diff options
Diffstat (limited to 'src/sync/mutex_test.go')
-rw-r--r-- | src/sync/mutex_test.go | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/src/sync/mutex_test.go b/src/sync/mutex_test.go new file mode 100644 index 000000000..151b25c10 --- /dev/null +++ b/src/sync/mutex_test.go @@ -0,0 +1,136 @@ +// Copyright 2009 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// GOMAXPROCS=10 go test + +package sync_test + +import ( + "runtime" + . "sync" + "testing" +) + +func HammerSemaphore(s *uint32, loops int, cdone chan bool) { + for i := 0; i < loops; i++ { + Runtime_Semacquire(s) + Runtime_Semrelease(s) + } + cdone <- true +} + +func TestSemaphore(t *testing.T) { + s := new(uint32) + *s = 1 + c := make(chan bool) + for i := 0; i < 10; i++ { + go HammerSemaphore(s, 1000, c) + } + for i := 0; i < 10; i++ { + <-c + } +} + +func BenchmarkUncontendedSemaphore(b *testing.B) { + s := new(uint32) + *s = 1 + HammerSemaphore(s, b.N, make(chan bool, 2)) +} + +func BenchmarkContendedSemaphore(b *testing.B) { + b.StopTimer() + s := new(uint32) + *s = 1 + c := make(chan bool) + defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(2)) + b.StartTimer() + + go HammerSemaphore(s, b.N/2, c) + go HammerSemaphore(s, b.N/2, c) + <-c + <-c +} + +func HammerMutex(m *Mutex, loops int, cdone chan bool) { + for i := 0; i < loops; i++ { + m.Lock() + m.Unlock() + } + cdone <- true +} + +func TestMutex(t *testing.T) { + m := new(Mutex) + c := make(chan bool) + for i := 0; i < 10; i++ { + go HammerMutex(m, 1000, c) + } + for i := 0; i < 10; i++ { + <-c + } +} + +func TestMutexPanic(t *testing.T) { + defer func() { + if recover() == nil { + t.Fatalf("unlock of unlocked mutex did not panic") + } + }() + + var mu Mutex + mu.Lock() + mu.Unlock() + mu.Unlock() +} + +func BenchmarkMutexUncontended(b *testing.B) { + type PaddedMutex struct { + Mutex + pad [128]uint8 + } + b.RunParallel(func(pb *testing.PB) { + var mu PaddedMutex + for pb.Next() { + mu.Lock() + mu.Unlock() + } + }) +} + +func benchmarkMutex(b *testing.B, slack, work bool) { + var mu Mutex + if slack { + b.SetParallelism(10) + } + b.RunParallel(func(pb *testing.PB) { + foo := 0 + for pb.Next() { + mu.Lock() + mu.Unlock() + if work { + for i := 0; i < 100; i++ { + foo *= 2 + foo /= 2 + } + } + } + _ = foo + }) +} + +func BenchmarkMutex(b *testing.B) { + benchmarkMutex(b, false, false) +} + +func BenchmarkMutexSlack(b *testing.B) { + benchmarkMutex(b, true, false) +} + +func BenchmarkMutexWork(b *testing.B) { + benchmarkMutex(b, false, true) +} + +func BenchmarkMutexWorkSlack(b *testing.B) { + benchmarkMutex(b, true, true) +} |