Golang Concurrent Programming: In-depth understanding of the principles and usage of Goroutines

Golang Concurrent Programming: In-depth understanding of the principles and usage of Goroutines

[Introduction]
With the increase in the number of computer processor cores, multi-threaded programming has become important to improve application performance and responsiveness. means. However, the traditional multi-threaded programming model has certain complexity and difficulty in implementation and debugging. In Golang, Goroutines provide a simple and powerful way of concurrent programming. This article will delve into the principles and usage of Goroutines.

[Principle of Goroutines]
Goroutines are lightweight threads of Golang, which are scheduled by the Go language runtime system (Goruntime). Compared with ordinary threads, the creation and destruction overhead of Goroutines is very small, so a large number of Goroutines can be created to execute tasks concurrently.

The implementation of Goroutines is based on the M:N thread model, which maps M Goroutines to N operating system threads. In this way, multiple Goroutines can be executed at the same time, whether on a single-core or multi-core computer, to fully utilize the performance of computing resources.

[Creation and Scheduling of Goroutines]
In Golang, you can create a Goroutine using the go keyword. The following is a simple sample code:

func main() {
    go printHello()
    fmt.Println("Main Goroutine")
    time.Sleep(time.Second)
}

func printHello() {
    time.Sleep(time.Second)
    fmt.Println("Hello Goroutine")
}

In the above code, the printHello function is created as a Goroutine, which will be executed asynchronously. In the main function, we can see that the program will first output "Main Goroutine", then wait for one second and then output "Hello Goroutine".

Goruntime is responsible for the scheduling of Goroutines, which allocates the Goroutines to be executed to available operating system threads. On an operating system thread, Goruntime maintains a Goroutine queue and selects the next Goroutine to be executed based on the scheduling policy. If a Goroutine is blocked (such as waiting for an I/O operation), Goroutine will temporarily suspend it and switch execution in other Goroutines.

[Communication between Goroutines]
In concurrent programming, Goroutines need to communicate and share data. Golang provides Channel to achieve this. Channels are a special type in Golang that allow Goroutines to send and receive data safely between each other.

The following is a sample code for communication using channels:

func main() {
    ch := make(chan string)
    go sendMessage(ch, "Hello Goroutine!")
    msg := <-ch
    fmt.Println(msg)
}

func sendMessage(ch chan<- string, msg string) {
    time.Sleep(time.Second)
    ch <- msg
}

In the above code, we create a channel ch of string type and use the go keyword to use the sendMessage function as a Goroutine starts. The sendMessage function will send the message to the channel. In the main function, we use the <-ch syntax to receive the message from the channel and print it out.

[Synchronization and Mutual Exclusion of Goroutines]
When multiple Goroutines access shared resources at the same time, race condition problems may occur. In order to ensure the correctness and consistency of resources, Golang provides mutex locks (Mutex) and read-write locks (RWMutex) to achieve resource synchronization and mutual exclusion.

The following is a sample code that uses a mutex lock for synchronization:

func main() {
    var counter int
    var wg sync.WaitGroup
    var mu sync.Mutex

    for i := 0; i < 10; i++ {
        wg.Add(1)
        go increment(&counter, &wg, &mu)
    }

    wg.Wait()
    fmt.Println("Counter:", counter)
}

func increment(counter *int, wg *sync.WaitGroup, mu *sync.Mutex) {
    mu.Lock()
    *counter++
    mu.Unlock()

    wg.Done()
}

In the above code, we create a shared counter variable and use the mutex mu to protect it . In the increment function, we use mu.Lock() and mu.Unlock() to lock and release the mutex respectively.

[Summary]
Through this article we have learned about the principles and usage of Goroutines in Golang concurrent programming. Goroutines provide a simple and powerful concurrent programming method that can make full use of computing resources. We learned about the creation and scheduling of Goroutines, communication between Goroutines, and how to use mutex locks for synchronization. I hope this article will help you gain a deeper understanding of Golang concurrent programming.

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