Golang CAS操作

for {
    // 假设data为共享变量，同一时刻可能有多个线程会更新它
    old := data
    ok := atomic.CompareAndSwapInt64(&data, old, new) 
    if ok {
        return new
    }
}

package main

import (
	"fmt"
	"sync"
	"sync/atomic"
)

var (
	counter int32          //计数器
	wg      sync.WaitGroup //信号量
)

func main() {
	nums := 10000
	// 开启多个goroutine
	for i := 0; i < nums; i++ {
		wg.Add(1)
		go incCounter(i)
	}
	wg.Wait()
	fmt.Println(counter)
}

func incCounter(index int) {
	defer wg.Done()
	// 自旋次数
	spinNum := 0
	for {
		//CAS操作
		old := counter
		ok := atomic.CompareAndSwapInt32(&counter, old, old+1)
		if ok {
			break
		} else {
			spinNum++
		}
	}
	if spinNum > 0 {
		fmt.Printf("goroutine: %d, spinnum: %d\n", index, spinNum)
	}
}