uhd/host/lib/utils/thread.cpp

//
// Copyright 2010-2011,2015 Ettus Research LLC
// Copyright 2018-2020 Ettus Research, a National Instruments Company
//
// SPDX-License-Identifier: GPL-3.0-or-later
//

#include <uhd/exception.hpp>
#include <uhd/utils/log.hpp>
#include <uhd/utils/thread.hpp>
#include <vector>

bool uhd::set_thread_priority_safe(float priority, bool realtime)
{
    try {
        set_thread_priority(priority, realtime);
        return true;
    } catch (const std::exception& e) {
        UHD_LOGGER_WARNING("UHD")
            << "Unable to set the thread priority. Performance may be "
               "negatively affected.\n"
               "Please see the general application notes in the manual for "
               "instructions.\n"
            << e.what();
        return false;
    }
}

static void check_priority_range(float priority)
{
    if (priority > +1.0 or priority < -1.0) {
        throw uhd::value_error("priority out of range [-1.0, +1.0]");
    }
}

/***********************************************************************
 * Pthread API to set priority
 **********************************************************************/
#ifdef HAVE_PTHREAD_SETSCHEDPARAM
#    include <pthread.h>

void uhd::set_thread_priority(float priority, bool realtime)
{
    check_priority_range(priority);

    // when realtime is not enabled, use sched other
    int policy = (realtime) ? SCHED_RR : SCHED_OTHER;

    // we cannot have below normal priority, set to zero
    if (priority < 0)
        priority = 0;

    // get the priority bounds for the selected policy
    int min_pri = sched_get_priority_min(policy);
    int max_pri = sched_get_priority_max(policy);
    if (min_pri == -1 or max_pri == -1)
        throw uhd::os_error("error in sched_get_priority_min/max");

    // set the new priority and policy
    sched_param sp;
    sp.sched_priority = int(priority * (max_pri - min_pri)) + min_pri;
    int ret           = pthread_setschedparam(pthread_self(), policy, &sp);
    if (ret != 0)
        throw uhd::os_error("error in pthread_setschedparam");
}
#endif /* HAVE_PTHREAD_SETSCHEDPARAM */

/***********************************************************************
 * Pthread API to set affinity
 **********************************************************************/
#ifdef HAVE_PTHREAD_SETAFFINITY_NP
#    include <pthread.h>
void uhd::set_thread_affinity(const std::vector<size_t>& cpu_affinity_list)
{
    if (cpu_affinity_list.empty()) {
        return;
    }

    cpu_set_t cpu_set;
    CPU_ZERO(&cpu_set);
    for (auto cpu_num : cpu_affinity_list) {
        if (cpu_num > CPU_SETSIZE) {
            UHD_LOG_WARNING(
                "UHD", "CPU index " << cpu_num << " in affinity list out of range");
        }
        CPU_SET(cpu_num, &cpu_set);
    }

    int status = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set_t), &cpu_set);
    if (status != 0) {
        UHD_LOG_WARNING("UHD", "Failed to set desired affinity for thread");
    }
}
#endif /* HAVE_PTHREAD_SETAFFINITYNP */

/***********************************************************************
 * Windows API to set priority
 **********************************************************************/
#ifdef HAVE_WIN_SETTHREADPRIORITY
#    include <windows.h>

void uhd::set_thread_priority(float priority, UHD_UNUSED(bool realtime))
{
    check_priority_range(priority);

    /*
     * Process wide priority is no longer set.
     * This is the responsibility of the application.
    //set the priority class on the process
    int pri_class = (realtime)? REALTIME_PRIORITY_CLASS : NORMAL_PRIORITY_CLASS;
    if (SetPriorityClass(GetCurrentProcess(), pri_class) == 0)
        throw uhd::os_error("error in SetPriorityClass");
     */

    // scale the priority value to the constants
    int priorities[] = {THREAD_PRIORITY_IDLE,
        THREAD_PRIORITY_LOWEST,
        THREAD_PRIORITY_BELOW_NORMAL,
        THREAD_PRIORITY_NORMAL,
        THREAD_PRIORITY_ABOVE_NORMAL,
        THREAD_PRIORITY_HIGHEST,
        THREAD_PRIORITY_TIME_CRITICAL};
    size_t pri_index = size_t((priority + 1.0) * 6 / 2.0); // -1 -> 0, +1 -> 6

    // set the thread priority on the thread
    if (SetThreadPriority(GetCurrentThread(), priorities[pri_index]) == 0)
        throw uhd::os_error("error in SetThreadPriority");
}
#endif /* HAVE_WIN_SETTHREADPRIORITY */

/***********************************************************************
 * Windows API to set affinity
 **********************************************************************/
#ifdef HAVE_WIN_SETTHREADAFFINITYMASK
#    include <windows.h>
void uhd::set_thread_affinity(const std::vector<size_t>& cpu_affinity_list)
{
    if (cpu_affinity_list.empty()) {
        return;
    }

    DWORD_PTR cpu_set{0};
    for (auto cpu_num : cpu_affinity_list) {
        if (cpu_num > 8 * sizeof(DWORD_PTR)) {
            UHD_LOG_WARNING(
                "UHD", "CPU index " << cpu_num << " in affinity list out of range");
        }
        cpu_set |= ((DWORD_PTR)1 << cpu_num);
    }

    DWORD_PTR status = SetThreadAffinityMask(GetCurrentThread(), cpu_set);
    if (status == 0) {
        UHD_LOG_WARNING("UHD", "Failed to set desired affinity for thread");
    }
}
#endif /* HAVE_WIN_SETTHREADAFFINITYMASK */

/***********************************************************************
 * Unimplemented API to set priority
 **********************************************************************/
#ifdef HAVE_THREAD_PRIO_DUMMY
void uhd::set_thread_priority(float, bool)
{
    UHD_LOG_DEBUG("UHD", "Setting thread priority is not implemented");
}

#endif /* HAVE_THREAD_PRIO_DUMMY */

/***********************************************************************
 * Unimplemented API to set affinity
 **********************************************************************/
#ifdef HAVE_THREAD_SETAFFINITY_DUMMY
void uhd::set_thread_affinity(const std::vector<size_t>& cpu_affinity_list)
{
    UHD_LOG_DEBUG("UHD", "Setting thread affinity is not implemented");
}
#endif /* HAVE_THREAD_SETAFFINITY_DUMMY */

void uhd::set_thread_name(boost::thread* thrd, const std::string& name)
{
#ifdef HAVE_PTHREAD_SETNAME
    pthread_setname_np(thrd->native_handle(), name.substr(0, 16).c_str());
#endif /* HAVE_PTHREAD_SETNAME */
#ifdef HAVE_THREAD_SETNAME_DUMMY
    // Then we can't set the thread name. This function may get called
    // before the logger starts, and thus can't log any error messages.
    // Note that CMake will also tell the user about not being able to set
    // thread names.
#endif /* HAVE_THREAD_SETNAME_DUMMY */
}

void uhd::set_thread_name(std::thread* thrd, const std::string& name)
{
#ifdef HAVE_PTHREAD_SETNAME
    pthread_setname_np(thrd->native_handle(), name.substr(0, 16).c_str());
#endif /* HAVE_PTHREAD_SETNAME */
#ifdef HAVE_THREAD_SETNAME_DUMMY
    // Then we can't set the thread name. This function may get called
    // before the logger starts, and thus can't log any error messages.
    // Note that CMake will also tell the user about not being able to set
    // thread names.
#endif /* HAVE_THREAD_SETNAME_DUMMY */
}