1 files changed, 21 insertions, 51 deletions
diff --git a/src/pkg/sync/mutex_test.go b/src/pkg/sync/mutex_test.go
index bf78c6f60..151b25c10 100644
--- a/src/pkg/sync/mutex_test.go
+++ b/src/pkg/sync/mutex_test.go
@@ -9,7 +9,6 @@ package sync_test
 import (
 	"runtime"
 	. "sync"
-	"sync/atomic"
 	"testing"
 )
 
@@ -90,63 +89,34 @@ func BenchmarkMutexUncontended(b *testing.B) {
 		Mutex
 		pad [128]uint8
 	}
-	const CallsPerSched = 1000
-	procs := runtime.GOMAXPROCS(-1)
-	N := int32(b.N / CallsPerSched)
-	c := make(chan bool, procs)
-	for p := 0; p < procs; p++ {
-		go func() {
-			var mu PaddedMutex
-			for atomic.AddInt32(&N, -1) >= 0 {
-				runtime.Gosched()
-				for g := 0; g < CallsPerSched; g++ {
-					mu.Lock()
-					mu.Unlock()
-				}
-			}
-			c <- true
-		}()
-	}
-	for p := 0; p < procs; p++ {
-		<-c
-	}
+	b.RunParallel(func(pb *testing.PB) {
+		var mu PaddedMutex
+		for pb.Next() {
+			mu.Lock()
+			mu.Unlock()
+		}
+	})
 }
 
 func benchmarkMutex(b *testing.B, slack, work bool) {
-	const (
-		CallsPerSched  = 1000
-		LocalWork      = 100
-		GoroutineSlack = 10
-	)
-	procs := runtime.GOMAXPROCS(-1)
+	var mu Mutex
 	if slack {
-		procs *= GoroutineSlack
+		b.SetParallelism(10)
 	}
-	N := int32(b.N / CallsPerSched)
-	c := make(chan bool, procs)
-	var mu Mutex
-	for p := 0; p < procs; p++ {
-		go func() {
-			foo := 0
-			for atomic.AddInt32(&N, -1) >= 0 {
-				runtime.Gosched()
-				for g := 0; g < CallsPerSched; g++ {
-					mu.Lock()
-					mu.Unlock()
-					if work {
-						for i := 0; i < LocalWork; i++ {
-							foo *= 2
-							foo /= 2
-						}
-					}
+	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
 				}
 			}
-			c <- foo == 42
-		}()
-	}
-	for p := 0; p < procs; p++ {
-		<-c
-	}
+		}
+		_ = foo
+	})
 }
 
 func BenchmarkMutex(b *testing.B) {