Coroutine scheduling algorithm in Golang function concurrent programming

The coroutine scheduling algorithm in Go function concurrent programming uses multi-level scheduling to divide coroutines into run, system and ready queues. The round-robin scheduling algorithm schedules coroutines sequentially in the same priority queue, regardless of priority.

Coroutine scheduling algorithm in Go function concurrent programming

In Go function concurrent programming, coroutines are lightweight Threads are scheduled by the scheduler. The Go scheduler uses an algorithm called Multi-level scheduling, which divides coroutines into different priority queues.

Multi-level scheduling algorithm

The multi-level scheduling algorithm divides coroutines into the following priority queues:

• Run queue : Contains coroutines that are ready for execution.
• System queue: Contains running coroutines for blocking operations such as system calls.
• Ready queue: Contains coroutines that cannot be executed due to contention for locks or other resources.

The scheduler first attempts to schedule the coroutine from the run queue. If there is no runnable coroutine, it is moved to the system queue, and so on. When a coroutine completes waiting operations in the system queue or ready queue, it is moved to the ready queue and rescheduled.

Scheduling algorithm

The Go scheduler uses Round-robin scheduling algorithm to schedule between coroutines in the same priority queue. Round-robin scheduling means that the scheduler will execute the coroutines in the queue sequentially, regardless of their priorities.

Practical case

The following is a simple example showing the scheduling algorithm:

package main

import (
    "fmt"
    "runtime"
)

func main() {
    // 创建几个协程并输出它们各自的 GID（协程ID）
    for i := 0; i < 10; i++ {
        go func(i int) {
            fmt.Printf("协程 %v 的 GID: %v\n", i, runtime.Goid())
        }(i)
    }

    // 手动执行调度器以强制执行调度
    runtime.Gosched()
}

Running this program will output the GID of a series of coroutines, displaying How the Go scheduler schedules between coroutines based on the round-robin scheduling algorithm.

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