Revealing the runtime mechanism of go language

Answer: The runtime mechanism of the Go language achieves efficiency through garbage collection, schedulers, and concurrency primitives. Detailed description: Garbage collection: Automatically clear memory that is no longer used to avoid programmers from manually managing memory. Scheduler: Allocates goroutines (concurrent functions) according to priority and available CPU cores to improve concurrency. Concurrency primitives: Provide tools such as channels and mutex locks to achieve safe communication and synchronization between goroutines.

Revealing the runtime mechanism of Go language

The runtime mechanism of Go language is the key to its efficiency and scalability , which includes components such as garbage collector, scheduler, and concurrency primitives. This article will take a deep dive into Go’s runtime mechanics and provide a practical example to illustrate how it works.

Garbage Collection

The Go language uses a concurrent mark-and-sweep algorithm for automatic garbage collection. The garbage collector periodically scans memory and marks live objects. After marking is complete, all unmarked objects will be recycled. This mechanism ensures that Go language programmers do not have to manually manage memory, thereby improving development efficiency.

Scheduler

The Go language scheduler is responsible for allocating CPU time among multiple goroutines (concurrently executed functions). The scheduler allocates goroutines to different threads based on their priority and the number of available CPU cores. This allows Go programs to take full advantage of multi-core CPUs and improve concurrency performance.

Concurrency primitives

The Go language provides a wealth of concurrency primitives, including channels, mutex locks, atomic variables, etc. These primitives allow safe and efficient communication and synchronization between goroutines.

Practical case

The following is a simple Go program that demonstrates various aspects of the runtime mechanism:

package main

import (
    "fmt"
    "runtime"
    "sync"
)

func main() {
    // 创建一个 goroutine
    go func() {
        // 循环 1000 次，消耗 CPU 时间
        for i := 0; i < 1000; i++ {
            fmt.Print(".")
        }
    }()

    // 主 goroutine 休眠 2 秒，让子 goroutine 有足够的时间执行
    time.Sleep(2 * time.Second)

    // 打印 goroutine 的数量和线程的数量
    fmt.Printf("Number of goroutines: %d\n", runtime.NumGoroutine())
    fmt.Printf("Number of threads: %d\n", runtime.NumCPU())

    // 强制垃圾回收
    runtime.GC()

    // 再次打印 goroutine 的数量
    fmt.Printf("Number of goroutines after GC: %d\n", runtime.NumGoroutine())
}

In this program:

• Creates a goroutine that will execute in a separate thread.
• The main goroutine sleeps for 2 seconds, giving the child goroutine enough time to execute.
• The program prints the number of goroutines and threads, showing that the scheduler is allocating goroutines to different threads.
• The program forces garbage collection and releases the memory consumed by child goroutines.
• Printing the number of goroutines again shows that the garbage collector has recycled child goroutines.

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