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les: improved header fetcher and server statistics

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This commit is contained in:
Zsolt Felfoldi
2016-11-30 06:02:08 +01:00
parent e67500aa15
commit af8a742d00
10 changed files with 820 additions and 489 deletions
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204
les/serverpool.go
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@ -59,6 +59,9 @@ const (
targetKnownSelect = 3
// after dialTimeout, consider the server unavailable and adjust statistics
dialTimeout = time.Second * 30
// targetConnTime is the minimum expected connection duration before a server
// drops a client without any specific reason
targetConnTime = time.Minute * 10
// new entry selection weight calculation based on most recent discovery time:
// unity until discoverExpireStart, then exponential decay with discoverExpireConst
discoverExpireStart = time.Minute * 20
@ -75,6 +78,17 @@ const (
// node address selection weight is dropped by a factor of exp(-addrFailDropLn) after
// each unsuccessful connection (restored after a successful one)
addrFailDropLn = math.Ln2
// responseScoreTC and delayScoreTC are exponential decay time constants for
// calculating selection chances from response times and block delay times
responseScoreTC = time.Millisecond * 100
delayScoreTC = time.Second * 5
timeoutPow = 10
// peerSelectMinWeight is added to calculated weights at request peer selection
// to give poorly performing peers a little chance of coming back
peerSelectMinWeight = 0.005
// initStatsWeight is used to initialize previously unknown peers with good
// statistics to give a chance to prove themselves
initStatsWeight = 1
)
// serverPool implements a pool for storing and selecting newly discovered and already
@ -95,6 +109,7 @@ type serverPool struct {
entries map[discover.NodeID]*poolEntry
lock sync.Mutex
timeout, enableRetry chan *poolEntry
adjustStats chan poolStatAdjust
knownQueue, newQueue poolEntryQueue
knownSelect, newSelect *weightedRandomSelect
@ -112,6 +127,7 @@ func newServerPool(db ethdb.Database, dbPrefix []byte, server *p2p.Server, topic
wg: wg,
entries: make(map[discover.NodeID]*poolEntry),
timeout: make(chan *poolEntry, 1),
adjustStats: make(chan poolStatAdjust, 100),
enableRetry: make(chan *poolEntry, 1),
knownSelect: newWeightedRandomSelect(),
newSelect: newWeightedRandomSelect(),
@ -139,18 +155,19 @@ func newServerPool(db ethdb.Database, dbPrefix []byte, server *p2p.Server, topic
// Otherwise, the connection should be rejected.
// Note that whenever a connection has been accepted and a pool entry has been returned,
// disconnect should also always be called.
func (pool *serverPool) connect(id discover.NodeID, ip net.IP, port uint16) *poolEntry {
func (pool *serverPool) connect(p *peer, ip net.IP, port uint16) *poolEntry {
pool.lock.Lock()
defer pool.lock.Unlock()
entry := pool.entries[id]
entry := pool.entries[p.ID()]
if entry == nil {
return nil
}
glog.V(logger.Debug).Infof("connecting to %v, state: %v", id.String(), entry.state)
glog.V(logger.Debug).Infof("connecting to %v, state: %v", p.id, entry.state)
if entry.state != psDialed {
return nil
}
pool.connWg.Add(1)
entry.peer = p
entry.state = psConnected
addr := &poolEntryAddress{
ip: ip,
@ -172,42 +189,111 @@ func (pool *serverPool) registered(entry *poolEntry) {
defer pool.lock.Unlock()
entry.state = psRegistered
entry.regTime = mclock.Now()
if !entry.known {
pool.newQueue.remove(entry)
entry.known = true
}
pool.knownQueue.setLatest(entry)
entry.shortRetry = shortRetryCnt
entry.connectStats.add(1)
}
// disconnect should be called when ending a connection. Service quality statistics
// can be updated optionally (not updated if no registration happened, in this case
// only connection statistics are updated, just like in case of timeout)
func (pool *serverPool) disconnect(entry *poolEntry, quality float64, setQuality bool) {
func (pool *serverPool) disconnect(entry *poolEntry) {
glog.V(logger.Debug).Infof("disconnected %v", entry.id.String())
pool.lock.Lock()
defer pool.lock.Unlock()
if entry.state != psRegistered {
setQuality = false
if entry.state == psRegistered {
connTime := mclock.Now() - entry.regTime
connAdjust := float64(connTime) / float64(targetConnTime)
if connAdjust > 1 {
connAdjust = 1
}
stopped := false
select {
case <-pool.quit:
stopped = true
default:
}
if stopped {
entry.connectStats.add(1, connAdjust)
} else {
entry.connectStats.add(connAdjust, 1)
}
}
entry.state = psNotConnected
if entry.knownSelected {
pool.knownSelected--
} else {
pool.newSelected--
}
if setQuality {
glog.V(logger.Debug).Infof("update quality %v %v", quality, entry.id.String())
entry.qualityStats.add(quality)
} else {
glog.V(logger.Debug).Infof("do not update quality")
}
pool.setRetryDial(entry)
pool.connWg.Done()
}
const (
pseBlockDelay = iota
pseResponseTime
pseResponseTimeout
)
// poolStatAdjust records are sent to adjust peer block delay/response time statistics
type poolStatAdjust struct {
adjustType int
entry *poolEntry
time time.Duration
}
// adjustBlockDelay adjusts the block announce delay statistics of a node
func (pool *serverPool) adjustBlockDelay(entry *poolEntry, time time.Duration) {
pool.adjustStats <- poolStatAdjust{pseBlockDelay, entry, time}
}
// adjustResponseTime adjusts the request response time statistics of a node
func (pool *serverPool) adjustResponseTime(entry *poolEntry, time time.Duration, timeout bool) {
if timeout {
pool.adjustStats <- poolStatAdjust{pseResponseTimeout, entry, time}
} else {
pool.adjustStats <- poolStatAdjust{pseResponseTime, entry, time}
}
}
type selectPeerItem struct {
peer *peer
weight int64
}
func (sp selectPeerItem) Weight() int64 {
return sp.weight
}
// selectPeer selects a suitable peer for a request
func (pool *serverPool) selectPeer(canSend func(*peer) (bool, uint64)) *peer {
pool.lock.Lock()
defer pool.lock.Unlock()
sel := newWeightedRandomSelect()
for _, entry := range pool.entries {
if entry.state == psRegistered {
p := entry.peer
ok, cost := canSend(p)
if ok {
w := int64(1000000000 * (peerSelectMinWeight + math.Exp(-(entry.responseStats.recentAvg()+float64(cost))/float64(responseScoreTC))*math.Pow((1-entry.timeoutStats.recentAvg()), timeoutPow)))
sel.update(selectPeerItem{peer: p, weight: w})
}
}
}
choice := sel.choose()
if choice == nil {
return nil
}
return choice.(selectPeerItem).peer
}
// eventLoop handles pool events and mutex locking for all internal functions
func (pool *serverPool) eventLoop() {
lookupCnt := 0
@ -230,6 +316,19 @@ func (pool *serverPool) eventLoop() {
}
pool.lock.Unlock()
case adj := <-pool.adjustStats:
pool.lock.Lock()
switch adj.adjustType {
case pseBlockDelay:
adj.entry.delayStats.add(float64(adj.time), 1)
case pseResponseTime:
adj.entry.responseStats.add(float64(adj.time), 1)
adj.entry.timeoutStats.add(0, 1)
case pseResponseTimeout:
adj.entry.timeoutStats.add(1, 1)
}
pool.lock.Unlock()
case node := <-pool.discNodes:
pool.lock.Lock()
now := mclock.Now()
@ -244,6 +343,11 @@ func (pool *serverPool) eventLoop() {
shortRetry: shortRetryCnt,
}
pool.entries[id] = entry
// initialize previously unknown peers with good statistics to give a chance to prove themselves
entry.connectStats.add(1, initStatsWeight)
entry.delayStats.add(0, initStatsWeight)
entry.responseStats.add(0, initStatsWeight)
entry.timeoutStats.add(0, initStatsWeight)
}
entry.lastDiscovered = now
addr := &poolEntryAddress{
@ -298,9 +402,8 @@ func (pool *serverPool) loadNodes() {
glog.V(logger.Debug).Infof("node list decode error: %v", err)
return
}
glog.V(logger.Debug).Infof("loaded node list")
for _, e := range list {
glog.V(logger.Debug).Infof(" adding node %v fails: %v connStats sum: %v cnt: %v qualityStats sum: %v cnt: %v", e.id.String()+"@"+e.lastConnected.strKey(), e.lastConnected.fails, e.connectStats.sum, e.connectStats.cnt, e.qualityStats.sum, e.qualityStats.cnt)
glog.V(logger.Debug).Infof("loaded server stats %016x fails: %v connStats: %v / %v delayStats: %v / %v responseStats: %v / %v timeoutStats: %v / %v", e.id[0:8], e.lastConnected.fails, e.connectStats.avg, e.connectStats.weight, time.Duration(e.delayStats.avg), e.delayStats.weight, time.Duration(e.responseStats.avg), e.responseStats.weight, e.timeoutStats.avg, e.timeoutStats.weight)
pool.entries[e.id] = e
pool.knownQueue.setLatest(e)
pool.knownSelect.update((*knownEntry)(e))
@ -433,7 +536,7 @@ func (pool *serverPool) checkDialTimeout(entry *poolEntry) {
} else {
pool.newSelected--
}
entry.connectStats.add(0)
entry.connectStats.add(0, 1)
entry.dialed.fails++
pool.setRetryDial(entry)
}
@ -447,33 +550,36 @@ const (
// poolEntry represents a server node and stores its current state and statistics.
type poolEntry struct {
peer *peer
id discover.NodeID
addr map[string]*poolEntryAddress
lastConnected, dialed *poolEntryAddress
addrSelect weightedRandomSelect
lastDiscovered mclock.AbsTime
known, knownSelected bool
connectStats, qualityStats poolStats
state int
queueIdx int
removed bool
lastDiscovered mclock.AbsTime
known, knownSelected bool
connectStats, delayStats poolStats
responseStats, timeoutStats poolStats
state int
regTime mclock.AbsTime
queueIdx int
removed bool
delayedRetry bool
shortRetry int
}
func (e *poolEntry) EncodeRLP(w io.Writer) error {
return rlp.Encode(w, []interface{}{e.id, e.lastConnected.ip, e.lastConnected.port, e.lastConnected.fails, &e.connectStats, &e.qualityStats})
return rlp.Encode(w, []interface{}{e.id, e.lastConnected.ip, e.lastConnected.port, e.lastConnected.fails, &e.connectStats, &e.delayStats, &e.responseStats, &e.timeoutStats})
}
func (e *poolEntry) DecodeRLP(s *rlp.Stream) error {
var entry struct {
ID discover.NodeID
IP net.IP
Port uint16
Fails uint
CStat, QStat poolStats
ID discover.NodeID
IP net.IP
Port uint16
Fails uint
CStat, DStat, RStat, TStat poolStats
}
if err := s.Decode(&entry); err != nil {
return err
@ -486,7 +592,9 @@ func (e *poolEntry) DecodeRLP(s *rlp.Stream) error {
e.addrSelect.update(addr)
e.lastConnected = addr
e.connectStats = entry.CStat
e.qualityStats = entry.QStat
e.delayStats = entry.DStat
e.responseStats = entry.RStat
e.timeoutStats = entry.TStat
e.shortRetry = shortRetryCnt
e.known = true
return nil
@ -516,7 +624,7 @@ func (e *knownEntry) Weight() int64 {
if e.state != psNotConnected || !e.known || e.delayedRetry {
return 0
}
return int64(1000000000 * e.connectStats.recentAvg() * (e.qualityStats.recentAvg() + 0.001) * math.Exp(-float64(e.lastConnected.fails)*failDropLn))
return int64(1000000000 * e.connectStats.recentAvg() * math.Exp(-float64(e.lastConnected.fails)*failDropLn-e.responseStats.recentAvg()/float64(responseScoreTC)-e.delayStats.recentAvg()/float64(delayScoreTC)) * math.Pow((1-e.timeoutStats.recentAvg()), timeoutPow))
}
// poolEntryAddress is a separate object because currently it is necessary to remember
@ -544,18 +652,17 @@ func (a *poolEntryAddress) strKey() string {
// pstatRecentAdjust with each update and also returned exponentially to the
// average with the time constant pstatReturnToMeanTC
type poolStats struct {
sum, avg, recent float64
cnt uint
lastRecalc mclock.AbsTime
sum, weight, avg, recent float64
lastRecalc mclock.AbsTime
}
// init initializes stats with a long term sum/update count pair retrieved from the database
func (s *poolStats) init(sum float64, cnt uint) {
func (s *poolStats) init(sum, weight float64) {
s.sum = sum
s.cnt = cnt
s.weight = weight
var avg float64
if cnt > 0 {
avg = s.sum / float64(cnt)
if weight > 0 {
avg = s.sum / weight
}
s.avg = avg
s.recent = avg
@ -566,16 +673,22 @@ func (s *poolStats) init(sum float64, cnt uint) {
func (s *poolStats) recalc() {
now := mclock.Now()
s.recent = s.avg + (s.recent-s.avg)*math.Exp(-float64(now-s.lastRecalc)/float64(pstatReturnToMeanTC))
if s.cnt > 0 {
s.avg = s.sum / float64(s.cnt)
if s.sum == 0 {
s.avg = 0
} else {
if s.sum > s.weight*1e30 {
s.avg = 1e30
} else {
s.avg = s.sum / s.weight
}
}
s.lastRecalc = now
}
// add updates the stats with a new value
func (s *poolStats) add(val float64) {
s.cnt++
s.sum += val
func (s *poolStats) add(value, weight float64) {
s.weight += weight
s.sum += value * weight
s.recalc()
}
@ -586,18 +699,17 @@ func (s *poolStats) recentAvg() float64 {
}
func (s *poolStats) EncodeRLP(w io.Writer) error {
return rlp.Encode(w, []interface{}{math.Float64bits(s.sum), s.cnt})
return rlp.Encode(w, []interface{}{math.Float64bits(s.sum), math.Float64bits(s.weight)})
}
func (s *poolStats) DecodeRLP(st *rlp.Stream) error {
var stats struct {
SumUint uint64
Cnt uint
SumUint, WeightUint uint64
}
if err := st.Decode(&stats); err != nil {
return err
}
s.init(math.Float64frombits(stats.SumUint), stats.Cnt)
s.init(math.Float64frombits(stats.SumUint), math.Float64frombits(stats.WeightUint))
return nil
}