mirror of git://gcc.gnu.org/git/gcc.git
313 lines
6.4 KiB
Go
313 lines
6.4 KiB
Go
// Copyright 2011 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package runtime_test
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import (
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"fmt"
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"testing"
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)
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const N = 20
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func BenchmarkMakeSlice(b *testing.B) {
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var x []byte
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for i := 0; i < b.N; i++ {
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x = make([]byte, 32)
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_ = x
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}
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}
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func BenchmarkGrowSliceBytes(b *testing.B) {
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b.StopTimer()
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var x = make([]byte, 9)
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b.StartTimer()
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for i := 0; i < b.N; i++ {
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_ = append([]byte(nil), x...)
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}
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}
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func BenchmarkGrowSliceInts(b *testing.B) {
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b.StopTimer()
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var x = make([]int, 9)
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b.StartTimer()
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for i := 0; i < b.N; i++ {
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_ = append([]int(nil), x...)
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}
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}
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func BenchmarkGrowSlicePtr(b *testing.B) {
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b.StopTimer()
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var x = make([]*byte, 9)
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b.StartTimer()
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for i := 0; i < b.N; i++ {
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_ = append([]*byte(nil), x...)
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}
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}
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type struct24 struct{ a, b, c int64 }
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func BenchmarkGrowSliceStruct24Bytes(b *testing.B) {
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b.StopTimer()
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var x = make([]struct24, 9)
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b.StartTimer()
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for i := 0; i < b.N; i++ {
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_ = append([]struct24(nil), x...)
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}
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}
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func BenchmarkAppend(b *testing.B) {
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b.StopTimer()
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x := make([]int, 0, N)
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b.StartTimer()
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for i := 0; i < b.N; i++ {
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x = x[0:0]
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for j := 0; j < N; j++ {
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x = append(x, j)
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}
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}
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}
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func BenchmarkAppendGrowByte(b *testing.B) {
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for i := 0; i < b.N; i++ {
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var x []byte
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for j := 0; j < 1<<20; j++ {
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x = append(x, byte(j))
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}
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}
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}
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func BenchmarkAppendGrowString(b *testing.B) {
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var s string
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for i := 0; i < b.N; i++ {
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var x []string
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for j := 0; j < 1<<20; j++ {
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x = append(x, s)
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}
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}
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}
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func BenchmarkAppendSlice(b *testing.B) {
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for _, length := range []int{1, 4, 7, 8, 15, 16, 32} {
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b.Run(fmt.Sprint(length, "Bytes"), func(b *testing.B) {
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x := make([]byte, 0, N)
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y := make([]byte, length)
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for i := 0; i < b.N; i++ {
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x = x[0:0]
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x = append(x, y...)
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}
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})
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}
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}
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func BenchmarkAppendStr(b *testing.B) {
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for _, str := range []string{
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"1",
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"1234",
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"12345678",
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"1234567890123456",
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"12345678901234567890123456789012",
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} {
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b.Run(fmt.Sprint(len(str), "Bytes"), func(b *testing.B) {
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x := make([]byte, 0, N)
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for i := 0; i < b.N; i++ {
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x = x[0:0]
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x = append(x, str...)
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}
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})
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}
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}
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func BenchmarkAppendSpecialCase(b *testing.B) {
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b.StopTimer()
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x := make([]int, 0, N)
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b.StartTimer()
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for i := 0; i < b.N; i++ {
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x = x[0:0]
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for j := 0; j < N; j++ {
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if len(x) < cap(x) {
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x = x[:len(x)+1]
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x[len(x)-1] = j
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} else {
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x = append(x, j)
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}
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}
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}
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}
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var x []int
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func f() int {
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x[:1][0] = 3
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return 2
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}
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func TestSideEffectOrder(t *testing.T) {
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x = make([]int, 0, 10)
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x = append(x, 1, f())
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if x[0] != 1 || x[1] != 2 {
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t.Error("append failed: ", x[0], x[1])
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}
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}
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func TestAppendOverlap(t *testing.T) {
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x := []byte("1234")
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x = append(x[1:], x...) // p > q in runtime·appendslice.
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got := string(x)
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want := "2341234"
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if got != want {
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t.Errorf("overlap failed: got %q want %q", got, want)
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}
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}
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func BenchmarkCopy(b *testing.B) {
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for _, l := range []int{1, 2, 4, 8, 12, 16, 32, 128, 1024} {
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buf := make([]byte, 4096)
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b.Run(fmt.Sprint(l, "Byte"), func(b *testing.B) {
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s := make([]byte, l)
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var n int
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for i := 0; i < b.N; i++ {
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n = copy(buf, s)
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}
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b.SetBytes(int64(n))
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})
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b.Run(fmt.Sprint(l, "String"), func(b *testing.B) {
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s := string(make([]byte, l))
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var n int
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for i := 0; i < b.N; i++ {
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n = copy(buf, s)
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}
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b.SetBytes(int64(n))
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})
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}
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}
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var (
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sByte []byte
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s1Ptr []uintptr
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s2Ptr [][2]uintptr
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s3Ptr [][3]uintptr
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s4Ptr [][4]uintptr
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)
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// BenchmarkAppendInPlace tests the performance of append
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// when the result is being written back to the same slice.
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// In order for the in-place optimization to occur,
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// the slice must be referred to by address;
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// using a global is an easy way to trigger that.
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// We test the "grow" and "no grow" paths separately,
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// but not the "normal" (occasionally grow) path,
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// because it is a blend of the other two.
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// We use small numbers and small sizes in an attempt
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// to avoid benchmarking memory allocation and copying.
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// We use scalars instead of pointers in an attempt
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// to avoid benchmarking the write barriers.
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// We benchmark four common sizes (byte, pointer, string/interface, slice),
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// and one larger size.
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func BenchmarkAppendInPlace(b *testing.B) {
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b.Run("NoGrow", func(b *testing.B) {
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const C = 128
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b.Run("Byte", func(b *testing.B) {
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for i := 0; i < b.N; i++ {
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sByte = make([]byte, C)
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for j := 0; j < C; j++ {
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sByte = append(sByte, 0x77)
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}
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}
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})
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b.Run("1Ptr", func(b *testing.B) {
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for i := 0; i < b.N; i++ {
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s1Ptr = make([]uintptr, C)
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for j := 0; j < C; j++ {
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s1Ptr = append(s1Ptr, 0x77)
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}
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}
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})
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b.Run("2Ptr", func(b *testing.B) {
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for i := 0; i < b.N; i++ {
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s2Ptr = make([][2]uintptr, C)
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for j := 0; j < C; j++ {
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s2Ptr = append(s2Ptr, [2]uintptr{0x77, 0x88})
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}
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}
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})
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b.Run("3Ptr", func(b *testing.B) {
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for i := 0; i < b.N; i++ {
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s3Ptr = make([][3]uintptr, C)
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for j := 0; j < C; j++ {
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s3Ptr = append(s3Ptr, [3]uintptr{0x77, 0x88, 0x99})
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}
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}
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})
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b.Run("4Ptr", func(b *testing.B) {
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for i := 0; i < b.N; i++ {
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s4Ptr = make([][4]uintptr, C)
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for j := 0; j < C; j++ {
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s4Ptr = append(s4Ptr, [4]uintptr{0x77, 0x88, 0x99, 0xAA})
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}
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}
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})
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})
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b.Run("Grow", func(b *testing.B) {
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const C = 5
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b.Run("Byte", func(b *testing.B) {
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for i := 0; i < b.N; i++ {
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sByte = make([]byte, 0)
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for j := 0; j < C; j++ {
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sByte = append(sByte, 0x77)
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sByte = sByte[:cap(sByte)]
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}
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}
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})
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b.Run("1Ptr", func(b *testing.B) {
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for i := 0; i < b.N; i++ {
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s1Ptr = make([]uintptr, 0)
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for j := 0; j < C; j++ {
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s1Ptr = append(s1Ptr, 0x77)
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s1Ptr = s1Ptr[:cap(s1Ptr)]
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}
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}
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})
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b.Run("2Ptr", func(b *testing.B) {
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for i := 0; i < b.N; i++ {
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s2Ptr = make([][2]uintptr, 0)
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for j := 0; j < C; j++ {
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s2Ptr = append(s2Ptr, [2]uintptr{0x77, 0x88})
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s2Ptr = s2Ptr[:cap(s2Ptr)]
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}
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}
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})
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b.Run("3Ptr", func(b *testing.B) {
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for i := 0; i < b.N; i++ {
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s3Ptr = make([][3]uintptr, 0)
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for j := 0; j < C; j++ {
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s3Ptr = append(s3Ptr, [3]uintptr{0x77, 0x88, 0x99})
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s3Ptr = s3Ptr[:cap(s3Ptr)]
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}
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}
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})
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b.Run("4Ptr", func(b *testing.B) {
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for i := 0; i < b.N; i++ {
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s4Ptr = make([][4]uintptr, 0)
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for j := 0; j < C; j++ {
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s4Ptr = append(s4Ptr, [4]uintptr{0x77, 0x88, 0x99, 0xAA})
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s4Ptr = s4Ptr[:cap(s4Ptr)]
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}
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}
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})
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})
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}
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