scheduler.cpp

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2020, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */

#include "system-precomp.h"  // Precompiled headers

#include <mrpt/config.h>
#include <mrpt/core/exceptions.h>
#include <mrpt/system/scheduler.h>

#ifdef MRPT_OS_WINDOWS
#include <windows.h>

#include <process.h>
#include <tlhelp32.h>
#else
#include <pthread.h>
#include <sys/select.h>
#include <sys/time.h>
#include <unistd.h>
#include <utime.h>
#include <cerrno>
#include <csignal>
#include <cstring>  // strerror()
#include <ctime>
#endif

#include <sys/stat.h>
#include <sys/types.h>
#ifdef MRPT_OS_APPLE
#include <mach/mach_init.h>
#include <mach/thread_act.h>
#include <sys/sysctl.h>
#endif

#include <iostream>

void mrpt::system::changeCurrentThreadPriority(TThreadPriority priority)
{
#ifdef MRPT_OS_WINDOWS
    // TThreadPriority is defined to agree with numbers expected by Win32 API:
    SetThreadPriority(GetCurrentThread(), priority);
#else
    const pthread_t tid = pthread_self();

    int ret, policy;
    struct sched_param param
    {
    };

    if (0 != (ret = pthread_getschedparam(tid, &policy, &param)))
    {
        std::cerr
            << "[mrpt::system::changeThreadPriority] Warning: Failed call to "
               "pthread_getschedparam (error: `"
            << strerror(ret) << "`)" << std::endl;
        return;
    }

    policy = SCHED_RR;
    int min_prio = sched_get_priority_min(policy),
        max_prio = sched_get_priority_max(policy);
    if (min_prio < 0) min_prio = 1;  // Just in case of error to calls above (!)
    if (max_prio < 0) max_prio = 99;

    int prio = 0;
    switch (priority)
    {
        case tpLowests:
            prio = min_prio;
            break;
        case tpLower:
            prio = (max_prio + 3 * min_prio) / 4;
            break;
        case tpLow:
            prio = (max_prio + 2 * min_prio) / 3;
            break;
        case tpNormal:
            prio = (max_prio + min_prio) / 2;
            break;
        case tpHigh:
            prio = (2 * max_prio + min_prio) / 3;
            break;
        case tpHigher:
            prio = (3 * max_prio + min_prio) / 4;
            break;
        case tpHighest:
            prio = max_prio;
            break;
    }

    param.sched_priority = prio;
    if (0 != (ret = pthread_setschedparam(tid, policy, &param)))
    {
        std::cerr
            << "[mrpt::system::changeThreadPriority] Warning: Failed call to "
               "pthread_setschedparam (error: `"
            << strerror(ret) << "`)" << std::endl;
        return;
    }
#endif
}

void mrpt::system::changeCurrentProcessPriority(TProcessPriority priority)
{
#ifdef MRPT_OS_WINDOWS
    DWORD dwPri;
    switch (priority)
    {
        case ppIdle:
            dwPri = IDLE_PRIORITY_CLASS;
            break;
        case ppNormal:
            dwPri = NORMAL_PRIORITY_CLASS;
            break;
        case ppHigh:
            dwPri = HIGH_PRIORITY_CLASS;
            break;
        case ppVeryHigh:
            dwPri = REALTIME_PRIORITY_CLASS;
            break;
        default:
            THROW_EXCEPTION("Invalid priority value");
    }
    SetPriorityClass(GetCurrentProcess(), dwPri);
#else
    int nice_val;
    switch (priority)
    {
        case ppIdle:
            nice_val = +19;
            break;
        case ppNormal:
            nice_val = 0;
            break;
        case ppHigh:
            nice_val = -10;
            break;
        case ppVeryHigh:
            nice_val = -20;
            break;
        default:
            THROW_EXCEPTION("Invalid priority value");
    }
    errno = 0;
    const int ret = nice(nice_val);
    if (ret == -1 && errno == EPERM)
    {
        std::cerr << "[mrpt::system::changeCurrentProcessPriority] Error "
                     "calling nice(): Not enough permissions.\n";
    }
#endif
}