compute-sum.go

package main

import (
	"math/rand"
	"strconv"
	"testing"
)

var res int64

func BenchmarkSum(b *testing.B) {
	var sum int64
	benchmarks := []int{1024, 1025}
	for _, bm := range benchmarks {
		s := createMatrix(1000, bm)
		b.Run(strconv.Itoa(bm), func(b *testing.B) {
			for i := 0; i < b.N; i++ {
				sum = calculateSum(s)
			}
			res = sum
		})
	}
}

func calculateSum(s [][]int64) int64 {
	var sum int64
	for i := 0; i < len(s); i++ {
		for j := 0; j < 8; j++ {
			sum += s[i][j]
		}
	}
	return sum
}

func createMatrix(rows, columns int) [][]int64 {
	s := make([][]int64, rows)
	for i := 0; i < rows; i++ {
		s[i] = make([]int64, columns)
		for j := 0; j < columns; j++ {
			s[i][j] = rand.Int63()
		}
	}
	return s
}

goos: darwin
goarch: amd64
cpu: Intel(R) Core(TM) i5-7360U CPU @ 2.30GHz
BenchmarkSum
BenchmarkSum/1024
BenchmarkSum/1024-4         	   62149	     19349 ns/op
BenchmarkSum/1025
BenchmarkSum/1025-4         	  114414	     10093 ns/op