I/O reuse mechanism in Go language

Go language is a programming language specifically designed for concurrent programming. It is characterized by being lightweight, easy to learn and powerful. In order to support a large number of concurrent operations, the Go language provides an I/O reuse mechanism, which can effectively reduce system overhead and improve program efficiency.

I/O multiplexing mechanism, also known as multiplexing technology, is a method that can monitor multiple file descriptors at the same time and wait for any one or several file descriptors to become readable, writable, or Abnormal event technology can reduce the consumption of system resources during runtime and improve program efficiency.

In the Go language, using the I/O reuse mechanism requires the use of the select statement. Before briefly explaining the select statement, we need to first understand the file descriptors and channels of the Go language.

(1) File descriptor

In the Linux system, all I/O operations are performed through the file descriptor, which is a non-negative integer used to identify an open file or I/O device. Since a file descriptor is just a non-negative integer, in the Go language, an integer type is used to represent the file descriptor.

(2) Channel

Channel is a basic data type of Go language, used to transfer data between multiple Goroutines. It is similar to a pipe and can be used to deliver synchronous and asynchronous messages. There are two types of channels: Buffered Channel and Unbuffered Channel.

Now, let’s go back to the select statement. The select statement is an operator provided by the Go language for processing multiple channels. It will wait for the first ready IO operation in each channel, and then execute the ready operation. This mechanism can effectively reduce system overhead and improve program efficiency.

The following is an example of a simple select statement:

select {
case ch1 <- 1:
    // 执行ch1的发送操作
case data := <-ch2:
    // 执行ch2的接收操作
default:
    // 默认操作
}

In this statement, the select statement will wait until the ch1 channel can successfully send a piece of data, or the ch2 channel can successfully receive a piece of data. data. If none of the above conditions are met, the default operation in the default statement is executed.

In addition to the channel operations in the above code, the select statement can also handle I/O events of the file descriptor. For example:

select {
case conn1 := <-listen.Accept():
    // 处理conn1的连接请求
case conn2 := <-listen.Accept():
    // 处理conn2的连接请求
case <-time.After(time.Second * 2):
    // 超时处理
}

In this statement, wait for two connection requests on the listener. If there are no connection requests for more than 2 seconds, a timeout is performed.

In summary, the I/O multiplexing mechanism is a very practical technology in the Go language. It can improve the running efficiency of the program without blocking threads, and can handle multiple processes at the same time. Events for file descriptors and channels. In Go language programming, it is crucial to be proficient in the I/O reuse mechanism and the use of select statements.

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