Golang's gc introduction and principle analysis

Title: Golang’s GC introduction and principle analysis

Golang (Go language), as an open source programming language developed by Google, has always been known for its efficient concurrency model and fast compilation speed have received widespread attention. Among them, Garbage Collection (GC) is a major feature of Golang. By automatically managing memory, it avoids many problems caused by developers' manual memory management. This article will briefly introduce Golang's garbage collection mechanism, while also deeply analyzing its principles and giving specific code examples.

1. Introduction to GC in Golang

The garbage collection mechanism in Golang adopts the mark-sweep algorithm, which is mainly divided into two stages: the marking stage and the clearing stage. In the marking phase, the system will mark all surviving objects; in the clearing phase, the system will clear all unmarked objects and release the memory space they occupy. The process is automated and the programmer does not need to do manual memory management.

2. Golang’s GC principle analysis

Golang’s GC mainly identifies and processes garbage objects in three ways:

• Memory allocator: Golang’s memory The allocator divides memory into different size classes based on the size of the object and allocates memory to the object. This memory is released when the object is no longer used.
• Root object: GC uses a series of root objects (such as global variables, variables in the stack, etc.) as a starting point to traverse the reference relationships between objects. Only objects reachable from the root object will be retained, and objects that have not been accessed will be cleared.
• Concurrent marking: Golang's GC adopts concurrent marking during the marking phase, that is, while marking the object, the execution of the program continues, saving time.

3. Specific code example

The following is a simple code example to demonstrate Golang’s garbage collection process:

package main

import (
    "fmt"
    "runtime"
)

func main() {
    var a []int

    for i := 0; i < 1000000; i++ {
        a = append(a, i)
    }

    fmt.Println("Number of Goroutines before GC:", runtime.NumGoroutine())

    runtime.GC()

    fmt.Println("Number of Goroutines after GC:", runtime.NumGoroutine())
}

In this example, we create a Contain a slice of 1 million integers, and then call runtime.GC() to manually trigger garbage collection. By printing runtime.NumGoroutine() you can observe the change in the number of Goroutines before and after GC execution.

Conclusion

In general, Golang’s garbage collection mechanism effectively simplifies the complexity of memory management, allowing developers to focus more on writing business logic rather than the details of memory management. . Through the introduction and examples of this article, I hope readers will have a clearer understanding of Golang's GC and be able to better utilize the garbage collection mechanism to improve program performance and maintainability.

The above is an article about the introduction and principle analysis of Golang's GC. I hope readers can gain some new knowledge from it.

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