#golang for vs for-range benchmark

loops_test.go

package loops_test

import (
	"testing"
)

var totalPkg byte

func BenchmarkForRangeArray(b *testing.B) {
	var arr [128 * 1024]byte
	var total byte

	for n := 0; n < b.N; n++ {
		for _, v := range arr {
			total += v
		}
	}
	totalPkg = total
}

func BenchmarkForRangeSlice(b *testing.B) {
	var arr [128 * 1024]byte
	var total byte

	for n := 0; n < b.N; n++ {
		for _, v := range arr[:] {
			total += v
		}
	}
	totalPkg = total
}

func BenchmarkClassicFor(b *testing.B) {
	var arr [128 * 1024]byte
	var total byte

	for n := 0; n < b.N; n++ {
		for i := 0; i < len(arr); i++ {
			total += arr[i]
		}
	}
	totalPkg = total
}

To run this: put loops_test.go in its own directory, and run:

go test -bench .