Go language coroutine technical documentation

A coroutine (goroutine) is a lightweight thread in the Go language, which can run multiple coroutines in one thread to implement high-concurrency programs. Coroutines have the advantages of low overhead, high efficiency, and easy management, and are widely used in network services, cloud computing, big data processing, and artificial intelligence. This article will introduce the basic concepts and usage of Go language coroutines.

The concept of coroutines

A coroutine is a user-level thread that is scheduled by the Go language's runtime system. The running overhead of coroutines is much smaller than that of threads, and a program can run thousands of coroutines without exhausting system resources. Coroutines have the following characteristics:

1. Lightweight: The running overhead of coroutines is much smaller than that of threads.
2. High efficiency: The switching speed of coroutines is very fast.
3. Ease of management: Coroutines can be managed automatically by the Go language's runtime system.

Create a coroutine

Creating a coroutine in Go language is very simple, just use the go keyword. Here is a simple example program:

goCopy codepackage main

import "fmt"

func printHello() {
    fmt.Println("Hello World!")
}

func main() {
    go printHello()
    fmt.Println("main function")
}

The above program uses the go keyword to create a coroutine that calls the printHello function to output "Hello World!". The main function continues to execute and outputs "main function".

Coroutine communication

Communication between coroutines is an important part of concurrent programming in Go language. The Go language provides a channel mechanism for data transfer between coroutines. The channel has blocking read and write characteristics, which can avoid problems such as data competition and lock competition. Here is a simple example program:

goCopy codepackage main
import "fmt"

func counter(ch chan int) {
    for i := 1; i <= 5; i++ {
        ch <- i
    }
    close(ch)
}

func main() {
    ch := make(chan int)
    go counter(ch)
    for num := range ch {
        fmt.Println(num)
    }
}

The above program defines a counter function, which is used to send numbers 1~5 to the channel ch. The channel ch is created in the main function, and a coroutine is started to call the counter function. The main function reads the data in the channel ch using the range statement and outputs each number.

Coroutine pool

The coroutine pool is a mechanism for managing coroutines, which can control the number of concurrency, reuse coroutines, etc. In the Go language, you can use the WaitGroup and Pool types in the sync package to implement a coroutine pool. Here is a simple example program:

goCopy codepackage main

import (
    "fmt"
    "sync"
)

func worker(id int, pool *sync.Pool) {
    fmt.Printf("Worker %d is working
    }

Author: Li Songwen