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sems/core/AmPeriodicThread.cpp

98 lines
2.9 KiB

/*
* Copyright (C) 2012 Frafos GmbH
*
* This file is part of SEMS, a free SIP media server.
*
* SEMS 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 2 of the License, or
* (at your option) any later version. This program is released under
* the GPL with the additional exemption that compiling, linking,
* and/or using OpenSSL is allowed.
*
* For a license to use the SEMS software under conditions
* other than those described here, or to purchase support for this
* software, please contact iptel.org by e-mail at the following addresses:
* info@iptel.org
*
* SEMS 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
*/
/** @file AmPeriodicThread.cpp */
#include "AmPeriodicThread.h"
#include <assert.h>
#include "log.h"
void AmPeriodicThread::infinite_loop(struct timeval* tick, unsigned int max_ticks_behind, void* usr_data)
{
struct timeval now,next_tick,diff;
unsigned int ticks_passed;
unsigned long ms_diff, ms_tick;
assert(tick);
ms_tick = tick->tv_sec * 1000 + tick->tv_usec / 1000;
gettimeofday(&next_tick,NULL);
while (true) {
gettimeofday(&now,NULL);
timeradd(tick,&next_tick,&next_tick);
if(timercmp(&now,&next_tick,<)){
struct timespec sdiff,rem;
timersub(&next_tick,&now,&diff);
// detect backward clockdrift
ms_diff = diff.tv_sec * 1000 + diff.tv_usec / 1000;
if(ms_diff / ms_tick > 1) {
// at least 2 ticks ahead...
next_tick = now;
sdiff.tv_sec = tick->tv_sec;
sdiff.tv_nsec = tick->tv_usec * 1000;
WARN("clock drift backwards detected (%lu ticks ahead), "
"resetting sw clock\n", ms_diff / ms_tick - 1);
}
else {
// everything ok
sdiff.tv_sec = diff.tv_sec;
sdiff.tv_nsec = diff.tv_usec * 1000;
}
if(sdiff.tv_nsec > 2000000) // 2 ms
nanosleep(&sdiff,&rem);
ticks_passed = 1;
}
else {
// compute missed ticks
unsigned long ms_diff;
timersub(&now,&next_tick,&diff);
ms_diff = diff.tv_sec * 1000 + diff.tv_usec / 1000;
ticks_passed = ms_diff / ms_tick + 1;
// missed too many ticks: resync
if(ticks_passed > max_ticks_behind) {
// resync to clock if clock is farther than max_behind_tick in the future
WARN("clock drift detected (missed %d ticks), resetting sw clock\n",
ticks_passed);
next_tick = now;
}
}
// execute looping step code
if(!looping_step(usr_data))
break;
}
}