ceremonyclient/go-libp2p/p2p/host/peerstore/metrics.go

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2023-08-21 03:50:38 +00:00
package peerstore
import (
"sync"
"time"
"github.com/libp2p/go-libp2p/core/peer"
)
// LatencyEWMASmoothing 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
type metrics struct {
mutex sync.RWMutex
latmap map[peer.ID]time.Duration
}
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.mutex.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.mutex.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.mutex.RLock()
defer m.mutex.RUnlock()
return m.latmap[p]
}
func (m *metrics) RemovePeer(p peer.ID) {
m.mutex.Lock()
delete(m.latmap, p)
m.mutex.Unlock()
}