metrics: improve reading Go runtime metrics (#25886)

This changes how we read performance metrics from the Go runtime. Instead
of using runtime.ReadMemStats, we now rely on the API provided by package
runtime/metrics.

runtime/metrics provides more accurate information. For example, the new
interface has better reporting of memory use. In my testing, the reported
value of held memory more accurately reflects the usage reported by the OS.

The semantics of metrics system/memory/allocs and system/memory/frees have
changed to report amounts in bytes. ReadMemStats only reported the count of
allocations in number-of-objects. This is imprecise: 'tiny objects' are not
counted because the runtime allocates them in batches; and certain
improvements in allocation behavior, such as struct size optimizations,
will be less visible when the number of allocs doesn't change.

Changing allocation reports to be in bytes makes it appear in graphs that
lots more is being allocated. I don't think that's a problem because this
metric is primarily interesting for geth developers.

The metric system/memory/pauses has been changed to report statistical
values from the histogram provided by the runtime. Its name in influxdb has
changed from geth.system/memory/pauses.meter to
geth.system/memory/pauses.histogram.

We also have a new histogram metric, system/cpu/schedlatency, reporting the
Go scheduler latency.
This commit is contained in:
Felix Lange 2022-11-11 13:16:13 +01:00 committed by GitHub
parent 62c973eba6
commit c539bda166
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
11 changed files with 598 additions and 427 deletions

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@ -160,27 +160,28 @@ func (r *reporter) send() error {
})
case metrics.Histogram:
ms := metric.Snapshot()
if ms.Count() > 0 {
ps := ms.Percentiles([]float64{0.5, 0.75, 0.95, 0.99, 0.999, 0.9999})
ps := ms.Percentiles([]float64{0.25, 0.5, 0.75, 0.95, 0.99, 0.999, 0.9999})
fields := map[string]interface{}{
"count": ms.Count(),
"max": ms.Max(),
"mean": ms.Mean(),
"min": ms.Min(),
"stddev": ms.StdDev(),
"variance": ms.Variance(),
"p25": ps[0],
"p50": ps[1],
"p75": ps[2],
"p95": ps[3],
"p99": ps[4],
"p999": ps[5],
"p9999": ps[6],
}
pts = append(pts, client.Point{
Measurement: fmt.Sprintf("%s%s.histogram", namespace, name),
Tags: r.tags,
Fields: map[string]interface{}{
"count": ms.Count(),
"max": ms.Max(),
"mean": ms.Mean(),
"min": ms.Min(),
"stddev": ms.StdDev(),
"variance": ms.Variance(),
"p50": ps[0],
"p75": ps[1],
"p95": ps[2],
"p99": ps[3],
"p999": ps[4],
"p9999": ps[5],
},
Time: now,
Fields: fields,
Time: now,
})
}
case metrics.Meter:

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@ -7,7 +7,8 @@ package metrics
import (
"os"
"runtime"
"runtime/metrics"
"runtime/pprof"
"strings"
"time"
@ -54,38 +55,106 @@ func init() {
}
}
// CollectProcessMetrics periodically collects various metrics about the running
// process.
var threadCreateProfile = pprof.Lookup("threadcreate")
type runtimeStats struct {
GCPauses *metrics.Float64Histogram
GCAllocBytes uint64
GCFreedBytes uint64
MemTotal uint64
HeapObjects uint64
HeapFree uint64
HeapReleased uint64
HeapUnused uint64
Goroutines uint64
SchedLatency *metrics.Float64Histogram
}
var runtimeSamples = []metrics.Sample{
{Name: "/gc/pauses:seconds"}, // histogram
{Name: "/gc/heap/allocs:bytes"},
{Name: "/gc/heap/frees:bytes"},
{Name: "/memory/classes/total:bytes"},
{Name: "/memory/classes/heap/objects:bytes"},
{Name: "/memory/classes/heap/free:bytes"},
{Name: "/memory/classes/heap/released:bytes"},
{Name: "/memory/classes/heap/unused:bytes"},
{Name: "/sched/goroutines:goroutines"},
{Name: "/sched/latencies:seconds"}, // histogram
}
func readRuntimeStats(v *runtimeStats) {
metrics.Read(runtimeSamples)
for _, s := range runtimeSamples {
// Skip invalid/unknown metrics. This is needed because some metrics
// are unavailable in older Go versions, and attempting to read a 'bad'
// metric panics.
if s.Value.Kind() == metrics.KindBad {
continue
}
switch s.Name {
case "/gc/pauses:seconds":
v.GCPauses = s.Value.Float64Histogram()
case "/gc/heap/allocs:bytes":
v.GCAllocBytes = s.Value.Uint64()
case "/gc/heap/frees:bytes":
v.GCFreedBytes = s.Value.Uint64()
case "/memory/classes/total:bytes":
v.MemTotal = s.Value.Uint64()
case "/memory/classes/heap/objects:bytes":
v.HeapObjects = s.Value.Uint64()
case "/memory/classes/heap/free:bytes":
v.HeapFree = s.Value.Uint64()
case "/memory/classes/heap/released:bytes":
v.HeapReleased = s.Value.Uint64()
case "/memory/classes/heap/unused:bytes":
v.HeapUnused = s.Value.Uint64()
case "/sched/goroutines:goroutines":
v.Goroutines = s.Value.Uint64()
case "/sched/latencies:seconds":
v.SchedLatency = s.Value.Float64Histogram()
}
}
}
// CollectProcessMetrics periodically collects various metrics about the running process.
func CollectProcessMetrics(refresh time.Duration) {
// Short circuit if the metrics system is disabled
if !Enabled {
return
}
refreshFreq := int64(refresh / time.Second)
// Create the various data collectors
cpuStats := make([]*CPUStats, 2)
memstats := make([]*runtime.MemStats, 2)
diskstats := make([]*DiskStats, 2)
for i := 0; i < len(memstats); i++ {
cpuStats[i] = new(CPUStats)
memstats[i] = new(runtime.MemStats)
diskstats[i] = new(DiskStats)
}
var (
cpustats = make([]CPUStats, 2)
diskstats = make([]DiskStats, 2)
rstats = make([]runtimeStats, 2)
)
// This scale factor is used for the runtime's time metrics. It's useful to convert to
// ns here because the runtime gives times in float seconds, but runtimeHistogram can
// only provide integers for the minimum and maximum values.
const secondsToNs = float64(time.Second)
// Define the various metrics to collect
var (
cpuSysLoad = GetOrRegisterGauge("system/cpu/sysload", DefaultRegistry)
cpuSysWait = GetOrRegisterGauge("system/cpu/syswait", DefaultRegistry)
cpuProcLoad = GetOrRegisterGauge("system/cpu/procload", DefaultRegistry)
cpuThreads = GetOrRegisterGauge("system/cpu/threads", DefaultRegistry)
cpuGoroutines = GetOrRegisterGauge("system/cpu/goroutines", DefaultRegistry)
memPauses = GetOrRegisterMeter("system/memory/pauses", DefaultRegistry)
memAllocs = GetOrRegisterMeter("system/memory/allocs", DefaultRegistry)
memFrees = GetOrRegisterMeter("system/memory/frees", DefaultRegistry)
memHeld = GetOrRegisterGauge("system/memory/held", DefaultRegistry)
memUsed = GetOrRegisterGauge("system/memory/used", DefaultRegistry)
cpuSysLoad = GetOrRegisterGauge("system/cpu/sysload", DefaultRegistry)
cpuSysWait = GetOrRegisterGauge("system/cpu/syswait", DefaultRegistry)
cpuProcLoad = GetOrRegisterGauge("system/cpu/procload", DefaultRegistry)
cpuThreads = GetOrRegisterGauge("system/cpu/threads", DefaultRegistry)
cpuGoroutines = GetOrRegisterGauge("system/cpu/goroutines", DefaultRegistry)
cpuSchedLatency = getOrRegisterRuntimeHistogram("system/cpu/schedlatency", secondsToNs, nil)
memPauses = getOrRegisterRuntimeHistogram("system/memory/pauses", secondsToNs, nil)
memAllocs = GetOrRegisterMeter("system/memory/allocs", DefaultRegistry)
memFrees = GetOrRegisterMeter("system/memory/frees", DefaultRegistry)
memTotal = GetOrRegisterGauge("system/memory/held", DefaultRegistry)
heapUsed = GetOrRegisterGauge("system/memory/used", DefaultRegistry)
heapObjects = GetOrRegisterGauge("system/memory/objects", DefaultRegistry)
diskReads = GetOrRegisterMeter("system/disk/readcount", DefaultRegistry)
diskReadBytes = GetOrRegisterMeter("system/disk/readdata", DefaultRegistry)
diskReadBytesCounter = GetOrRegisterCounter("system/disk/readbytes", DefaultRegistry)
@ -93,34 +162,43 @@ func CollectProcessMetrics(refresh time.Duration) {
diskWriteBytes = GetOrRegisterMeter("system/disk/writedata", DefaultRegistry)
diskWriteBytesCounter = GetOrRegisterCounter("system/disk/writebytes", DefaultRegistry)
)
// Iterate loading the different stats and updating the meters
for i := 1; ; i++ {
location1 := i % 2
location2 := (i - 1) % 2
ReadCPUStats(cpuStats[location1])
cpuSysLoad.Update((cpuStats[location1].GlobalTime - cpuStats[location2].GlobalTime) / refreshFreq)
cpuSysWait.Update((cpuStats[location1].GlobalWait - cpuStats[location2].GlobalWait) / refreshFreq)
cpuProcLoad.Update((cpuStats[location1].LocalTime - cpuStats[location2].LocalTime) / refreshFreq)
// Iterate loading the different stats and updating the meters.
now, prev := 0, 1
for ; ; now, prev = prev, now {
// CPU
ReadCPUStats(&cpustats[now])
cpuSysLoad.Update((cpustats[now].GlobalTime - cpustats[prev].GlobalTime) / refreshFreq)
cpuSysWait.Update((cpustats[now].GlobalWait - cpustats[prev].GlobalWait) / refreshFreq)
cpuProcLoad.Update((cpustats[now].LocalTime - cpustats[prev].LocalTime) / refreshFreq)
// Threads
cpuThreads.Update(int64(threadCreateProfile.Count()))
cpuGoroutines.Update(int64(runtime.NumGoroutine()))
runtime.ReadMemStats(memstats[location1])
memPauses.Mark(int64(memstats[location1].PauseTotalNs - memstats[location2].PauseTotalNs))
memAllocs.Mark(int64(memstats[location1].Mallocs - memstats[location2].Mallocs))
memFrees.Mark(int64(memstats[location1].Frees - memstats[location2].Frees))
memHeld.Update(int64(memstats[location1].HeapSys - memstats[location1].HeapReleased))
memUsed.Update(int64(memstats[location1].Alloc))
// Go runtime metrics
readRuntimeStats(&rstats[now])
if ReadDiskStats(diskstats[location1]) == nil {
diskReads.Mark(diskstats[location1].ReadCount - diskstats[location2].ReadCount)
diskReadBytes.Mark(diskstats[location1].ReadBytes - diskstats[location2].ReadBytes)
diskWrites.Mark(diskstats[location1].WriteCount - diskstats[location2].WriteCount)
diskWriteBytes.Mark(diskstats[location1].WriteBytes - diskstats[location2].WriteBytes)
cpuGoroutines.Update(int64(rstats[now].Goroutines))
cpuSchedLatency.update(rstats[now].SchedLatency)
memPauses.update(rstats[now].GCPauses)
diskReadBytesCounter.Inc(diskstats[location1].ReadBytes - diskstats[location2].ReadBytes)
diskWriteBytesCounter.Inc(diskstats[location1].WriteBytes - diskstats[location2].WriteBytes)
memAllocs.Mark(int64(rstats[now].GCAllocBytes - rstats[prev].GCAllocBytes))
memFrees.Mark(int64(rstats[now].GCFreedBytes - rstats[prev].GCFreedBytes))
memTotal.Update(int64(rstats[now].MemTotal))
heapUsed.Update(int64(rstats[now].MemTotal - rstats[now].HeapUnused - rstats[now].HeapFree - rstats[now].HeapReleased))
heapObjects.Update(int64(rstats[now].HeapObjects))
// Disk
if ReadDiskStats(&diskstats[now]) == nil {
diskReads.Mark(diskstats[now].ReadCount - diskstats[prev].ReadCount)
diskReadBytes.Mark(diskstats[now].ReadBytes - diskstats[prev].ReadBytes)
diskWrites.Mark(diskstats[now].WriteCount - diskstats[prev].WriteCount)
diskWriteBytes.Mark(diskstats[now].WriteBytes - diskstats[prev].WriteBytes)
diskReadBytesCounter.Inc(diskstats[now].ReadBytes - diskstats[prev].ReadBytes)
diskWriteBytesCounter.Inc(diskstats[now].WriteBytes - diskstats[prev].WriteBytes)
}
time.Sleep(refresh)
}
}

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@ -2,8 +2,6 @@ package metrics
import (
"fmt"
"io"
"log"
"sync"
"testing"
"time"
@ -11,11 +9,11 @@ import (
const FANOUT = 128
// Stop the compiler from complaining during debugging.
var (
_ = io.Discard
_ = log.LstdFlags
)
func TestReadRuntimeValues(t *testing.T) {
var v runtimeStats
readRuntimeStats(&v)
t.Logf("%+v", v)
}
func BenchmarkMetrics(b *testing.B) {
r := NewRegistry()
@ -26,7 +24,6 @@ func BenchmarkMetrics(b *testing.B) {
m := NewRegisteredMeter("meter", r)
t := NewRegisteredTimer("timer", r)
RegisterDebugGCStats(r)
RegisterRuntimeMemStats(r)
b.ResetTimer()
ch := make(chan bool)
@ -48,24 +45,6 @@ func BenchmarkMetrics(b *testing.B) {
}()
//*/
wgR := &sync.WaitGroup{}
//*
wgR.Add(1)
go func() {
defer wgR.Done()
//log.Println("go CaptureRuntimeMemStats")
for {
select {
case <-ch:
//log.Println("done CaptureRuntimeMemStats")
return
default:
CaptureRuntimeMemStatsOnce(r)
}
}
}()
//*/
wgW := &sync.WaitGroup{}
/*
wgW.Add(1)
@ -104,7 +83,6 @@ func BenchmarkMetrics(b *testing.B) {
wg.Wait()
close(ch)
wgD.Wait()
wgR.Wait()
wgW.Wait()
}

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@ -1,212 +0,0 @@
package metrics
import (
"runtime"
"runtime/pprof"
"time"
)
var (
memStats runtime.MemStats
runtimeMetrics struct {
MemStats struct {
Alloc Gauge
BuckHashSys Gauge
DebugGC Gauge
EnableGC Gauge
Frees Gauge
HeapAlloc Gauge
HeapIdle Gauge
HeapInuse Gauge
HeapObjects Gauge
HeapReleased Gauge
HeapSys Gauge
LastGC Gauge
Lookups Gauge
Mallocs Gauge
MCacheInuse Gauge
MCacheSys Gauge
MSpanInuse Gauge
MSpanSys Gauge
NextGC Gauge
NumGC Gauge
GCCPUFraction GaugeFloat64
PauseNs Histogram
PauseTotalNs Gauge
StackInuse Gauge
StackSys Gauge
Sys Gauge
TotalAlloc Gauge
}
NumCgoCall Gauge
NumGoroutine Gauge
NumThread Gauge
ReadMemStats Timer
}
frees uint64
lookups uint64
mallocs uint64
numGC uint32
numCgoCalls int64
threadCreateProfile = pprof.Lookup("threadcreate")
)
// Capture new values for the Go runtime statistics exported in
// runtime.MemStats. This is designed to be called as a goroutine.
func CaptureRuntimeMemStats(r Registry, d time.Duration) {
for range time.Tick(d) {
CaptureRuntimeMemStatsOnce(r)
}
}
// Capture new values for the Go runtime statistics exported in
// runtime.MemStats. This is designed to be called in a background
// goroutine. Giving a registry which has not been given to
// RegisterRuntimeMemStats will panic.
//
// Be very careful with this because runtime.ReadMemStats calls the C
// functions runtime·semacquire(&runtime·worldsema) and runtime·stoptheworld()
// and that last one does what it says on the tin.
func CaptureRuntimeMemStatsOnce(r Registry) {
t := time.Now()
runtime.ReadMemStats(&memStats) // This takes 50-200us.
runtimeMetrics.ReadMemStats.UpdateSince(t)
runtimeMetrics.MemStats.Alloc.Update(int64(memStats.Alloc))
runtimeMetrics.MemStats.BuckHashSys.Update(int64(memStats.BuckHashSys))
if memStats.DebugGC {
runtimeMetrics.MemStats.DebugGC.Update(1)
} else {
runtimeMetrics.MemStats.DebugGC.Update(0)
}
if memStats.EnableGC {
runtimeMetrics.MemStats.EnableGC.Update(1)
} else {
runtimeMetrics.MemStats.EnableGC.Update(0)
}
runtimeMetrics.MemStats.Frees.Update(int64(memStats.Frees - frees))
runtimeMetrics.MemStats.HeapAlloc.Update(int64(memStats.HeapAlloc))
runtimeMetrics.MemStats.HeapIdle.Update(int64(memStats.HeapIdle))
runtimeMetrics.MemStats.HeapInuse.Update(int64(memStats.HeapInuse))
runtimeMetrics.MemStats.HeapObjects.Update(int64(memStats.HeapObjects))
runtimeMetrics.MemStats.HeapReleased.Update(int64(memStats.HeapReleased))
runtimeMetrics.MemStats.HeapSys.Update(int64(memStats.HeapSys))
runtimeMetrics.MemStats.LastGC.Update(int64(memStats.LastGC))
runtimeMetrics.MemStats.Lookups.Update(int64(memStats.Lookups - lookups))
runtimeMetrics.MemStats.Mallocs.Update(int64(memStats.Mallocs - mallocs))
runtimeMetrics.MemStats.MCacheInuse.Update(int64(memStats.MCacheInuse))
runtimeMetrics.MemStats.MCacheSys.Update(int64(memStats.MCacheSys))
runtimeMetrics.MemStats.MSpanInuse.Update(int64(memStats.MSpanInuse))
runtimeMetrics.MemStats.MSpanSys.Update(int64(memStats.MSpanSys))
runtimeMetrics.MemStats.NextGC.Update(int64(memStats.NextGC))
runtimeMetrics.MemStats.NumGC.Update(int64(memStats.NumGC - numGC))
runtimeMetrics.MemStats.GCCPUFraction.Update(gcCPUFraction(&memStats))
// <https://code.google.com/p/go/source/browse/src/pkg/runtime/mgc0.c>
i := numGC % uint32(len(memStats.PauseNs))
ii := memStats.NumGC % uint32(len(memStats.PauseNs))
if memStats.NumGC-numGC >= uint32(len(memStats.PauseNs)) {
for i = 0; i < uint32(len(memStats.PauseNs)); i++ {
runtimeMetrics.MemStats.PauseNs.Update(int64(memStats.PauseNs[i]))
}
} else {
if i > ii {
for ; i < uint32(len(memStats.PauseNs)); i++ {
runtimeMetrics.MemStats.PauseNs.Update(int64(memStats.PauseNs[i]))
}
i = 0
}
for ; i < ii; i++ {
runtimeMetrics.MemStats.PauseNs.Update(int64(memStats.PauseNs[i]))
}
}
frees = memStats.Frees
lookups = memStats.Lookups
mallocs = memStats.Mallocs
numGC = memStats.NumGC
runtimeMetrics.MemStats.PauseTotalNs.Update(int64(memStats.PauseTotalNs))
runtimeMetrics.MemStats.StackInuse.Update(int64(memStats.StackInuse))
runtimeMetrics.MemStats.StackSys.Update(int64(memStats.StackSys))
runtimeMetrics.MemStats.Sys.Update(int64(memStats.Sys))
runtimeMetrics.MemStats.TotalAlloc.Update(int64(memStats.TotalAlloc))
currentNumCgoCalls := numCgoCall()
runtimeMetrics.NumCgoCall.Update(currentNumCgoCalls - numCgoCalls)
numCgoCalls = currentNumCgoCalls
runtimeMetrics.NumGoroutine.Update(int64(runtime.NumGoroutine()))
runtimeMetrics.NumThread.Update(int64(threadCreateProfile.Count()))
}
// Register runtimeMetrics for the Go runtime statistics exported in runtime and
// specifically runtime.MemStats. The runtimeMetrics are named by their
// fully-qualified Go symbols, i.e. runtime.MemStats.Alloc.
func RegisterRuntimeMemStats(r Registry) {
runtimeMetrics.MemStats.Alloc = NewGauge()
runtimeMetrics.MemStats.BuckHashSys = NewGauge()
runtimeMetrics.MemStats.DebugGC = NewGauge()
runtimeMetrics.MemStats.EnableGC = NewGauge()
runtimeMetrics.MemStats.Frees = NewGauge()
runtimeMetrics.MemStats.HeapAlloc = NewGauge()
runtimeMetrics.MemStats.HeapIdle = NewGauge()
runtimeMetrics.MemStats.HeapInuse = NewGauge()
runtimeMetrics.MemStats.HeapObjects = NewGauge()
runtimeMetrics.MemStats.HeapReleased = NewGauge()
runtimeMetrics.MemStats.HeapSys = NewGauge()
runtimeMetrics.MemStats.LastGC = NewGauge()
runtimeMetrics.MemStats.Lookups = NewGauge()
runtimeMetrics.MemStats.Mallocs = NewGauge()
runtimeMetrics.MemStats.MCacheInuse = NewGauge()
runtimeMetrics.MemStats.MCacheSys = NewGauge()
runtimeMetrics.MemStats.MSpanInuse = NewGauge()
runtimeMetrics.MemStats.MSpanSys = NewGauge()
runtimeMetrics.MemStats.NextGC = NewGauge()
runtimeMetrics.MemStats.NumGC = NewGauge()
runtimeMetrics.MemStats.GCCPUFraction = NewGaugeFloat64()
runtimeMetrics.MemStats.PauseNs = NewHistogram(NewExpDecaySample(1028, 0.015))
runtimeMetrics.MemStats.PauseTotalNs = NewGauge()
runtimeMetrics.MemStats.StackInuse = NewGauge()
runtimeMetrics.MemStats.StackSys = NewGauge()
runtimeMetrics.MemStats.Sys = NewGauge()
runtimeMetrics.MemStats.TotalAlloc = NewGauge()
runtimeMetrics.NumCgoCall = NewGauge()
runtimeMetrics.NumGoroutine = NewGauge()
runtimeMetrics.NumThread = NewGauge()
runtimeMetrics.ReadMemStats = NewTimer()
r.Register("runtime.MemStats.Alloc", runtimeMetrics.MemStats.Alloc)
r.Register("runtime.MemStats.BuckHashSys", runtimeMetrics.MemStats.BuckHashSys)
r.Register("runtime.MemStats.DebugGC", runtimeMetrics.MemStats.DebugGC)
r.Register("runtime.MemStats.EnableGC", runtimeMetrics.MemStats.EnableGC)
r.Register("runtime.MemStats.Frees", runtimeMetrics.MemStats.Frees)
r.Register("runtime.MemStats.HeapAlloc", runtimeMetrics.MemStats.HeapAlloc)
r.Register("runtime.MemStats.HeapIdle", runtimeMetrics.MemStats.HeapIdle)
r.Register("runtime.MemStats.HeapInuse", runtimeMetrics.MemStats.HeapInuse)
r.Register("runtime.MemStats.HeapObjects", runtimeMetrics.MemStats.HeapObjects)
r.Register("runtime.MemStats.HeapReleased", runtimeMetrics.MemStats.HeapReleased)
r.Register("runtime.MemStats.HeapSys", runtimeMetrics.MemStats.HeapSys)
r.Register("runtime.MemStats.LastGC", runtimeMetrics.MemStats.LastGC)
r.Register("runtime.MemStats.Lookups", runtimeMetrics.MemStats.Lookups)
r.Register("runtime.MemStats.Mallocs", runtimeMetrics.MemStats.Mallocs)
r.Register("runtime.MemStats.MCacheInuse", runtimeMetrics.MemStats.MCacheInuse)
r.Register("runtime.MemStats.MCacheSys", runtimeMetrics.MemStats.MCacheSys)
r.Register("runtime.MemStats.MSpanInuse", runtimeMetrics.MemStats.MSpanInuse)
r.Register("runtime.MemStats.MSpanSys", runtimeMetrics.MemStats.MSpanSys)
r.Register("runtime.MemStats.NextGC", runtimeMetrics.MemStats.NextGC)
r.Register("runtime.MemStats.NumGC", runtimeMetrics.MemStats.NumGC)
r.Register("runtime.MemStats.GCCPUFraction", runtimeMetrics.MemStats.GCCPUFraction)
r.Register("runtime.MemStats.PauseNs", runtimeMetrics.MemStats.PauseNs)
r.Register("runtime.MemStats.PauseTotalNs", runtimeMetrics.MemStats.PauseTotalNs)
r.Register("runtime.MemStats.StackInuse", runtimeMetrics.MemStats.StackInuse)
r.Register("runtime.MemStats.StackSys", runtimeMetrics.MemStats.StackSys)
r.Register("runtime.MemStats.Sys", runtimeMetrics.MemStats.Sys)
r.Register("runtime.MemStats.TotalAlloc", runtimeMetrics.MemStats.TotalAlloc)
r.Register("runtime.NumCgoCall", runtimeMetrics.NumCgoCall)
r.Register("runtime.NumGoroutine", runtimeMetrics.NumGoroutine)
r.Register("runtime.NumThread", runtimeMetrics.NumThread)
r.Register("runtime.ReadMemStats", runtimeMetrics.ReadMemStats)
}

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@ -1,10 +0,0 @@
//go:build cgo && !appengine && !js
// +build cgo,!appengine,!js
package metrics
import "runtime"
func numCgoCall() int64 {
return runtime.NumCgoCall()
}

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@ -1,10 +0,0 @@
//go:build go1.5
// +build go1.5
package metrics
import "runtime"
func gcCPUFraction(memStats *runtime.MemStats) float64 {
return memStats.GCCPUFraction
}

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@ -1,8 +0,0 @@
//go:build !cgo || appengine || js
// +build !cgo appengine js
package metrics
func numCgoCall() int64 {
return 0
}

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@ -1,10 +0,0 @@
//go:build !go1.5
// +build !go1.5
package metrics
import "runtime"
func gcCPUFraction(memStats *runtime.MemStats) float64 {
return 0
}

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@ -1,88 +0,0 @@
package metrics
import (
"runtime"
"testing"
"time"
)
func BenchmarkRuntimeMemStats(b *testing.B) {
r := NewRegistry()
RegisterRuntimeMemStats(r)
b.ResetTimer()
for i := 0; i < b.N; i++ {
CaptureRuntimeMemStatsOnce(r)
}
}
func TestRuntimeMemStats(t *testing.T) {
r := NewRegistry()
RegisterRuntimeMemStats(r)
CaptureRuntimeMemStatsOnce(r)
zero := runtimeMetrics.MemStats.PauseNs.Count() // Get a "zero" since GC may have run before these tests.
runtime.GC()
CaptureRuntimeMemStatsOnce(r)
if count := runtimeMetrics.MemStats.PauseNs.Count(); count-zero != 1 {
t.Fatal(count - zero)
}
runtime.GC()
runtime.GC()
CaptureRuntimeMemStatsOnce(r)
if count := runtimeMetrics.MemStats.PauseNs.Count(); count-zero != 3 {
t.Fatal(count - zero)
}
for i := 0; i < 256; i++ {
runtime.GC()
}
CaptureRuntimeMemStatsOnce(r)
if count := runtimeMetrics.MemStats.PauseNs.Count(); count-zero != 259 {
t.Fatal(count - zero)
}
for i := 0; i < 257; i++ {
runtime.GC()
}
CaptureRuntimeMemStatsOnce(r)
if count := runtimeMetrics.MemStats.PauseNs.Count(); count-zero != 515 { // We lost one because there were too many GCs between captures.
t.Fatal(count - zero)
}
}
func TestRuntimeMemStatsNumThread(t *testing.T) {
r := NewRegistry()
RegisterRuntimeMemStats(r)
CaptureRuntimeMemStatsOnce(r)
if value := runtimeMetrics.NumThread.Value(); value < 1 {
t.Fatalf("got NumThread: %d, wanted at least 1", value)
}
}
func TestRuntimeMemStatsBlocking(t *testing.T) {
if g := runtime.GOMAXPROCS(0); g < 2 {
t.Skipf("skipping TestRuntimeMemStatsBlocking with GOMAXPROCS=%d\n", g)
}
ch := make(chan int)
go testRuntimeMemStatsBlocking(ch)
var memStats runtime.MemStats
t0 := time.Now()
runtime.ReadMemStats(&memStats)
t1 := time.Now()
t.Log("i++ during runtime.ReadMemStats:", <-ch)
go testRuntimeMemStatsBlocking(ch)
d := t1.Sub(t0)
t.Log(d)
time.Sleep(d)
t.Log("i++ during time.Sleep:", <-ch)
}
func testRuntimeMemStatsBlocking(ch chan int) {
i := 0
for {
select {
case ch <- i:
return
default:
i++
}
}
}

319
metrics/runtimehistogram.go Normal file
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package metrics
import (
"math"
"runtime/metrics"
"sort"
"sync/atomic"
)
func getOrRegisterRuntimeHistogram(name string, scale float64, r Registry) *runtimeHistogram {
if r == nil {
r = DefaultRegistry
}
constructor := func() Histogram { return newRuntimeHistogram(scale) }
return r.GetOrRegister(name, constructor).(*runtimeHistogram)
}
// runtimeHistogram wraps a runtime/metrics histogram.
type runtimeHistogram struct {
v atomic.Value
scaleFactor float64
}
func newRuntimeHistogram(scale float64) *runtimeHistogram {
h := &runtimeHistogram{scaleFactor: scale}
h.update(&metrics.Float64Histogram{})
return h
}
func (h *runtimeHistogram) update(mh *metrics.Float64Histogram) {
if mh == nil {
// The update value can be nil if the current Go version doesn't support a
// requested metric. It's just easier to handle nil here than putting
// conditionals everywhere.
return
}
s := runtimeHistogramSnapshot{
Counts: make([]uint64, len(mh.Counts)),
Buckets: make([]float64, len(mh.Buckets)),
}
copy(s.Counts, mh.Counts)
copy(s.Buckets, mh.Buckets)
for i, b := range s.Buckets {
s.Buckets[i] = b * h.scaleFactor
}
h.v.Store(&s)
}
func (h *runtimeHistogram) load() *runtimeHistogramSnapshot {
return h.v.Load().(*runtimeHistogramSnapshot)
}
func (h *runtimeHistogram) Clear() {
panic("runtimeHistogram does not support Clear")
}
func (h *runtimeHistogram) Update(int64) {
panic("runtimeHistogram does not support Update")
}
func (h *runtimeHistogram) Sample() Sample {
return NilSample{}
}
// Snapshot returns a non-changing cop of the histogram.
func (h *runtimeHistogram) Snapshot() Histogram {
return h.load()
}
// Count returns the sample count.
func (h *runtimeHistogram) Count() int64 {
return h.load().Count()
}
// Mean returns an approximation of the mean.
func (h *runtimeHistogram) Mean() float64 {
return h.load().Mean()
}
// StdDev approximates the standard deviation of the histogram.
func (h *runtimeHistogram) StdDev() float64 {
return h.load().StdDev()
}
// Variance approximates the variance of the histogram.
func (h *runtimeHistogram) Variance() float64 {
return h.load().Variance()
}
// Percentile computes the p'th percentile value.
func (h *runtimeHistogram) Percentile(p float64) float64 {
return h.load().Percentile(p)
}
// Percentiles computes all requested percentile values.
func (h *runtimeHistogram) Percentiles(ps []float64) []float64 {
return h.load().Percentiles(ps)
}
// Max returns the highest sample value.
func (h *runtimeHistogram) Max() int64 {
return h.load().Max()
}
// Min returns the lowest sample value.
func (h *runtimeHistogram) Min() int64 {
return h.load().Min()
}
// Sum returns the sum of all sample values.
func (h *runtimeHistogram) Sum() int64 {
return h.load().Sum()
}
type runtimeHistogramSnapshot metrics.Float64Histogram
func (h *runtimeHistogramSnapshot) Clear() {
panic("runtimeHistogram does not support Clear")
}
func (h *runtimeHistogramSnapshot) Update(int64) {
panic("runtimeHistogram does not support Update")
}
func (h *runtimeHistogramSnapshot) Sample() Sample {
return NilSample{}
}
func (h *runtimeHistogramSnapshot) Snapshot() Histogram {
return h
}
// Count returns the sample count.
func (h *runtimeHistogramSnapshot) Count() int64 {
var count int64
for _, c := range h.Counts {
count += int64(c)
}
return count
}
// Mean returns an approximation of the mean.
func (h *runtimeHistogramSnapshot) Mean() float64 {
if len(h.Counts) == 0 {
return 0
}
mean, _ := h.mean()
return mean
}
// mean computes the mean and also the total sample count.
func (h *runtimeHistogramSnapshot) mean() (mean, totalCount float64) {
var sum float64
for i, c := range h.Counts {
midpoint := h.midpoint(i)
sum += midpoint * float64(c)
totalCount += float64(c)
}
return sum / totalCount, totalCount
}
func (h *runtimeHistogramSnapshot) midpoint(bucket int) float64 {
high := h.Buckets[bucket+1]
low := h.Buckets[bucket]
if math.IsInf(high, 1) {
// The edge of the highest bucket can be +Inf, and it's supposed to mean that this
// bucket contains all remaining samples > low. We can't get the middle of an
// infinite range, so just return the lower bound of this bucket instead.
return low
}
if math.IsInf(low, -1) {
// Similarly, we can get -Inf in the left edge of the lowest bucket,
// and it means the bucket contains all remaining values < high.
return high
}
return (low + high) / 2
}
// StdDev approximates the standard deviation of the histogram.
func (h *runtimeHistogramSnapshot) StdDev() float64 {
return math.Sqrt(h.Variance())
}
// Variance approximates the variance of the histogram.
func (h *runtimeHistogramSnapshot) Variance() float64 {
if len(h.Counts) == 0 {
return 0
}
mean, totalCount := h.mean()
if totalCount <= 1 {
// There is no variance when there are zero or one items.
return 0
}
var sum float64
for i, c := range h.Counts {
midpoint := h.midpoint(i)
d := midpoint - mean
sum += float64(c) * (d * d)
}
return sum / (totalCount - 1)
}
// Percentile computes the p'th percentile value.
func (h *runtimeHistogramSnapshot) Percentile(p float64) float64 {
threshold := float64(h.Count()) * p
values := [1]float64{threshold}
h.computePercentiles(values[:])
return values[0]
}
// Percentiles computes all requested percentile values.
func (h *runtimeHistogramSnapshot) Percentiles(ps []float64) []float64 {
// Compute threshold values. We need these to be sorted
// for the percentile computation, but restore the original
// order later, so keep the indexes as well.
count := float64(h.Count())
thresholds := make([]float64, len(ps))
indexes := make([]int, len(ps))
for i, percentile := range ps {
thresholds[i] = count * math.Max(0, math.Min(1.0, percentile))
indexes[i] = i
}
sort.Sort(floatsAscendingKeepingIndex{thresholds, indexes})
// Now compute. The result is stored back into the thresholds slice.
h.computePercentiles(thresholds)
// Put the result back into the requested order.
sort.Sort(floatsByIndex{thresholds, indexes})
return thresholds
}
func (h *runtimeHistogramSnapshot) computePercentiles(thresh []float64) {
var totalCount float64
for i, count := range h.Counts {
totalCount += float64(count)
for len(thresh) > 0 && thresh[0] < totalCount {
thresh[0] = h.Buckets[i]
thresh = thresh[1:]
}
if len(thresh) == 0 {
return
}
}
}
// Note: runtime/metrics.Float64Histogram is a collection of float64s, but the methods
// below need to return int64 to satisfy the interface. The histogram provided by runtime
// also doesn't keep track of individual samples, so results are approximated.
// Max returns the highest sample value.
func (h *runtimeHistogramSnapshot) Max() int64 {
for i := len(h.Counts) - 1; i >= 0; i-- {
count := h.Counts[i]
if count > 0 {
edge := h.Buckets[i+1]
if math.IsInf(edge, 1) {
edge = h.Buckets[i]
}
return int64(math.Ceil(edge))
}
}
return 0
}
// Min returns the lowest sample value.
func (h *runtimeHistogramSnapshot) Min() int64 {
for i, count := range h.Counts {
if count > 0 {
return int64(math.Floor(h.Buckets[i]))
}
}
return 0
}
// Sum returns the sum of all sample values.
func (h *runtimeHistogramSnapshot) Sum() int64 {
var sum float64
for i := range h.Counts {
sum += h.Buckets[i] * float64(h.Counts[i])
}
return int64(math.Ceil(sum))
}
type floatsAscendingKeepingIndex struct {
values []float64
indexes []int
}
func (s floatsAscendingKeepingIndex) Len() int {
return len(s.values)
}
func (s floatsAscendingKeepingIndex) Less(i, j int) bool {
return s.values[i] < s.values[j]
}
func (s floatsAscendingKeepingIndex) Swap(i, j int) {
s.values[i], s.values[j] = s.values[j], s.values[i]
s.indexes[i], s.indexes[j] = s.indexes[j], s.indexes[i]
}
type floatsByIndex struct {
values []float64
indexes []int
}
func (s floatsByIndex) Len() int {
return len(s.values)
}
func (s floatsByIndex) Less(i, j int) bool {
return s.indexes[i] < s.indexes[j]
}
func (s floatsByIndex) Swap(i, j int) {
s.values[i], s.values[j] = s.values[j], s.values[i]
s.indexes[i], s.indexes[j] = s.indexes[j], s.indexes[i]
}

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package metrics
import (
"fmt"
"math"
"reflect"
"runtime/metrics"
"testing"
)
var _ Histogram = (*runtimeHistogram)(nil)
type runtimeHistogramTest struct {
h metrics.Float64Histogram
Count int64
Min int64
Max int64
Sum int64
Mean float64
Variance float64
StdDev float64
Percentiles []float64 // .5 .8 .9 .99 .995
}
// This test checks the results of statistical functions implemented
// by runtimeHistogramSnapshot.
func TestRuntimeHistogramStats(t *testing.T) {
tests := []runtimeHistogramTest{
0: {
h: metrics.Float64Histogram{
Counts: []uint64{},
Buckets: []float64{},
},
Count: 0,
Max: 0,
Min: 0,
Sum: 0,
Mean: 0,
Variance: 0,
StdDev: 0,
Percentiles: []float64{0, 0, 0, 0, 0},
},
1: {
// This checks the case where the highest bucket is +Inf.
h: metrics.Float64Histogram{
Counts: []uint64{0, 1, 2},
Buckets: []float64{0, 0.5, 1, math.Inf(1)},
},
Count: 3,
Max: 1,
Min: 0,
Sum: 3,
Mean: 0.9166666,
Percentiles: []float64{1, 1, 1, 1, 1},
Variance: 0.020833,
StdDev: 0.144433,
},
2: {
h: metrics.Float64Histogram{
Counts: []uint64{8, 6, 3, 1},
Buckets: []float64{12, 16, 18, 24, 25},
},
Count: 18,
Max: 25,
Min: 12,
Sum: 270,
Mean: 16.75,
Variance: 10.3015,
StdDev: 3.2096,
Percentiles: []float64{16, 18, 18, 24, 24},
},
}
for i, test := range tests {
t.Run(fmt.Sprint(i), func(t *testing.T) {
s := runtimeHistogramSnapshot(test.h)
if v := s.Count(); v != test.Count {
t.Errorf("Count() = %v, want %v", v, test.Count)
}
if v := s.Min(); v != test.Min {
t.Errorf("Min() = %v, want %v", v, test.Min)
}
if v := s.Max(); v != test.Max {
t.Errorf("Max() = %v, want %v", v, test.Max)
}
if v := s.Sum(); v != test.Sum {
t.Errorf("Sum() = %v, want %v", v, test.Sum)
}
if v := s.Mean(); !approxEqual(v, test.Mean, 0.0001) {
t.Errorf("Mean() = %v, want %v", v, test.Mean)
}
if v := s.Variance(); !approxEqual(v, test.Variance, 0.0001) {
t.Errorf("Variance() = %v, want %v", v, test.Variance)
}
if v := s.StdDev(); !approxEqual(v, test.StdDev, 0.0001) {
t.Errorf("StdDev() = %v, want %v", v, test.StdDev)
}
ps := []float64{.5, .8, .9, .99, .995}
if v := s.Percentiles(ps); !reflect.DeepEqual(v, test.Percentiles) {
t.Errorf("Percentiles(%v) = %v, want %v", ps, v, test.Percentiles)
}
})
}
}
func approxEqual(x, y, ε float64) bool {
if math.IsInf(x, -1) && math.IsInf(y, -1) {
return true
}
if math.IsInf(x, 1) && math.IsInf(y, 1) {
return true
}
if math.IsNaN(x) && math.IsNaN(y) {
return true
}
return math.Abs(x-y) < ε
}
// This test verifies that requesting Percentiles in unsorted order
// returns them in the requested order.
func TestRuntimeHistogramStatsPercentileOrder(t *testing.T) {
p := runtimeHistogramSnapshot{
Counts: []uint64{1, 1, 1, 1, 1, 1, 1, 1, 1, 1},
Buckets: []float64{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10},
}
result := p.Percentiles([]float64{1, 0.2, 0.5, 0.1, 0.2})
expected := []float64{10, 2, 5, 1, 2}
if !reflect.DeepEqual(result, expected) {
t.Fatal("wrong result:", result)
}
}