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/*
* Copyright (c) 2011 Advanced Micro Devices, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Authors: Gabe Black
*/
/**
* @file This file defines the Root simobject and the methods used to control
* the time syncing mechanism provided through it.
*
* Time syncing prevents simulated time from passing faster than real time. It
* works by scheduling a periodic event that checks to see if its simulated
* period is shorter than its real period. If it is, it stalls the simulation
* until they're equal.
*/
#ifndef __SIM_ROOT_HH__
#define __SIM_ROOT_HH__
#include "base/time.hh"
#include "params/Root.hh"
#include "sim/eventq.hh"
#include "sim/sim_object.hh"
class Root : public SimObject
{
private:
static Root *_root;
protected:
bool _enabled;
Time _period;
Tick _periodTick;
Time _spinThreshold;
Time lastTime;
void timeSync();
EventFunctionWrapper syncEvent;
public:
/**
* Use this function to get a pointer to the single Root object in the
* simulation. This function asserts that such an object has actual been
* constructed to avoid having to perform that check everywhere the root
* is used. This is to allow calling the functions below.
*
* @return Pointer to the single root object.
*/
static Root *
root()
{
assert(_root);
return _root;
}
public:
/// Check whether time syncing is enabled.
bool timeSyncEnabled() const { return _enabled; }
/// Retrieve the period for the sync event.
const Time timeSyncPeriod() const { return _period; }
/// Retrieve the threshold for time remaining to spin wait.
const Time timeSyncSpinThreshold() const { return _spinThreshold; }
/// Enable or disable time syncing.
void timeSyncEnable(bool en);
/// Configure the period for time sync events.
void timeSyncPeriod(Time newPeriod);
/// Set the threshold for time remaining to spin wait.
void timeSyncSpinThreshold(Time newThreshold);
typedef RootParams Params;
const Params *
params() const
{
return dynamic_cast<const Params *>(_params);
}
Root(Params *p);
/** Schedule the timesync event at loadState() so that curTick is correct
*/
void loadState(CheckpointIn &cp) override;
/** Schedule the timesync event at initState() when not unserializing
*/
void initState() override;
void serialize(CheckpointOut &cp) const override;
void unserialize(CheckpointIn &cp) override;
};
#endif // __SIM_ROOT_HH__
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