encoding/gob: fix data races in benchmarks

All goroutines decode into the same value.

LGTM=r
R=r, abursavich
CC=golang-codereviews
https://golang.org/cl/123930043

diff --git a/src/pkg/encoding/gob/timing_test.go b/src/pkg/encoding/gob/timing_test.go
index 29c9b858b6b20dc873002bb20b99eb7f649fcbb2..ec55c4d63dbeab4e2b002fd7f54f4fea250543a6 100644 (file)
--- a/src/pkg/encoding/gob/timing_test.go
+++ b/src/pkg/encoding/gob/timing_test.go
@@ -19,12 +19,13 @@ type Bench struct {
        D []byte
 }
 
-func benchmarkEndToEnd(b *testing.B, v interface{}, pipe func() (r io.Reader, w io.Writer, err error)) {
+func benchmarkEndToEnd(b *testing.B, ctor func() interface{}, pipe func() (r io.Reader, w io.Writer, err error)) {
        b.RunParallel(func(pb *testing.PB) {
                r, w, err := pipe()
                if err != nil {
                        b.Fatal("can't get pipe:", err)
                }
+               v := ctor()
                enc := NewEncoder(w)
                dec := NewDecoder(r)
                for pb.Next() {
@@ -39,29 +40,33 @@ func benchmarkEndToEnd(b *testing.B, v interface{}, pipe func() (r io.Reader, w
 }
 
 func BenchmarkEndToEndPipe(b *testing.B) {
-       v := &Bench{7, 3.2, "now is the time", bytes.Repeat([]byte("for all good men"), 100)}
-       benchmarkEndToEnd(b, v, func() (r io.Reader, w io.Writer, err error) {
+       benchmarkEndToEnd(b, func() interface{} {
+               return &Bench{7, 3.2, "now is the time", bytes.Repeat([]byte("for all good men"), 100)}
+       }, func() (r io.Reader, w io.Writer, err error) {
                r, w, err = os.Pipe()
                return
        })
 }
 
 func BenchmarkEndToEndByteBuffer(b *testing.B) {
-       v := &Bench{7, 3.2, "now is the time", bytes.Repeat([]byte("for all good men"), 100)}
-       benchmarkEndToEnd(b, v, func() (r io.Reader, w io.Writer, err error) {
+       benchmarkEndToEnd(b, func() interface{} {
+               return &Bench{7, 3.2, "now is the time", bytes.Repeat([]byte("for all good men"), 100)}
+       }, func() (r io.Reader, w io.Writer, err error) {
                var buf bytes.Buffer
                return &buf, &buf, nil
        })
 }
 
 func BenchmarkEndToEndSliceByteBuffer(b *testing.B) {
-       v := &Bench{7, 3.2, "now is the time", nil}
-       Register(v)
-       arr := make([]interface{}, 100)
-       for i := range arr {
-               arr[i] = v
-       }
-       benchmarkEndToEnd(b, &arr, func() (r io.Reader, w io.Writer, err error) {
+       benchmarkEndToEnd(b, func() interface{} {
+               v := &Bench{7, 3.2, "now is the time", nil}
+               Register(v)
+               arr := make([]interface{}, 100)
+               for i := range arr {
+                       arr[i] = v
+               }
+               return &arr
+       }, func() (r io.Reader, w io.Writer, err error) {
                var buf bytes.Buffer
                return &buf, &buf, nil
        })