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/* -*- c++ -*- */
/*
* Copyright 2006,2007,2008 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* GNU Radio is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3, or (at your option)
* any later version.
*
* GNU Radio is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU Radio; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <gruel/realtime.h>
#ifdef HAVE_SCHED_H
#include <sched.h>
#endif
#include <algorithm>
#include <math.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#if defined(HAVE_PTHREAD_SETSCHEDPARAM) || defined(HAVE_SCHED_SETSCHEDULER)
#include <pthread.h>
namespace gruel {
/*!
* Rescale our virtual priority so that it maps to the middle 1/2 of
* the priorities given by min_real_pri and max_real_pri.
*/
static int
rescale_virtual_pri(int virtual_pri, int min_real_pri, int max_real_pri)
{
float rmin = min_real_pri + (0.25 * (max_real_pri - min_real_pri));
float rmax = min_real_pri + (0.75 * (max_real_pri - min_real_pri));
float m = (rmax - rmin) / (rt_priority_max() - rt_priority_min());
float y = m * (virtual_pri - rt_priority_min()) + rmin;
int y_int = static_cast<int>(rint(y));
return std::max(min_real_pri, std::min(max_real_pri, y_int));
}
} // namespace gruel
#endif
#if defined(HAVE_PTHREAD_SETSCHEDPARAM)
namespace gruel {
rt_status_t
enable_realtime_scheduling(rt_sched_param p)
{
int policy = p.policy == RT_SCHED_FIFO ? SCHED_FIFO : SCHED_RR;
int min_real_pri = sched_get_priority_min(policy);
int max_real_pri = sched_get_priority_max(policy);
int pri = rescale_virtual_pri(p.priority, min_real_pri, max_real_pri);
// FIXME check hard and soft limits with getrlimit, and limit the value we ask for.
// fprintf(stderr, "pthread_setschedparam: policy = %d, pri = %d\n", policy, pri);
struct sched_param param;
memset (¶m, 0, sizeof (param));
param.sched_priority = pri;
int result = pthread_setschedparam (pthread_self(), policy, ¶m);
if (result != 0) {
if (result == EPERM) // N.B., return value, not errno
return RT_NO_PRIVS;
else {
fprintf(stderr,
"pthread_setschedparam: failed to set real time priority: %s\n",
strerror(result));
return RT_OTHER_ERROR;
}
}
//printf("SCHED_FIFO enabled with priority = %d\n", pri);
return RT_OK;
}
} // namespace gruel
#elif defined(HAVE_SCHED_SETSCHEDULER)
namespace gruel {
rt_status_t
enable_realtime_scheduling(rt_sched_param p)
{
int policy = p.policy == RT_SCHED_FIFO ? SCHED_FIFO : SCHED_RR;
int min_real_pri = sched_get_priority_min(policy);
int max_real_pri = sched_get_priority_max(policy);
int pri = rescale_virtual_pri(p.priority, min_real_pri, max_real_pri);
// FIXME check hard and soft limits with getrlimit, and limit the value we ask for.
// fprintf(stderr, "sched_setscheduler: policy = %d, pri = %d\n", policy, pri);
int pid = 0; // this process
struct sched_param param;
memset(¶m, 0, sizeof(param));
param.sched_priority = pri;
int result = sched_setscheduler(pid, policy, ¶m);
if (result != 0){
if (errno == EPERM)
return RT_NO_PRIVS;
else {
perror ("sched_setscheduler: failed to set real time priority");
return RT_OTHER_ERROR;
}
}
//printf("SCHED_FIFO enabled with priority = %d\n", pri);
return RT_OK;
}
} // namespace gruel
#else
namespace gruel {
rt_status_t
enable_realtime_scheduling(rt_sched_param p)
{
return RT_NOT_IMPLEMENTED;
}
} // namespace gruel
#endif
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