escapes_test.go

package main

import (
	"testing"
)


type box struct {
	data *byte
}

// 11.2 ns/op
func dumberFieldInHeap() {
	b := new(box)
	b.data = new(byte) // b.data escapes to heap (conservative way)
}

// 0.287 ns/op
func dumber1() {
	b := &box{data: new(byte)} // escape analysis detect work on stack (no heap)
	_ = b
}

// 0.285 ns/op
func dumber2() {
	var b box
	b.data = new(byte) // // escape analysis detect work on stack (no heap)
}

//  2.261e-06 sec
func BenchmarkEscapeStructAndPointerField(b *testing.B) {
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		dumberFieldInHeap()
	}
}

// 1.43e-07
func BenchmarkEscapeStructAndPointerField_NoEscapes_1(b *testing.B) {
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		dumber1()
	}
}

// 1.69e-07
func BenchmarkEscapeStructAndPointerField_NoEscapes_2(b *testing.B) {
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		dumber2()
	}
}