runtime,runtime/metrics: add heap goal and GC cycle metrics

This change adds three new metrics: the heap goal, GC cycle count, and
forced GC count. These metrics are identical to their MemStats
counterparts.

For #37112.

Change-Id: I5a5e8dd550c0d646e5dcdbdf38274895e27cdd88
Reviewed-on: https://go-review.googlesource.com/c/go/+/247044
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>

diff --git a/src/runtime/metrics.go b/src/runtime/metrics.go
index cf619cca4bcd2782b477f731edf675f32f0e7dee..6595a4342c4adc77d709af632f434e0ffbfd40ee 100644 (file)
--- a/src/runtime/metrics.go
+++ b/src/runtime/metrics.go
@@ -7,6 +7,7 @@ package runtime
 // Metrics implementation exported to runtime/metrics.
 
 import (
+       "runtime/internal/atomic"
        "unsafe"
 )
 
@@ -38,6 +39,34 @@ func initMetrics() {
                return
        }
        metrics = map[string]metricData{
+               "/gc/cycles/automatic:gc-cycles": {
+                       deps: makeStatDepSet(sysStatsDep),
+                       compute: func(in *statAggregate, out *metricValue) {
+                               out.kind = metricKindUint64
+                               out.scalar = in.sysStats.gcCyclesDone - in.sysStats.gcCyclesForced
+                       },
+               },
+               "/gc/cycles/forced:gc-cycles": {
+                       deps: makeStatDepSet(sysStatsDep),
+                       compute: func(in *statAggregate, out *metricValue) {
+                               out.kind = metricKindUint64
+                               out.scalar = in.sysStats.gcCyclesForced
+                       },
+               },
+               "/gc/cycles/total:gc-cycles": {
+                       deps: makeStatDepSet(sysStatsDep),
+                       compute: func(in *statAggregate, out *metricValue) {
+                               out.kind = metricKindUint64
+                               out.scalar = in.sysStats.gcCyclesDone
+                       },
+               },
+               "/gc/heap/goal:bytes": {
+                       deps: makeStatDepSet(sysStatsDep),
+                       compute: func(in *statAggregate, out *metricValue) {
+                               out.kind = metricKindUint64
+                               out.scalar = in.sysStats.heapGoal
+                       },
+               },
                "/gc/heap/objects:objects": {
                        deps: makeStatDepSet(heapStatsDep),
                        compute: func(in *statAggregate, out *metricValue) {
@@ -248,14 +277,17 @@ func (a *heapStatsAggregate) compute() {
 // heapStatsAggregate, means there could be some skew, but because of
 // these stats are independent, there's no real consistency issue here.
 type sysStatsAggregate struct {
-       stacksSys   uint64
-       mSpanSys    uint64
-       mSpanInUse  uint64
-       mCacheSys   uint64
-       mCacheInUse uint64
-       buckHashSys uint64
-       gcMiscSys   uint64
-       otherSys    uint64
+       stacksSys      uint64
+       mSpanSys       uint64
+       mSpanInUse     uint64
+       mCacheSys      uint64
+       mCacheInUse    uint64
+       buckHashSys    uint64
+       gcMiscSys      uint64
+       otherSys       uint64
+       heapGoal       uint64
+       gcCyclesDone   uint64
+       gcCyclesForced uint64
 }
 
 // compute populates the sysStatsAggregate with values from the runtime.
@@ -264,6 +296,9 @@ func (a *sysStatsAggregate) compute() {
        a.buckHashSys = memstats.buckhash_sys.load()
        a.gcMiscSys = memstats.gcMiscSys.load()
        a.otherSys = memstats.other_sys.load()
+       a.heapGoal = atomic.Load64(&memstats.next_gc)
+       a.gcCyclesDone = uint64(memstats.numgc)
+       a.gcCyclesForced = uint64(memstats.numforcedgc)
 
        systemstack(func() {
                lock(&mheap_.lock)

diff --git a/src/runtime/metrics/description.go b/src/runtime/metrics/description.go
index 47013e1451dd8a94a1bd7cd8cb85260596deaf9d..66d229c270e8082b6d7f35e09a1203bcf3f46b5e 100644 (file)
--- a/src/runtime/metrics/description.go
+++ b/src/runtime/metrics/description.go
@@ -50,6 +50,29 @@ type Description struct {
 // The English language descriptions below must be kept in sync with the
 // descriptions of each metric in doc.go.
 var allDesc = []Description{
+       {
+               Name:        "/gc/cycles/automatic:gc-cycles",
+               Description: "Count of completed GC cycles generated by the Go runtime.",
+               Kind:        KindUint64,
+               Cumulative:  true,
+       },
+       {
+               Name:        "/gc/cycles/forced:gc-cycles",
+               Description: "Count of completed forced GC cycles.",
+               Kind:        KindUint64,
+               Cumulative:  true,
+       },
+       {
+               Name:        "/gc/cycles/total:gc-cycles",
+               Description: "Count of all completed GC cycles.",
+               Kind:        KindUint64,
+               Cumulative:  true,
+       },
+       {
+               Name:        "/gc/heap/goal:bytes",
+               Description: "Heap size target for the end of the GC cycle.",
+               Kind:        KindUint64,
+       },
        {
                Name:        "/gc/heap/objects:objects",
                Description: "Number of objects, live or unswept, occupying heap memory.",

diff --git a/src/runtime/metrics/doc.go b/src/runtime/metrics/doc.go
index 4ac44bb19c5d62f8cb3a835607160c57542777ea..9b44e73ee6b515fe552d95bd9b2cdb8e44fcd274 100644 (file)
--- a/src/runtime/metrics/doc.go
+++ b/src/runtime/metrics/doc.go
@@ -44,6 +44,18 @@ the documentation of the Name field of the Description struct.
 
 Supported metrics
 
+       /gc/cycles/automatic:gc-cycles
+               Count of completed GC cycles generated by the Go runtime.
+
+       /gc/cycles/forced:gc-cycles
+               Count of completed forced GC cycles.
+
+       /gc/cycles/total:gc-cycles
+               Count of all completed GC cycles.
+
+       /gc/heap/goal:bytes
+               Heap size target for the end of the GC cycle.
+
        /gc/heap/objects:objects
                Number of objects, live or unswept, occupying heap memory.
 

diff --git a/src/runtime/metrics_test.go b/src/runtime/metrics_test.go
index 6c0be7dc0bfaca77b7a9ee1a74fb8f1f12284016..37247602947f28cc4a1b76f1736bc5703b5537c3 100644 (file)
--- a/src/runtime/metrics_test.go
+++ b/src/runtime/metrics_test.go
@@ -72,6 +72,14 @@ func TestReadMetrics(t *testing.T) {
                        checkUint64(t, name, samples[i].Value.Uint64(), mstats.Sys)
                case "/gc/heap/objects:objects":
                        checkUint64(t, name, samples[i].Value.Uint64(), mstats.HeapObjects)
+               case "/gc/heap/goal:bytes":
+                       checkUint64(t, name, samples[i].Value.Uint64(), mstats.NextGC)
+               case "/gc/cycles/automatic:gc-cycles":
+                       checkUint64(t, name, samples[i].Value.Uint64(), uint64(mstats.NumGC-mstats.NumForcedGC))
+               case "/gc/cycles/forced:gc-cycles":
+                       checkUint64(t, name, samples[i].Value.Uint64(), uint64(mstats.NumForcedGC))
+               case "/gc/cycles/total:gc-cycles":
+                       checkUint64(t, name, samples[i].Value.Uint64(), uint64(mstats.NumGC))
                }
        }
 }