image/gif: add BenchmarkDecode.

Also add some b.ReportAllocs calls to other image codec benchmarks.

Change-Id: I0f055dc76bffb66329c621a5f1ccd239f0cdd30b
Reviewed-on: https://go-review.googlesource.com/68390
Reviewed-by: Jed Denlea <jed@fastly.com>
Reviewed-by: Nigel Tao <nigeltao@golang.org>

6 files changed, 46 insertions, 30 deletions

diff --git a/src/image/gif/reader_test.go b/src/image/gif/reader_test.go
index 51c64b7328..4b83c9662a 100644
--- a/src/image/gif/reader_test.go
+++ b/src/image/gif/reader_test.go
@@ -9,6 +9,7 @@ import (
 	"compress/lzw"
 	"image"
 	"image/color"
+	"io/ioutil"
 	"reflect"
 	"strings"
 	"testing"
@@ -342,3 +343,20 @@ func TestUnexpectedEOF(t *testing.T) {
 		}
 	}
 }
+
+func BenchmarkDecode(b *testing.B) {
+	data, err := ioutil.ReadFile("../testdata/video-001.gif")
+	if err != nil {
+		b.Fatal(err)
+	}
+	cfg, err := DecodeConfig(bytes.NewReader(data))
+	if err != nil {
+		b.Fatal(err)
+	}
+	b.SetBytes(int64(cfg.Width * cfg.Height))
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		Decode(bytes.NewReader(data))
+	}
+}
diff --git a/src/image/gif/writer_test.go b/src/image/gif/writer_test.go
index 1bba9b8ece..eb17cf28ed 100644
--- a/src/image/gif/writer_test.go
+++ b/src/image/gif/writer_test.go
@@ -500,8 +500,6 @@ func TestEncodeCroppedSubImages(t *testing.T) {
 }
 
 func BenchmarkEncode(b *testing.B) {
-	b.StopTimer()
-
 	bo := image.Rect(0, 0, 640, 480)
 	rnd := rand.New(rand.NewSource(123))
 
@@ -523,14 +521,14 @@ func BenchmarkEncode(b *testing.B) {
 	}
 
 	b.SetBytes(640 * 480 * 4)
-	b.StartTimer()
+	b.ReportAllocs()
+	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		Encode(ioutil.Discard, img, nil)
 	}
 }
 
 func BenchmarkQuantizedEncode(b *testing.B) {
-	b.StopTimer()
 	img := image.NewRGBA(image.Rect(0, 0, 640, 480))
 	bo := img.Bounds()
 	rnd := rand.New(rand.NewSource(123))
@@ -545,7 +543,8 @@ func BenchmarkQuantizedEncode(b *testing.B) {
 		}
 	}
 	b.SetBytes(640 * 480 * 4)
-	b.StartTimer()
+	b.ReportAllocs()
+	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		Encode(ioutil.Discard, img, nil)
 	}
diff --git a/src/image/jpeg/reader_test.go b/src/image/jpeg/reader_test.go
index 77376152bc..a62b509234 100644
--- a/src/image/jpeg/reader_test.go
+++ b/src/image/jpeg/reader_test.go
@@ -323,7 +323,6 @@ func TestExtraneousData(t *testing.T) {
 }
 
 func benchmarkDecode(b *testing.B, filename string) {
-	b.StopTimer()
 	data, err := ioutil.ReadFile(filename)
 	if err != nil {
 		b.Fatal(err)
@@ -333,7 +332,8 @@ func benchmarkDecode(b *testing.B, filename string) {
 		b.Fatal(err)
 	}
 	b.SetBytes(int64(cfg.Width * cfg.Height * 4))
-	b.StartTimer()
+	b.ReportAllocs()
+	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		Decode(bytes.NewReader(data))
 	}
diff --git a/src/image/jpeg/writer_test.go b/src/image/jpeg/writer_test.go
index a6c056174b..3aff742632 100644
--- a/src/image/jpeg/writer_test.go
+++ b/src/image/jpeg/writer_test.go
@@ -243,7 +243,6 @@ func TestEncodeYCbCr(t *testing.T) {
 }
 
 func BenchmarkEncodeRGBA(b *testing.B) {
-	b.StopTimer()
 	img := image.NewRGBA(image.Rect(0, 0, 640, 480))
 	bo := img.Bounds()
 	rnd := rand.New(rand.NewSource(123))
@@ -258,7 +257,8 @@ func BenchmarkEncodeRGBA(b *testing.B) {
 		}
 	}
 	b.SetBytes(640 * 480 * 4)
-	b.StartTimer()
+	b.ReportAllocs()
+	b.ResetTimer()
 	options := &Options{Quality: 90}
 	for i := 0; i < b.N; i++ {
 		Encode(ioutil.Discard, img, options)
@@ -266,7 +266,6 @@ func BenchmarkEncodeRGBA(b *testing.B) {
 }
 
 func BenchmarkEncodeYCbCr(b *testing.B) {
-	b.StopTimer()
 	img := image.NewYCbCr(image.Rect(0, 0, 640, 480), image.YCbCrSubsampleRatio420)
 	bo := img.Bounds()
 	rnd := rand.New(rand.NewSource(123))
@@ -280,7 +279,8 @@ func BenchmarkEncodeYCbCr(b *testing.B) {
 		}
 	}
 	b.SetBytes(640 * 480 * 3)
-	b.StartTimer()
+	b.ReportAllocs()
+	b.ResetTimer()
 	options := &Options{Quality: 90}
 	for i := 0; i < b.N; i++ {
 		Encode(ioutil.Discard, img, options)
diff --git a/src/image/png/reader_test.go b/src/image/png/reader_test.go
index cabf533adc..da498fe207 100644
--- a/src/image/png/reader_test.go
+++ b/src/image/png/reader_test.go
@@ -650,20 +650,19 @@ func TestGray8Transparent(t *testing.T) {
 }
 
 func benchmarkDecode(b *testing.B, filename string, bytesPerPixel int) {
-	b.StopTimer()
 	data, err := ioutil.ReadFile(filename)
 	if err != nil {
 		b.Fatal(err)
 	}
-	s := string(data)
-	cfg, err := DecodeConfig(strings.NewReader(s))
+	cfg, err := DecodeConfig(bytes.NewReader(data))
 	if err != nil {
 		b.Fatal(err)
 	}
 	b.SetBytes(int64(cfg.Width * cfg.Height * bytesPerPixel))
-	b.StartTimer()
+	b.ReportAllocs()
+	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		Decode(strings.NewReader(s))
+		Decode(bytes.NewReader(data))
 	}
 }
 
diff --git a/src/image/png/writer_test.go b/src/image/png/writer_test.go
index b1f97b1d7b..1107ea0e7f 100644
--- a/src/image/png/writer_test.go
+++ b/src/image/png/writer_test.go
@@ -121,10 +121,10 @@ func TestSubImage(t *testing.T) {
 }
 
 func BenchmarkEncodeGray(b *testing.B) {
-	b.StopTimer()
 	img := image.NewGray(image.Rect(0, 0, 640, 480))
 	b.SetBytes(640 * 480 * 1)
-	b.StartTimer()
+	b.ReportAllocs()
+	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		Encode(ioutil.Discard, img)
 	}
@@ -143,20 +143,19 @@ func (p *pool) Put(b *EncoderBuffer) {
 }
 
 func BenchmarkEncodeGrayWithBufferPool(b *testing.B) {
-	b.StopTimer()
 	img := image.NewGray(image.Rect(0, 0, 640, 480))
 	e := Encoder{
 		BufferPool: &pool{},
 	}
 	b.SetBytes(640 * 480 * 1)
-	b.StartTimer()
+	b.ReportAllocs()
+	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		e.Encode(ioutil.Discard, img)
 	}
 }
 
 func BenchmarkEncodeNRGBOpaque(b *testing.B) {
-	b.StopTimer()
 	img := image.NewNRGBA(image.Rect(0, 0, 640, 480))
 	// Set all pixels to 0xFF alpha to force opaque mode.
 	bo := img.Bounds()
@@ -169,40 +168,40 @@ func BenchmarkEncodeNRGBOpaque(b *testing.B) {
 		b.Fatal("expected image to be opaque")
 	}
 	b.SetBytes(640 * 480 * 4)
-	b.StartTimer()
+	b.ReportAllocs()
+	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		Encode(ioutil.Discard, img)
 	}
 }
 
 func BenchmarkEncodeNRGBA(b *testing.B) {
-	b.StopTimer()
 	img := image.NewNRGBA(image.Rect(0, 0, 640, 480))
 	if img.Opaque() {
 		b.Fatal("expected image not to be opaque")
 	}
 	b.SetBytes(640 * 480 * 4)
-	b.StartTimer()
+	b.ReportAllocs()
+	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		Encode(ioutil.Discard, img)
 	}
 }
 
 func BenchmarkEncodePaletted(b *testing.B) {
-	b.StopTimer()
 	img := image.NewPaletted(image.Rect(0, 0, 640, 480), color.Palette{
 		color.RGBA{0, 0, 0, 255},
 		color.RGBA{255, 255, 255, 255},
 	})
 	b.SetBytes(640 * 480 * 1)
-	b.StartTimer()
+	b.ReportAllocs()
+	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		Encode(ioutil.Discard, img)
 	}
 }
 
 func BenchmarkEncodeRGBOpaque(b *testing.B) {
-	b.StopTimer()
 	img := image.NewRGBA(image.Rect(0, 0, 640, 480))
 	// Set all pixels to 0xFF alpha to force opaque mode.
 	bo := img.Bounds()
@@ -215,20 +214,21 @@ func BenchmarkEncodeRGBOpaque(b *testing.B) {
 		b.Fatal("expected image to be opaque")
 	}
 	b.SetBytes(640 * 480 * 4)
-	b.StartTimer()
+	b.ReportAllocs()
+	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		Encode(ioutil.Discard, img)
 	}
 }
 
 func BenchmarkEncodeRGBA(b *testing.B) {
-	b.StopTimer()
 	img := image.NewRGBA(image.Rect(0, 0, 640, 480))
 	if img.Opaque() {
 		b.Fatal("expected image not to be opaque")
 	}
 	b.SetBytes(640 * 480 * 4)
-	b.StartTimer()
+	b.ReportAllocs()
+	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		Encode(ioutil.Discard, img)
 	}