54 lines
994 B
Go
54 lines
994 B
Go
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package main
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import (
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"fmt"
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"sync"
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"time"
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)
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// 读写互斥锁，读的时候远远大于写的场景
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// rwlock
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// 当读的时候加读锁，写的时候加写锁。和互斥锁相比性能差很多
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// 当持有写锁，所有的goroutine都需要等待写锁解锁不能读也不能写，当持有读锁，所有goroutine仍然能够读访问共享资源，但不允许写
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var (
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v = 0
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locker sync.Mutex
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w sync.WaitGroup
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rwlocker sync.RWMutex
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)
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func read() {
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defer w.Done()
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locker.Lock()
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//rwlocker.RLock()
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fmt.Println(v)
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time.Sleep(time.Millisecond * 1)
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locker.Unlock()
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//rwlocker.RUnlock()
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}
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func write() {
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defer w.Done()
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locker.Lock()
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//rwlocker.Lock()
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v += 1
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time.Sleep(time.Millisecond * 5)
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locker.Unlock()
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//rwlocker.Unlock()
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}
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func main() {
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start := time.Now()
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for i := 0; i < 10; i++ {
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w.Add(1)
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go write()
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}
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time.Sleep(time.Second)
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for i := 0; i < 1000; i++ {
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w.Add(1)
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go read()
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}
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w.Wait()
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fmt.Println(time.Now().Sub(start))
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}
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