {
median = rttMaxEstimate
}
return median
}