mirror of
https://github.com/golang/go
synced 2024-10-04 22:21:22 -06:00
915784e11a
Allocs of size 16 can bypass atomic set of the allocated bit, while allocs of size 8 can not. Allocs with and w/o type info hit different paths inside of malloc. Current results on linux/amd64: BenchmarkMalloc8 50000000 43.6 ns/op BenchmarkMalloc16 50000000 46.7 ns/op BenchmarkMallocTypeInfo8 50000000 61.3 ns/op BenchmarkMallocTypeInfo16 50000000 63.5 ns/op R=golang-dev, remyoudompheng, minux.ma, bradfitz, iant CC=golang-dev https://golang.org/cl/9090045
53 lines
976 B
Go
53 lines
976 B
Go
// Copyright 2013 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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"testing"
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"unsafe"
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)
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var mallocSink uintptr
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func BenchmarkMalloc8(b *testing.B) {
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var x uintptr
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for i := 0; i < b.N; i++ {
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p := new(int64)
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x ^= uintptr(unsafe.Pointer(p))
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}
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mallocSink = x
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}
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func BenchmarkMalloc16(b *testing.B) {
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var x uintptr
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for i := 0; i < b.N; i++ {
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p := new([2]int64)
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x ^= uintptr(unsafe.Pointer(p))
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}
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mallocSink = x
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}
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func BenchmarkMallocTypeInfo8(b *testing.B) {
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var x uintptr
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for i := 0; i < b.N; i++ {
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p := new(struct {
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p [8 / unsafe.Sizeof(uintptr(0))]*int
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})
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x ^= uintptr(unsafe.Pointer(p))
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}
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mallocSink = x
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}
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func BenchmarkMallocTypeInfo16(b *testing.B) {
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var x uintptr
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for i := 0; i < b.N; i++ {
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p := new(struct {
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p [16 / unsafe.Sizeof(uintptr(0))]*int
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})
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x ^= uintptr(unsafe.Pointer(p))
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}
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mallocSink = x
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}
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