Scheduling strategy and performance optimization of Goroutines in Golang concurrent programming

Scheduling strategy and performance optimization of Goroutines in Golang concurrent programming

Abstract: In Golang, Goroutines is one of the core concepts of concurrent programming. This article will introduce the scheduling strategy of Goroutines and how to improve the efficiency of concurrent programs through performance optimization. Articles will contain specific code examples to help readers better understand and apply related concepts and techniques.

1. Introduction

With the improvement of computer processing power and the popularity of multi-core processors, the demand for concurrent programming has gradually increased. As a programming language that supports high concurrency, Golang provides Goroutines, a powerful concurrency mechanism. Goroutines can be regarded as lightweight threads that can be executed concurrently in the program.

2. Scheduling strategy of Goroutines

Golang’s scheduler executes Goroutines according to a certain strategy to achieve concurrency effects. The scheduling strategies of Goroutines can be divided into three types:

1. Pull-type preemptive scheduling: When a Goroutine encounters a blockage, the scheduler will pause it and allocate the processor to other runnable Goroutines. Once the blocked Goroutine returns to a runnable state, the scheduler will schedule it again.
2. Non-preemptive voluntary scheduling: Goroutines actively give up the processor during execution so that other Goroutines can execute. In Golang, we can implement voluntary scheduling by calling the runtime.Gosched() function.
3. System call: When a Goroutine executes a system call, the scheduler will pause the Goroutine and assign the processor to other runnable Goroutines. Once the system call returns, the suspended Goroutine will be scheduled again.

3. Performance Optimization and Scheduling

When writing concurrent programs, reasonable scheduling strategies and performance optimization are the keys to improving program efficiency. Below we will introduce some commonly used performance optimization strategies.

1. Reduce the number of Goroutines created: Creating too many Goroutines will lead to increased memory overhead and scheduling pressure. Therefore, when writing code, you should try to reduce the number of Goroutines created and make reasonable use of existing Goroutines.
2. Control the life cycle of Goroutines: In programming, we can reduce the pressure on the scheduler by controlling the life cycle of Goroutines. You can use sync.WaitGroup to wait for all Goroutines to complete their tasks, or use context.Context to cancel the execution of Goroutines.
3. Reasonable use of concurrency primitives: Golang provides some concurrency primitives, such as locks, condition variables, and channels, to coordinate communication and synchronization between Goroutines. Reasonable use of these primitives can effectively reduce competition and conflicts and improve program performance.

5. Code Example

The following is a simple code example that demonstrates how to use Goroutines for concurrent processing:

package main

import (
    "fmt"
    "time"
)

func main() {
    // 创建一个Goroutine来执行任务1
    go task1()

    // 创建一个Goroutine来执行任务2
    go task2()

    // 主Goroutine等待1秒钟
    time.Sleep(time.Second)
}

func task1() {
    for i := 0; i < 10; i++ {
        fmt.Println("Task 1:", i)
        time.Sleep(time.Millisecond * 500)
    }
}

func task2() {
    for i := 0; i < 10; i++ {
        fmt.Println("Task 2:", i)
        time.Sleep(time.Millisecond * 500)
    }
}

In the above code, we create Two Goroutines are used to execute task 1 and task 2 concurrently. Each task will be looped 10 times, and the task execution time will be simulated through the time.Sleep function. By observing the output results, we can see that Task 1 and Task 2 are executed alternately, achieving the effect of concurrent processing.

6. Summary

This article introduces the scheduling strategy and performance optimization of Goroutines in Golang. When writing concurrent programs, reasonable scheduling strategies and performance optimization are the keys to improving program efficiency. By mastering the scheduling strategies of Goroutines and flexibly using related performance optimization strategies, developers can write efficient, stable and scalable concurrent programs.

Reference:

Golang Concurrency

https://golang.org/doc/effective_go.html#concurrency

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