Go 如何用硬件同步原语（CAS）替代锁

硬件同步原语其实对应的是 Go 语言 atomic 包下的一些原子操作

package main

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

func main() {
    // 账户初始值为0元
    var balance int32
    balance = int32(0)
    done := make(chan bool)
    // 执行10000次转账，每次转入1元
    count := 10000

    //var lock sync.Mutex

    for i := 0; i < count; i++ {
        // 这里模拟异步并发转账
        //go transfer(&balance, 1, done, &lock)
        //go transferCas(&balance, 1, done)
        go transferFaa(&balance, 1, done)
    }
    // 等待所有转账都完成
    for i := 0; i < count; i++ {
        <-done
    }
    // 打印账户余额
    fmt.Printf("balance = %d \n", balance)
}
// 转账服务
func transfer(balance *int32, amount int, done chan bool, lock *sync.Mutex) {
    lock.Lock()
    *balance = *balance + int32(amount)
    lock.Unlock()
    done <- true
}

// CAS原语
func transferCas(balance *int32, amount int, done chan bool) {
    for {
        oldValue := atomic.LoadInt32(balance)
        newValue := oldValue + int32(amount)
        if atomic.CompareAndSwapInt32(balance, oldValue, newValue) {
            break
        }
    }
    done <- true
}

// FAA原语
func transferFaa(balance *int32, amount int, done chan bool) {
    atomic.AddInt32(balance, int32(amount))
    done <- true
}