https://groups.google.com/forum/#!topic/golang-nuts/lWvJDHkDU-c

gistfile1.go

package foo

import (
	"fmt"
	"testing"
)

const M = 32768

const M0 = M / 8192 // play with this knob ...

var arr, arr0 [M]int

func init() {
	fmt.Printf("----- using subset %d of %d\n", M0, M)
}

/// test access pattrens //////////////////////////////

func BenchmarkSlice(b *testing.B) {
	for n := 0; n < b.N; n++ {
		passSliceUseSlice(arr[:], arr0[:])
	}
}
func BenchmarkSliceSpecBounds(b *testing.B) {
	for n := 0; n < b.N; n++ {
		passSliceUseSlice(arr[0:M], arr0[0:M])
	}
}
func BenchmarkArrayPtr(b *testing.B) {
	for n := 0; n < b.N; n++ {
		passArraryPtrUseDeref(&arr, &arr0)
	}
}
func BenchmarkArrayPtrToSlice(b *testing.B) {
	for n := 0; n < b.N; n++ {
		passArraryPtrUseSlice(&arr, &arr0)
	}
}

/// access pattrens ///////////////////////////////////
// note: Mo-2 to allow for M0 == M
func passSliceUseSlice(s, s0 []int) {
	for i := 0; i < M0-2; i++ {
		arr[i] = arr[2+i]
	}
}

func passArraryPtrUseSlice(arr, arr0 *[M]int) {
	var s = (*arr)[:] // don't spec bounds here ..
	var s0 = (*arr)[:]
	for i := 0; i < M0-2; i++ {
		s[i] = s0[2+i]
	}
}

func passArraryPtrUseDeref(arr, arr0 *[M]int) {
	for i := 0; i < M0-2; i++ {
		(*arr)[i] = (*arr0)[2+i]
	}
}