The difference between golang and coroutines

Golang is a relatively new programming language. It is an open source programming language launched by Google. The characteristics of Golang language are efficiency, simplicity, reliability, security and easy expansion. In the Golang language, coroutines are a very important feature.

What is a coroutine?
Coroutine is a lightweight thread, which is generally managed by the language runtime system. In Golang, a coroutine can be understood as an independent execution thread, which can execute multiple coroutines at the same time. The coroutines are independent of each other, avoiding a series of problems with traditional threads. In Golang, the term "goroutine" is used for coroutines.

The difference between coroutines, threads, and processes
Compared with threads and processes, coroutines have the following differences:

1. Coroutines are lightweight threads , more lightweight than traditional threads, so more coroutines can be created, but the number of threads will be limited;
2. Switching between coroutines is very cheap, because between coroutines The CPU context will not be switched (that is, there is no thread switching overhead);
3. The scheduling and management of coroutines is the responsibility of the programming language runtime system, while the threads are the responsibility of the operating system;
4. Among coroutines It is easier to achieve communication and synchronization between the two;
5. The execution of the coroutine is in function units, and function calls can be converted into the execution of the coroutine.

How to use coroutines in Golang
Using coroutines in Golang is very simple, just use the keyword "go" before the function, for example:

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

The above code snippet indicates that a new coroutine is created to execute the code in the function body.

Coroutines and multi-core CPU
In the case of a single-core CPU, the coroutines are freely switched for execution on a single CPU through the scheduling algorithm, which can easily achieve code concurrency and asynchronous execution. However, in the case of multi-core CPUs, if you want each coroutine to take advantage of the multi-core CPU, you need to limit the execution of the coroutine to a certain thread. This method is called a "global coroutine". Scheduling".

Using global coroutine scheduling in Golang is very simple. You only need to set the environment variable "GOMAXPROCS" in the Golang running environment. For example:

import "runtime"

func main() {
    runtime.GOMAXPROCS(4)
    // do something
}

The above code snippet indicates that the number of threads Set to 4 to achieve concurrent execution of coroutines.

Summary
Coroutines are a very important feature in the Golang language, which can easily achieve code concurrency and asynchronous execution. Compared with traditional threads and processes, coroutines are lighter, faster to switch, and more controllable in execution. Through the reasonable use of coroutines, efficient, reliable, safe and highly scalable concurrent programming can be achieved.

The above is the detailed content of The difference between golang and coroutines. For more information, please follow other related articles on the PHP Chinese website!