The difference and application of threads and coroutines in Golang

The difference and application of threads and coroutines in Golang

Golang is a programming language with high development efficiency and powerful concurrency performance. Among them, threads (goroutine) and coroutines Thread is the key concept of concurrent programming. In Golang, a goroutine is a lightweight thread that is managed by the Go language runtime and can be created and destroyed very efficiently. Coroutines are a collaborative concurrency structure whose scheduling and execution are controlled by programmers.

The difference between threads and coroutines in Golang is the scheduling method and resource consumption. Threads are scheduled by the operating system kernel and occupy the thread resources of the operating system. Context switching and conversion between kernel mode and user mode are required, which is relatively costly. Coroutines are scheduled by the Go language runtime and do not occupy the thread resources of the operating system. They only occupy user space memory. The switching cost is low and concurrency and parallelism can be efficiently achieved.

Next we will demonstrate the application and difference between threads and coroutines through specific code examples:

1. Thread example:

package main

import (
    "fmt"
    "sync"
)

func printNumbers() {
    for i := 0; i < 10; i++ {
        fmt.Println("线程：", i)
    }
}

func main() {
    var wg sync.WaitGroup
    wg.Add(1)
    
    go func() {
        defer wg.Done()
        printNumbers()
    }()
    
    wg.Wait()
    fmt.Println("线程执行完毕！")
}

In this example , we use sync.WaitGroup to wait for the thread to complete execution. Through the go func() statement, we create a goroutine to execute the printNumbers() function. The program will output numbers from 0 to 9, and after all numbers are printed, it will output "Thread execution completed!".

2. Coroutine example:

package main

import (
    "fmt"
)

func printLetters() {
    for i := 'A'; i <= 'J'; i++ {
        fmt.Println("协程：", string(i))
    }
}

func main() {
    go printLetters()
    
    for i := 0; i < 10; i++ {
        fmt.Println("主程序：", i)
    }
    fmt.Println("协程执行完毕！")
}

In this example, we create a coroutine to execute ## through the go printLetters() statement #printLetters()Function. The program will alternately output the letters A to J and 0 to 9, and finally output "Coroutine execution completed!". Through this example, we can see how lightweight and efficient coroutines are.

Through the above examples, we can see the applications and differences of threads and coroutines in Golang. Threads are suitable for scenarios that require operating system-level thread scheduling and resource management, while coroutines are suitable for scenarios that efficiently implement concurrency, parallelism, and task scheduling. In actual development, choosing the appropriate concurrency method according to specific needs and scenarios can improve the performance and efficiency of the program.

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