1 files changed, 114 insertions, 0 deletions
diff --git a/src/pkg/sync/rwmutex_test.go b/src/pkg/sync/rwmutex_test.go
new file mode 100644
index 000000000..ad3560800
--- /dev/null
+++ b/src/pkg/sync/rwmutex_test.go
@@ -0,0 +1,114 @@
+// 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 gotest
+
+package sync_test
+
+import (
+	"fmt";
+	"runtime";
+	. "sync";
+	"testing";
+)
+
+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) {
+	doTestParallelReaders(1, 4);
+	doTestParallelReaders(3, 4);
+	doTestParallelReaders(4, 2);
+}
+
+func reader(rwm *RWMutex, num_iterations int, activity *uint32, cdone chan bool) {
+	for i := 0; i < num_iterations; i++ {
+		rwm.RLock();
+		n := Xadd(activity, 1);
+		if n < 1 || n >= 10000 {
+			panic(fmt.Sprintf("wlock(%d)\n", n))
+		}
+		for i := 0; i < 100; i++ {
+		}
+		Xadd(activity, -1);
+		rwm.RUnlock();
+	}
+	cdone <- true;
+}
+
+func writer(rwm *RWMutex, num_iterations int, activity *uint32, cdone chan bool) {
+	for i := 0; i < num_iterations; i++ {
+		rwm.Lock();
+		n := Xadd(activity, 10000);
+		if n != 10000 {
+			panic(fmt.Sprintf("wlock(%d)\n", n))
+		}
+		for i := 0; i < 100; i++ {
+		}
+		Xadd(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 uint32;
+	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) {
+	HammerRWMutex(1, 1, 1000);
+	HammerRWMutex(1, 3, 1000);
+	HammerRWMutex(1, 10, 1000);
+	HammerRWMutex(4, 1, 1000);
+	HammerRWMutex(4, 3, 1000);
+	HammerRWMutex(4, 10, 1000);
+	HammerRWMutex(10, 1, 1000);
+	HammerRWMutex(10, 3, 1000);
+	HammerRWMutex(10, 10, 1000);
+	HammerRWMutex(10, 5, 10000);
+}