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runtime: make NumGoroutine and Stack agree not to include system goroutines
Before, NumGoroutine counted system goroutines and Stack (usually) didn't show them, which was inconsistent and confusing. To resolve which way they should be consistent, it seems like package main import "runtime" func main() { println(runtime.NumGoroutine()) } should print 1 regardless of internal runtime details. Make it so. Fixes golang#11706. Change-Id: I6bfe26a901de517728192cfb26a5568c4ef4fe47 Reviewed-on: https://go-review.googlesource.com/18343 Reviewed-by: Austin Clements <[email protected]>
1 parent 20d745c commit c5bafc8

5 files changed

Lines changed: 47 additions & 1 deletion

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‎src/runtime/mprof.go‎

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -576,12 +576,17 @@ func Stack(buf []byte, all bool) int {
576576
pc := getcallerpc(unsafe.Pointer(&buf))
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systemstack(func() {
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g0 := getg()
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// Force traceback=1 to override GOTRACEBACK setting,
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// so that Stack's results are consistent.
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// GOTRACEBACK is only about crash dumps.
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g0.m.traceback = 1
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g0.writebuf = buf[0:0:len(buf)]
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goroutineheader(gp)
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traceback(pc, sp, 0, gp)
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if all {
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tracebackothers(gp)
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}
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g0.m.traceback = 0
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n = len(g0.writebuf)
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g0.writebuf = nil
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})

‎src/runtime/proc.go‎

Lines changed: 7 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -2162,6 +2162,9 @@ func goexit0(gp *g) {
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_g_ := getg()
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casgstatus(gp, _Grunning, _Gdead)
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if isSystemGoroutine(gp) {
2166+
atomic.Xadd(&sched.ngsys, -1)
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}
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gp.m = nil
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gp.lockedm = nil
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_g_.m.lockedg = nil
@@ -2693,6 +2696,9 @@ func newproc1(fn *funcval, argp *uint8, narg int32, nret int32, callerpc uintptr
26932696
gostartcallfn(&newg.sched, fn)
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newg.gopc = callerpc
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newg.startpc = fn.fn
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if isSystemGoroutine(newg) {
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atomic.Xadd(&sched.ngsys, +1)
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}
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casgstatus(newg, _Gdead, _Grunnable)
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26982704
if _p_.goidcache == _p_.goidcacheend {
@@ -2885,7 +2891,7 @@ func badunlockosthread() {
28852891
}
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func gcount() int32 {
2888-
n := int32(allglen) - sched.ngfree
2894+
n := int32(allglen) - sched.ngfree - int32(atomic.Load(&sched.ngsys))
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for i := 0; ; i++ {
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_p_ := allp[i]
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if _p_ == nil {

‎src/runtime/proc_test.go‎

Lines changed: 18 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -9,6 +9,7 @@ import (
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"net"
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"runtime"
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"runtime/debug"
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"strings"
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"sync"
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"sync/atomic"
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"syscall"
@@ -336,6 +337,23 @@ func TestGCFairness(t *testing.T) {
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}
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}
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func TestNumGoroutine(t *testing.T) {
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output := runTestProg(t, "testprog", "NumGoroutine")
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want := "1\n"
343+
if output != want {
344+
t.Fatalf("want %q, got %q", want, output)
345+
}
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347+
buf := make([]byte, 1<<20)
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buf = buf[:runtime.Stack(buf, true)]
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350+
n := runtime.NumGoroutine()
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352+
if nstk := strings.Count(string(buf), "goroutine "); n != nstk {
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t.Fatalf("NumGoroutine=%d, but found %d goroutines in stack dump", n, nstk)
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}
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}
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339357
func TestPingPongHog(t *testing.T) {
340358
if testing.Short() {
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t.Skip("skipping in -short mode")

‎src/runtime/runtime2.go‎

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -418,6 +418,8 @@ type schedt struct {
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mcount int32 // number of m's that have been created
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maxmcount int32 // maximum number of m's allowed (or die)
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ngsys uint32 // number of system goroutines; updated atomically
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pidle puintptr // idle p's
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npidle uint32
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nmspinning uint32 // See "Worker thread parking/unparking" comment in proc.go.

‎src/runtime/testdata/testprog/misc.go‎

Lines changed: 15 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,15 @@
1+
// Copyright 2016 The Go Authors. All rights reserved.
2+
// Use of this source code is governed by a BSD-style
3+
// license that can be found in the LICENSE file.
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package main
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7+
import "runtime"
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func init() {
10+
register("NumGoroutine", NumGoroutine)
11+
}
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13+
func NumGoroutine() {
14+
println(runtime.NumGoroutine())
15+
}

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