go map/slice/array benchmark

gistfile1.txt

package main

import (
	"fmt"
	"testing"
)

const Size = 1e6
var (
	array [Size]int
	slice = make([]int, Size)
	Map   = make(map[int]int)
	r int		// to avoid the compiler optimising away the access
)

func init() {
	for i, _ := range array {
		array[i] = i
		slice[i] = i
		Map[i] = i
	}
}

func main() {
	fmt.Printf("array %v\n", testing.Benchmark(BenchmarkArrayAccess))
	fmt.Printf("slice %v\n", testing.Benchmark(BenchmarkSliceAccess))
	fmt.Printf("map %v\n", testing.Benchmark(BenchmarkMapAccess))
	fmt.Printf("array range %v\n", testing.Benchmark(BenchmarkArrayRangeAccess))
	fmt.Printf("array slice range %v\n", testing.Benchmark(BenchmarkArraySliceRangeAccess))
	fmt.Printf("slice range %v\n", testing.Benchmark(BenchmarkSliceRangeAccess))
	fmt.Printf("map range %v\n", testing.Benchmark(BenchmarkMapRangeAccess))
}

func BenchmarkArrayAccess(b *testing.B) {
	for i := b.N-1; i >= 0; i-- {
		k := 0
		for j := Size-1; j >= 0; j-- {
			k += array[j]
		}
		r = k
	}
}

func BenchmarkArrayRangeAccess(b *testing.B) {
	for i := b.N-1; i >= 0; i-- {
		k := 0
		for _, x := range array {
			k += x
		}
		r = k
	}
}

func BenchmarkArraySliceRangeAccess(b *testing.B) {
	for i := b.N-1; i >= 0; i-- {
		k := 0
		for _, x := range array[:] {
			k += x
		}
		r = k
	}
}

func BenchmarkSliceRangeAccess(b *testing.B) {
	a := slice
	for i := b.N-1; i >= 0; i-- {
		k := 0
		for _, x := range a {
			k += x
		}
		r = k
	}
}

func BenchmarkSliceAccess(b *testing.B) {
	a := slice
	for i := b.N-1; i >= 0; i-- {
		k := 0
		for j := Size-1; j >= 0; j-- {
			k += a[j]
		}
		r = k
	}
}

func BenchmarkMapRangeAccess(b *testing.B) {
	a := Map
	for i := b.N-1; i >= 0; i-- {
		k := 0
		for _, x := range a {
			k += x
		}
		r = k
	}
}

func BenchmarkMapAccess(b *testing.B) {
	a := Map
	for i := b.N-1; i >= 0; i-- {
		k := 0
		for j := Size-1; j >= 0; j-- {
			k += a[j]
		}
		r = k
	}
}