gistfile1.txt

package main

import (
	"testing"
)

func BenchmarkAaa(b *testing.B) {
	ints := make([]int, 0)
	for i := 0; i < b.N; i++ {
		ints = append(ints, i)
	}
}

func BenchmarkBbb(b *testing.B) {
	ints := make([]int, b.N)
	for i := 0; i < b.N; i++ {
		ints[i] = i
	}
}

BenchmarkAaa 200000000 8.36 ns/op
BenchmarkBbb 2000000000 39.1 ns/op

BenchmarkBbb 2000000000 31.5 ns/op
BenchmarkAaa 50000000 27.8 ns/op

BenchmarkBbb 2000000000 36.0 ns/op
BenchmarkAaa 100000000 23.1 ns/op

BenchmarkAaa 200000000 7.62 ns/op
BenchmarkBbb 2000000000 36.7 ns/op

For some reason flipping the run order of the benchmarks makes Aaa take much longer.