go doc sync/atomic

import "sync/atomic"
func AddInt32(addr *int32, delta int32) (new int32)
func AddInt64(addr *int64, delta int64) (new int64)

func CompareAndSwapInt32(addr *int32, old, new int32) (swapped bool)
func CompareAndSwapInt64(addr *int64, old, new int64) (swapped bool)

func LoadInt32(addr *int32) (val int32)
func LoadInt64(addr *int64) (val int64)
func StoreInt32(addr *int32, val int32)
func StoreInt64(addr *int64, val int64)

Add  CompareAndSwap Load Store
读写 增加 比较和交换


var count int32
atomic.AddInt32(&count,1)


并发递增计数
count3.go

package main

import "fmt"
import "time"
import "sync"
import "sync/atomic"


var count int32
var NUM = 1000000
var GONUM = 100
var wg sync.WaitGroup

func main() {
   wg.Add(GONUM)
   start := time.Now()
   for i := 0; i < GONUM; i++ {
      go countadd()
   }
   wg.Wait()
   cost := time.Since(start)
   fmt.Println(count,cost)
}
func countadd(){
   defer wg.Done()
   for i := 0; i < NUM; i++ {
         atomic.AddInt32(&count,1)
   }
}



go run count3.go
100000000 3.296716571s

go run count3.go
100000000 3.185218237s


完整代码
https://gitee.com/dyyx/hellocode/blob/master/web/tech/go/demo/count3.go