Comparing ordinary routine and goroutine execution speed

routineComparison.go

package main

import (
  "math/rand"
  "time"
  "log"
)

func randomArray(n int) []int {
   array := make([]int, n)
   for i := 0; i < n; i++ {
     array[i] = rand.Intn(10)
   }
   return array
}

func randomArrayChannel(n int) []int {
  array := make([]int, n)
  go func(){
    for i := 0; i < n; i++ {
      array[i] = rand.Intn(10)
    }
    }()
  return array
}

func main() {
  size := 50000000
  start := time.Now()
  _ = randomArray(size)
  log.Printf("Ordinary Random Array takes %s", time.Since(start))

  start = time.Now()
  _ = randomArrayChannel(size)
  log.Printf("Goroutine Random Array takes %s", time.Since(start))
}

// In my computer goroutine 18 times faster than ordinary routine; different computer may generate different result