Go并发之锁

互斥锁

package main

import (
	"fmt"
	"sync"
	"time"
)

//使用互斥锁计算时间

var(
	mu sync.Mutex
	x int64
	wg sync.WaitGroup
)

func write()  {
	defer wg.Done()
	mu.Lock()
	x = x+1
	time.Sleep(time.Millisecond*10)
	mu.Unlock()
}

func read()  {
	defer wg.Done()
	mu.Lock()
	time.Sleep(time.Millisecond*1)
	mu.Unlock()
}

func main() {
	now := time.Now()
	for i :=0;i<10;i++{
		wg.Add(1)
		go write()
	}

	for j :=0;j<10000;j++{
		wg.Add(1)
		go read()
	}

	wg.Wait()
	fmt.Println(time.Since(now))
}

　　

 

读写锁

package main

import (
	"fmt"
	"sync"
	"time"
)

//读写锁
//使用场景，在读多写少的情况下使用，性能很高
//当写锁获取之后，读锁就会阻塞等待锁的释放，才能获取

var(
	mu sync.RWMutex
	x int64
	wg sync.WaitGroup
)

func writer()  {
	defer wg.Done()
	mu.Lock()
	x = x+1
	time.Sleep(time.Millisecond*10)
	mu.Unlock()
}

func read()  {
	defer wg.Done()
	mu.RLock()
	time.Sleep(time.Millisecond*1)
	mu.RUnlock()
}

func main() {
	now := time.Now()
	for i :=0;i<10;i++{
		wg.Add(1)
		go writer()
	}

	for j :=0;j<10000;j++{
		wg.Add(1)
		go read()
	}
	wg.Wait()
	fmt.Println(time.Since(now))
}