runtime: use RunParallel in more benchmarks

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/68020043

src/pkg/runtime/chan_test.go

@@ -431,27 +431,15 @@ func TestMultiConsumer(t *testing.T) {
 }
 
 func BenchmarkChanNonblocking(b *testing.B) {
-	const CallsPerSched = 1000
-	procs := runtime.GOMAXPROCS(-1)
-	N := int32(b.N / CallsPerSched)
-	c := make(chan bool, procs)
 	myc := make(chan int)
-	for p := 0; p < procs; p++ {
-		go func() {
-			for atomic.AddInt32(&N, -1) >= 0 {
-				for g := 0; g < CallsPerSched; g++ {
-					select {
-					case <-myc:
-					default:
-					}
-				}
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			select {
+			case <-myc:
+			default:
 			}
-			c <- true
-		}()
-	}
-	for p := 0; p < procs; p++ {
-		<-c
-	}
+		}
+	})
 }
 
 func BenchmarkSelectUncontended(b *testing.B) {
@@ -713,23 +701,11 @@ func BenchmarkChanCreation(b *testing.B) {
 
 func BenchmarkChanSem(b *testing.B) {
 	type Empty struct{}
-	const CallsPerSched = 1000
-	procs := runtime.GOMAXPROCS(0)
-	N := int32(b.N / CallsPerSched)
-	c := make(chan bool, procs)
-	myc := make(chan Empty, procs)
-	for p := 0; p < procs; p++ {
-		go func() {
-			for atomic.AddInt32(&N, -1) >= 0 {
-				for g := 0; g < CallsPerSched; g++ {
-					myc <- Empty{}
-					<-myc
-				}
-			}
-			c <- true
-		}()
-	}
-	for p := 0; p < procs; p++ {
-		<-c
-	}
+	myc := make(chan Empty, runtime.GOMAXPROCS(0))
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			myc <- Empty{}
+			<-myc
+		}
+	})
 }

src/pkg/runtime/mfinal_test.go

@@ -6,8 +6,6 @@ package runtime_test
 
 import (
 	"runtime"
-	"sync"
-	"sync/atomic"
 	"testing"
 	"time"
 )
@@ -112,50 +110,28 @@ func TestFinalizerZeroSizedStruct(t *testing.T) {
 }
 
 func BenchmarkFinalizer(b *testing.B) {
-	const CallsPerSched = 1000
-	procs := runtime.GOMAXPROCS(-1)
-	N := int32(b.N / CallsPerSched)
-	var wg sync.WaitGroup
-	wg.Add(procs)
-	for p := 0; p < procs; p++ {
-		go func() {
-			var data [CallsPerSched]*int
-			for i := 0; i < CallsPerSched; i++ {
-				data[i] = new(int)
+	const Batch = 1000
+	b.RunParallel(func(pb *testing.PB) {
+		var data [Batch]*int
+		for i := 0; i < Batch; i++ {
+			data[i] = new(int)
+		}
+		for pb.Next() {
+			for i := 0; i < Batch; i++ {
+				runtime.SetFinalizer(data[i], fin)
 			}
-			for atomic.AddInt32(&N, -1) >= 0 {
-				runtime.Gosched()
-				for i := 0; i < CallsPerSched; i++ {
-					runtime.SetFinalizer(data[i], fin)
-				}
-				for i := 0; i < CallsPerSched; i++ {
-					runtime.SetFinalizer(data[i], nil)
-				}
+			for i := 0; i < Batch; i++ {
+				runtime.SetFinalizer(data[i], nil)
 			}
-			wg.Done()
-		}()
-	}
-	wg.Wait()
+		}
+	})
 }
 
 func BenchmarkFinalizerRun(b *testing.B) {
-	const CallsPerSched = 1000
-	procs := runtime.GOMAXPROCS(-1)
-	N := int32(b.N / CallsPerSched)
-	var wg sync.WaitGroup
-	wg.Add(procs)
-	for p := 0; p < procs; p++ {
-		go func() {
-			for atomic.AddInt32(&N, -1) >= 0 {
-				runtime.Gosched()
-				for i := 0; i < CallsPerSched; i++ {
-					v := new(int)
-					runtime.SetFinalizer(v, fin)
-				}
-				runtime.GC()
-			}
-			wg.Done()
-		}()
-	}
-	wg.Wait()
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			v := new(int)
+			runtime.SetFinalizer(v, fin)
+		}
+	})
 }

src/pkg/runtime/norace_test.go

@@ -9,7 +9,6 @@ package runtime_test
 
 import (
 	"runtime"
-	"sync/atomic"
 	"testing"
 )
 
@@ -31,28 +30,17 @@ func BenchmarkSyscallExcessWork(b *testing.B) {
 }
 
 func benchmarkSyscall(b *testing.B, work, excess int) {
-	const CallsPerSched = 1000
-	procs := runtime.GOMAXPROCS(-1) * excess
-	N := int32(b.N / CallsPerSched)
-	c := make(chan bool, procs)
-	for p := 0; p < procs; p++ {
-		go func() {
-			foo := 42
-			for atomic.AddInt32(&N, -1) >= 0 {
-				runtime.Gosched()
-				for g := 0; g < CallsPerSched; g++ {
-					runtime.Entersyscall()
-					for i := 0; i < work; i++ {
-						foo *= 2
-						foo /= 2
-					}
-					runtime.Exitsyscall()
-				}
+	b.SetParallelism(excess)
+	b.RunParallel(func(pb *testing.PB) {
+		foo := 42
+		for pb.Next() {
+			runtime.Entersyscall()
+			for i := 0; i < work; i++ {
+				foo *= 2
+				foo /= 2
 			}
-			c <- foo == 42
-		}()
-	}
-	for p := 0; p < procs; p++ {
-		<-c
-	}
+			runtime.Exitsyscall()
+		}
+		_ = foo
+	})
 }

src/pkg/runtime/proc_test.go

@@ -370,24 +370,11 @@ func TestSchedLocalQueueSteal(t *testing.T) {
 }
 
 func benchmarkStackGrowth(b *testing.B, rec int) {
-	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() {
-			for atomic.AddInt32(&N, -1) >= 0 {
-				runtime.Gosched()
-				for g := 0; g < CallsPerSched; g++ {
-					stackGrowthRecursive(rec)
-				}
-			}
-			c <- true
-		}()
-	}
-	for p := 0; p < procs; p++ {
-		<-c
-	}
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			stackGrowthRecursive(rec)
+		}
+	})
 }
 
 func BenchmarkStackGrowth(b *testing.B) {