mirror of
https://github.com/golang/go
synced 2024-11-20 07:14:40 -07:00
77a2113925
Consider an interface value i of type I and concrete value c of type C. Prior to this CL, i==c was evaluated as I(c) == i Evaluating I(c) can allocate. This CL changes the evaluation of i==c to x, ok := i.(C); ok && x == c The new generated code is shorter and does not allocate directly. If C is small, as it is in every instance in the stdlib, the new code also uses less stack space and makes one runtime call instead of two. If C is very large, the original implementation is used. The cutoff for "very large" is 1<<16, following the stack vs heap cutoff used elsewhere. This kind of comparison occurs in 38 places in the stdlib, mostly in the net and os packages. benchmark old ns/op new ns/op delta BenchmarkEqEfaceConcrete 29.5 7.92 -73.15% BenchmarkEqIfaceConcrete 32.1 7.90 -75.39% BenchmarkNeEfaceConcrete 29.9 7.90 -73.58% BenchmarkNeIfaceConcrete 35.9 7.90 -77.99% Fixes #9370. Change-Id: I7c4555950bcd6406ee5c613be1f2128da2c9a2b7 Reviewed-on: https://go-review.googlesource.com/2096 Reviewed-by: Russ Cox <rsc@golang.org> Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
181 lines
2.6 KiB
Go
181 lines
2.6 KiB
Go
// Copyright 2012 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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"runtime"
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"testing"
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)
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type I1 interface {
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Method1()
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}
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type I2 interface {
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Method1()
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Method2()
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}
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type TS uint16
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type TM uintptr
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type TL [2]uintptr
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func (TS) Method1() {}
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func (TS) Method2() {}
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func (TM) Method1() {}
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func (TM) Method2() {}
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func (TL) Method1() {}
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func (TL) Method2() {}
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var (
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e interface{}
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e_ interface{}
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i1 I1
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i2 I2
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ts TS
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tm TM
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tl TL
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)
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// Issue 9370
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func TestCmpIfaceConcreteAlloc(t *testing.T) {
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if runtime.Compiler != "gc" {
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t.Skip("skipping on non-gc compiler")
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}
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n := testing.AllocsPerRun(1, func() {
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_ = e == ts
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_ = i1 == ts
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_ = e == 1
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})
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if n > 0 {
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t.Fatalf("iface cmp allocs=%v; want 0", n)
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}
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}
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func BenchmarkEqEfaceConcrete(b *testing.B) {
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for i := 0; i < b.N; i++ {
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_ = e == ts
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}
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}
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func BenchmarkEqIfaceConcrete(b *testing.B) {
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for i := 0; i < b.N; i++ {
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_ = i1 == ts
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}
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}
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func BenchmarkNeEfaceConcrete(b *testing.B) {
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for i := 0; i < b.N; i++ {
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_ = e != ts
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}
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}
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func BenchmarkNeIfaceConcrete(b *testing.B) {
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for i := 0; i < b.N; i++ {
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_ = i1 != ts
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}
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}
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func BenchmarkConvT2ESmall(b *testing.B) {
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for i := 0; i < b.N; i++ {
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e = ts
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}
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}
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func BenchmarkConvT2EUintptr(b *testing.B) {
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for i := 0; i < b.N; i++ {
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e = tm
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}
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}
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func BenchmarkConvT2ELarge(b *testing.B) {
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for i := 0; i < b.N; i++ {
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e = tl
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}
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}
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func BenchmarkConvT2ISmall(b *testing.B) {
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for i := 0; i < b.N; i++ {
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i1 = ts
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}
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}
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func BenchmarkConvT2IUintptr(b *testing.B) {
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for i := 0; i < b.N; i++ {
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i1 = tm
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}
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}
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func BenchmarkConvT2ILarge(b *testing.B) {
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for i := 0; i < b.N; i++ {
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i1 = tl
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}
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}
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func BenchmarkConvI2E(b *testing.B) {
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i2 = tm
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for i := 0; i < b.N; i++ {
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e = i2
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}
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}
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func BenchmarkConvI2I(b *testing.B) {
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i2 = tm
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for i := 0; i < b.N; i++ {
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i1 = i2
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}
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}
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func BenchmarkAssertE2T(b *testing.B) {
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e = tm
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for i := 0; i < b.N; i++ {
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tm = e.(TM)
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}
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}
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func BenchmarkAssertE2TLarge(b *testing.B) {
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e = tl
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for i := 0; i < b.N; i++ {
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tl = e.(TL)
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}
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}
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func BenchmarkAssertE2I(b *testing.B) {
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e = tm
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for i := 0; i < b.N; i++ {
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i1 = e.(I1)
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}
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}
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func BenchmarkAssertI2T(b *testing.B) {
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i1 = tm
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for i := 0; i < b.N; i++ {
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tm = i1.(TM)
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}
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}
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func BenchmarkAssertI2I(b *testing.B) {
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i1 = tm
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for i := 0; i < b.N; i++ {
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i2 = i1.(I2)
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}
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}
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func BenchmarkAssertI2E(b *testing.B) {
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i1 = tm
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for i := 0; i < b.N; i++ {
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e = i1.(interface{})
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}
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}
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func BenchmarkAssertE2E(b *testing.B) {
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e = tm
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for i := 0; i < b.N; i++ {
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e_ = e
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}
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}
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