eth: limit number of sent transactions based on message size

Nodes that are out of sync will queue many transactions, which causes
the initial transactions message to grow very large. Larger transactions
messages can make communication impossible if the message is too big to
send. Big transactions messages also exhaust egress bandwidth, which
degrades other peer connections.

The new approach to combat these issues is to send transactions in
smaller batches. This commit introduces a new goroutine that handles
delivery of all initial transaction transfers. Size-limited packs of
transactions are sent to one peer at a time, conserving precious egress
bandwidth.
This commit is contained in:
Felix Lange 2015-06-09 12:03:14 +02:00
parent 41b2008a66
commit 6c73a59806
2 changed files with 109 additions and 9 deletions

View File

@ -53,9 +53,11 @@ type ProtocolManager struct {
txSub event.Subscription
minedBlockSub event.Subscription
// channels for fetcher, syncer, txsyncLoop
newPeerCh chan *peer
newHashCh chan []*blockAnnounce
newBlockCh chan chan []*types.Block
txsyncCh chan *txsync
quitSync chan struct{}
// wait group is used for graceful shutdowns during downloading
@ -76,9 +78,9 @@ func NewProtocolManager(protocolVersion, networkId int, mux *event.TypeMux, txpo
newPeerCh: make(chan *peer, 1),
newHashCh: make(chan []*blockAnnounce, 1),
newBlockCh: make(chan chan []*types.Block),
txsyncCh: make(chan *txsync),
quitSync: make(chan struct{}),
}
manager.SubProtocol = p2p.Protocol{
Name: "eth",
Version: uint(protocolVersion),
@ -118,13 +120,14 @@ func (pm *ProtocolManager) Start() {
// broadcast transactions
pm.txSub = pm.eventMux.Subscribe(core.TxPreEvent{})
go pm.txBroadcastLoop()
// broadcast mined blocks
pm.minedBlockSub = pm.eventMux.Subscribe(core.NewMinedBlockEvent{})
go pm.minedBroadcastLoop()
// start sync handlers
go pm.syncer()
go pm.fetcher()
go pm.txsyncLoop()
}
func (pm *ProtocolManager) Stop() {
@ -135,7 +138,7 @@ func (pm *ProtocolManager) Stop() {
pm.quit = true
pm.txSub.Unsubscribe() // quits txBroadcastLoop
pm.minedBlockSub.Unsubscribe() // quits blockBroadcastLoop
close(pm.quitSync) // quits the sync handler
close(pm.quitSync) // quits syncer, fetcher, txsyncLoop
// Wait for any process action
pm.wg.Wait()
@ -150,11 +153,12 @@ func (pm *ProtocolManager) newPeer(pv, nv int, p *p2p.Peer, rw p2p.MsgReadWriter
}
func (pm *ProtocolManager) handle(p *peer) error {
// Execute the Ethereum handshake, short circuit if fails
// Execute the Ethereum handshake.
if err := p.handleStatus(); err != nil {
return err
}
// Register the peer locally and in the downloader too
// Register the peer locally.
glog.V(logger.Detail).Infoln("Adding peer", p.id)
if err := pm.peers.Register(p); err != nil {
glog.V(logger.Error).Infoln("Addition failed:", err)
@ -162,14 +166,16 @@ func (pm *ProtocolManager) handle(p *peer) error {
}
defer pm.removePeer(p.id)
// Register the peer in the downloader. If the downloader
// considers it banned, we disconnect.
if err := pm.downloader.RegisterPeer(p.id, p.Head(), p.requestHashes, p.requestBlocks); err != nil {
return err
}
// propagate existing transactions. new transactions appearing
// Propagate existing transactions. new transactions appearing
// after this will be sent via broadcasts.
if err := p.sendTransactions(pm.txpool.GetTransactions()); err != nil {
return err
}
pm.syncTransactions(p)
// main loop. handle incoming messages.
for {
if err := pm.handleMsg(p); err != nil {

View File

@ -2,6 +2,7 @@ package eth
import (
"math"
"math/rand"
"sync/atomic"
"time"
@ -10,6 +11,7 @@ import (
"github.com/ethereum/go-ethereum/eth/downloader"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
"github.com/ethereum/go-ethereum/p2p/discover"
)
const (
@ -20,6 +22,10 @@ const (
notifyFetchTimeout = 5 * time.Second // Maximum alloted time to return an explicitly requested block
minDesiredPeerCount = 5 // Amount of peers desired to start syncing
blockProcAmount = 256
// This is the target size for the packs of transactions sent by txsyncLoop.
// A pack can get larger than this if a single transactions exceeds this size.
txsyncPackSize = 100 * 1024
)
// blockAnnounce is the hash notification of the availability of a new block in
@ -30,6 +36,94 @@ type blockAnnounce struct {
time time.Time
}
type txsync struct {
p *peer
txs []*types.Transaction
}
// syncTransactions starts sending all currently pending transactions to the given peer.
func (pm *ProtocolManager) syncTransactions(p *peer) {
txs := pm.txpool.GetTransactions()
if len(txs) == 0 {
return
}
select {
case pm.txsyncCh <- &txsync{p, txs}:
case <-pm.quitSync:
}
}
// txsyncLoop takes care of the initial transaction sync for each new
// connection. When a new peer appears, we relay all currently pending
// transactions. In order to minimise egress bandwidth usage, we send
// the transactions in small packs to one peer at a time.
func (pm *ProtocolManager) txsyncLoop() {
var (
pending = make(map[discover.NodeID]*txsync)
sending = false // whether a send is active
pack = new(txsync) // the pack that is being sent
done = make(chan error, 1) // result of the send
)
// send starts a sending a pack of transactions from the sync.
send := func(s *txsync) {
// Fill pack with transactions up to the target size.
size := common.StorageSize(0)
pack.p = s.p
pack.txs = pack.txs[:0]
for i := 0; i < len(s.txs) && size < txsyncPackSize; i++ {
pack.txs = append(pack.txs, s.txs[i])
size += s.txs[i].Size()
}
// Remove the transactions that will be sent.
s.txs = s.txs[:copy(s.txs, s.txs[len(pack.txs):])]
if len(s.txs) == 0 {
delete(pending, s.p.ID())
}
// Send the pack in the background.
glog.V(logger.Detail).Infof("%v: sending %d transactions (%v)", s.p.Peer, len(pack.txs), size)
sending = true
go func() { done <- pack.p.sendTransactions(pack.txs) }()
}
// pick chooses the next pending sync.
pick := func() *txsync {
if len(pending) == 0 {
return nil
}
n := rand.Intn(len(pending)) + 1
for _, s := range pending {
if n--; n == 0 {
return s
}
}
return nil
}
for {
select {
case s := <-pm.txsyncCh:
pending[s.p.ID()] = s
if !sending {
send(s)
}
case err := <-done:
sending = false
// Stop tracking peers that cause send failures.
if err != nil {
glog.V(logger.Debug).Infof("%v: tx send failed: %v", pack.p.Peer, err)
delete(pending, pack.p.ID())
}
// Schedule the next send.
if s := pick(); s != nil {
send(s)
}
case <-pm.quitSync:
return
}
}
}
// fetcher is responsible for collecting hash notifications, and periodically
// checking all unknown ones and individually fetching them.
func (pm *ProtocolManager) fetcher() {