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-rw-r--r--src/sync/rwmutex_test.go217
1 files changed, 217 insertions, 0 deletions
diff --git a/src/sync/rwmutex_test.go b/src/sync/rwmutex_test.go
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+++ b/src/sync/rwmutex_test.go
@@ -0,0 +1,217 @@
+// 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 (
+ "fmt"
+ "runtime"
+ . "sync"
+ "sync/atomic"
+ "testing"
+)
+
+// There is a modified copy of this file in runtime/rwmutex_test.go.
+// If you make any changes here, see if you should make them there.
+
+func parallelReader(m *RWMutex, clocked, cunlock, cdone chan bool) {
+ m.RLock()
+ clocked <- true
+ <-cunlock
+ m.RUnlock()
+ cdone <- true
+}
+
+func doTestParallelReaders(numReaders, gomaxprocs int) {
+ runtime.GOMAXPROCS(gomaxprocs)
+ var m RWMutex
+ clocked := make(chan bool)
+ cunlock := make(chan bool)
+ cdone := make(chan bool)
+ for i := 0; i < numReaders; i++ {
+ go parallelReader(&m, clocked, cunlock, cdone)
+ }
+ // Wait for all parallel RLock()s to succeed.
+ for i := 0; i < numReaders; i++ {
+ <-clocked
+ }
+ for i := 0; i < numReaders; i++ {
+ cunlock <- true
+ }
+ // Wait for the goroutines to finish.
+ for i := 0; i < numReaders; i++ {
+ <-cdone
+ }
+}
+
+func TestParallelReaders(t *testing.T) {
+ defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(-1))
+ doTestParallelReaders(1, 4)
+ doTestParallelReaders(3, 4)
+ doTestParallelReaders(4, 2)
+}
+
+func reader(rwm *RWMutex, num_iterations int, activity *int32, cdone chan bool) {
+ for i := 0; i < num_iterations; i++ {
+ rwm.RLock()
+ n := atomic.AddInt32(activity, 1)
+ if n < 1 || n >= 10000 {
+ rwm.RUnlock()
+ panic(fmt.Sprintf("wlock(%d)\n", n))
+ }
+ for i := 0; i < 100; i++ {
+ }
+ atomic.AddInt32(activity, -1)
+ rwm.RUnlock()
+ }
+ cdone <- true
+}
+
+func writer(rwm *RWMutex, num_iterations int, activity *int32, cdone chan bool) {
+ for i := 0; i < num_iterations; i++ {
+ rwm.Lock()
+ n := atomic.AddInt32(activity, 10000)
+ if n != 10000 {
+ rwm.Unlock()
+ panic(fmt.Sprintf("wlock(%d)\n", n))
+ }
+ for i := 0; i < 100; i++ {
+ }
+ atomic.AddInt32(activity, -10000)
+ rwm.Unlock()
+ }
+ cdone <- true
+}
+
+func HammerRWMutex(gomaxprocs, numReaders, num_iterations int) {
+ runtime.GOMAXPROCS(gomaxprocs)
+ // Number of active readers + 10000 * number of active writers.
+ var activity int32
+ var rwm RWMutex
+ cdone := make(chan bool)
+ go writer(&rwm, num_iterations, &activity, cdone)
+ var i int
+ for i = 0; i < numReaders/2; i++ {
+ go reader(&rwm, num_iterations, &activity, cdone)
+ }
+ go writer(&rwm, num_iterations, &activity, cdone)
+ for ; i < numReaders; i++ {
+ go reader(&rwm, num_iterations, &activity, cdone)
+ }
+ // Wait for the 2 writers and all readers to finish.
+ for i := 0; i < 2+numReaders; i++ {
+ <-cdone
+ }
+}
+
+func TestRWMutex(t *testing.T) {
+ defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(-1))
+ n := 1000
+ if testing.Short() {
+ n = 5
+ }
+ HammerRWMutex(1, 1, n)
+ HammerRWMutex(1, 3, n)
+ HammerRWMutex(1, 10, n)
+ HammerRWMutex(4, 1, n)
+ HammerRWMutex(4, 3, n)
+ HammerRWMutex(4, 10, n)
+ HammerRWMutex(10, 1, n)
+ HammerRWMutex(10, 3, n)
+ HammerRWMutex(10, 10, n)
+ HammerRWMutex(10, 5, n)
+}
+
+func TestRLocker(t *testing.T) {
+ var wl RWMutex
+ var rl Locker
+ wlocked := make(chan bool, 1)
+ rlocked := make(chan bool, 1)
+ rl = wl.RLocker()
+ n := 10
+ go func() {
+ for i := 0; i < n; i++ {
+ rl.Lock()
+ rl.Lock()
+ rlocked <- true
+ wl.Lock()
+ wlocked <- true
+ }
+ }()
+ for i := 0; i < n; i++ {
+ <-rlocked
+ rl.Unlock()
+ select {
+ case <-wlocked:
+ t.Fatal("RLocker() didn't read-lock it")
+ default:
+ }
+ rl.Unlock()
+ <-wlocked
+ select {
+ case <-rlocked:
+ t.Fatal("RLocker() didn't respect the write lock")
+ default:
+ }
+ wl.Unlock()
+ }
+}
+
+func BenchmarkRWMutexUncontended(b *testing.B) {
+ type PaddedRWMutex struct {
+ RWMutex
+ pad [32]uint32
+ }
+ b.RunParallel(func(pb *testing.PB) {
+ var rwm PaddedRWMutex
+ for pb.Next() {
+ rwm.RLock()
+ rwm.RLock()
+ rwm.RUnlock()
+ rwm.RUnlock()
+ rwm.Lock()
+ rwm.Unlock()
+ }
+ })
+}
+
+func benchmarkRWMutex(b *testing.B, localWork, writeRatio int) {
+ var rwm RWMutex
+ b.RunParallel(func(pb *testing.PB) {
+ foo := 0
+ for pb.Next() {
+ foo++
+ if foo%writeRatio == 0 {
+ rwm.Lock()
+ rwm.Unlock()
+ } else {
+ rwm.RLock()
+ for i := 0; i != localWork; i += 1 {
+ foo *= 2
+ foo /= 2
+ }
+ rwm.RUnlock()
+ }
+ }
+ _ = foo
+ })
+}
+
+func BenchmarkRWMutexWrite100(b *testing.B) {
+ benchmarkRWMutex(b, 0, 100)
+}
+
+func BenchmarkRWMutexWrite10(b *testing.B) {
+ benchmarkRWMutex(b, 0, 10)
+}
+
+func BenchmarkRWMutexWorkWrite100(b *testing.B) {
+ benchmarkRWMutex(b, 100, 100)
+}
+
+func BenchmarkRWMutexWorkWrite10(b *testing.B) {
+ benchmarkRWMutex(b, 100, 10)
+}