go_routine_mutex.go

package main

import (
	"fmt"
	"math/rand"
	"sync"
	"time"
)

var sumPool int
var mutex = &sync.Mutex{}
var channel = make(chan (int))

func main() {
	all := 1000
	fmt.Println("Init value of sumPool :", sumPool)
	t1 := time.Now().Nanosecond()
	// fmt.Println(t1)

	for i := 0; i < all; i++ {
		go add()
	}
	for i := 0; i < all; i++ {
		<-channel
	}
	fmt.Println("After value of sumPool :", sumPool)
	t2 := time.Now().Nanosecond()
	fmt.Printf("Time elapsed: %f msec\n", float32(t2-t1)/1000000.0)

}

func add() {

	s1 := rand.NewSource(time.Now().UnixNano())
	r1 := rand.New(s1)
	time.Sleep(time.Duration(r1.Intn(10)) * time.Millisecond)
	mutex.Lock()
	sumPool++
	mutex.Unlock()
	channel <- 1

}