两个版本 加锁和不加锁

不加锁的版本
count1.go 

package main

import "fmt"
import "sync"


var count int
var NUM = 1000000
var GONUM = 100
var wg sync.WaitGroup

func main() {
   wg.Add(GONUM)
   for i := 0; i < GONUM; i++ {
      go countadd()
   }
   wg.Wait()
   fmt.Println(count)
}
func countadd(){
   defer wg.Done()
   for i := 0; i < NUM; i++ {
      count++;
   }
}


加锁的版本
count2.go

package main

import "fmt"
import "sync"


var count int
var NUM = 1000000
var GONUM = 100
var wg sync.WaitGroup
var lock sync.Mutex

func main() {
   wg.Add(GONUM)
   for i := 0; i < GONUM; i++ {
      go countadd()
   }
   wg.Wait()
   fmt.Println(count)
}
func countadd(){
   defer wg.Done()
   lock.Lock()  
   defer lock.Unlock()
   for i := 0; i < NUM; i++ {
      count++;
   }
}


输出结果

go run count1.go
31019733

go run count1.go
30088065

go run count2.go
100000000

go run count2.go
100000000


完整代码
https://gitee.com/dyyx/hellocode/blob/master/web/tech/go/demo/count1.go
https://gitee.com/dyyx/hellocode/blob/master/web/tech/go/demo/count2.go