In-depth understanding: Concurrency processing and blocking in Go language

With the advent of the Internet era, the demand for concurrent processing and blocking continues to increase. As a programming language that supports concurrent processing, Go language is very popular in development. This article will provide an in-depth understanding of concurrency processing and blocking in Go language from the aspects of Go language's concurrency model, goroutine, channel, and blocking.

1. Concurrency model of Go language

Concurrent programming of Go language is based on the CSP model (Communicating Sequential Processes, communication sequence process). This model was first proposed by Tony Hoare in 1977 and is a message-oriented programming paradigm. This programming method is more direct and concise, and can effectively avoid thread safety issues.

The core of the CSP model is to decompose concurrent programs into a series of independent processes, which communicate and synchronize through channels. Such an architecture can reduce the use of locks in concurrent programs, reduce competition between processes, and improve program concurrency performance.

In addition to the CSP model, the Go language also inherits the actor model of programming languages ​​such as Erlang, which can easily handle large-scale concurrency issues and better meet the needs of high concurrency and distributed applications.

2. goroutine

Goroutine is the most basic concurrency processing method in Go language. It is a lightweight thread that can execute concurrently in the same address space. . Compared with traditional threads, the switching cost of Goroutine is often relatively low during context switching, so a large number of Goroutines can be created in the Go language without depleting system resources.

Creating a Goroutine is very simple, just add the go keyword in front of the function. For example:

func main() {
    go func() {
        // do something
    }()
}

In this example, we use the go keyword to open a new Goroutine, which will execute an unnamed function in the background. Since the creation of Goroutine is asynchronous, asynchronous tasks can be easily implemented and the concurrency performance of the program can be improved.

3. channel

Channel is a very important data type in the Go language, used for communication and synchronization between Goroutines. It can be regarded as a channel for transmitting data and ensuring the security and correctness of the transmitted data.

Through channels, we can transfer data between Goroutines to achieve synchronization and communication between threads. When using channels, we need to pay attention to the following points:

• As long as a value is sent to the channel, the value will be blocked until the value is received by another Goroutine.
• You can read data from the same channel from multiple Goroutines at the same time, but the same channel can only be written by one Goroutine.
• Channel's blocking rules can ensure the correctness of data synchronization in multiple Goroutines, but it will also bring a certain blocking cost.

For example, the following code demonstrates how to pass data through channels between Goroutines:

func main() {
    ch := make(chan int)
    go func() {
        ch <- 1
        ch <- 2
    }()
    fmt.Println(<-ch) // 1
    fmt.Println(<-ch) // 2
}

In this example, we create a buffered channel, and then A Goroutine sends two integers to the channel through ch <- 1 and ch <- 2. Subsequently, in the main function, we obtained these two integers through <-ch, and output them in the order they were sent.

4. Blocking

In the Go language, due to the use of channels to achieve synchronization and communication mechanisms between threads, between Goroutine and channels, inevitable occurrences will occur. blocking situation. At this time, if we do not handle the blocking situation well, it will lead to a decrease in program performance or a direct deadlock.

In order to avoid blocking, we can use the following methods:

• Buffered channel: Allows some buffered data to be stored in the channel. Once a certain amount is reached, Blocking will occur. By using buffered channels, programs can achieve better efficiency in communication and synchronization.
• Select statement: You can monitor the operations of multiple channels. When one channel is blocked, it will switch to another channel operation. This method solves the blocking problem when operating a single channel and improves the efficiency of communication and synchronization between Goroutines.
• Timeout mechanism: For some long-time operations, we can use the Timeout mechanism to avoid long-term blocking of the program. This mechanism can set a time limit, and the operation will not be blocked if the operation is completed within the timeout period.

Summary

This article starts from the concurrency model, goroutine, channel, blocking and other aspects of the Go language, and discusses concurrency processing and blocking in the Go language in detail. It is precisely because the Go language has such an excellent concurrency processing mechanism that it can occupy a place in the field of distributed and high concurrency and become the programming language of choice for many developers.

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