Add benchmarks for commonly used routines.

R=rsc, r, r1
http://codereview.appspot.com/160046

Committer: Russ Cox <rsc@golang.org>

1 files changed, 44 insertions, 6 deletions

diff --git a/src/pkg/sync/mutex_test.go b/src/pkg/sync/mutex_test.go
index 72c9c4342..05fef786a 100644
--- a/src/pkg/sync/mutex_test.go
+++ b/src/pkg/sync/mutex_test.go
@@ -12,8 +12,8 @@ import (
 	"testing";
 )
 
-func HammerSemaphore(s *uint32, cdone chan bool) {
-	for i := 0; i < 1000; i++ {
+func HammerSemaphore(s *uint32, loops int, cdone chan bool) {
+	for i := 0; i < loops; i++ {
 		runtime.Semacquire(s);
 		runtime.Semrelease(s);
 	}
@@ -25,16 +25,36 @@ func TestSemaphore(t *testing.T) {
 	*s = 1;
 	c := make(chan bool);
 	for i := 0; i < 10; i++ {
-		go HammerSemaphore(s, c)
+		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);
+	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, cdone chan bool) {
-	for i := 0; i < 1000; i++ {
+
+func HammerMutex(m *Mutex, loops int, cdone chan bool) {
+	for i := 0; i < loops; i++ {
 		m.Lock();
 		m.Unlock();
 	}
@@ -45,9 +65,27 @@ func TestMutex(t *testing.T) {
 	m := new(Mutex);
 	c := make(chan bool);
 	for i := 0; i < 10; i++ {
-		go HammerMutex(m, c)
+		go HammerMutex(m, 1000, c)
 	}
 	for i := 0; i < 10; i++ {
 		<-c
 	}
 }
+
+func BenchmarkUncontendedMutex(b *testing.B) {
+	m := new(Mutex);
+	HammerMutex(m, b.N, make(chan bool, 2));
+}
+
+func BenchmarkContendedMutex(b *testing.B) {
+	b.StopTimer();
+	m := new(Mutex);
+	c := make(chan bool);
+	runtime.GOMAXPROCS(2);
+	b.StartTimer();
+
+	go HammerMutex(m, b.N/2, c);
+	go HammerMutex(m, b.N/2, c);
+	<-c;
+	<-c;
+}