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| author | Peter Weinberger <pjw@google.com> | 2016-09-22 09:48:30 -0400 |
|---|---|---|
| committer | Peter Weinberger <pjw@google.com> | 2016-10-28 11:47:16 +0000 |
| commit | ca922b6d363b6ca47822188dcbc5b92d912c7a4b (patch) | |
| tree | 5bee54a86cd9db992e5d77e735b94d9a0eed9a17 /src/sync | |
| parent | b679665a182bd6ec2989ae759df6b11142921cfb (diff) | |
| download | go-ca922b6d363b6ca47822188dcbc5b92d912c7a4b.tar.xz | |
runtime: Profile goroutines holding contended mutexes.
runtime.SetMutexProfileFraction(n int) will capture 1/n-th of stack
traces of goroutines holding contended mutexes if n > 0. From runtime/pprof,
pprot.Lookup("mutex").WriteTo writes the accumulated
stack traces to w (in essentially the same format that blocking
profiling uses).
Change-Id: Ie0b54fa4226853d99aa42c14cb529ae586a8335a
Reviewed-on: https://go-review.googlesource.com/29650
Reviewed-by: Austin Clements <austin@google.com>
Diffstat (limited to 'src/sync')
| -rw-r--r-- | src/sync/mutex.go | 2 | ||||
| -rw-r--r-- | src/sync/mutex_test.go | 4 | ||||
| -rw-r--r-- | src/sync/runtime.go | 3 |
3 files changed, 8 insertions, 1 deletions
diff --git a/src/sync/mutex.go b/src/sync/mutex.go index 717934344e..8c9366f4fe 100644 --- a/src/sync/mutex.go +++ b/src/sync/mutex.go @@ -84,7 +84,7 @@ func (m *Mutex) Lock() { if old&mutexLocked == 0 { break } - runtime_Semacquire(&m.sema) + runtime_SemacquireMutex(&m.sema) awoke = true iter = 0 } diff --git a/src/sync/mutex_test.go b/src/sync/mutex_test.go index fbfe4b77fe..88dbccf3ad 100644 --- a/src/sync/mutex_test.go +++ b/src/sync/mutex_test.go @@ -66,6 +66,10 @@ func HammerMutex(m *Mutex, loops int, cdone chan bool) { } func TestMutex(t *testing.T) { + if n := runtime.SetMutexProfileFraction(1); n != 0 { + t.Logf("got mutexrate %d expected 0", n) + } + defer runtime.SetMutexProfileFraction(0) m := new(Mutex) c := make(chan bool) for i := 0; i < 10; i++ { diff --git a/src/sync/runtime.go b/src/sync/runtime.go index 96c56c8522..4d22ce6b0d 100644 --- a/src/sync/runtime.go +++ b/src/sync/runtime.go @@ -13,6 +13,9 @@ import "unsafe" // library and should not be used directly. func runtime_Semacquire(s *uint32) +// SemacquireMutex is like Semacquire, but for profiling contended Mutexes. +func runtime_SemacquireMutex(*uint32) + // Semrelease atomically increments *s and notifies a waiting goroutine // if one is blocked in Semacquire. // It is intended as a simple wakeup primitive for use by the synchronization |