libgo/go/runtime/append_test.go

   1 // Copyright 2011 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4 package runtime_test
   5
   6 import "testing"
   7
   8 const N = 20
   9
  10 func BenchmarkAppend(b *testing.B) {
  11         b.StopTimer()
  12         x := make([]int, 0, N)
  13         b.StartTimer()
  14         for i := 0; i < b.N; i++ {
  15                 x = x[0:0]
  16                 for j := 0; j < N; j++ {
  17                         x = append(x, j)
  18                 }
  19         }
  20 }
  21
  22 func BenchmarkAppendGrowByte(b *testing.B) {
  23         for i := 0; i < b.N; i++ {
  24                 var x []byte
  25                 for j := 0; j < 1<<20; j++ {
  26                         x = append(x, byte(j))
  27                 }
  28         }
  29 }
  30
  31 func BenchmarkAppendGrowString(b *testing.B) {
  32         var s string
  33         for i := 0; i < b.N; i++ {
  34                 var x []string
  35                 for j := 0; j < 1<<20; j++ {
  36                         x = append(x, s)
  37                 }
  38         }
  39 }
  40
  41 func benchmarkAppendBytes(b *testing.B, length int) {
  42         b.StopTimer()
  43         x := make([]byte, 0, N)
  44         y := make([]byte, length)
  45         b.StartTimer()
  46         for i := 0; i < b.N; i++ {
  47                 x = x[0:0]
  48                 x = append(x, y...)
  49         }
  50 }
  51
  52 func BenchmarkAppend1Byte(b *testing.B) {
  53         benchmarkAppendBytes(b, 1)
  54 }
  55
  56 func BenchmarkAppend4Bytes(b *testing.B) {
  57         benchmarkAppendBytes(b, 4)
  58 }
  59
  60 func BenchmarkAppend7Bytes(b *testing.B) {
  61         benchmarkAppendBytes(b, 7)
  62 }
  63
  64 func BenchmarkAppend8Bytes(b *testing.B) {
  65         benchmarkAppendBytes(b, 8)
  66 }
  67
  68 func BenchmarkAppend15Bytes(b *testing.B) {
  69         benchmarkAppendBytes(b, 15)
  70 }
  71
  72 func BenchmarkAppend16Bytes(b *testing.B) {
  73         benchmarkAppendBytes(b, 16)
  74 }
  75
  76 func BenchmarkAppend32Bytes(b *testing.B) {
  77         benchmarkAppendBytes(b, 32)
  78 }
  79
  80 func benchmarkAppendStr(b *testing.B, str string) {
  81         b.StopTimer()
  82         x := make([]byte, 0, N)
  83         b.StartTimer()
  84         for i := 0; i < b.N; i++ {
  85                 x = x[0:0]
  86                 x = append(x, str...)
  87         }
  88 }
  89
  90 func BenchmarkAppendStr1Byte(b *testing.B) {
  91         benchmarkAppendStr(b, "1")
  92 }
  93
  94 func BenchmarkAppendStr4Bytes(b *testing.B) {
  95         benchmarkAppendStr(b, "1234")
  96 }
  97
  98 func BenchmarkAppendStr8Bytes(b *testing.B) {
  99         benchmarkAppendStr(b, "12345678")
 100 }
 101
 102 func BenchmarkAppendStr16Bytes(b *testing.B) {
 103         benchmarkAppendStr(b, "1234567890123456")
 104 }
 105
 106 func BenchmarkAppendStr32Bytes(b *testing.B) {
 107         benchmarkAppendStr(b, "12345678901234567890123456789012")
 108 }
 109
 110 func BenchmarkAppendSpecialCase(b *testing.B) {
 111         b.StopTimer()
 112         x := make([]int, 0, N)
 113         b.StartTimer()
 114         for i := 0; i < b.N; i++ {
 115                 x = x[0:0]
 116                 for j := 0; j < N; j++ {
 117                         if len(x) < cap(x) {
 118                                 x = x[:len(x)+1]
 119                                 x[len(x)-1] = j
 120                         } else {
 121                                 x = append(x, j)
 122                         }
 123                 }
 124         }
 125 }
 126
 127 var x []int
 128
 129 func f() int {
 130         x[:1][0] = 3
 131         return 2
 132 }
 133
 134 func TestSideEffectOrder(t *testing.T) {
 135         x = make([]int, 0, 10)
 136         x = append(x, 1, f())
 137         if x[0] != 1 || x[1] != 2 {
 138                 t.Error("append failed: ", x[0], x[1])
 139         }
 140 }
 141
 142 func TestAppendOverlap(t *testing.T) {
 143         x := []byte("1234")
 144         x = append(x[1:], x...) // p > q in runtime·appendslice.
 145         got := string(x)
 146         want := "2341234"
 147         if got != want {
 148                 t.Errorf("overlap failed: got %q want %q", got, want)
 149         }
 150 }
 151
 152 func benchmarkCopySlice(b *testing.B, l int) {
 153         s := make([]byte, l)
 154         buf := make([]byte, 4096)
 155         var n int
 156         for i := 0; i < b.N; i++ {
 157                 n = copy(buf, s)
 158         }
 159         b.SetBytes(int64(n))
 160 }
 161
 162 func benchmarkCopyStr(b *testing.B, l int) {
 163         s := string(make([]byte, l))
 164         buf := make([]byte, 4096)
 165         var n int
 166         for i := 0; i < b.N; i++ {
 167                 n = copy(buf, s)
 168         }
 169         b.SetBytes(int64(n))
 170 }
 171
 172 func BenchmarkCopy1Byte(b *testing.B)    { benchmarkCopySlice(b, 1) }
 173 func BenchmarkCopy2Byte(b *testing.B)    { benchmarkCopySlice(b, 2) }
 174 func BenchmarkCopy4Byte(b *testing.B)    { benchmarkCopySlice(b, 4) }
 175 func BenchmarkCopy8Byte(b *testing.B)    { benchmarkCopySlice(b, 8) }
 176 func BenchmarkCopy12Byte(b *testing.B)   { benchmarkCopySlice(b, 12) }
 177 func BenchmarkCopy16Byte(b *testing.B)   { benchmarkCopySlice(b, 16) }
 178 func BenchmarkCopy32Byte(b *testing.B)   { benchmarkCopySlice(b, 32) }
 179 func BenchmarkCopy128Byte(b *testing.B)  { benchmarkCopySlice(b, 128) }
 180 func BenchmarkCopy1024Byte(b *testing.B) { benchmarkCopySlice(b, 1024) }
 181
 182 func BenchmarkCopy1String(b *testing.B)    { benchmarkCopyStr(b, 1) }
 183 func BenchmarkCopy2String(b *testing.B)    { benchmarkCopyStr(b, 2) }
 184 func BenchmarkCopy4String(b *testing.B)    { benchmarkCopyStr(b, 4) }
 185 func BenchmarkCopy8String(b *testing.B)    { benchmarkCopyStr(b, 8) }
 186 func BenchmarkCopy12String(b *testing.B)   { benchmarkCopyStr(b, 12) }
 187 func BenchmarkCopy16String(b *testing.B)   { benchmarkCopyStr(b, 16) }
 188 func BenchmarkCopy32String(b *testing.B)   { benchmarkCopyStr(b, 32) }
 189 func BenchmarkCopy128String(b *testing.B)  { benchmarkCopyStr(b, 128) }
 190 func BenchmarkCopy1024String(b *testing.B) { benchmarkCopyStr(b, 1024) }