59bf0e7eb4
Setup initial timesync event in initState or loadState so that curTick has been updated to the new value, otherwise the event is scheduled in the past.
135 lines
4 KiB
C++
135 lines
4 KiB
C++
/*
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* Copyright (c) 2002-2005 The Regents of The University of Michigan
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* Copyright (c) 2011 Advanced Micro Devices
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* Authors: Nathan Binkert
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* Steve Reinhardt
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* Gabe Black
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*/
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#include "base/misc.hh"
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#include "sim/root.hh"
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Root *Root::_root = NULL;
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/*
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* This function is called periodically by an event in M5 and ensures that
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* at least as much real time has passed between invocations as simulated time.
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* If not, the function either sleeps, or if the difference is small enough
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* spin waits.
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*/
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void
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Root::timeSync()
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{
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Time cur_time, diff, period = timeSyncPeriod();
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do {
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cur_time.setTimer();
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diff = cur_time - lastTime;
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Time remainder = period - diff;
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if (diff < period && remainder > _spinThreshold) {
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DPRINTF(TimeSync, "Sleeping to sync with real time.\n");
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// Sleep until the end of the period, or until a signal.
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sleep(remainder);
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// Refresh the current time.
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cur_time.setTimer();
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}
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} while (diff < period);
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lastTime = cur_time;
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schedule(&syncEvent, curTick() + _periodTick);
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}
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void
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Root::timeSyncEnable(bool en)
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{
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if (en == _enabled)
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return;
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_enabled = en;
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if (_enabled) {
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// Get event going.
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Tick periods = ((curTick() + _periodTick - 1) / _periodTick);
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Tick nextPeriod = periods * _periodTick;
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schedule(&syncEvent, nextPeriod);
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} else {
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// Stop event.
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deschedule(&syncEvent);
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}
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}
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/// Configure the period for time sync events.
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void
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Root::timeSyncPeriod(Time newPeriod)
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{
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bool en = timeSyncEnabled();
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_period = newPeriod;
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_periodTick = _period.getTick();
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timeSyncEnable(en);
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}
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/// Set the threshold for time remaining to spin wait.
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void
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Root::timeSyncSpinThreshold(Time newThreshold)
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{
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bool en = timeSyncEnabled();
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_spinThreshold = newThreshold;
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timeSyncEnable(en);
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}
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Root::Root(RootParams *p) : SimObject(p), _enabled(false),
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_periodTick(p->time_sync_period), syncEvent(this)
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{
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_period.setTick(p->time_sync_period);
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_spinThreshold.setTick(p->time_sync_spin_threshold);
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assert(_root == NULL);
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_root = this;
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lastTime.setTimer();
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}
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void
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Root::initState()
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{
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timeSyncEnable(params()->time_sync_enable);
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}
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void
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Root::loadState(Checkpoint *cp)
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{
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timeSyncEnable(params()->time_sync_enable);
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}
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Root *
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RootParams::create()
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{
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static bool created = false;
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if (created)
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panic("only one root object allowed!");
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created = true;
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return new Root(this);
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}
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