rtposixsolver.cc

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/* $Header: /var/cvs/mbdyn/mbdyn/mbdyn-1.0/mbdyn/base/rtposixsolver.cc,v 1.20 2017/01/12 14:46:10 masarati Exp $ */
/* 
 * MBDyn (C) is a multibody analysis code. 
 * http://www.mbdyn.org
 *
 * Copyright (C) 1996-2017
 *
 * Pierangelo Masarati  <masarati@aero.polimi.it>
 * Paolo Mantegazza     <mantegazza@aero.polimi.it>
 *
 * Dipartimento di Ingegneria Aerospaziale - Politecnico di Milano
 * via La Masa, 34 - 20156 Milano, Italy
 * http://www.aero.polimi.it
 *
 * Changing this copyright notice is forbidden.
 *
 * This program 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 (version 2 of the License).
 * 
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "mbconfig.h"           /* This goes first in every *.c,*.cc file */

#include <cerrno>
#include "myassert.h"
#include "solver.h"
#include "solver_impl.h"
#include "rtsolver.h"
#include "rtposixsolver.h"
 
#ifdef USE_RT

/* RTPOSIXSolver - begin */

RTPOSIXSolver::RTPOSIXSolver(Solver *pS,
        RTMode eRTMode,
        unsigned long lRTPeriod,
        unsigned long RTStackSize,
        bool bRTAllowNonRoot,
        int RTCpuMap,
        bool bNoOutput)
: RTSolverBase(pS, eRTMode, lRTPeriod, RTStackSize, bRTAllowNonRoot, RTCpuMap, bNoOutput),
clock_flags(TIMER_ABSTIME)
{
        NO_OP;
}

RTPOSIXSolver::~RTPOSIXSolver(void)
{
        NO_OP;
}

// write contribution to restart file
std::ostream&
RTPOSIXSolver::Restart(std::ostream& out) const
{
        return out;
}

// very first setup, to be always performed
void
RTPOSIXSolver::Setup(void)
{
        // allow-nonroot should go here; something like
        // capset(CAP_SYS_NICE);

        struct sched_param sched;
        int policy = SCHED_FIFO;
        int priority = 1;
        int min_priority = sched_get_priority_min(policy);

        sched.sched_priority = sched_get_priority_max(policy) - priority;

        if (sched.sched_priority < min_priority) {
                sched.sched_priority = min_priority;
        }

        if (sched_setscheduler(0, policy, &sched) < 0) {
                silent_cerr("RTPOSIXSolver: sched_setscheduler failed" << std::endl);
                if (bRTAllowNonRoot) {
                        // FIXME: hack (let it run without priority)
                        return;
                }
                throw ErrGeneric(MBDYN_EXCEPT_ARGS);
        }

#ifdef HAVE_SCHED_SETAFFINITY
        if (RTCpuMap != 0xFF) {
                cpu_set_t cpuset;

                CPU_ZERO(&cpuset);
                for (int cpu = 0; cpu < 8; cpu++) {
                        if ((RTCpuMap >> cpu) & 0x1) {
                                CPU_SET(cpu, &cpuset);
                        }
                }

                if (sched_setaffinity(0, sizeof(cpu_set_t), &cpuset)) {
                        silent_cerr("RTPOSIXSolver: sched_setaffinity failed" << std::endl);
                        throw ErrGeneric(MBDYN_EXCEPT_ARGS);
                }
        }
#endif // HAVE_SCHED_SETAFFINITY
}

// to be performed when stop is commanded by someone else
void
RTPOSIXSolver::StopCommanded(void)
{
        // do nothing
        NO_OP;
}

// write real-time related message when stop commanded by someone else
void
RTPOSIXSolver::Log(void)
{
        // TODO: print info about overruns?
        NO_OP;
}

// wait for period to expire
void
RTPOSIXSolver::Wait(void)
{
        if (RTWaitPeriod()) {
                if (RTSteps == 0) {
                        clock_gettime(CLOCK_MONOTONIC, &t0);
                        t = t0;
                }

                t.tv_nsec += lRTPeriod;
                if (t.tv_nsec >= 1000000000L) {
                        t.tv_nsec -= 1000000000L;
                        t.tv_sec++;
                }

                int rc = clock_nanosleep(CLOCK_MONOTONIC, clock_flags, &t, NULL);
                switch (rc) {
                case 0:
                        break;

                case EINTR:
                        silent_cerr("RTPOSIXSolver: clock_nanosleep interrupted" << std::endl);
                        break;

                default:
                        silent_cerr("RTPOSIXSolver: clock_nanosleep failed "
                                "(rc=" << rc << ")" << std::endl);
                        throw ErrGeneric(MBDYN_EXCEPT_ARGS);
                }

#if 0
        } else if (RTSemWait()) {
#endif
        } /* else RTBlockingIO(): do nothing */

        RTSteps++;
}

#endif // USE_RT

RTSolverBase *
ReadRTPOSIXSolver(Solver *pS, MBDynParser& HP)
{
#ifdef USE_RT
        RTSolverBase::RTMode eRTMode;
        unsigned long lRTPeriod;
        unsigned long RTStackSize;
        bool bRTAllowNonRoot;
        int RTCpuMap;
        ReadRTParams(pS, HP, eRTMode, lRTPeriod, RTStackSize, bRTAllowNonRoot, RTCpuMap);

        bool bNoOutput = true;
        if (HP.IsKeyWord("output")) {
                bNoOutput = HP.GetYesNoOrBool(bNoOutput);
        }

        RTSolverBase *pRTSolver(0);
        SAFENEWWITHCONSTRUCTOR(pRTSolver, RTPOSIXSolver,
                RTPOSIXSolver(pS, eRTMode, lRTPeriod,
                        RTStackSize, bRTAllowNonRoot, RTCpuMap,
                        bNoOutput));
        return pRTSolver;

#else // !USE_RT
        silent_cerr("ReadRTPOSIXSolver: need to configure --with-rt "
                "to use POSIX realtime" << std::endl);
        throw ErrGeneric(MBDYN_EXCEPT_ARGS);

        return 0;
#endif // USE_RT
}

/* RTPOSIXSolver - end */