Golang Concurrent Programming Exploration: Detailed Explanation of Goroutines' Threading Model

Golang Concurrent Programming Exploration: Detailed Explanation of Goroutines' Threading Model

In today's Internet era, high concurrency has become a very important topic in the development of various systems. The traditional single-threaded programming model is difficult to meet the needs of a large number of concurrent requests. In many programming languages, multi-threaded programming also has complex race conditions, deadlocks and other problems. In Golang, concurrent programming becomes simpler and more efficient through lightweight Goroutines and a communication-based concurrency model.

Goroutines is a very important concept in Golang. It is a lightweight execution thread. In Golang's design philosophy, Goroutines are distinguished from threads, and Goroutines are designed to be more lightweight and efficient.

Goroutines are called lightweight because their creation and destruction costs are very low. Creating a Goroutine in Golang is very simple, just add the "go" keyword before the function call. A Golang program can start thousands of Goroutines at the same time, and the scheduling and resource management of these Goroutines are taken care of by the Golang runtime system.

So how do Goroutines achieve concurrency? Within Golang, Goroutines are scheduled for execution by one or more threads (Theads). These threads will be managed by Golang's runtime system, and one thread is called the M (machine) thread, which is responsible for the execution of Goroutines. When Goroutines need to be executed, the M thread will take out a Goroutine from a global Goroutines queue (Goroutines Queue) and put it into its own Goroutine queue (Local Queue) for execution.

When a Goroutine encounters IO blocking (such as waiting for network connections, reading and writing files, etc.), Golang's runtime system will remove the Goroutine from the M thread and put it into a dedicated Waiting Queue. When the IO operation is completed, the runtime system will rejoin the Goroutine to an idle M thread and continue execution. This method of removing Goroutines that are waiting for IO from the M thread can ensure that the execution of other Goroutines will not be blocked, thus improving the concurrency performance of the system.

The following is a simple example to illustrate the use and scheduling process of Goroutines:

package main

import (
    "fmt"
    "sync"
)

func main() {
    var wg sync.WaitGroup
    wg.Add(1)
    go func() {
        defer wg.Done()
        fmt.Println("Hello, Goroutine!")
    }()
    wg.Wait()
}

In the above example, we created a Goroutine and output a Hello, Goroutine! . In the main function, we use WaitGroup in the sync package to wait for the Goroutine to complete execution. Specify the number of Goroutines to wait by calling the Add method, and call the Done method in the Goroutine to indicate that the Goroutine execution is completed. Finally, call the Wait method to wait for all Goroutines to complete execution.

When executing the above code, Golang's runtime system will automatically create an M thread and put Goroutine into the local queue of the M thread for execution. When the Goroutine is executed, the Done method is called to indicate that the Goroutine is executed and the waiting number in the WaitGroup is decremented by 1. When all Goroutines are executed, the Wait method returns and the program exits.

Through the above examples, we can see that concurrent programming can be easily achieved using Goroutines. With the support of Goroutines, we can write concurrent programs more efficiently and take full advantage of multi-core or multi-threading.

To sum up, Goroutines in Golang are lightweight execution threads that can easily implement concurrent programming. By separating Goroutines from threads, Golang implements a concurrent programming model that is efficient and easy to use. Through the scheduling and resource management of Goroutines, Golang implements a communication-based concurrency model, making concurrent programming simpler and more efficient.

I hope that through the introduction of this article, readers can have a deep understanding of the threading model of Goroutines and be able to flexibly use Golang's concurrent programming features in actual development.

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