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eth, p2p/msgrate: move peer QoS tracking to its own package and use it for snap (#22876)

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This change extracts the peer QoS tracking logic from eth/downloader, moving
it into the new package p2p/msgrate. The job of msgrate.Tracker is determining
suitable timeout values and request sizes per peer.

The snap sync scheduler now uses msgrate.Tracker instead of the hard-coded 15s
timeout. This should make the sync work better on network links with high latency.
This commit is contained in:
Péter Szilágyi 2021-05-19 15:09:03 +03:00 committed by GitHub
parent b3a1fda650
commit 3e795881ea
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GPG Key ID: 4AEE18F83AFDEB23
7 changed files with 745 additions and 409 deletions
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119
eth/downloader/downloader.go
View File

@ -47,16 +47,6 @@ var (
MaxReceiptFetch = 256 // Amount of transaction receipts to allow fetching per request MaxReceiptFetch = 256 // Amount of transaction receipts to allow fetching per request
MaxStateFetch = 384 // Amount of node state values to allow fetching per request MaxStateFetch = 384 // Amount of node state values to allow fetching per request
rttMinEstimate = 2 * time.Second // Minimum round-trip time to target for download requests
rttMaxEstimate = 20 * time.Second // Maximum round-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
maxQueuedHeaders = 32 * 1024 // [eth/62] Maximum number of headers to queue for import (DOS protection) maxQueuedHeaders = 32 * 1024 // [eth/62] Maximum number of headers to queue for import (DOS protection)
maxHeadersProcess = 2048 // Number of header download results to import at once into the chain maxHeadersProcess = 2048 // Number of header download results to import at once into the chain
maxResultsProcess = 2048 // Number of content download results to import at once into the chain maxResultsProcess = 2048 // Number of content download results to import at once into the chain
@ -96,13 +86,6 @@ var (
) )
type Downloader struct { type Downloader struct {
// WARNING: The `rttEstimate` and `rttConfidence` fields are accessed atomically.
// On 32 bit platforms, only 64-bit aligned fields can be atomic. The struct is
// guaranteed to be so aligned, so take advantage of that. For more information,
// see https://golang.org/pkg/sync/atomic/#pkg-note-BUG.
rttEstimate uint64 // Round trip time to target for download requests
rttConfidence uint64 // Confidence in the estimated RTT (unit: millionths to allow atomic ops)
mode uint32 // Synchronisation mode defining the strategy used (per sync cycle), use d.getMode() to get the SyncMode mode uint32 // Synchronisation mode defining the strategy used (per sync cycle), use d.getMode() to get the SyncMode
mux *event.TypeMux // Event multiplexer to announce sync operation events mux *event.TypeMux // Event multiplexer to announce sync operation events
@ -232,8 +215,6 @@ func New(checkpoint uint64, stateDb ethdb.Database, stateBloom *trie.SyncBloom,
checkpoint: checkpoint, checkpoint: checkpoint,
queue: newQueue(blockCacheMaxItems, blockCacheInitialItems), queue: newQueue(blockCacheMaxItems, blockCacheInitialItems),
peers: newPeerSet(), peers: newPeerSet(),
rttEstimate: uint64(rttMaxEstimate),
rttConfidence: uint64(1000000),
blockchain: chain, blockchain: chain,
lightchain: lightchain, lightchain: lightchain,
dropPeer: dropPeer, dropPeer: dropPeer,
@ -252,7 +233,6 @@ func New(checkpoint uint64, stateDb ethdb.Database, stateBloom *trie.SyncBloom,
}, },
trackStateReq: make(chan *stateReq), trackStateReq: make(chan *stateReq),
} }
go dl.qosTuner()
go dl.stateFetcher() go dl.stateFetcher()
return dl return dl
} }
@ -310,8 +290,6 @@ func (d *Downloader) RegisterPeer(id string, version uint, peer Peer) error {
logger.Error("Failed to register sync peer", "err", err) logger.Error("Failed to register sync peer", "err", err)
return err return err
} }
d.qosReduceConfidence()
return nil return nil
} }
@ -670,7 +648,7 @@ func (d *Downloader) fetchHead(p *peerConnection) (head *types.Header, pivot *ty
} }
go p.peer.RequestHeadersByHash(latest, fetch, fsMinFullBlocks-1, true) go p.peer.RequestHeadersByHash(latest, fetch, fsMinFullBlocks-1, true)
ttl := d.requestTTL() ttl := d.peers.rates.TargetTimeout()
timeout := time.After(ttl) timeout := time.After(ttl)
for { for {
select { select {
@ -853,7 +831,7 @@ func (d *Downloader) findAncestorSpanSearch(p *peerConnection, mode SyncMode, re
// Wait for the remote response to the head fetch // Wait for the remote response to the head fetch
number, hash := uint64(0), common.Hash{} number, hash := uint64(0), common.Hash{}
ttl := d.requestTTL() ttl := d.peers.rates.TargetTimeout()
timeout := time.After(ttl) timeout := time.After(ttl)
for finished := false; !finished; { for finished := false; !finished; {
@ -942,7 +920,7 @@ func (d *Downloader) findAncestorBinarySearch(p *peerConnection, mode SyncMode,
// Split our chain interval in two, and request the hash to cross check // Split our chain interval in two, and request the hash to cross check
check := (start + end) / 2 check := (start + end) / 2
ttl := d.requestTTL() ttl := d.peers.rates.TargetTimeout()
timeout := time.After(ttl) timeout := time.After(ttl)
go p.peer.RequestHeadersByNumber(check, 1, 0, false) go p.peer.RequestHeadersByNumber(check, 1, 0, false)
@ -1035,7 +1013,7 @@ func (d *Downloader) fetchHeaders(p *peerConnection, from uint64) error {
getHeaders := func(from uint64) { getHeaders := func(from uint64) {
request = time.Now() request = time.Now()
ttl = d.requestTTL() ttl = d.peers.rates.TargetTimeout()
timeout.Reset(ttl) timeout.Reset(ttl)
if skeleton { if skeleton {
@ -1050,7 +1028,7 @@ func (d *Downloader) fetchHeaders(p *peerConnection, from uint64) error {
pivoting = true pivoting = true
request = time.Now() request = time.Now()
ttl = d.requestTTL() ttl = d.peers.rates.TargetTimeout()
timeout.Reset(ttl) timeout.Reset(ttl)
d.pivotLock.RLock() d.pivotLock.RLock()
@ -1262,12 +1240,12 @@ func (d *Downloader) fillHeaderSkeleton(from uint64, skeleton []*types.Header) (
pack := packet.(*headerPack) pack := packet.(*headerPack)
return d.queue.DeliverHeaders(pack.peerID, pack.headers, d.headerProcCh) return d.queue.DeliverHeaders(pack.peerID, pack.headers, d.headerProcCh)
} }
expire = func() map[string]int { return d.queue.ExpireHeaders(d.requestTTL()) } expire = func() map[string]int { return d.queue.ExpireHeaders(d.peers.rates.TargetTimeout()) }
reserve = func(p *peerConnection, count int) (*fetchRequest, bool, bool) { reserve = func(p *peerConnection, count int) (*fetchRequest, bool, bool) {
return d.queue.ReserveHeaders(p, count), false, false return d.queue.ReserveHeaders(p, count), false, false
} }
fetch = func(p *peerConnection, req *fetchRequest) error { return p.FetchHeaders(req.From, MaxHeaderFetch) } fetch = func(p *peerConnection, req *fetchRequest) error { return p.FetchHeaders(req.From, MaxHeaderFetch) }
capacity = func(p *peerConnection) int { return p.HeaderCapacity(d.requestRTT()) } capacity = func(p *peerConnection) int { return p.HeaderCapacity(d.peers.rates.TargetRoundTrip()) }
setIdle = func(p *peerConnection, accepted int, deliveryTime time.Time) { setIdle = func(p *peerConnection, accepted int, deliveryTime time.Time) {
p.SetHeadersIdle(accepted, deliveryTime) p.SetHeadersIdle(accepted, deliveryTime)
} }
@ -1293,9 +1271,9 @@ func (d *Downloader) fetchBodies(from uint64) error {
pack := packet.(*bodyPack) pack := packet.(*bodyPack)
return d.queue.DeliverBodies(pack.peerID, pack.transactions, pack.uncles) return d.queue.DeliverBodies(pack.peerID, pack.transactions, pack.uncles)
} }
expire = func() map[string]int { return d.queue.ExpireBodies(d.requestTTL()) } expire = func() map[string]int { return d.queue.ExpireBodies(d.peers.rates.TargetTimeout()) }
fetch = func(p *peerConnection, req *fetchRequest) error { return p.FetchBodies(req) } fetch = func(p *peerConnection, req *fetchRequest) error { return p.FetchBodies(req) }
capacity = func(p *peerConnection) int { return p.BlockCapacity(d.requestRTT()) } capacity = func(p *peerConnection) int { return p.BlockCapacity(d.peers.rates.TargetRoundTrip()) }
setIdle = func(p *peerConnection, accepted int, deliveryTime time.Time) { p.SetBodiesIdle(accepted, deliveryTime) } setIdle = func(p *peerConnection, accepted int, deliveryTime time.Time) { p.SetBodiesIdle(accepted, deliveryTime) }
) )
err := d.fetchParts(d.bodyCh, deliver, d.bodyWakeCh, expire, err := d.fetchParts(d.bodyCh, deliver, d.bodyWakeCh, expire,
@ -1317,9 +1295,9 @@ func (d *Downloader) fetchReceipts(from uint64) error {
pack := packet.(*receiptPack) pack := packet.(*receiptPack)
return d.queue.DeliverReceipts(pack.peerID, pack.receipts) return d.queue.DeliverReceipts(pack.peerID, pack.receipts)
} }
expire = func() map[string]int { return d.queue.ExpireReceipts(d.requestTTL()) } expire = func() map[string]int { return d.queue.ExpireReceipts(d.peers.rates.TargetTimeout()) }
fetch = func(p *peerConnection, req *fetchRequest) error { return p.FetchReceipts(req) } fetch = func(p *peerConnection, req *fetchRequest) error { return p.FetchReceipts(req) }
capacity = func(p *peerConnection) int { return p.ReceiptCapacity(d.requestRTT()) } capacity = func(p *peerConnection) int { return p.ReceiptCapacity(d.peers.rates.TargetRoundTrip()) }
setIdle = func(p *peerConnection, accepted int, deliveryTime time.Time) { setIdle = func(p *peerConnection, accepted int, deliveryTime time.Time) {
p.SetReceiptsIdle(accepted, deliveryTime) p.SetReceiptsIdle(accepted, deliveryTime)
} }
@ -2031,78 +2009,3 @@ func (d *Downloader) deliver(destCh chan dataPack, packet dataPack, inMeter, dro
return errNoSyncActive 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((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
log.Debug("Recalculated downloader QoS values", "rtt", rtt, "confidence", float64(conf)/1000000.0, "ttl", 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 == 0 {
// Ensure peer connectivity races don't catch us off guard
return
}
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))
log.Debug("Relaxed downloader QoS values", "rtt", rtt, "confidence", float64(conf)/1000000.0, "ttl", 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 preferred (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
}

165
eth/downloader/peer.go
View File

@ -32,11 +32,11 @@ import (
"github.com/ethereum/go-ethereum/eth/protocols/eth" "github.com/ethereum/go-ethereum/eth/protocols/eth"
"github.com/ethereum/go-ethereum/event" "github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/log" "github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/p2p/msgrate"
) )
const ( const (
maxLackingHashes = 4096 // Maximum number of entries allowed on the list or lacking items 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.
) )
var ( var (
@ -54,18 +54,12 @@ type peerConnection struct {
receiptIdle int32 // Current receipt activity state of the peer (idle = 0, active = 1) receiptIdle int32 // Current receipt activity state of the peer (idle = 0, active = 1)
stateIdle int32 // Current node data activity state of the peer (idle = 0, active = 1) stateIdle int32 // Current node data activity state of the peer (idle = 0, active = 1)
headerThroughput float64 // Number of headers measured to be retrievable per second
blockThroughput float64 // Number of blocks (bodies) measured to be retrievable per second
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 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 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 receiptStarted time.Time // Time instance when the last receipt fetch was started
stateStarted time.Time // Time instance when the last node data fetch was started stateStarted time.Time // Time instance when the last node data fetch was started
rates *msgrate.Tracker // Tracker to hone in on the number of items retrievable per second
lacking map[common.Hash]struct{} // Set of hashes not to request (didn't have previously) lacking map[common.Hash]struct{} // Set of hashes not to request (didn't have previously)
peer Peer peer Peer
@ -133,11 +127,6 @@ func (p *peerConnection) Reset() {
atomic.StoreInt32(&p.receiptIdle, 0) atomic.StoreInt32(&p.receiptIdle, 0)
atomic.StoreInt32(&p.stateIdle, 0) atomic.StoreInt32(&p.stateIdle, 0)
p.headerThroughput = 0
p.blockThroughput = 0
p.receiptThroughput = 0
p.stateThroughput = 0
p.lacking = make(map[common.Hash]struct{}) p.lacking = make(map[common.Hash]struct{})
} }
@ -212,93 +201,72 @@ func (p *peerConnection) FetchNodeData(hashes []common.Hash) error {
// requests. Its estimated header retrieval throughput is updated with that measured // requests. Its estimated header retrieval throughput is updated with that measured
// just now. // just now.
func (p *peerConnection) SetHeadersIdle(delivered int, deliveryTime time.Time) { func (p *peerConnection) SetHeadersIdle(delivered int, deliveryTime time.Time) {
p.setIdle(deliveryTime.Sub(p.headerStarted), delivered, &p.headerThroughput, &p.headerIdle) p.rates.Update(eth.BlockHeadersMsg, deliveryTime.Sub(p.headerStarted), delivered)
atomic.StoreInt32(&p.headerIdle, 0)
} }
// SetBodiesIdle sets the peer to idle, allowing it to execute block body retrieval // SetBodiesIdle sets the peer to idle, allowing it to execute block body retrieval
// requests. Its estimated body retrieval throughput is updated with that measured // requests. Its estimated body retrieval throughput is updated with that measured
// just now. // just now.
func (p *peerConnection) SetBodiesIdle(delivered int, deliveryTime time.Time) { func (p *peerConnection) SetBodiesIdle(delivered int, deliveryTime time.Time) {
p.setIdle(deliveryTime.Sub(p.blockStarted), delivered, &p.blockThroughput, &p.blockIdle) p.rates.Update(eth.BlockBodiesMsg, deliveryTime.Sub(p.blockStarted), delivered)
atomic.StoreInt32(&p.blockIdle, 0)
} }
// SetReceiptsIdle sets the peer to idle, allowing it to execute new receipt // SetReceiptsIdle sets the peer to idle, allowing it to execute new receipt
// retrieval requests. Its estimated receipt retrieval throughput is updated // retrieval requests. Its estimated receipt retrieval throughput is updated
// with that measured just now. // with that measured just now.
func (p *peerConnection) SetReceiptsIdle(delivered int, deliveryTime time.Time) { func (p *peerConnection) SetReceiptsIdle(delivered int, deliveryTime time.Time) {
p.setIdle(deliveryTime.Sub(p.receiptStarted), delivered, &p.receiptThroughput, &p.receiptIdle) p.rates.Update(eth.ReceiptsMsg, deliveryTime.Sub(p.receiptStarted), delivered)
atomic.StoreInt32(&p.receiptIdle, 0)
} }
// SetNodeDataIdle sets the peer to idle, allowing it to execute new state trie // SetNodeDataIdle sets the peer to idle, allowing it to execute new state trie
// data retrieval requests. Its estimated state retrieval throughput is updated // data retrieval requests. Its estimated state retrieval throughput is updated
// with that measured just now. // with that measured just now.
func (p *peerConnection) SetNodeDataIdle(delivered int, deliveryTime time.Time) { func (p *peerConnection) SetNodeDataIdle(delivered int, deliveryTime time.Time) {
p.setIdle(deliveryTime.Sub(p.stateStarted), delivered, &p.stateThroughput, &p.stateIdle) p.rates.Update(eth.NodeDataMsg, deliveryTime.Sub(p.stateStarted), delivered)
} atomic.StoreInt32(&p.stateIdle, 0)
// setIdle sets the peer to idle, allowing it to execute new retrieval requests.
// Its estimated retrieval throughput is updated with that measured just now.
func (p *peerConnection) setIdle(elapsed time.Duration, delivered int, throughput *float64, idle *int32) {
// Irrelevant of the scaling, make sure the peer ends up idle
defer atomic.StoreInt32(idle, 0)
p.lock.Lock()
defer p.lock.Unlock()
// If nothing was delivered (hard timeout / unavailable data), reduce throughput to minimum
if delivered == 0 {
*throughput = 0
return
}
// Otherwise update the throughput with a new measurement
if elapsed <= 0 {
elapsed = 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))
p.log.Trace("Peer throughput measurements updated",
"hps", p.headerThroughput, "bps", p.blockThroughput,
"rps", p.receiptThroughput, "sps", p.stateThroughput,
"miss", len(p.lacking), "rtt", p.rtt)
} }
// HeaderCapacity retrieves the peers header download allowance based on its // HeaderCapacity retrieves the peers header download allowance based on its
// previously discovered throughput. // previously discovered throughput.
func (p *peerConnection) HeaderCapacity(targetRTT time.Duration) int { func (p *peerConnection) HeaderCapacity(targetRTT time.Duration) int {
p.lock.RLock() cap := int(math.Ceil(p.rates.Capacity(eth.BlockHeadersMsg, targetRTT)))
defer p.lock.RUnlock() if cap > MaxHeaderFetch {
cap = MaxHeaderFetch
return int(math.Min(1+math.Max(1, p.headerThroughput*float64(targetRTT)/float64(time.Second)), float64(MaxHeaderFetch))) }
return cap
} }
// BlockCapacity retrieves the peers block download allowance based on its // BlockCapacity retrieves the peers block download allowance based on its
// previously discovered throughput. // previously discovered throughput.
func (p *peerConnection) BlockCapacity(targetRTT time.Duration) int { func (p *peerConnection) BlockCapacity(targetRTT time.Duration) int {
p.lock.RLock() cap := int(math.Ceil(p.rates.Capacity(eth.BlockBodiesMsg, targetRTT)))
defer p.lock.RUnlock() if cap > MaxBlockFetch {
cap = MaxBlockFetch
return int(math.Min(1+math.Max(1, p.blockThroughput*float64(targetRTT)/float64(time.Second)), float64(MaxBlockFetch))) }
return cap
} }
// ReceiptCapacity retrieves the peers receipt download allowance based on its // ReceiptCapacity retrieves the peers receipt download allowance based on its
// previously discovered throughput. // previously discovered throughput.
func (p *peerConnection) ReceiptCapacity(targetRTT time.Duration) int { func (p *peerConnection) ReceiptCapacity(targetRTT time.Duration) int {
p.lock.RLock() cap := int(math.Ceil(p.rates.Capacity(eth.ReceiptsMsg, targetRTT)))
defer p.lock.RUnlock() if cap > MaxReceiptFetch {
cap = MaxReceiptFetch
return int(math.Min(1+math.Max(1, p.receiptThroughput*float64(targetRTT)/float64(time.Second)), float64(MaxReceiptFetch))) }
return cap
} }
// NodeDataCapacity retrieves the peers state download allowance based on its // NodeDataCapacity retrieves the peers state download allowance based on its
// previously discovered throughput. // previously discovered throughput.
func (p *peerConnection) NodeDataCapacity(targetRTT time.Duration) int { func (p *peerConnection) NodeDataCapacity(targetRTT time.Duration) int {
p.lock.RLock() cap := int(math.Ceil(p.rates.Capacity(eth.NodeDataMsg, targetRTT)))
defer p.lock.RUnlock() if cap > MaxStateFetch {
cap = MaxStateFetch
return int(math.Min(1+math.Max(1, p.stateThroughput*float64(targetRTT)/float64(time.Second)), float64(MaxStateFetch))) }
return cap
} }
// MarkLacking appends a new entity to the set of items (blocks, receipts, states) // MarkLacking appends a new entity to the set of items (blocks, receipts, states)
@ -331,8 +299,11 @@ func (p *peerConnection) Lacks(hash common.Hash) bool {
// download procedure. // download procedure.
type peerSet struct { type peerSet struct {
peers map[string]*peerConnection peers map[string]*peerConnection
rates *msgrate.Trackers // Set of rate trackers to give the sync a common beat
newPeerFeed event.Feed newPeerFeed event.Feed
peerDropFeed event.Feed peerDropFeed event.Feed
lock sync.RWMutex lock sync.RWMutex
} }
@ -340,6 +311,7 @@ type peerSet struct {
func newPeerSet() *peerSet { func newPeerSet() *peerSet {
return &peerSet{ return &peerSet{
peers: make(map[string]*peerConnection), peers: make(map[string]*peerConnection),
rates: msgrate.NewTrackers(log.New("proto", "eth")),
} }
} }
@ -371,30 +343,15 @@ func (ps *peerSet) Reset() {
// average of all existing peers, to give it a realistic chance of being used // average of all existing peers, to give it a realistic chance of being used
// for data retrievals. // for data retrievals.
func (ps *peerSet) Register(p *peerConnection) error { func (ps *peerSet) Register(p *peerConnection) error {
// Retrieve the current median RTT as a sane default
p.rtt = ps.medianRTT()
// Register the new peer with some meaningful defaults // Register the new peer with some meaningful defaults
ps.lock.Lock() ps.lock.Lock()
if _, ok := ps.peers[p.id]; ok { if _, ok := ps.peers[p.id]; ok {
ps.lock.Unlock() ps.lock.Unlock()
return errAlreadyRegistered return errAlreadyRegistered
} }
if len(ps.peers) > 0 { p.rates = msgrate.NewTracker(ps.rates.MeanCapacities(), ps.rates.MedianRoundTrip())
p.headerThroughput, p.blockThroughput, p.receiptThroughput, p.stateThroughput = 0, 0, 0, 0 if err := ps.rates.Track(p.id, p.rates); err != nil {
return err
for _, peer := range ps.peers {
peer.lock.RLock()
p.headerThroughput += peer.headerThroughput
p.blockThroughput += peer.blockThroughput
p.receiptThroughput += peer.receiptThroughput
p.stateThroughput += peer.stateThroughput
peer.lock.RUnlock()
}
p.headerThroughput /= float64(len(ps.peers))
p.blockThroughput /= float64(len(ps.peers))
p.receiptThroughput /= float64(len(ps.peers))
p.stateThroughput /= float64(len(ps.peers))
} }
ps.peers[p.id] = p ps.peers[p.id] = p
ps.lock.Unlock() ps.lock.Unlock()
@ -413,6 +370,7 @@ func (ps *peerSet) Unregister(id string) error {
return errNotRegistered return errNotRegistered
} }
delete(ps.peers, id) delete(ps.peers, id)
ps.rates.Untrack(id)
ps.lock.Unlock() ps.lock.Unlock()
ps.peerDropFeed.Send(p) ps.peerDropFeed.Send(p)
@ -454,9 +412,7 @@ func (ps *peerSet) HeaderIdlePeers() ([]*peerConnection, int) {
return atomic.LoadInt32(&p.headerIdle) == 0 return atomic.LoadInt32(&p.headerIdle) == 0
} }
throughput := func(p *peerConnection) float64 { throughput := func(p *peerConnection) float64 {
p.lock.RLock() return p.rates.Capacity(eth.BlockHeadersMsg, time.Second)
defer p.lock.RUnlock()
return p.headerThroughput
} }
return ps.idlePeers(eth.ETH65, eth.ETH66, idle, throughput) return ps.idlePeers(eth.ETH65, eth.ETH66, idle, throughput)
} }
@ -468,9 +424,7 @@ func (ps *peerSet) BodyIdlePeers() ([]*peerConnection, int) {
return atomic.LoadInt32(&p.blockIdle) == 0 return atomic.LoadInt32(&p.blockIdle) == 0
} }
throughput := func(p *peerConnection) float64 { throughput := func(p *peerConnection) float64 {
p.lock.RLock() return p.rates.Capacity(eth.BlockBodiesMsg, time.Second)
defer p.lock.RUnlock()
return p.blockThroughput
} }
return ps.idlePeers(eth.ETH65, eth.ETH66, idle, throughput) return ps.idlePeers(eth.ETH65, eth.ETH66, idle, throughput)
} }
@ -482,9 +436,7 @@ func (ps *peerSet) ReceiptIdlePeers() ([]*peerConnection, int) {
return atomic.LoadInt32(&p.receiptIdle) == 0 return atomic.LoadInt32(&p.receiptIdle) == 0
} }
throughput := func(p *peerConnection) float64 { throughput := func(p *peerConnection) float64 {
p.lock.RLock() return p.rates.Capacity(eth.ReceiptsMsg, time.Second)
defer p.lock.RUnlock()
return p.receiptThroughput
} }
return ps.idlePeers(eth.ETH65, eth.ETH66, idle, throughput) return ps.idlePeers(eth.ETH65, eth.ETH66, idle, throughput)
} }
@ -496,9 +448,7 @@ func (ps *peerSet) NodeDataIdlePeers() ([]*peerConnection, int) {
return atomic.LoadInt32(&p.stateIdle) == 0 return atomic.LoadInt32(&p.stateIdle) == 0
} }
throughput := func(p *peerConnection) float64 { throughput := func(p *peerConnection) float64 {
p.lock.RLock() return p.rates.Capacity(eth.NodeDataMsg, time.Second)
defer p.lock.RUnlock()
return p.stateThroughput
} }
return ps.idlePeers(eth.ETH65, eth.ETH66, idle, throughput) return ps.idlePeers(eth.ETH65, eth.ETH66, idle, throughput)
} }
@ -527,37 +477,6 @@ func (ps *peerSet) idlePeers(minProtocol, maxProtocol uint, idleCheck func(*peer
return sortPeers.p, total return sortPeers.p, total
} }
// medianRTT returns the median RTT of the peerset, considering only the tuning
// peers if there are more peers available.
func (ps *peerSet) medianRTT() time.Duration {
// Gather all the currently 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
}
// peerThroughputSort implements the Sort interface, and allows for // peerThroughputSort implements the Sort interface, and allows for
// sorting a set of peers by their throughput // sorting a set of peers by their throughput
// The sorted data is with the _highest_ throughput first // The sorted data is with the _highest_ throughput first

53
eth/downloader/peer_test.go
View File

@ -1,53 +0,0 @@
// Copyright 2020 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
package downloader
import (
"sort"
"testing"
)
func TestPeerThroughputSorting(t *testing.T) {
a := &peerConnection{
id: "a",
headerThroughput: 1.25,
}
b := &peerConnection{
id: "b",
headerThroughput: 1.21,
}
c := &peerConnection{
id: "c",
headerThroughput: 1.23,
}
peers := []*peerConnection{a, b, c}
tps := []float64{a.headerThroughput,
b.headerThroughput, c.headerThroughput}
sortPeers := &peerThroughputSort{peers, tps}
sort.Sort(sortPeers)
if got, exp := sortPeers.p[0].id, "a"; got != exp {
t.Errorf("sort fail, got %v exp %v", got, exp)
}
if got, exp := sortPeers.p[1].id, "c"; got != exp {
t.Errorf("sort fail, got %v exp %v", got, exp)
}
if got, exp := sortPeers.p[2].id, "b"; got != exp {
t.Errorf("sort fail, got %v exp %v", got, exp)
}
}

4
eth/downloader/statesync.go
View File

@ -433,8 +433,8 @@ func (s *stateSync) assignTasks() {
peers, _ := s.d.peers.NodeDataIdlePeers() peers, _ := s.d.peers.NodeDataIdlePeers()
for _, p := range peers { for _, p := range peers {
// Assign a batch of fetches proportional to the estimated latency/bandwidth // Assign a batch of fetches proportional to the estimated latency/bandwidth
cap := p.NodeDataCapacity(s.d.requestRTT()) cap := p.NodeDataCapacity(s.d.peers.rates.TargetRoundTrip())
req := &stateReq{peer: p, timeout: s.d.requestTTL()} req := &stateReq{peer: p, timeout: s.d.peers.rates.TargetTimeout()}
nodes, _, codes := s.fillTasks(cap, req) nodes, _, codes := s.fillTasks(cap, req)

311
eth/protocols/snap/sync.go
View File

@ -37,6 +37,7 @@ import (
"github.com/ethereum/go-ethereum/event" "github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/light" "github.com/ethereum/go-ethereum/light"
"github.com/ethereum/go-ethereum/log" "github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/p2p/msgrate"
"github.com/ethereum/go-ethereum/rlp" "github.com/ethereum/go-ethereum/rlp"
"github.com/ethereum/go-ethereum/trie" "github.com/ethereum/go-ethereum/trie"
"golang.org/x/crypto/sha3" "golang.org/x/crypto/sha3"
@ -51,14 +52,15 @@ var (
) )
const ( const (
// maxRequestSize is the maximum number of bytes to request from a remote peer. // minRequestSize is the minimum number of bytes to request from a remote peer.
maxRequestSize = 128 * 1024 // This number is used as the low cap for account and storage range requests.
// Bytecode and trienode are limited inherently by item count (1).
minRequestSize = 64 * 1024
// maxStorageSetRequestCount is the maximum number of contracts to request the // maxRequestSize is the maximum number of bytes to request from a remote peer.
// storage of in a single query. If this number is too low, we're not filling // This number is used as the high cap for account and storage range requests.
// responses fully and waste round trip times. If it's too high, we're capping // Bytecode and trienode are limited more explicitly by the caps below.
// responses and waste bandwidth. maxRequestSize = 512 * 1024
maxStorageSetRequestCount = maxRequestSize / 1024
// maxCodeRequestCount is the maximum number of bytecode blobs to request in a // maxCodeRequestCount is the maximum number of bytecode blobs to request in a
// single query. If this number is too low, we're not filling responses fully // single query. If this number is too low, we're not filling responses fully
@ -74,7 +76,7 @@ const (
// a single query. If this number is too low, we're not filling responses fully // a single query. If this number is too low, we're not filling responses fully
// and waste round trip times. If it's too high, we're capping responses and // and waste round trip times. If it's too high, we're capping responses and
// waste bandwidth. // waste bandwidth.
maxTrieRequestCount = 256 maxTrieRequestCount = maxRequestSize / 512
) )
var ( var (
@ -85,10 +87,6 @@ var (
// storageConcurrency is the number of chunks to split the a large contract // storageConcurrency is the number of chunks to split the a large contract
// storage trie into to allow concurrent retrievals. // storage trie into to allow concurrent retrievals.
storageConcurrency = 16 storageConcurrency = 16
// requestTimeout is the maximum time a peer is allowed to spend on serving
// a single network request.
requestTimeout = 15 * time.Second // TODO(karalabe): Make it dynamic ala fast-sync?
) )
// ErrCancelled is returned from snap syncing if the operation was prematurely // ErrCancelled is returned from snap syncing if the operation was prematurely
@ -107,6 +105,7 @@ var ErrCancelled = errors.New("sync cancelled")
type accountRequest struct { type accountRequest struct {
peer string // Peer to which this request is assigned peer string // Peer to which this request is assigned
id uint64 // Request ID of this request id uint64 // Request ID of this request
time time.Time // Timestamp when the request was sent
deliver chan *accountResponse // Channel to deliver successful response on deliver chan *accountResponse // Channel to deliver successful response on
revert chan *accountRequest // Channel to deliver request failure on revert chan *accountRequest // Channel to deliver request failure on
@ -144,6 +143,7 @@ type accountResponse struct {
type bytecodeRequest struct { type bytecodeRequest struct {
peer string // Peer to which this request is assigned peer string // Peer to which this request is assigned
id uint64 // Request ID of this request id uint64 // Request ID of this request
time time.Time // Timestamp when the request was sent
deliver chan *bytecodeResponse // Channel to deliver successful response on deliver chan *bytecodeResponse // Channel to deliver successful response on
revert chan *bytecodeRequest // Channel to deliver request failure on revert chan *bytecodeRequest // Channel to deliver request failure on
@ -175,6 +175,7 @@ type bytecodeResponse struct {
type storageRequest struct { type storageRequest struct {
peer string // Peer to which this request is assigned peer string // Peer to which this request is assigned
id uint64 // Request ID of this request id uint64 // Request ID of this request
time time.Time // Timestamp when the request was sent
deliver chan *storageResponse // Channel to deliver successful response on deliver chan *storageResponse // Channel to deliver successful response on
revert chan *storageRequest // Channel to deliver request failure on revert chan *storageRequest // Channel to deliver request failure on
@ -220,6 +221,7 @@ type storageResponse struct {
type trienodeHealRequest struct { type trienodeHealRequest struct {
peer string // Peer to which this request is assigned peer string // Peer to which this request is assigned
id uint64 // Request ID of this request id uint64 // Request ID of this request
time time.Time // Timestamp when the request was sent
deliver chan *trienodeHealResponse // Channel to deliver successful response on deliver chan *trienodeHealResponse // Channel to deliver successful response on
revert chan *trienodeHealRequest // Channel to deliver request failure on revert chan *trienodeHealRequest // Channel to deliver request failure on
@ -254,6 +256,7 @@ type trienodeHealResponse struct {
type bytecodeHealRequest struct { type bytecodeHealRequest struct {
peer string // Peer to which this request is assigned peer string // Peer to which this request is assigned
id uint64 // Request ID of this request id uint64 // Request ID of this request
time time.Time // Timestamp when the request was sent
deliver chan *bytecodeHealResponse // Channel to deliver successful response on deliver chan *bytecodeHealResponse // Channel to deliver successful response on
revert chan *bytecodeHealRequest // Channel to deliver request failure on revert chan *bytecodeHealRequest // Channel to deliver request failure on
@ -396,6 +399,7 @@ type Syncer struct {
peers map[string]SyncPeer // Currently active peers to download from peers map[string]SyncPeer // Currently active peers to download from
peerJoin *event.Feed // Event feed to react to peers joining peerJoin *event.Feed // Event feed to react to peers joining
peerDrop *event.Feed // Event feed to react to peers dropping peerDrop *event.Feed // Event feed to react to peers dropping
rates *msgrate.Trackers // Message throughput rates for peers
// Request tracking during syncing phase // Request tracking during syncing phase
statelessPeers map[string]struct{} // Peers that failed to deliver state data statelessPeers map[string]struct{} // Peers that failed to deliver state data
@ -452,6 +456,7 @@ func NewSyncer(db ethdb.KeyValueStore) *Syncer {
peers: make(map[string]SyncPeer), peers: make(map[string]SyncPeer),
peerJoin: new(event.Feed), peerJoin: new(event.Feed),
peerDrop: new(event.Feed), peerDrop: new(event.Feed),
rates: msgrate.NewTrackers(log.New("proto", "snap")),
update: make(chan struct{}, 1), update: make(chan struct{}, 1),
accountIdlers: make(map[string]struct{}), accountIdlers: make(map[string]struct{}),
@ -484,6 +489,7 @@ func (s *Syncer) Register(peer SyncPeer) error {
return errors.New("already registered") return errors.New("already registered")
} }
s.peers[id] = peer s.peers[id] = peer
s.rates.Track(id, msgrate.NewTracker(s.rates.MeanCapacities(), s.rates.MedianRoundTrip()))
// Mark the peer as idle, even if no sync is running // Mark the peer as idle, even if no sync is running
s.accountIdlers[id] = struct{}{} s.accountIdlers[id] = struct{}{}
@ -509,6 +515,7 @@ func (s *Syncer) Unregister(id string) error {
return errors.New("not registered") return errors.New("not registered")
} }
delete(s.peers, id) delete(s.peers, id)
s.rates.Untrack(id)
// Remove status markers, even if no sync is running // Remove status markers, even if no sync is running
delete(s.statelessPeers, id) delete(s.statelessPeers, id)
@ -851,10 +858,24 @@ func (s *Syncer) assignAccountTasks(success chan *accountResponse, fail chan *ac
s.lock.Lock() s.lock.Lock()
defer s.lock.Unlock() defer s.lock.Unlock()
// If there are no idle peers, short circuit assignment // Sort the peers by download capacity to use faster ones if many available
if len(s.accountIdlers) == 0 { idlers := &capacitySort{
ids: make([]string, 0, len(s.accountIdlers)),
caps: make([]float64, 0, len(s.accountIdlers)),
}
targetTTL := s.rates.TargetTimeout()
for id := range s.accountIdlers {
if _, ok := s.statelessPeers[id]; ok {
continue
}
idlers.ids = append(idlers.ids, id)
idlers.caps = append(idlers.caps, s.rates.Capacity(id, AccountRangeMsg, targetTTL))
}
if len(idlers.ids) == 0 {
return return
} }
sort.Sort(sort.Reverse(idlers))
// Iterate over all the tasks and try to find a pending one // Iterate over all the tasks and try to find a pending one
for _, task := range s.tasks { for _, task := range s.tasks {
// Skip any tasks already filling // Skip any tasks already filling
@ -864,20 +885,15 @@ func (s *Syncer) assignAccountTasks(success chan *accountResponse, fail chan *ac
// Task pending retrieval, try to find an idle peer. If no such peer // Task pending retrieval, try to find an idle peer. If no such peer
// exists, we probably assigned tasks for all (or they are stateless). // exists, we probably assigned tasks for all (or they are stateless).
// Abort the entire assignment mechanism. // Abort the entire assignment mechanism.
var idle string if len(idlers.ids) == 0 {
for id := range s.accountIdlers {
// If the peer rejected a query in this sync cycle, don't bother asking
// again for anything, it's either out of sync or already pruned
if _, ok := s.statelessPeers[id]; ok {
continue
}
idle = id
break
}
if idle == "" {
return return
} }
peer := s.peers[idle] var (
idle = idlers.ids[0]
peer = s.peers[idle]
cap = idlers.caps[0]
)
idlers.ids, idlers.caps = idlers.ids[1:], idlers.caps[1:]
// Matched a pending task to an idle peer, allocate a unique request id // Matched a pending task to an idle peer, allocate a unique request id
var reqid uint64 var reqid uint64
@ -895,6 +911,7 @@ func (s *Syncer) assignAccountTasks(success chan *accountResponse, fail chan *ac
req := &accountRequest{ req := &accountRequest{
peer: idle, peer: idle,
id: reqid, id: reqid,
time: time.Now(),
deliver: success, deliver: success,
revert: fail, revert: fail,
cancel: cancel, cancel: cancel,
@ -903,8 +920,9 @@ func (s *Syncer) assignAccountTasks(success chan *accountResponse, fail chan *ac
limit: task.Last, limit: task.Last,
task: task, task: task,
} }
req.timeout = time.AfterFunc(requestTimeout, func() { req.timeout = time.AfterFunc(s.rates.TargetTimeout(), func() {
peer.Log().Debug("Account range request timed out", "reqid", reqid) peer.Log().Debug("Account range request timed out", "reqid", reqid)
s.rates.Update(idle, AccountRangeMsg, 0, 0)
s.scheduleRevertAccountRequest(req) s.scheduleRevertAccountRequest(req)
}) })
s.accountReqs[reqid] = req s.accountReqs[reqid] = req
@ -915,7 +933,13 @@ func (s *Syncer) assignAccountTasks(success chan *accountResponse, fail chan *ac
defer s.pend.Done() defer s.pend.Done()
// Attempt to send the remote request and revert if it fails // Attempt to send the remote request and revert if it fails
if err := peer.RequestAccountRange(reqid, root, req.origin, req.limit, maxRequestSize); err != nil { if cap > maxRequestSize {
cap = maxRequestSize
}
if cap < minRequestSize { // Don't bother with peers below a bare minimum performance
cap = minRequestSize
}
if err := peer.RequestAccountRange(reqid, root, req.origin, req.limit, uint64(cap)); err != nil {
peer.Log().Debug("Failed to request account range", "err", err) peer.Log().Debug("Failed to request account range", "err", err)
s.scheduleRevertAccountRequest(req) s.scheduleRevertAccountRequest(req)
} }
@ -931,10 +955,24 @@ func (s *Syncer) assignBytecodeTasks(success chan *bytecodeResponse, fail chan *
s.lock.Lock() s.lock.Lock()
defer s.lock.Unlock() defer s.lock.Unlock()
// If there are no idle peers, short circuit assignment // Sort the peers by download capacity to use faster ones if many available
if len(s.bytecodeIdlers) == 0 { idlers := &capacitySort{
ids: make([]string, 0, len(s.bytecodeIdlers)),
caps: make([]float64, 0, len(s.bytecodeIdlers)),
}
targetTTL := s.rates.TargetTimeout()
for id := range s.bytecodeIdlers {
if _, ok := s.statelessPeers[id]; ok {
continue
}
idlers.ids = append(idlers.ids, id)
idlers.caps = append(idlers.caps, s.rates.Capacity(id, ByteCodesMsg, targetTTL))
}
if len(idlers.ids) == 0 {
return return
} }
sort.Sort(sort.Reverse(idlers))
// Iterate over all the tasks and try to find a pending one // Iterate over all the tasks and try to find a pending one
for _, task := range s.tasks { for _, task := range s.tasks {
// Skip any tasks not in the bytecode retrieval phase // Skip any tasks not in the bytecode retrieval phase
@ -948,20 +986,15 @@ func (s *Syncer) assignBytecodeTasks(success chan *bytecodeResponse, fail chan *
// Task pending retrieval, try to find an idle peer. If no such peer // Task pending retrieval, try to find an idle peer. If no such peer
// exists, we probably assigned tasks for all (or they are stateless). // exists, we probably assigned tasks for all (or they are stateless).
// Abort the entire assignment mechanism. // Abort the entire assignment mechanism.
var idle string if len(idlers.ids) == 0 {
for id := range s.bytecodeIdlers {
// If the peer rejected a query in this sync cycle, don't bother asking
// again for anything, it's either out of sync or already pruned
if _, ok := s.statelessPeers[id]; ok {
continue
}
idle = id
break
}
if idle == "" {
return return
} }
peer := s.peers[idle] var (
idle = idlers.ids[0]
peer = s.peers[idle]
cap = idlers.caps[0]
)
idlers.ids, idlers.caps = idlers.ids[1:], idlers.caps[1:]
// Matched a pending task to an idle peer, allocate a unique request id // Matched a pending task to an idle peer, allocate a unique request id
var reqid uint64 var reqid uint64
@ -976,17 +1009,21 @@ func (s *Syncer) assignBytecodeTasks(success chan *bytecodeResponse, fail chan *
break break
} }
// Generate the network query and send it to the peer // Generate the network query and send it to the peer
hashes := make([]common.Hash, 0, maxCodeRequestCount) if cap > maxCodeRequestCount {
cap = maxCodeRequestCount
}
hashes := make([]common.Hash, 0, int(cap))
for hash := range task.codeTasks { for hash := range task.codeTasks {
delete(task.codeTasks, hash) delete(task.codeTasks, hash)
hashes = append(hashes, hash) hashes = append(hashes, hash)
if len(hashes) >= maxCodeRequestCount { if len(hashes) >= int(cap) {
break break
} }
} }
req := &bytecodeRequest{ req := &bytecodeRequest{
peer: idle, peer: idle,
id: reqid, id: reqid,
time: time.Now(),
deliver: success, deliver: success,
revert: fail, revert: fail,
cancel: cancel, cancel: cancel,
@ -994,8 +1031,9 @@ func (s *Syncer) assignBytecodeTasks(success chan *bytecodeResponse, fail chan *
hashes: hashes, hashes: hashes,
task: task, task: task,
} }
req.timeout = time.AfterFunc(requestTimeout, func() { req.timeout = time.AfterFunc(s.rates.TargetTimeout(), func() {
peer.Log().Debug("Bytecode request timed out", "reqid", reqid) peer.Log().Debug("Bytecode request timed out", "reqid", reqid)
s.rates.Update(idle, ByteCodesMsg, 0, 0)
s.scheduleRevertBytecodeRequest(req) s.scheduleRevertBytecodeRequest(req)
}) })
s.bytecodeReqs[reqid] = req s.bytecodeReqs[reqid] = req
@ -1020,10 +1058,24 @@ func (s *Syncer) assignStorageTasks(success chan *storageResponse, fail chan *st
s.lock.Lock() s.lock.Lock()
defer s.lock.Unlock() defer s.lock.Unlock()
// If there are no idle peers, short circuit assignment // Sort the peers by download capacity to use faster ones if many available
if len(s.storageIdlers) == 0 { idlers := &capacitySort{
ids: make([]string, 0, len(s.storageIdlers)),
caps: make([]float64, 0, len(s.storageIdlers)),
}
targetTTL := s.rates.TargetTimeout()
for id := range s.storageIdlers {
if _, ok := s.statelessPeers[id]; ok {
continue
}
idlers.ids = append(idlers.ids, id)
idlers.caps = append(idlers.caps, s.rates.Capacity(id, StorageRangesMsg, targetTTL))
}
if len(idlers.ids) == 0 {
return return
} }
sort.Sort(sort.Reverse(idlers))
// Iterate over all the tasks and try to find a pending one // Iterate over all the tasks and try to find a pending one
for _, task := range s.tasks { for _, task := range s.tasks {
// Skip any tasks not in the storage retrieval phase // Skip any tasks not in the storage retrieval phase
@ -1037,20 +1089,15 @@ func (s *Syncer) assignStorageTasks(success chan *storageResponse, fail chan *st
// Task pending retrieval, try to find an idle peer. If no such peer // Task pending retrieval, try to find an idle peer. If no such peer
// exists, we probably assigned tasks for all (or they are stateless). // exists, we probably assigned tasks for all (or they are stateless).
// Abort the entire assignment mechanism. // Abort the entire assignment mechanism.
var idle string if len(idlers.ids) == 0 {
for id := range s.storageIdlers {
// If the peer rejected a query in this sync cycle, don't bother asking
// again for anything, it's either out of sync or already pruned
if _, ok := s.statelessPeers[id]; ok {
continue
}
idle = id
break
}
if idle == "" {
return return
} }
peer := s.peers[idle] var (
idle = idlers.ids[0]
peer = s.peers[idle]
cap = idlers.caps[0]
)
idlers.ids, idlers.caps = idlers.ids[1:], idlers.caps[1:]
// Matched a pending task to an idle peer, allocate a unique request id // Matched a pending task to an idle peer, allocate a unique request id
var reqid uint64 var reqid uint64
@ -1067,9 +1114,17 @@ func (s *Syncer) assignStorageTasks(success chan *storageResponse, fail chan *st
// Generate the network query and send it to the peer. If there are // Generate the network query and send it to the peer. If there are
// large contract tasks pending, complete those before diving into // large contract tasks pending, complete those before diving into
// even more new contracts. // even more new contracts.
if cap > maxRequestSize {
cap = maxRequestSize
}
if cap < minRequestSize { // Don't bother with peers below a bare minimum performance
cap = minRequestSize
}
storageSets := int(cap / 1024)
var ( var (
accounts = make([]common.Hash, 0, maxStorageSetRequestCount) accounts = make([]common.Hash, 0, storageSets)
roots = make([]common.Hash, 0, maxStorageSetRequestCount) roots = make([]common.Hash, 0, storageSets)
subtask *storageTask subtask *storageTask
) )
for account, subtasks := range task.SubTasks { for account, subtasks := range task.SubTasks {
@ -1096,7 +1151,7 @@ func (s *Syncer) assignStorageTasks(success chan *storageResponse, fail chan *st
accounts = append(accounts, acccount) accounts = append(accounts, acccount)
roots = append(roots, root) roots = append(roots, root)
if len(accounts) >= maxStorageSetRequestCount { if len(accounts) >= storageSets {
break break
} }
} }
@ -1109,6 +1164,7 @@ func (s *Syncer) assignStorageTasks(success chan *storageResponse, fail chan *st
req := &storageRequest{ req := &storageRequest{
peer: idle, peer: idle,
id: reqid, id: reqid,
time: time.Now(),
deliver: success, deliver: success,
revert: fail, revert: fail,
cancel: cancel, cancel: cancel,
@ -1122,8 +1178,9 @@ func (s *Syncer) assignStorageTasks(success chan *storageResponse, fail chan *st
req.origin = subtask.Next req.origin = subtask.Next
req.limit = subtask.Last req.limit = subtask.Last
} }
req.timeout = time.AfterFunc(requestTimeout, func() { req.timeout = time.AfterFunc(s.rates.TargetTimeout(), func() {
peer.Log().Debug("Storage request timed out", "reqid", reqid) peer.Log().Debug("Storage request timed out", "reqid", reqid)
s.rates.Update(idle, StorageRangesMsg, 0, 0)
s.scheduleRevertStorageRequest(req) s.scheduleRevertStorageRequest(req)
}) })
s.storageReqs[reqid] = req s.storageReqs[reqid] = req
@ -1138,7 +1195,7 @@ func (s *Syncer) assignStorageTasks(success chan *storageResponse, fail chan *st
if subtask != nil { if subtask != nil {
origin, limit = req.origin[:], req.limit[:] origin, limit = req.origin[:], req.limit[:]
} }
if err := peer.RequestStorageRanges(reqid, root, accounts, origin, limit, maxRequestSize); err != nil { if err := peer.RequestStorageRanges(reqid, root, accounts, origin, limit, uint64(cap)); err != nil {
log.Debug("Failed to request storage", "err", err) log.Debug("Failed to request storage", "err", err)
s.scheduleRevertStorageRequest(req) s.scheduleRevertStorageRequest(req)
} }
@ -1157,10 +1214,24 @@ func (s *Syncer) assignTrienodeHealTasks(success chan *trienodeHealResponse, fai
s.lock.Lock() s.lock.Lock()
defer s.lock.Unlock() defer s.lock.Unlock()
// If there are no idle peers, short circuit assignment // Sort the peers by download capacity to use faster ones if many available
if len(s.trienodeHealIdlers) == 0 { idlers := &capacitySort{
ids: make([]string, 0, len(s.trienodeHealIdlers)),
caps: make([]float64, 0, len(s.trienodeHealIdlers)),
}
targetTTL := s.rates.TargetTimeout()
for id := range s.trienodeHealIdlers {
if _, ok := s.statelessPeers[id]; ok {
continue
}
idlers.ids = append(idlers.ids, id)
idlers.caps = append(idlers.caps, s.rates.Capacity(id, TrieNodesMsg, targetTTL))
}
if len(idlers.ids) == 0 {
return return
} }
sort.Sort(sort.Reverse(idlers))
// Iterate over pending tasks and try to find a peer to retrieve with // Iterate over pending tasks and try to find a peer to retrieve with
for len(s.healer.trieTasks) > 0 || s.healer.scheduler.Pending() > 0 { for len(s.healer.trieTasks) > 0 || s.healer.scheduler.Pending() > 0 {
// If there are not enough trie tasks queued to fully assign, fill the // If there are not enough trie tasks queued to fully assign, fill the
@ -1186,20 +1257,15 @@ func (s *Syncer) assignTrienodeHealTasks(success chan *trienodeHealResponse, fai
// Task pending retrieval, try to find an idle peer. If no such peer // Task pending retrieval, try to find an idle peer. If no such peer
// exists, we probably assigned tasks for all (or they are stateless). // exists, we probably assigned tasks for all (or they are stateless).
// Abort the entire assignment mechanism. // Abort the entire assignment mechanism.
var idle string if len(idlers.ids) == 0 {
for id := range s.trienodeHealIdlers {
// If the peer rejected a query in this sync cycle, don't bother asking
// again for anything, it's either out of sync or already pruned
if _, ok := s.statelessPeers[id]; ok {
continue
}
idle = id
break
}
if idle == "" {
return return
} }
peer := s.peers[idle] var (
idle = idlers.ids[0]
peer = s.peers[idle]
cap = idlers.caps[0]
)
idlers.ids, idlers.caps = idlers.ids[1:], idlers.caps[1:]
// Matched a pending task to an idle peer, allocate a unique request id // Matched a pending task to an idle peer, allocate a unique request id
var reqid uint64 var reqid uint64
@ -1214,10 +1280,13 @@ func (s *Syncer) assignTrienodeHealTasks(success chan *trienodeHealResponse, fai
break break
} }
// Generate the network query and send it to the peer // Generate the network query and send it to the peer
if cap > maxTrieRequestCount {
cap = maxTrieRequestCount
}
var ( var (
hashes = make([]common.Hash, 0, maxTrieRequestCount) hashes = make([]common.Hash, 0, int(cap))
paths = make([]trie.SyncPath, 0, maxTrieRequestCount) paths = make([]trie.SyncPath, 0, int(cap))
pathsets = make([]TrieNodePathSet, 0, maxTrieRequestCount) pathsets = make([]TrieNodePathSet, 0, int(cap))
) )
for hash, pathset := range s.healer.trieTasks { for hash, pathset := range s.healer.trieTasks {
delete(s.healer.trieTasks, hash) delete(s.healer.trieTasks, hash)
@ -1226,13 +1295,14 @@ func (s *Syncer) assignTrienodeHealTasks(success chan *trienodeHealResponse, fai
paths = append(paths, pathset) paths = append(paths, pathset)
pathsets = append(pathsets, [][]byte(pathset)) // TODO(karalabe): group requests by account hash pathsets = append(pathsets, [][]byte(pathset)) // TODO(karalabe): group requests by account hash
if len(hashes) >= maxTrieRequestCount { if len(hashes) >= int(cap) {
break break
} }
} }
req := &trienodeHealRequest{ req := &trienodeHealRequest{
peer: idle, peer: idle,
id: reqid, id: reqid,
time: time.Now(),
deliver: success, deliver: success,
revert: fail, revert: fail,
cancel: cancel, cancel: cancel,
@ -1241,8 +1311,9 @@ func (s *Syncer) assignTrienodeHealTasks(success chan *trienodeHealResponse, fai
paths: paths, paths: paths,
task: s.healer, task: s.healer,
} }
req.timeout = time.AfterFunc(requestTimeout, func() { req.timeout = time.AfterFunc(s.rates.TargetTimeout(), func() {
peer.Log().Debug("Trienode heal request timed out", "reqid", reqid) peer.Log().Debug("Trienode heal request timed out", "reqid", reqid)
s.rates.Update(idle, TrieNodesMsg, 0, 0)
s.scheduleRevertTrienodeHealRequest(req) s.scheduleRevertTrienodeHealRequest(req)
}) })
s.trienodeHealReqs[reqid] = req s.trienodeHealReqs[reqid] = req
@ -1267,10 +1338,24 @@ func (s *Syncer) assignBytecodeHealTasks(success chan *bytecodeHealResponse, fai
s.lock.Lock() s.lock.Lock()
defer s.lock.Unlock() defer s.lock.Unlock()
// If there are no idle peers, short circuit assignment // Sort the peers by download capacity to use faster ones if many available
if len(s.bytecodeHealIdlers) == 0 { idlers := &capacitySort{
ids: make([]string, 0, len(s.bytecodeHealIdlers)),
caps: make([]float64, 0, len(s.bytecodeHealIdlers)),
}
targetTTL := s.rates.TargetTimeout()
for id := range s.bytecodeHealIdlers {
if _, ok := s.statelessPeers[id]; ok {
continue
}
idlers.ids = append(idlers.ids, id)
idlers.caps = append(idlers.caps, s.rates.Capacity(id, ByteCodesMsg, targetTTL))
}
if len(idlers.ids) == 0 {
return return
} }
sort.Sort(sort.Reverse(idlers))
// Iterate over pending tasks and try to find a peer to retrieve with // Iterate over pending tasks and try to find a peer to retrieve with
for len(s.healer.codeTasks) > 0 || s.healer.scheduler.Pending() > 0 { for len(s.healer.codeTasks) > 0 || s.healer.scheduler.Pending() > 0 {
// If there are not enough trie tasks queued to fully assign, fill the // If there are not enough trie tasks queued to fully assign, fill the
@ -1296,20 +1381,15 @@ func (s *Syncer) assignBytecodeHealTasks(success chan *bytecodeHealResponse, fai
// Task pending retrieval, try to find an idle peer. If no such peer // Task pending retrieval, try to find an idle peer. If no such peer
// exists, we probably assigned tasks for all (or they are stateless). // exists, we probably assigned tasks for all (or they are stateless).
// Abort the entire assignment mechanism. // Abort the entire assignment mechanism.
var idle string if len(idlers.ids) == 0 {
for id := range s.bytecodeHealIdlers {
// If the peer rejected a query in this sync cycle, don't bother asking
// again for anything, it's either out of sync or already pruned
if _, ok := s.statelessPeers[id]; ok {
continue
}
idle = id
break
}
if idle == "" {
return return
} }
peer := s.peers[idle] var (
idle = idlers.ids[0]
peer = s.peers[idle]
cap = idlers.caps[0]
)
idlers.ids, idlers.caps = idlers.ids[1:], idlers.caps[1:]
// Matched a pending task to an idle peer, allocate a unique request id // Matched a pending task to an idle peer, allocate a unique request id
var reqid uint64 var reqid uint64
@ -1324,18 +1404,22 @@ func (s *Syncer) assignBytecodeHealTasks(success chan *bytecodeHealResponse, fai
break break
} }
// Generate the network query and send it to the peer // Generate the network query and send it to the peer
hashes := make([]common.Hash, 0, maxCodeRequestCount) if cap > maxCodeRequestCount {
cap = maxCodeRequestCount
}
hashes := make([]common.Hash, 0, int(cap))
for hash := range s.healer.codeTasks { for hash := range s.healer.codeTasks {
delete(s.healer.codeTasks, hash) delete(s.healer.codeTasks, hash)
hashes = append(hashes, hash) hashes = append(hashes, hash)
if len(hashes) >= maxCodeRequestCount { if len(hashes) >= int(cap) {
break break
} }
} }
req := &bytecodeHealRequest{ req := &bytecodeHealRequest{
peer: idle, peer: idle,
id: reqid, id: reqid,
time: time.Now(),
deliver: success, deliver: success,
revert: fail, revert: fail,
cancel: cancel, cancel: cancel,
@ -1343,8 +1427,9 @@ func (s *Syncer) assignBytecodeHealTasks(success chan *bytecodeHealResponse, fai
hashes: hashes, hashes: hashes,
task: s.healer, task: s.healer,
} }
req.timeout = time.AfterFunc(requestTimeout, func() { req.timeout = time.AfterFunc(s.rates.TargetTimeout(), func() {
peer.Log().Debug("Bytecode heal request timed out", "reqid", reqid) peer.Log().Debug("Bytecode heal request timed out", "reqid", reqid)
s.rates.Update(idle, ByteCodesMsg, 0, 0)
s.scheduleRevertBytecodeHealRequest(req) s.scheduleRevertBytecodeHealRequest(req)
}) })
s.bytecodeHealReqs[reqid] = req s.bytecodeHealReqs[reqid] = req
@ -2142,6 +2227,7 @@ func (s *Syncer) OnAccounts(peer SyncPeer, id uint64, hashes []common.Hash, acco
return nil return nil
} }
delete(s.accountReqs, id) delete(s.accountReqs, id)
s.rates.Update(peer.ID(), AccountRangeMsg, time.Since(req.time), int(size))
// Clean up the request timeout timer, we'll see how to proceed further based // Clean up the request timeout timer, we'll see how to proceed further based
// on the actual delivered content // on the actual delivered content
@ -2253,6 +2339,7 @@ func (s *Syncer) onByteCodes(peer SyncPeer, id uint64, bytecodes [][]byte) error
return nil return nil
} }
delete(s.bytecodeReqs, id) delete(s.bytecodeReqs, id)
s.rates.Update(peer.ID(), ByteCodesMsg, time.Since(req.time), len(bytecodes))
// Clean up the request timeout timer, we'll see how to proceed further based // Clean up the request timeout timer, we'll see how to proceed further based
// on the actual delivered content // on the actual delivered content
@ -2361,6 +2448,7 @@ func (s *Syncer) OnStorage(peer SyncPeer, id uint64, hashes [][]common.Hash, slo
return nil return nil
} }
delete(s.storageReqs, id) delete(s.storageReqs, id)
s.rates.Update(peer.ID(), StorageRangesMsg, time.Since(req.time), int(size))
// Clean up the request timeout timer, we'll see how to proceed further based // Clean up the request timeout timer, we'll see how to proceed further based
// on the actual delivered content // on the actual delivered content
@ -2487,6 +2575,7 @@ func (s *Syncer) OnTrieNodes(peer SyncPeer, id uint64, trienodes [][]byte) error
return nil return nil
} }
delete(s.trienodeHealReqs, id) delete(s.trienodeHealReqs, id)
s.rates.Update(peer.ID(), TrieNodesMsg, time.Since(req.time), len(trienodes))
// Clean up the request timeout timer, we'll see how to proceed further based // Clean up the request timeout timer, we'll see how to proceed further based
// on the actual delivered content // on the actual delivered content
@ -2581,6 +2670,7 @@ func (s *Syncer) onHealByteCodes(peer SyncPeer, id uint64, bytecodes [][]byte) e
return nil return nil
} }
delete(s.bytecodeHealReqs, id) delete(s.bytecodeHealReqs, id)
s.rates.Update(peer.ID(), ByteCodesMsg, time.Since(req.time), len(bytecodes))
// Clean up the request timeout timer, we'll see how to proceed further based // Clean up the request timeout timer, we'll see how to proceed further based
// on the actual delivered content // on the actual delivered content
@ -2756,3 +2846,24 @@ func estimateRemainingSlots(hashes int, last common.Hash) (uint64, error) {
} }
return space.Uint64() - uint64(hashes), nil return space.Uint64() - uint64(hashes), nil
} }
// capacitySort implements the Sort interface, allowing sorting by peer message
// throughput. Note, callers should use sort.Reverse to get the desired effect
// of highest capacity being at the front.
type capacitySort struct {
ids []string
caps []float64
}
func (s *capacitySort) Len() int {
return len(s.ids)
}
func (s *capacitySort) Less(i, j int) bool {
return s.caps[i] < s.caps[j]
}
func (s *capacitySort) Swap(i, j int) {
s.ids[i], s.ids[j] = s.ids[j], s.ids[i]
s.caps[i], s.caps[j] = s.caps[j], s.caps[i]
}

18
eth/protocols/snap/sync_test.go
View File

@ -796,12 +796,6 @@ func TestMultiSyncManyUseless(t *testing.T) {
// TestMultiSyncManyUseless contains one good peer, and many which doesn't return anything valuable at all // TestMultiSyncManyUseless contains one good peer, and many which doesn't return anything valuable at all
func TestMultiSyncManyUselessWithLowTimeout(t *testing.T) { func TestMultiSyncManyUselessWithLowTimeout(t *testing.T) {
// We're setting the timeout to very low, to increase the chance of the timeout
// being triggered. This was previously a cause of panic, when a response
// arrived simultaneously as a timeout was triggered.
defer func(old time.Duration) { requestTimeout = old }(requestTimeout)
requestTimeout = time.Millisecond
var ( var (
once sync.Once once sync.Once
cancel = make(chan struct{}) cancel = make(chan struct{})
@ -838,6 +832,11 @@ func TestMultiSyncManyUselessWithLowTimeout(t *testing.T) {
mkSource("noStorage", true, false, true), mkSource("noStorage", true, false, true),
mkSource("noTrie", true, true, false), mkSource("noTrie", true, true, false),
) )
// We're setting the timeout to very low, to increase the chance of the timeout
// being triggered. This was previously a cause of panic, when a response
// arrived simultaneously as a timeout was triggered.
syncer.rates.OverrideTTLLimit = time.Millisecond
done := checkStall(t, term) done := checkStall(t, term)
if err := syncer.Sync(sourceAccountTrie.Hash(), cancel); err != nil { if err := syncer.Sync(sourceAccountTrie.Hash(), cancel); err != nil {
t.Fatalf("sync failed: %v", err) t.Fatalf("sync failed: %v", err)
@ -848,10 +847,6 @@ func TestMultiSyncManyUselessWithLowTimeout(t *testing.T) {
// TestMultiSyncManyUnresponsive contains one good peer, and many which doesn't respond at all // TestMultiSyncManyUnresponsive contains one good peer, and many which doesn't respond at all
func TestMultiSyncManyUnresponsive(t *testing.T) { func TestMultiSyncManyUnresponsive(t *testing.T) {
// We're setting the timeout to very low, to make the test run a bit faster
defer func(old time.Duration) { requestTimeout = old }(requestTimeout)
requestTimeout = time.Millisecond
var ( var (
once sync.Once once sync.Once
cancel = make(chan struct{}) cancel = make(chan struct{})
@ -888,6 +883,9 @@ func TestMultiSyncManyUnresponsive(t *testing.T) {
mkSource("noStorage", true, false, true), mkSource("noStorage", true, false, true),
mkSource("noTrie", true, true, false), mkSource("noTrie", true, true, false),
) )
// We're setting the timeout to very low, to make the test run a bit faster
syncer.rates.OverrideTTLLimit = time.Millisecond
done := checkStall(t, term) done := checkStall(t, term)
if err := syncer.Sync(sourceAccountTrie.Hash(), cancel); err != nil { if err := syncer.Sync(sourceAccountTrie.Hash(), cancel); err != nil {
t.Fatalf("sync failed: %v", err) t.Fatalf("sync failed: %v", err)

458
p2p/msgrate/msgrate.go Normal file
View File

@ -0,0 +1,458 @@
// Copyright 2021 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 msgrate allows estimating the throughput of peers for more balanced syncs.
package msgrate
import (
"errors"
"sort"
"sync"
"time"
"github.com/ethereum/go-ethereum/log"
)
// measurementImpact is the impact a single measurement has on a peer's final
// capacity value. A value closer to 0 reacts slower to sudden network changes,
// but it is also more stable against temporary hiccups. 0.1 worked well for
// most of Ethereum's existence, so might as well go with it.
const measurementImpact = 0.1
// capacityOverestimation is the ratio of items to over-estimate when retrieving
// a peer's capacity to avoid locking into a lower value due to never attempting
// to fetch more than some local stable value.
const capacityOverestimation = 1.01
// qosTuningPeers is the number of best peers to tune round trip times based on.
// An Ethereum node doesn't need hundreds of connections to operate correctly,
// so instead of lowering our download speed to the median of potentially many
// bad nodes, we can target a smaller set of vey good nodes. At worse this will
// result in less nodes to sync from, but that's still better than some hogging
// the pipeline.
const qosTuningPeers = 5
// rttMinEstimate is the minimal round trip time to target requests for. Since
// every request entails a 2 way latency + bandwidth + serving database lookups,
// it should be generous enough to permit meaningful work to be done on top of
// the transmission costs.
const rttMinEstimate = 2 * time.Second
// rttMaxEstimate is the maximal round trip time to target requests for. Although
// the expectation is that a well connected node will never reach this, certain
// special connectivity ones might experience significant delays (e.g. satellite
// uplink with 3s RTT). This value should be low enough to forbid stalling the
// pipeline too long, but large enough to cover the worst of the worst links.
const rttMaxEstimate = 20 * time.Second
// rttPushdownFactor is a multiplier to attempt forcing quicker requests than
// what the message rate tracker estimates. The reason is that message rate
// tracking adapts queries to the RTT, but multiple RTT values can be perfectly
// valid, they just result in higher packet sizes. Since smaller packets almost
// always result in stabler download streams, this factor hones in on the lowest
// RTT from all the functional ones.
const rttPushdownFactor = 0.9
// rttMinConfidence is the minimum value the roundtrip confidence factor may drop
// to. Since the target timeouts are based on how confident the tracker is in the
// true roundtrip, it's important to not allow too huge fluctuations.
const rttMinConfidence = 0.1
// ttlScaling is the multiplier that converts the estimated roundtrip time to a
// timeout cap for network requests. The expectation is that peers' response time
// will fluctuate around the estimated roundtrip, but depending in their load at
// request time, it might be higher than anticipated. This scaling factor ensures
// that we allow remote connections some slack but at the same time do enforce a
// behavior similar to our median peers.
const ttlScaling = 3
// ttlLimit is the maximum timeout allowance to prevent reaching crazy numbers
// if some unforeseen network events shappen. As much as we try to hone in on
// the most optimal values, it doesn't make any sense to go above a threshold,
// even if everything is slow and screwy.
const ttlLimit = time.Minute
// tuningConfidenceCap is the number of active peers above which to stop detuning
// the confidence number. The idea here is that once we hone in on the capacity
// of a meaningful number of peers, adding one more should ot have a significant
// impact on things, so just ron with the originals.
const tuningConfidenceCap = 10
// tuningImpact is the influence that a new tuning target has on the previously
// cached value. This number is mostly just an out-of-the-blue heuristic that
// prevents the estimates from jumping around. There's no particular reason for
// the current value.
const tuningImpact = 0.25
// Tracker estimates the throughput capacity of a peer with regard to each data
// type it can deliver. The goal is to dynamically adjust request sizes to max
// out network throughput without overloading either the peer or th elocal node.
//
// By tracking in real time the latencies and bandiwdths peers exhibit for each
// packet type, it's possible to prevent overloading by detecting a slowdown on
// one type when another type is pushed too hard.
//
// Similarly, real time measurements also help avoid overloading the local net
// connection if our peers would otherwise be capable to deliver more, but the
// local link is saturated. In that case, the live measurements will force us
// to reduce request sizes until the throughput gets stable.
//
// Lastly, message rate measurements allows us to detect if a peer is unsuaully
// slow compared to other peers, in which case we can decide to keep it around
// or free up the slot so someone closer.
//
// Since throughput tracking and estimation adapts dynamically to live network
// conditions, it's fine to have multiple trackers locally track the same peer
// in different subsystem. The throughput will simply be distributed across the
// two trackers if both are highly active.
type Tracker struct {
// capacity is the number of items retrievable per second of a given type.
// It is analogous to bandwidth, but we deliberately avoided using bytes
// as the unit, since serving nodes also spend a lot of time loading data
// from disk, which is linear in the number of items, but mostly constant
// in their sizes.
//
// Callers of course are free to use the item counter as a byte counter if
// or when their protocol of choise if capped by bytes instead of items.
// (eg. eth.getHeaders vs snap.getAccountRange).
capacity map[uint64]float64
// roundtrip is the latency a peer in general responds to data requests.
// This number is not used inside the tracker, but is exposed to compare
// peers to each other and filter out slow ones. Note however, it only
// makes sense to compare RTTs if the caller caters request sizes for
// each peer to target the same RTT. There's no need to make this number
// the real networking RTT, we just need a number to compare peers with.
roundtrip time.Duration
lock sync.RWMutex
}
// NewTracker creates a new message rate tracker for a specific peer. An initial
// RTT is needed to avoid a peer getting marked as an outlier compared to others
// right after joining. It's suggested to use the median rtt across all peers to
// init a new peer tracker.
func NewTracker(caps map[uint64]float64, rtt time.Duration) *Tracker {
if caps == nil {
caps = make(map[uint64]float64)
}
return &Tracker{
capacity: caps,
roundtrip: rtt,
}
}
// Capacity calculates the number of items the peer is estimated to be able to
// retrieve within the alloted time slot. The method will round up any division
// errors and will add an additional overestimation ratio on top. The reason for
// overshooting the capacity is because certain message types might not increase
// the load proportionally to the requested items, so fetching a bit more might
// still take the same RTT. By forcefully overshooting by a small amount, we can
// avoid locking into a lower-that-real capacity.
func (t *Tracker) Capacity(kind uint64, targetRTT time.Duration) float64 {
t.lock.RLock()
defer t.lock.RUnlock()
// Calculate the actual measured throughput
throughput := t.capacity[kind] * float64(targetRTT) / float64(time.Second)
// Return an overestimation to force the peer out of a stuck minima, adding
// +1 in case the item count is too low for the overestimator to dent
return 1 + capacityOverestimation*throughput
}
// Update modifies the peer's capacity values for a specific data type with a new
// measurement. If the delivery is zero, the peer is assumed to have either timed
// out or to not have the requested data, resulting in a slash to 0 capacity. This
// avoids assigning the peer retrievals that it won't be able to honour.
func (t *Tracker) Update(kind uint64, elapsed time.Duration, items int) {
t.lock.Lock()
defer t.lock.Unlock()
// If nothing was delivered (timeout / unavailable data), reduce throughput
// to minimum
if items == 0 {
t.capacity[kind] = 0
return
}
// Otherwise update the throughput with a new measurement
if elapsed <= 0 {
elapsed = 1 // +1 (ns) to ensure non-zero divisor
}
measured := float64(items) / (float64(elapsed) / float64(time.Second))
t.capacity[kind] = (1-measurementImpact)*(t.capacity[kind]) + measurementImpact*measured
t.roundtrip = time.Duration((1-measurementImpact)*float64(t.roundtrip) + measurementImpact*float64(elapsed))
}
// Trackers is a set of message rate trackers across a number of peers with the
// goal of aggregating certain measurements across the entire set for outlier
// filtering and newly joining initialization.
type Trackers struct {
trackers map[string]*Tracker
// roundtrip is the current best guess as to what is a stable round trip time
// across the entire collection of connected peers. This is derived from the
// various trackers added, but is used as a cache to avoid recomputing on each
// network request. The value is updated once every RTT to avoid fluctuations
// caused by hiccups or peer events.
roundtrip time.Duration
// confidence represents the probability that the estimated roundtrip value
// is the real one across all our peers. The confidence value is used as an
// impact factor of new measurements on old estimates. As our connectivity
// stabilizes, this value gravitates towards 1, new measurements havinng
// almost no impact. If there's a large peer churn and few peers, then new
// measurements will impact it more. The confidence is increased with every
// packet and dropped with every new connection.
confidence float64
// tuned is the time instance the tracker recalculated its cached roundtrip
// value and confidence values. A cleaner way would be to have a heartbeat
// goroutine do it regularly, but that requires a lot of maintenance to just
// run every now and again.
tuned time.Time
// The fields below can be used to override certain default values. Their
// purpose is to allow quicker tests. Don't use them in production.
OverrideTTLLimit time.Duration
log log.Logger
lock sync.RWMutex
}
// NewTrackers creates an empty set of trackers to be filled with peers.
func NewTrackers(log log.Logger) *Trackers {
return &Trackers{
trackers: make(map[string]*Tracker),
roundtrip: rttMaxEstimate,
confidence: 1,
tuned: time.Now(),
OverrideTTLLimit: ttlLimit,
log: log,
}
}
// Track inserts a new tracker into the set.
func (t *Trackers) Track(id string, tracker *Tracker) error {
t.lock.Lock()
defer t.lock.Unlock()
if _, ok := t.trackers[id]; ok {
return errors.New("already tracking")
}
t.trackers[id] = tracker
t.detune()
return nil
}
// Untrack stops tracking a previously added peer.
func (t *Trackers) Untrack(id string) error {
t.lock.Lock()
defer t.lock.Unlock()
if _, ok := t.trackers[id]; !ok {
return errors.New("not tracking")
}
delete(t.trackers, id)
return nil
}
// MedianRoundTrip returns the median RTT across all known trackers. The purpose
// of the median RTT is to initialize a new peer with sane statistics that it will
// hopefully outperform. If it seriously underperforms, there's a risk of dropping
// the peer, but that is ok as we're aiming for a strong median.
func (t *Trackers) MedianRoundTrip() time.Duration {
t.lock.RLock()
defer t.lock.RUnlock()
return t.medianRoundTrip()
}
// medianRoundTrip is the internal lockless version of MedianRoundTrip to be used
// by the QoS tuner.
func (t *Trackers) medianRoundTrip() time.Duration {
// Gather all the currently measured round trip times
rtts := make([]float64, 0, len(t.trackers))
for _, tt := range t.trackers {
tt.lock.RLock()
rtts = append(rtts, float64(tt.roundtrip))
tt.lock.RUnlock()
}
sort.Float64s(rtts)
median := rttMaxEstimate
if qosTuningPeers <= len(rtts) {
median = time.Duration(rtts[qosTuningPeers/2]) // Median of our best few peers
} else if len(rtts) > 0 {
median = time.Duration(rtts[len(rtts)/2]) // Median of all out connected peers
}
// Restrict the RTT into some QoS defaults, irrelevant of true RTT
if median < rttMinEstimate {
median = rttMinEstimate
}
if median > rttMaxEstimate {
median = rttMaxEstimate
}
return median
}
// MeanCapacities returns the capacities averaged across all the added trackers.
// The purpos of the mean capacities are to initialize a new peer with some sane
// starting values that it will hopefully outperform. If the mean overshoots, the
// peer will be cut back to minimal capacity and given another chance.
func (t *Trackers) MeanCapacities() map[uint64]float64 {
t.lock.RLock()
defer t.lock.RUnlock()
return t.meanCapacities()
}
// meanCapacities is the internal lockless version of MeanCapacities used for
// debug logging.
func (t *Trackers) meanCapacities() map[uint64]float64 {
capacities := make(map[uint64]float64)
for _, tt := range t.trackers {
tt.lock.RLock()
for key, val := range tt.capacity {
capacities[key] += val
}
tt.lock.RUnlock()
}
for key, val := range capacities {
capacities[key] = val / float64(len(t.trackers))
}
return capacities
}
// TargetRoundTrip returns the current target round trip time for a request to
// complete in.The returned RTT is slightly under the estimated RTT. The reason
// is that message rate estimation is a 2 dimensional problem which is solvable
// for any RTT. The goal is to gravitate towards smaller RTTs instead of large
// messages, to result in a stabler download stream.
func (t *Trackers) TargetRoundTrip() time.Duration {
// Recalculate the internal caches if it's been a while
t.tune()
// Caches surely recent, return target roundtrip
t.lock.RLock()
defer t.lock.RUnlock()
return time.Duration(float64(t.roundtrip) * rttPushdownFactor)
}
// TargetTimeout returns the timeout allowance for a single request to finish
// under. The timeout is proportional to the roundtrip, but also takes into
// consideration the tracker's confidence in said roundtrip and scales it
// accordingly. The final value is capped to avoid runaway requests.
func (t *Trackers) TargetTimeout() time.Duration {
// Recalculate the internal caches if it's been a while
t.tune()
// Caches surely recent, return target timeout
t.lock.RLock()
defer t.lock.RUnlock()
return t.targetTimeout()
}
// targetTimeout is the internal lockless version of TargetTimeout to be used
// during QoS tuning.
func (t *Trackers) targetTimeout() time.Duration {
timeout := time.Duration(ttlScaling * float64(t.roundtrip) / t.confidence)
if timeout > t.OverrideTTLLimit {
timeout = t.OverrideTTLLimit
}
return timeout
}
// tune gathers the individual tracker statistics and updates the estimated
// request round trip time.
func (t *Trackers) tune() {
// Tune may be called concurrently all over the place, but we only want to
// periodically update and even then only once. First check if it was updated
// recently and abort if so.
t.lock.RLock()
dirty := time.Since(t.tuned) > t.roundtrip
t.lock.RUnlock()
if !dirty {
return
}
// If an update is needed, obtain a write lock but make sure we don't update
// it on all concurrent threads one by one.
t.lock.Lock()
defer t.lock.Unlock()
if dirty := time.Since(t.tuned) > t.roundtrip; !dirty {
return // A concurrent request beat us to the tuning
}
// First thread reaching the tuning point, update the estimates and return
t.roundtrip = time.Duration((1-tuningImpact)*float64(t.roundtrip) + tuningImpact*float64(t.medianRoundTrip()))
t.confidence = t.confidence + (1-t.confidence)/2
t.tuned = time.Now()
t.log.Debug("Recalculated msgrate QoS values", "rtt", t.roundtrip, "confidence", t.confidence, "ttl", t.targetTimeout(), "next", t.tuned.Add(t.roundtrip))
t.log.Trace("Debug dump of mean capacities", "caps", log.Lazy{Fn: t.meanCapacities})
}
// detune reduces the tracker's confidence in order to make fresh measurements
// have a larger impact on the estimates. It is meant to be used during new peer
// connections so they can have a proper impact on the estimates.
func (t *Trackers) detune() {
// If we have a single peer, confidence is always 1
if len(t.trackers) == 1 {
t.confidence = 1
return
}
// If we have a ton of peers, don't drop the confidence since there's enough
// remaining to retain the same throughput
if len(t.trackers) >= tuningConfidenceCap {
return
}
// Otherwise drop the confidence factor
peers := float64(len(t.trackers))
t.confidence = t.confidence * (peers - 1) / peers
if t.confidence < rttMinConfidence {
t.confidence = rttMinConfidence
}
t.log.Debug("Relaxed msgrate QoS values", "rtt", t.roundtrip, "confidence", t.confidence, "ttl", t.targetTimeout())
}
// Capacity is a helper function to access a specific tracker without having to
// track it explicitly outside.
func (t *Trackers) Capacity(id string, kind uint64, targetRTT time.Duration) float64 {
t.lock.RLock()
defer t.lock.RUnlock()
tracker := t.trackers[id]
if tracker == nil {
return 1 // Unregister race, don't return 0, it's a dangerous number
}
return tracker.Capacity(kind, targetRTT)
}
// Update is a helper function to access a specific tracker without having to
// track it explicitly outside.
func (t *Trackers) Update(id string, kind uint64, elapsed time.Duration, items int) {
t.lock.RLock()
defer t.lock.RUnlock()
if tracker := t.trackers[id]; tracker != nil {
tracker.Update(kind, elapsed, items)
}
}