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package metrics
import (
"runtime/debug"
"time"
)
var (
debugMetrics struct {
GCStats struct {
LastGC Gauge
NumGC Gauge
Pause Histogram
//PauseQuantiles Histogram
PauseTotal Gauge
}
ReadGCStats Timer
}
gcStats debug.GCStats
)
// Capture new values for the Go garbage collector statistics exported in
// debug.GCStats. This is designed to be called as a goroutine.
func CaptureDebugGCStats(r Registry, d time.Duration) {
for _ = range time.Tick(d) {
CaptureDebugGCStatsOnce(r)
}
}
// Capture new values for the Go garbage collector statistics exported in
// debug.GCStats. This is designed to be called in a background goroutine.
// Giving a registry which has not been given to RegisterDebugGCStats will
// panic.
//
// Be careful (but much less so) with this because debug.ReadGCStats calls
// the C function runtime·lock(runtime·mheap) which, while not a stop-the-world
// operation, isn't something you want to be doing all the time.
func CaptureDebugGCStatsOnce(r Registry) {
lastGC := gcStats.LastGC
t := time.Now()
debug.ReadGCStats(&gcStats)
debugMetrics.ReadGCStats.UpdateSince(t)
debugMetrics.GCStats.LastGC.Update(int64(gcStats.LastGC.UnixNano()))
debugMetrics.GCStats.NumGC.Update(int64(gcStats.NumGC))
if lastGC != gcStats.LastGC && 0 < len(gcStats.Pause) {
debugMetrics.GCStats.Pause.Update(int64(gcStats.Pause[0]))
}
//debugMetrics.GCStats.PauseQuantiles.Update(gcStats.PauseQuantiles)
debugMetrics.GCStats.PauseTotal.Update(int64(gcStats.PauseTotal))
}
// Register metrics for the Go garbage collector statistics exported in
// debug.GCStats. The metrics are named by their fully-qualified Go symbols,
// i.e. debug.GCStats.PauseTotal.
func RegisterDebugGCStats(r Registry) {
debugMetrics.GCStats.LastGC = NewGauge()
debugMetrics.GCStats.NumGC = NewGauge()
debugMetrics.GCStats.Pause = NewHistogram(NewExpDecaySample(1028, 0.015))
//debugMetrics.GCStats.PauseQuantiles = NewHistogram(NewExpDecaySample(1028, 0.015))
debugMetrics.GCStats.PauseTotal = NewGauge()
debugMetrics.ReadGCStats = NewTimer()
r.Register("debug.GCStats.LastGC", debugMetrics.GCStats.LastGC)
r.Register("debug.GCStats.NumGC", debugMetrics.GCStats.NumGC)
r.Register("debug.GCStats.Pause", debugMetrics.GCStats.Pause)
//r.Register("debug.GCStats.PauseQuantiles", debugMetrics.GCStats.PauseQuantiles)
r.Register("debug.GCStats.PauseTotal", debugMetrics.GCStats.PauseTotal)
r.Register("debug.ReadGCStats", debugMetrics.ReadGCStats)
}
// Allocate an initial slice for gcStats.Pause to avoid allocations during
// normal operation.
func init() {
gcStats.Pause = make([]time.Duration, 11)
}