使用 Boost 在 Linux 中设置线程优先级 [英] Setting thread priority in Linux with Boost

问题描述

Boost 库似乎没有用于设置线程优先级的设备.这是在 Linux 上使用的最佳代码还是有更好的方法?

The Boost Libraries don't seem to have a device for setting a thread's priority. Would this be the best code to use on Linux or is there a better method?

boost::thread myThread( MyFunction() );

struct sched_param param;
param.sched_priority = 90;
pthread_attr_setschedparam( myThread.native_handle(), SCHED_RR, &param);

我没有很多 Linux 编程经验.

I don't have alot of Linux programming experience.

推荐答案

这是我将如何做的基本模板，但在四处搜索后我发现几乎没有代码示例，所以我想关于它是否最好的结论已经出来了与否.

That's the basic template for how I would do it but after searching around I found next to no code examples so I guess the verdict is out on whether it is best or not.

问题在于 boost::thread 没有允许在线程创建时传入 pthead 属性的构造函数，因此您必须在线程启动后进行更改.我知道的唯一另一种解决方法是通过进程/线程调度继承.除非另有指示，否则新线程将继承其创建者的调度/优先级，因此您可以在创建工作线程之前更改当前线程，然后根据需要更改回来.看起来很尴尬，但它是另一种选择.

The problem is that boost::thread does not have a constructor that allows pthead attributes to be passed in at thread creation so you have to make changes after the thread starts. The only other way I know to get around that is through the process/thread schedule inheritance. Unless directed otherwise, new threads will inherit the schedule/priority of their creator so you could change the current thread before creating worker threads and then change back if you want. Seems awkward but it is an alternative.

这里有一个示例，希望能同时演示两者.您可能需要根据需要更改策略和优先级并以 root 身份运行.

Here's a hack of an example that hopefully demostrates both. You may need to change policy and priority as appropriate and run as root.

请注意设置优先级的方式.适用各种限制.

Be careful with the way you set the priority. Various restrictions apply.

#include <iostream>
#include <boost/thread/thread.hpp>
#include <unistd.h>
#include <sched.h>
#include <cstdio>


void* threadfunc()
{
    sleep(5);
}

void displayAndChange(boost::thread& daThread)
{
    int retcode;
    int policy;

    pthread_t threadID = (pthread_t) daThread.native_handle();

    struct sched_param param;

    if ((retcode = pthread_getschedparam(threadID, &policy, &param)) != 0)
    {
        errno = retcode;
        perror("pthread_getschedparam");
        exit(EXIT_FAILURE);
    }

    std::cout << "INHERITED: ";
    std::cout << "policy=" << ((policy == SCHED_FIFO)  ? "SCHED_FIFO" :
                               (policy == SCHED_RR)    ? "SCHED_RR" :
                               (policy == SCHED_OTHER) ? "SCHED_OTHER" :
                                                         "???")
              << ", priority=" << param.sched_priority << std::endl;


    policy = SCHED_FIFO;
    param.sched_priority = 4;

    if ((retcode = pthread_setschedparam(threadID, policy, &param)) != 0)
    {
        errno = retcode;
        perror("pthread_setschedparam");
        exit(EXIT_FAILURE);
    }

    std::cout << "  CHANGED: ";
    std::cout << "policy=" << ((policy == SCHED_FIFO)  ? "SCHED_FIFO" :
                               (policy == SCHED_RR)    ? "SCHED_RR" :
                               (policy == SCHED_OTHER) ? "SCHED_OTHER" :
                                                          "???")
              << ", priority=" << param.sched_priority << std::endl;
}


int main(int argc, char* argv[])
{
    int policy, res;

    struct sched_param param;

    if ((policy = sched_getscheduler(getpid())) == -1)
    {
        perror("sched_getscheduler");
        exit(EXIT_FAILURE);
    }

    if ((res = sched_getparam(getpid(), &param)) == -1)
    {
        perror("sched_getparam");
        exit(EXIT_FAILURE);
    }

    std::cout << " ORIGINAL: ";
    std::cout << "policy=" << ((policy == SCHED_FIFO)  ? "SCHED_FIFO" :
                               (policy == SCHED_RR)    ? "SCHED_RR" :
                               (policy == SCHED_OTHER) ? "SCHED_OTHER" :
                                                          "???")
              << ", priority=" << param.sched_priority << std::endl;


    policy = SCHED_RR;
    param.sched_priority = 2;

    if ((res = sched_setscheduler(getpid(), policy, &param)) == -1)
    {
        perror("sched_setscheduler");
        exit(EXIT_FAILURE);
    }

    boost::thread t1(&threadfunc);

    displayAndChange(t1);

    t1.join();

    return 0;
}

这篇关于使用 Boost 在 Linux 中设置线程优先级的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！