compress/lzw: use Run for benchmarks

load file only once per group.

Change-Id: I965661507055e6e100506bf14d37133ecdd2cc5e
Reviewed-on: https://go-review.googlesource.com/23423
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/compress/lzw/reader_test.go b/src/compress/lzw/reader_test.go
index c3a5c3a0aaacdf3bfce7fbbf111786cb9310e98a..6b9f9a3da7035ddc80203c5b4730bc0f5d93eda0 100644 (file)
--- a/src/compress/lzw/reader_test.go
+++ b/src/compress/lzw/reader_test.go
@@ -6,8 +6,10 @@ package lzw
 
 import (
        "bytes"
+       "fmt"
        "io"
        "io/ioutil"
+       "math"
        "runtime"
        "strconv"
        "strings"
@@ -118,42 +120,37 @@ func TestReader(t *testing.T) {
        }
 }
 
-func benchmarkDecoder(b *testing.B, n int) {
-       b.StopTimer()
-       b.SetBytes(int64(n))
-       buf0, err := ioutil.ReadFile("../testdata/e.txt")
+func BenchmarkDecoder(b *testing.B) {
+       buf, err := ioutil.ReadFile("../testdata/e.txt")
        if err != nil {
                b.Fatal(err)
        }
-       if len(buf0) == 0 {
+       if len(buf) == 0 {
                b.Fatalf("test file has no data")
        }
-       compressed := new(bytes.Buffer)
-       w := NewWriter(compressed, LSB, 8)
-       for i := 0; i < n; i += len(buf0) {
-               if len(buf0) > n-i {
-                       buf0 = buf0[:n-i]
-               }
-               w.Write(buf0)
-       }
-       w.Close()
-       buf1 := compressed.Bytes()
-       buf0, compressed, w = nil, nil, nil
-       runtime.GC()
-       b.StartTimer()
-       for i := 0; i < b.N; i++ {
-               io.Copy(ioutil.Discard, NewReader(bytes.NewReader(buf1), LSB, 8))
-       }
-}
-
-func BenchmarkDecoder1e4(b *testing.B) {
-       benchmarkDecoder(b, 1e4)
-}
 
-func BenchmarkDecoder1e5(b *testing.B) {
-       benchmarkDecoder(b, 1e5)
-}
-
-func BenchmarkDecoder1e6(b *testing.B) {
-       benchmarkDecoder(b, 1e6)
+       for e := 4; e <= 6; e++ {
+               n := int(math.Pow10(e))
+               b.Run(fmt.Sprint("1e", e), func(b *testing.B) {
+                       b.StopTimer()
+                       b.SetBytes(int64(n))
+                       buf0 := buf
+                       compressed := new(bytes.Buffer)
+                       w := NewWriter(compressed, LSB, 8)
+                       for i := 0; i < n; i += len(buf0) {
+                               if len(buf0) > n-i {
+                                       buf0 = buf0[:n-i]
+                               }
+                               w.Write(buf0)
+                       }
+                       w.Close()
+                       buf1 := compressed.Bytes()
+                       buf0, compressed, w = nil, nil, nil
+                       runtime.GC()
+                       b.StartTimer()
+                       for i := 0; i < b.N; i++ {
+                               io.Copy(ioutil.Discard, NewReader(bytes.NewReader(buf1), LSB, 8))
+                       }
+               })
+       }
 }

diff --git a/src/compress/lzw/writer_test.go b/src/compress/lzw/writer_test.go
index 66d761727f481d81dabf05348d27ee0bddd95bf1..4979f8b35211397dddaa3d8d2b665e5967b457c8 100644 (file)
--- a/src/compress/lzw/writer_test.go
+++ b/src/compress/lzw/writer_test.go
@@ -5,9 +5,11 @@
 package lzw
 
 import (
+       "fmt"
        "internal/testenv"
        "io"
        "io/ioutil"
+       "math"
        "os"
        "runtime"
        "testing"
@@ -122,41 +124,34 @@ func TestSmallLitWidth(t *testing.T) {
        }
 }
 
-func benchmarkEncoder(b *testing.B, n int) {
-       b.StopTimer()
-       b.SetBytes(int64(n))
-       buf0, err := ioutil.ReadFile("../testdata/e.txt")
+func BenchmarkEncoder(b *testing.B) {
+       buf, err := ioutil.ReadFile("../testdata/e.txt")
        if err != nil {
                b.Fatal(err)
        }
-       if len(buf0) == 0 {
+       if len(buf) == 0 {
                b.Fatalf("test file has no data")
        }
-       buf1 := make([]byte, n)
-       for i := 0; i < n; i += len(buf0) {
-               if len(buf0) > n-i {
-                       buf0 = buf0[:n-i]
+
+       for e := 4; e <= 6; e++ {
+               n := int(math.Pow10(e))
+               buf0 := buf
+               buf1 := make([]byte, n)
+               for i := 0; i < n; i += len(buf0) {
+                       if len(buf0) > n-i {
+                               buf0 = buf0[:n-i]
+                       }
+                       copy(buf1[i:], buf0)
                }
-               copy(buf1[i:], buf0)
-       }
-       buf0 = nil
-       runtime.GC()
-       b.StartTimer()
-       for i := 0; i < b.N; i++ {
-               w := NewWriter(ioutil.Discard, LSB, 8)
-               w.Write(buf1)
-               w.Close()
+               buf0 = nil
+               runtime.GC()
+               b.Run(fmt.Sprint("1e", e), func(b *testing.B) {
+                       b.SetBytes(int64(n))
+                       for i := 0; i < b.N; i++ {
+                               w := NewWriter(ioutil.Discard, LSB, 8)
+                               w.Write(buf1)
+                               w.Close()
+                       }
+               })
        }
 }
-
-func BenchmarkEncoder1e4(b *testing.B) {
-       benchmarkEncoder(b, 1e4)
-}
-
-func BenchmarkEncoder1e5(b *testing.B) {
-       benchmarkEncoder(b, 1e5)
-}
-
-func BenchmarkEncoder1e6(b *testing.B) {
-       benchmarkEncoder(b, 1e6)
-}