How are coroutines implemented in golang functions?

Coroutine is a lightweight concurrent execution unit. Go language implements coroutine through goroutine. The implementation principle is to adopt the M:N model, and each thread has its own coroutine scheduler to manage the coroutine. The code example creates a coroutine as go func(){}; prints the number of current thread coroutines as runtime.NumGoroutine(); and gives up thread control as runtime.Gosched(). In practical cases, coroutines can be used to process requests or asynchronous tasks concurrently, but attention should be paid to concurrent access issues to shared resources and performance issues caused by excessive creation of coroutines.

Coroutine implementation in Golang function

Coroutine is a lightweight concurrent execution unit that is independent of threads. Can be executed simultaneously in the same thread. In the Go language, coroutines are implemented through goroutines.

Coroutine implementation principle

Go language coroutine is implemented using the M:N model, where M represents the number of operating system threads and N represents the number of coroutines. Each thread has its own coroutine scheduler, which is responsible for managing the coroutines on the thread. When a coroutine blocks, the scheduler removes it from the current thread and continues executing other coroutines in another thread.

Code Example

package main

import (
    "fmt"
    "runtime"
)

func main() {
    // 创建一个协程
    go func() {
        fmt.Println("Hello from goroutine")
    }()

    // 打印当前线程中执行的协程数量
    fmt.Println("Number of goroutines:", runtime.NumGoroutine())

    // 等待协程执行完成
    runtime.Gosched()
}

In the code example, the go statement creates a coroutine. runtime.NumGoroutine() The function is used to print the number of coroutines executed in the current thread. runtime.Gosched() The function gives up control of the current thread and allows other coroutines to execute.

Practical Case

In practical applications, coroutines can be used to concurrently process a large number of requests, asynchronous tasks or parallel calculations. For example, in a web service, you can create a coroutine for each request to process the requests in parallel.

It should be noted that:

• Coroutines are different from threads. They share the same memory space, so you need to pay attention to concurrent access to shared resources.
• Creating too many coroutines may cause performance problems because each coroutine requires certain memory and CPU resources.

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