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downloader: improved downloading and synchronisation

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* Downloader's peers keeps track of peer's previously requested hashes
  so that we don't have to re-request
* Changed `AddBlock` to be fully synchronous
This commit is contained in:
obscuren 2015-04-18 18:54:57 +02:00
parent 60613b57d1
commit c2c24b3bb4
4 changed files with 130 additions and 111 deletions
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146
eth/downloader/downloader.go
View File

@ -26,9 +26,12 @@ const (
)
var (
errLowTd = errors.New("peer's TD is too low")
errBusy = errors.New("busy")
errUnknownPeer = errors.New("peer's unknown or unhealthy")
errLowTd = errors.New("peer's TD is too low")
errBusy = errors.New("busy")
errUnknownPeer = errors.New("peer's unknown or unhealthy")
errBadPeer = errors.New("action from bad peer ignored")
errTimeout = errors.New("timeout")
errEmptyHashSet = errors.New("empty hash set by peer")
)
type hashCheckFn func(common.Hash) bool
@ -116,73 +119,6 @@ func (d *Downloader) UnregisterPeer(id string) {
delete(d.peers, id)
}
// SynchroniseWithPeer will select the peer and use it for synchronising. If an empty string is given
// it will use the best peer possible and synchronise if it's TD is higher than our own. If any of the
// checks fail an error will be returned. This method is synchronous
func (d *Downloader) SynchroniseWithPeer(id string) (types.Blocks, error) {
// Check if we're busy
if d.isBusy() {
return nil, errBusy
}
// Attempt to select a peer. This can either be nothing, which returns, best peer
// or selected peer. If no peer could be found an error will be returned
var p *peer
if len(id) == 0 {
p = d.peers[id]
if p == nil {
return nil, errUnknownPeer
}
} else {
p = d.peers.bestPeer()
}
// Make sure our td is lower than the peer's td
if p.td.Cmp(d.currentTd()) <= 0 || d.hasBlock(p.recentHash) {
return nil, errLowTd
}
// Get the hash from the peer and initiate the downloading progress.
err := d.getFromPeer(p, p.recentHash, false)
if err != nil {
return nil, err
}
return d.queue.blocks, nil
}
// Synchronise will synchronise using the best peer.
func (d *Downloader) Synchronise() (types.Blocks, error) {
return d.SynchroniseWithPeer("")
}
func (d *Downloader) getFromPeer(p *peer, hash common.Hash, ignoreInitial bool) error {
glog.V(logger.Detail).Infoln("Synchronising with the network using:", p.id)
// Start the fetcher. This will block the update entirely
// interupts need to be send to the appropriate channels
// respectively.
if err := d.startFetchingHashes(p, hash, ignoreInitial); err != nil {
// handle error
glog.V(logger.Debug).Infoln("Error fetching hashes:", err)
// XXX Reset
return err
}
// Start fetching blocks in paralel. The strategy is simple
// take any available peers, seserve a chunk for each peer available,
// let the peer deliver the chunkn and periodically check if a peer
// has timedout. When done downloading, process blocks.
if err := d.startFetchingBlocks(p); err != nil {
glog.V(logger.Debug).Infoln("Error downloading blocks:", err)
// XXX reset
return err
}
glog.V(logger.Detail).Infoln("Sync completed")
return nil
}
func (d *Downloader) peerHandler() {
// itimer is used to determine when to start ignoring `minDesiredPeerCount`
itimer := time.NewTimer(peerCountTimeout)
@ -236,34 +172,14 @@ out:
for {
select {
case sync := <-d.syncCh:
start := time.Now()
var peer *peer = sync.peer
d.activePeer = peer.id
glog.V(logger.Detail).Infoln("Synchronising with the network using:", peer.id)
// Start the fetcher. This will block the update entirely
// interupts need to be send to the appropriate channels
// respectively.
if err := d.startFetchingHashes(peer, sync.hash, sync.ignoreInitial); err != nil {
// handle error
glog.V(logger.Debug).Infoln("Error fetching hashes:", err)
// XXX Reset
err := d.getFromPeer(peer, sync.hash, sync.ignoreInitial)
if err != nil {
break
}
// Start fetching blocks in paralel. The strategy is simple
// take any available peers, seserve a chunk for each peer available,
// let the peer deliver the chunkn and periodically check if a peer
// has timedout. When done downloading, process blocks.
if err := d.startFetchingBlocks(peer); err != nil {
glog.V(logger.Debug).Infoln("Error downloading blocks:", err)
// XXX reset
break
}
glog.V(logger.Detail).Infoln("Network sync completed in", time.Since(start))
d.process()
case <-d.quit:
break out
@ -314,9 +230,8 @@ out:
glog.V(logger.Debug).Infof("Peer (%s) responded with empty hash set\n", p.id)
d.queue.reset()
break out
return errEmptyHashSet
} else if !done { // Check if we're done fetching
//fmt.Println("re-fetch. current =", d.queue.hashPool.Size())
// Get the next set of hashes
p.getHashes(hashes[len(hashes)-1])
} else { // we're done
@ -324,9 +239,12 @@ out:
}
case <-failureResponse.C:
glog.V(logger.Debug).Infof("Peer (%s) didn't respond in time for hash request\n", p.id)
// TODO instead of reseting the queue select a new peer from which we can start downloading hashes.
// 1. check for peer's best hash to be included in the current hash set;
// 2. resume from last point (hashes[len(hashes)-1]) using the newly selected peer.
d.queue.reset()
break out
return errTimeout
}
}
glog.V(logger.Detail).Infof("Downloaded hashes (%d) in %v\n", d.queue.hashPool.Size(), time.Since(start))
@ -367,7 +285,6 @@ out:
continue
}
//fmt.Println("fetching for", peer.id)
// XXX make fetch blocking.
// Fetch the chunk and check for error. If the peer was somehow
// already fetching a chunk due to a bug, it will be returned to
@ -417,7 +334,6 @@ out:
}
}
//fmt.Println(d.queue.hashPool.Size(), len(d.queue.fetching))
}
}
@ -441,11 +357,14 @@ func (d *Downloader) AddHashes(id string, hashes []common.Hash) error {
// Add an (unrequested) block to the downloader. This is usually done through the
// NewBlockMsg by the protocol handler.
func (d *Downloader) AddBlock(id string, block *types.Block, td *big.Int) {
// Adding blocks is done synchronously. if there are missing blocks, blocks will be
// fetched first. If the downloader is busy or if some other processed failed an error
// will be returned.
func (d *Downloader) AddBlock(id string, block *types.Block, td *big.Int) error {
hash := block.Hash()
if d.hasBlock(hash) {
return
return fmt.Errorf("known block %x", hash.Bytes()[:4])
}
peer := d.peers.getPeer(id)
@ -453,7 +372,7 @@ func (d *Downloader) AddBlock(id string, block *types.Block, td *big.Int) {
// and add the block. Otherwise just ignore it
if peer == nil {
glog.V(logger.Detail).Infof("Ignored block from bad peer %s\n", id)
return
return errBadPeer
}
peer.mu.Lock()
@ -466,17 +385,24 @@ func (d *Downloader) AddBlock(id string, block *types.Block, td *big.Int) {
d.queue.addBlock(id, block, td)
// if neither go ahead to process
if !d.isBusy() {
// Check if the parent of the received block is known.
// If the block is not know, request it otherwise, request.
phash := block.ParentHash()
if !d.hasBlock(phash) {
glog.V(logger.Detail).Infof("Missing parent %x, requires fetching\n", phash.Bytes()[:4])
d.syncCh <- syncPack{peer, peer.recentHash, true}
} else {
d.process()
if d.isBusy() {
return errBusy
}
// Check if the parent of the received block is known.
// If the block is not know, request it otherwise, request.
phash := block.ParentHash()
if !d.hasBlock(phash) {
glog.V(logger.Detail).Infof("Missing parent %x, requires fetching\n", phash.Bytes()[:4])
// Get the missing hashes from the peer (synchronously)
err := d.getFromPeer(peer, peer.recentHash, true)
if err != nil {
return err
}
}
return d.process()
}
// Deliver a chunk to the downloader. This is usually done through the BlocksMsg by

15
eth/downloader/peer.go
View File

@ -6,6 +6,7 @@ import (
"sync"
"github.com/ethereum/go-ethereum/common"
"gopkg.in/fatih/set.v0"
)
const (
@ -64,13 +65,23 @@ type peer struct {
td *big.Int
recentHash common.Hash
requested *set.Set
getHashes hashFetcherFn
getBlocks blockFetcherFn
}
// create a new peer
func newPeer(id string, td *big.Int, hash common.Hash, getHashes hashFetcherFn, getBlocks blockFetcherFn) *peer {
return &peer{id: id, td: td, recentHash: hash, getHashes: getHashes, getBlocks: getBlocks, state: idleState}
return &peer{
id: id,
td: td,
recentHash: hash,
getHashes: getHashes,
getBlocks: getBlocks,
state: idleState,
requested: set.New(),
}
}
// fetch a chunk using the peer
@ -82,6 +93,8 @@ func (p *peer) fetch(chunk *chunk) error {
return errors.New("peer already fetching chunk")
}
p.requested.Merge(chunk.hashes)
// set working state
p.state = workingState
// convert the set to a fetchable slice

3
eth/downloader/queue.go
View File

@ -65,6 +65,9 @@ func (c *queue) get(p *peer, max int) *chunk {
return true
})
// remove hashes that have previously been fetched
hashes.Separate(p.requested)
// remove the fetchable hashes from hash pool
c.hashPool.Separate(hashes)
c.fetchPool.Merge(hashes)

77
eth/downloader/synchronous.go Normal file
View File

@ -0,0 +1,77 @@
package downloader
import (
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
)
// THIS IS PENDING AND TO DO CHANGES FOR MAKING THE DOWNLOADER SYNCHRONOUS
// SynchroniseWithPeer will select the peer and use it for synchronising. If an empty string is given
// it will use the best peer possible and synchronise if it's TD is higher than our own. If any of the
// checks fail an error will be returned. This method is synchronous
func (d *Downloader) SynchroniseWithPeer(id string) (types.Blocks, error) {
// Check if we're busy
if d.isBusy() {
return nil, errBusy
}
// Attempt to select a peer. This can either be nothing, which returns, best peer
// or selected peer. If no peer could be found an error will be returned
var p *peer
if len(id) == 0 {
p = d.peers[id]
if p == nil {
return nil, errUnknownPeer
}
} else {
p = d.peers.bestPeer()
}
// Make sure our td is lower than the peer's td
if p.td.Cmp(d.currentTd()) <= 0 || d.hasBlock(p.recentHash) {
return nil, errLowTd
}
// Get the hash from the peer and initiate the downloading progress.
err := d.getFromPeer(p, p.recentHash, false)
if err != nil {
return nil, err
}
return d.queue.blocks, nil
}
// Synchronise will synchronise using the best peer.
func (d *Downloader) Synchronise() (types.Blocks, error) {
return d.SynchroniseWithPeer("")
}
func (d *Downloader) getFromPeer(p *peer, hash common.Hash, ignoreInitial bool) error {
glog.V(logger.Detail).Infoln("Synchronising with the network using:", p.id)
// Start the fetcher. This will block the update entirely
// interupts need to be send to the appropriate channels
// respectively.
if err := d.startFetchingHashes(p, hash, ignoreInitial); err != nil {
// handle error
glog.V(logger.Debug).Infoln("Error fetching hashes:", err)
// XXX Reset
return err
}
// Start fetching blocks in paralel. The strategy is simple
// take any available peers, seserve a chunk for each peer available,
// let the peer deliver the chunkn and periodically check if a peer
// has timedout. When done downloading, process blocks.
if err := d.startFetchingBlocks(p); err != nil {
glog.V(logger.Debug).Infoln("Error downloading blocks:", err)
// XXX reset
return err
}
glog.V(logger.Detail).Infoln("Sync completed")
return nil
}