如何在 golang for mac 中设置进程的优先级（由操作系统线程继承）？

Question

如何在 golang for mac 中设置进程的优先级（由操作系统线程继承）？ 带有 syscall.PRGRP 标志的 syscall.SetPriority 设置进程的优先级，并由 ubuntu 上的线程继承。 mac 有类似的方法吗？我们如何从golang访问苹果qos？

程序可以在 ubuntu 上运行，但不能在 mac 上运行

package main

import (
    "fmt"
    "os"
    "runtime"
    "sync"
    "syscall"
    "time"
)

func main() {
    // runtime.GOMAXPROCS(5)
    // Get the current process ID
    pid := os.Getpid()
    fmt.Printf("Current Process ID: %d\n", pid)

    // Set process priority to the lowest
    setProcessPriority(pid, syscall.PRIO_PGRP, 10)

    // Number of goroutines to spawn
    numGoroutines := 100

    // Use a wait group to wait for all goroutines to finish
    var wg sync.WaitGroup
    wg.Add(numGoroutines)
    start := time.Now()
    // Spawn goroutines
    for i := 0; i < numGoroutines; i++ {
        go func(id int) {
            defer wg.Done()
            fmt.Printf("Goroutine %d started.\n", id)
            cpuIntensiveWork()
            fmt.Printf("Goroutine %d completed.\n", id)
        }(i)
    }

    // Wait for all goroutines to finish
    wg.Wait()
    elapsed := time.Since(start)
    fmt.Printf("All goroutines completed in %f\n.", elapsed.Seconds())
}

func setProcessPriority(pid int, which int, priority int) {
    if runtime.GOOS == "windows" {
        fmt.Println("Setting process priority is not supported on Windows.")
        return
    }

    // Set process priority for Unix-like systems
    err := syscall.Setpriority(which, pid, priority)
    if err != nil {
        fmt.Println("Error setting process priority:", err)
    }
}

    func cpuIntensiveWork() {
        // Simulate CPU-intensive work
        for i := 0; i < 100000; i++ {
            for j := 0; j < 10000; j++ {
                _ = j * j
            }
            _ = i * i
        }
    }

Answer 1

你的程序在 Linux 和 macOS 上对我来说失败了。问题是你在应该使用

syscall.PRIO_PGRP

的地方使用了

syscall.PRIO_PROCESS

。我将您的程序简化为以下内容，它在 Linux 和 macOS 上按预期工作。

package main

import (
    "fmt"
    "os"
    "syscall"
)

func main() {
    pid := os.Getpid()
    fmt.Printf("Current Process ID: %d\n", pid)

    prio, err := syscall.Getpriority(syscall.PRIO_PROCESS, pid)
    if err != nil {
        fmt.Println("Error getting process priority:", err)
    }
    fmt.Println("Original priority:", prio)
    if err := syscall.Setpriority(syscall.PRIO_PROCESS, pid, 10); err != nil {
        fmt.Println("Error setting process priority:", err)
    }
    prio, err = syscall.Getpriority(syscall.PRIO_PROCESS, pid)
    if err != nil {
        fmt.Println("Error getting process priority:", err)
    }
    fmt.Println("New priority:", prio)
}

在 macOS 上：

$ go run x.go
Current Process ID: 27436
Original priority: 0
New priority: 10

在 Linux 上：

$ go run x.go
Current Process ID: 117032
Original priority: 20
New priority: 10

如果将

syscall.PRIO_PROCESS

更改为

syscall.PRIO_PGRP

，您将在两个平台上看到如下错误：

Current Process ID: 113604
Error getting process priority: no such process
Original priority: -1
Error setting process priority: no such process
Error getting process priority: no such process
New priority: -1