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-rw-r--r--src/runtime/slice_test.go501
1 files changed, 501 insertions, 0 deletions
diff --git a/src/runtime/slice_test.go b/src/runtime/slice_test.go
new file mode 100644
index 0000000..cd2bc26
--- /dev/null
+++ b/src/runtime/slice_test.go
@@ -0,0 +1,501 @@
+// Copyright 2011 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package runtime_test
+
+import (
+ "fmt"
+ "testing"
+)
+
+const N = 20
+
+func BenchmarkMakeSliceCopy(b *testing.B) {
+ const length = 32
+ var bytes = make([]byte, 8*length)
+ var ints = make([]int, length)
+ var ptrs = make([]*byte, length)
+ b.Run("mallocmove", func(b *testing.B) {
+ b.Run("Byte", func(b *testing.B) {
+ var x []byte
+ for i := 0; i < b.N; i++ {
+ x = make([]byte, len(bytes))
+ copy(x, bytes)
+ }
+ })
+ b.Run("Int", func(b *testing.B) {
+ var x []int
+ for i := 0; i < b.N; i++ {
+ x = make([]int, len(ints))
+ copy(x, ints)
+ }
+ })
+ b.Run("Ptr", func(b *testing.B) {
+ var x []*byte
+ for i := 0; i < b.N; i++ {
+ x = make([]*byte, len(ptrs))
+ copy(x, ptrs)
+ }
+
+ })
+ })
+ b.Run("makecopy", func(b *testing.B) {
+ b.Run("Byte", func(b *testing.B) {
+ var x []byte
+ for i := 0; i < b.N; i++ {
+ x = make([]byte, 8*length)
+ copy(x, bytes)
+ }
+ })
+ b.Run("Int", func(b *testing.B) {
+ var x []int
+ for i := 0; i < b.N; i++ {
+ x = make([]int, length)
+ copy(x, ints)
+ }
+ })
+ b.Run("Ptr", func(b *testing.B) {
+ var x []*byte
+ for i := 0; i < b.N; i++ {
+ x = make([]*byte, length)
+ copy(x, ptrs)
+ }
+
+ })
+ })
+ b.Run("nilappend", func(b *testing.B) {
+ b.Run("Byte", func(b *testing.B) {
+ var x []byte
+ for i := 0; i < b.N; i++ {
+ x = append([]byte(nil), bytes...)
+ _ = x
+ }
+ })
+ b.Run("Int", func(b *testing.B) {
+ var x []int
+ for i := 0; i < b.N; i++ {
+ x = append([]int(nil), ints...)
+ _ = x
+ }
+ })
+ b.Run("Ptr", func(b *testing.B) {
+ var x []*byte
+ for i := 0; i < b.N; i++ {
+ x = append([]*byte(nil), ptrs...)
+ _ = x
+ }
+ })
+ })
+}
+
+type (
+ struct24 struct{ a, b, c int64 }
+ struct32 struct{ a, b, c, d int64 }
+ struct40 struct{ a, b, c, d, e int64 }
+)
+
+func BenchmarkMakeSlice(b *testing.B) {
+ const length = 2
+ b.Run("Byte", func(b *testing.B) {
+ var x []byte
+ for i := 0; i < b.N; i++ {
+ x = make([]byte, length, 2*length)
+ _ = x
+ }
+ })
+ b.Run("Int16", func(b *testing.B) {
+ var x []int16
+ for i := 0; i < b.N; i++ {
+ x = make([]int16, length, 2*length)
+ _ = x
+ }
+ })
+ b.Run("Int", func(b *testing.B) {
+ var x []int
+ for i := 0; i < b.N; i++ {
+ x = make([]int, length, 2*length)
+ _ = x
+ }
+ })
+ b.Run("Ptr", func(b *testing.B) {
+ var x []*byte
+ for i := 0; i < b.N; i++ {
+ x = make([]*byte, length, 2*length)
+ _ = x
+ }
+ })
+ b.Run("Struct", func(b *testing.B) {
+ b.Run("24", func(b *testing.B) {
+ var x []struct24
+ for i := 0; i < b.N; i++ {
+ x = make([]struct24, length, 2*length)
+ _ = x
+ }
+ })
+ b.Run("32", func(b *testing.B) {
+ var x []struct32
+ for i := 0; i < b.N; i++ {
+ x = make([]struct32, length, 2*length)
+ _ = x
+ }
+ })
+ b.Run("40", func(b *testing.B) {
+ var x []struct40
+ for i := 0; i < b.N; i++ {
+ x = make([]struct40, length, 2*length)
+ _ = x
+ }
+ })
+
+ })
+}
+
+func BenchmarkGrowSlice(b *testing.B) {
+ b.Run("Byte", func(b *testing.B) {
+ x := make([]byte, 9)
+ for i := 0; i < b.N; i++ {
+ _ = append([]byte(nil), x...)
+ }
+ })
+ b.Run("Int16", func(b *testing.B) {
+ x := make([]int16, 9)
+ for i := 0; i < b.N; i++ {
+ _ = append([]int16(nil), x...)
+ }
+ })
+ b.Run("Int", func(b *testing.B) {
+ x := make([]int, 9)
+ for i := 0; i < b.N; i++ {
+ _ = append([]int(nil), x...)
+ }
+ })
+ b.Run("Ptr", func(b *testing.B) {
+ x := make([]*byte, 9)
+ for i := 0; i < b.N; i++ {
+ _ = append([]*byte(nil), x...)
+ }
+ })
+ b.Run("Struct", func(b *testing.B) {
+ b.Run("24", func(b *testing.B) {
+ x := make([]struct24, 9)
+ for i := 0; i < b.N; i++ {
+ _ = append([]struct24(nil), x...)
+ }
+ })
+ b.Run("32", func(b *testing.B) {
+ x := make([]struct32, 9)
+ for i := 0; i < b.N; i++ {
+ _ = append([]struct32(nil), x...)
+ }
+ })
+ b.Run("40", func(b *testing.B) {
+ x := make([]struct40, 9)
+ for i := 0; i < b.N; i++ {
+ _ = append([]struct40(nil), x...)
+ }
+ })
+
+ })
+}
+
+var (
+ SinkIntSlice []int
+ SinkIntPointerSlice []*int
+)
+
+func BenchmarkExtendSlice(b *testing.B) {
+ var length = 4 // Use a variable to prevent stack allocation of slices.
+ b.Run("IntSlice", func(b *testing.B) {
+ s := make([]int, 0, length)
+ for i := 0; i < b.N; i++ {
+ s = append(s[:0:length/2], make([]int, length)...)
+ }
+ SinkIntSlice = s
+ })
+ b.Run("PointerSlice", func(b *testing.B) {
+ s := make([]*int, 0, length)
+ for i := 0; i < b.N; i++ {
+ s = append(s[:0:length/2], make([]*int, length)...)
+ }
+ SinkIntPointerSlice = s
+ })
+ b.Run("NoGrow", func(b *testing.B) {
+ s := make([]int, 0, length)
+ for i := 0; i < b.N; i++ {
+ s = append(s[:0:length], make([]int, length)...)
+ }
+ SinkIntSlice = s
+ })
+}
+
+func BenchmarkAppend(b *testing.B) {
+ b.StopTimer()
+ x := make([]int, 0, N)
+ b.StartTimer()
+ for i := 0; i < b.N; i++ {
+ x = x[0:0]
+ for j := 0; j < N; j++ {
+ x = append(x, j)
+ }
+ }
+}
+
+func BenchmarkAppendGrowByte(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ var x []byte
+ for j := 0; j < 1<<20; j++ {
+ x = append(x, byte(j))
+ }
+ }
+}
+
+func BenchmarkAppendGrowString(b *testing.B) {
+ var s string
+ for i := 0; i < b.N; i++ {
+ var x []string
+ for j := 0; j < 1<<20; j++ {
+ x = append(x, s)
+ }
+ }
+}
+
+func BenchmarkAppendSlice(b *testing.B) {
+ for _, length := range []int{1, 4, 7, 8, 15, 16, 32} {
+ b.Run(fmt.Sprint(length, "Bytes"), func(b *testing.B) {
+ x := make([]byte, 0, N)
+ y := make([]byte, length)
+ for i := 0; i < b.N; i++ {
+ x = x[0:0]
+ x = append(x, y...)
+ }
+ })
+ }
+}
+
+var (
+ blackhole []byte
+)
+
+func BenchmarkAppendSliceLarge(b *testing.B) {
+ for _, length := range []int{1 << 10, 4 << 10, 16 << 10, 64 << 10, 256 << 10, 1024 << 10} {
+ y := make([]byte, length)
+ b.Run(fmt.Sprint(length, "Bytes"), func(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ blackhole = nil
+ blackhole = append(blackhole, y...)
+ }
+ })
+ }
+}
+
+func BenchmarkAppendStr(b *testing.B) {
+ for _, str := range []string{
+ "1",
+ "1234",
+ "12345678",
+ "1234567890123456",
+ "12345678901234567890123456789012",
+ } {
+ b.Run(fmt.Sprint(len(str), "Bytes"), func(b *testing.B) {
+ x := make([]byte, 0, N)
+ for i := 0; i < b.N; i++ {
+ x = x[0:0]
+ x = append(x, str...)
+ }
+ })
+ }
+}
+
+func BenchmarkAppendSpecialCase(b *testing.B) {
+ b.StopTimer()
+ x := make([]int, 0, N)
+ b.StartTimer()
+ for i := 0; i < b.N; i++ {
+ x = x[0:0]
+ for j := 0; j < N; j++ {
+ if len(x) < cap(x) {
+ x = x[:len(x)+1]
+ x[len(x)-1] = j
+ } else {
+ x = append(x, j)
+ }
+ }
+ }
+}
+
+var x []int
+
+func f() int {
+ x[:1][0] = 3
+ return 2
+}
+
+func TestSideEffectOrder(t *testing.T) {
+ x = make([]int, 0, 10)
+ x = append(x, 1, f())
+ if x[0] != 1 || x[1] != 2 {
+ t.Error("append failed: ", x[0], x[1])
+ }
+}
+
+func TestAppendOverlap(t *testing.T) {
+ x := []byte("1234")
+ x = append(x[1:], x...) // p > q in runtime·appendslice.
+ got := string(x)
+ want := "2341234"
+ if got != want {
+ t.Errorf("overlap failed: got %q want %q", got, want)
+ }
+}
+
+func BenchmarkCopy(b *testing.B) {
+ for _, l := range []int{1, 2, 4, 8, 12, 16, 32, 128, 1024} {
+ buf := make([]byte, 4096)
+ b.Run(fmt.Sprint(l, "Byte"), func(b *testing.B) {
+ s := make([]byte, l)
+ var n int
+ for i := 0; i < b.N; i++ {
+ n = copy(buf, s)
+ }
+ b.SetBytes(int64(n))
+ })
+ b.Run(fmt.Sprint(l, "String"), func(b *testing.B) {
+ s := string(make([]byte, l))
+ var n int
+ for i := 0; i < b.N; i++ {
+ n = copy(buf, s)
+ }
+ b.SetBytes(int64(n))
+ })
+ }
+}
+
+var (
+ sByte []byte
+ s1Ptr []uintptr
+ s2Ptr [][2]uintptr
+ s3Ptr [][3]uintptr
+ s4Ptr [][4]uintptr
+)
+
+// BenchmarkAppendInPlace tests the performance of append
+// when the result is being written back to the same slice.
+// In order for the in-place optimization to occur,
+// the slice must be referred to by address;
+// using a global is an easy way to trigger that.
+// We test the "grow" and "no grow" paths separately,
+// but not the "normal" (occasionally grow) path,
+// because it is a blend of the other two.
+// We use small numbers and small sizes in an attempt
+// to avoid benchmarking memory allocation and copying.
+// We use scalars instead of pointers in an attempt
+// to avoid benchmarking the write barriers.
+// We benchmark four common sizes (byte, pointer, string/interface, slice),
+// and one larger size.
+func BenchmarkAppendInPlace(b *testing.B) {
+ b.Run("NoGrow", func(b *testing.B) {
+ const C = 128
+
+ b.Run("Byte", func(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ sByte = make([]byte, C)
+ for j := 0; j < C; j++ {
+ sByte = append(sByte, 0x77)
+ }
+ }
+ })
+
+ b.Run("1Ptr", func(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ s1Ptr = make([]uintptr, C)
+ for j := 0; j < C; j++ {
+ s1Ptr = append(s1Ptr, 0x77)
+ }
+ }
+ })
+
+ b.Run("2Ptr", func(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ s2Ptr = make([][2]uintptr, C)
+ for j := 0; j < C; j++ {
+ s2Ptr = append(s2Ptr, [2]uintptr{0x77, 0x88})
+ }
+ }
+ })
+
+ b.Run("3Ptr", func(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ s3Ptr = make([][3]uintptr, C)
+ for j := 0; j < C; j++ {
+ s3Ptr = append(s3Ptr, [3]uintptr{0x77, 0x88, 0x99})
+ }
+ }
+ })
+
+ b.Run("4Ptr", func(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ s4Ptr = make([][4]uintptr, C)
+ for j := 0; j < C; j++ {
+ s4Ptr = append(s4Ptr, [4]uintptr{0x77, 0x88, 0x99, 0xAA})
+ }
+ }
+ })
+
+ })
+
+ b.Run("Grow", func(b *testing.B) {
+ const C = 5
+
+ b.Run("Byte", func(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ sByte = make([]byte, 0)
+ for j := 0; j < C; j++ {
+ sByte = append(sByte, 0x77)
+ sByte = sByte[:cap(sByte)]
+ }
+ }
+ })
+
+ b.Run("1Ptr", func(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ s1Ptr = make([]uintptr, 0)
+ for j := 0; j < C; j++ {
+ s1Ptr = append(s1Ptr, 0x77)
+ s1Ptr = s1Ptr[:cap(s1Ptr)]
+ }
+ }
+ })
+
+ b.Run("2Ptr", func(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ s2Ptr = make([][2]uintptr, 0)
+ for j := 0; j < C; j++ {
+ s2Ptr = append(s2Ptr, [2]uintptr{0x77, 0x88})
+ s2Ptr = s2Ptr[:cap(s2Ptr)]
+ }
+ }
+ })
+
+ b.Run("3Ptr", func(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ s3Ptr = make([][3]uintptr, 0)
+ for j := 0; j < C; j++ {
+ s3Ptr = append(s3Ptr, [3]uintptr{0x77, 0x88, 0x99})
+ s3Ptr = s3Ptr[:cap(s3Ptr)]
+ }
+ }
+ })
+
+ b.Run("4Ptr", func(b *testing.B) {
+ for i := 0; i < b.N; i++ {
+ s4Ptr = make([][4]uintptr, 0)
+ for j := 0; j < C; j++ {
+ s4Ptr = append(s4Ptr, [4]uintptr{0x77, 0x88, 0x99, 0xAA})
+ s4Ptr = s4Ptr[:cap(s4Ptr)]
+ }
+ }
+ })
+
+ })
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-14 02:35:32 +0000