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metrics.go
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/
metrics.go
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package peerstore
import (
"sync"
"time"
moved "github.com/libp2p/go-libp2p-core/peerstore"
"github.com/libp2p/go-libp2p-peer"
)
// LatencyEWMASmooting governs the decay of the EWMA (the speed
// at which it changes). This must be a normalized (0-1) value.
// 1 is 100% change, 0 is no change.
var LatencyEWMASmoothing = 0.1
// Deprecated: use github.com/libp2p/go-libp2p-core/peerstore.Metrics instead.
type Metrics = moved.Metrics
type metrics struct {
latmap map[peer.ID]time.Duration
latmu sync.RWMutex
}
func NewMetrics() *metrics {
return &metrics{
latmap: make(map[peer.ID]time.Duration),
}
}
// RecordLatency records a new latency measurement
func (m *metrics) RecordLatency(p peer.ID, next time.Duration) {
nextf := float64(next)
s := LatencyEWMASmoothing
if s > 1 || s < 0 {
s = 0.1 // ignore the knob. it's broken. look, it jiggles.
}
m.latmu.Lock()
ewma, found := m.latmap[p]
ewmaf := float64(ewma)
if !found {
m.latmap[p] = next // when no data, just take it as the mean.
} else {
nextf = ((1.0 - s) * ewmaf) + (s * nextf)
m.latmap[p] = time.Duration(nextf)
}
m.latmu.Unlock()
}
// LatencyEWMA returns an exponentially-weighted moving avg.
// of all measurements of a peer's latency.
func (m *metrics) LatencyEWMA(p peer.ID) time.Duration {
m.latmu.RLock()
lat := m.latmap[p]
m.latmu.RUnlock()
return time.Duration(lat)
}