需要帮助理解goroutine的奇怪行为。

huangapple go评论67阅读模式
英文:

Need help to understand this weird bahaviour of go routines

问题

我有以下使用Go协程的代码:

package main

import (
	"fmt"
	"time"
)

func thread_1(i int) {
	time.Sleep(time.Second * 1)
	fmt.Println("thread_1: i:", i)
}

func thread_2(i int) {
	time.Sleep(time.Second * 1)
	fmt.Println("thread_2: i:", i)
}

func main() {
	for i := 0; i < 100; i++ {
		go thread_1(i)
		go thread_2(i)
	}

	var input string
	fmt.Scanln(&input)
}

我原本期望每个Go协程都会等待1秒钟,然后打印出它们的i值。

然而,两个Go协程都等待了1秒钟,然后一次性打印出所有的i值。

在同样的背景下,另一个问题是:
我有一个服务器-客户端应用程序,服务器为每个客户端连接生成一个接收器Go协程来接收数据。然后接收器Go协程会生成一个名为processor的工作Go协程来处理数据。可能会有多个接收器Go协程和多个处理器Go协程。
在这种情况下,一些接收器和处理器Go协程可能会无限期地占用资源。

请帮助我理解这种行为。

英文:

I've following code using go routines:

package main
        
import  ( 
    &quot;fmt&quot;
    &quot;time&quot;
)

func thread_1(i int)    {
    time.Sleep(time.Second * 1)
    fmt.Println(&quot;thread_1: i: &quot;,i)
}   
        
func thread_2(i int)    {
    time.Sleep(time.Second * 1)
    fmt.Println(&quot;thread_2: i: &quot;,i)
}
        
func main() {
    for i := 0; i &lt; 100; i++    {
        go thread_1(i)
        go thread_2(i)
    }

    var input string
    fmt.Scanln(&amp;input)
} 

I was expecting each go routine would wait for a second and then print its value of i.

However, both the go routines waited for 1 second each and printed all the values of i at once.

Another question in the same context is:
I've a server-client application where server spawns a receiver go routine to receive data from client one for each client connection. Then the receiver go routine spawns a worker go routine called processor to process the data. There could be multiple receiver go routines and hence multiple processor go routines.
In such a case some receiver and processor go routines may hog indefinitely.

Please help me understand this behaviour.

答案1

得分: 3

你在一个大批处理中同时运行100个运行thread_1的goroutine和100个运行thread_2的goroutine。这200个goroutine中的每一个都会休眠一秒钟,然后打印输出并结束。所以,是的,这种行为是可以预期的:200个goroutine并行地休眠1秒钟,然后200个goroutine并行地打印输出。

(我不理解你的第二个问题)

英文:

You span 100 goroutines running thread_1 and 100 goroutines running thread_2 in one big batch. Each of these 200 goroutines sleeps for one second and then prints and ends. So yes, the behavior is to be expected: 200 goroutines sleeping each 1 second in parallel and then 200 goroutines printing in parallel.

(And I do not understand your second question)

huangapple
  • 本文由 发表于 2015年8月23日 02:24:30
  • 转载请务必保留本文链接:https://go.coder-hub.com/32159402.html
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