对 golang 中的 goroutine 数量进行控制
简介
- 在
golang 中开启一个 goroutine 是一件很便捷的事情
- 但是如果不对其进行控制，则可能造成 goroutine 泛滥成灾
- 本文就对如何控制 goroutine 数量进行一个尝试
- 主要思路是通过 chan 实现，取一个协程就向 chan 中写入，如果协程被取完则会阻塞，用完一个协程就从通道中拿出一个即可
代码
- for 循环中不停的开启新的协程
- 每隔一秒钟打印当前的协程数
没有协程池
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| package main
import (
"fmt"
"runtime"
"time"
)
func main() {
withoutGoroutinePool()
}
func withoutGoroutinePool() {
ticker := time.NewTicker(time.Second)
for {
select {
case <-ticker.C:
fmt.Println(time.Now().String(), runtime.NumGoroutine())
break
default:
go sleep()
}
}
}
func sleep() {
time.Sleep(100 * time.Millisecond)
}
|
- 输出结果如下所示，可以看出 Goroutine 的数量超多，在几十万之多，可能会瞬间打满 cpu
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| ➜ aaa git:(dev) ✗ go run main.go
2020-02-10 22:21:07.708449 +0800 CST m=+1.075829140 258734
2020-02-10 22:21:08.63268 +0800 CST m=+2.000078344 340130
2020-02-10 22:21:09.63266 +0800 CST m=+3.000079432 394476
2020-02-10 22:21:10.632632 +0800 CST m=+4.000071378 418946
2020-02-10 22:21:11.632619 +0800 CST m=+5.000079498 406332
2020-02-10 22:21:12.632586 +0800 CST m=+6.000066992 406157
2020-02-10 22:21:13.632612 +0800 CST m=+7.000113855 366507
2020-02-10 22:21:14.632658 +0800 CST m=+8.000180030 369627
2020-02-10 22:21:15.632572 +0800 CST m=+9.000114252 397764
^Csignal: interrupt
|
有协程池
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| package main
import (
"fmt"
"runtime"
"time"
)
type goroutinePool struct {
c chan interface{}
}
var pool *goroutinePool
func newGoroutinePool(size int) *goroutinePool {
return &goroutinePool{c: make(chan interface{}, size)}
}
func (goroutinePool *goroutinePool) Get() {
goroutinePool.c <- struct{}{}
}
func (goroutinePool *goroutinePool) Release() {
<-goroutinePool.c
}
func withGoroutinePool() {
pool = newGoroutinePool(100)
ticker := time.NewTicker(time.Second)
for {
select {
case <-ticker.C:
fmt.Println(time.Now().String(), runtime.NumGoroutine())
break
default:
pool.Get()
go func() {
sleep()
pool.Release()
}()
}
}
}
func main() {
withGoroutinePool()
}
func sleep() {
time.Sleep(100 * time.Millisecond)
}
|
- 输出结果如下所示，可以看出 Goroutine 的数量在 100 左右
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| ➜ aaa git:(dev) ✗ go run main.go
2020-02-10 22:23:57.4038 +0800 CST m=+1.017452302 45
2020-02-10 22:23:58.420406 +0800 CST m=+2.034076062 38
2020-02-10 22:23:59.450896 +0800 CST m=+3.064585392 86
2020-02-10 22:24:00.463936 +0800 CST m=+4.077642981 80
2020-02-10 22:24:01.480972 +0800 CST m=+5.094697456 71
2020-02-10 22:24:02.398438 +0800 CST m=+6.012179639 101
2020-02-10 22:24:03.416983 +0800 CST m=+7.030743402 88
2020-02-10 22:24:04.444314 +0800 CST m=+8.058093131 3
2020-02-10 22:24:05.457963 +0800 CST m=+9.071760019 78
^Csignal: interrupt
|
