src/sim/ticked_object.hh

   1 /*
   2  * Copyright (c) 2013-2014 ARM Limited
   3  * All rights reserved
   4  *
   5  * The license below extends only to copyright in the software and shall
   6  * not be construed as granting a license to any other intellectual
   7  * property including but not limited to intellectual property relating
   8  * to a hardware implementation of the functionality of the software
   9  * licensed hereunder.  You may use the software subject to the license
  10  * terms below provided that you ensure that this notice is replicated
  11  * unmodified and in its entirety in all distributions of the software,
  12  * modified or unmodified, in source code or in binary form.
  13  *
  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions are
  16  * met: redistributions of source code must retain the above copyright
  17  * notice, this list of conditions and the following disclaimer;
  18  * redistributions in binary form must reproduce the above copyright
  19  * notice, this list of conditions and the following disclaimer in the
  20  * documentation and/or other materials provided with the distribution;
  21  * neither the name of the copyright holders nor the names of its
  22  * contributors may be used to endorse or promote products derived from
  23  * this software without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  26  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  27  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  28  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  29  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  30  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  31  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  35  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  *
  37  * Authors: Andrew Bardsley
  38  */
  39
  40 /**
  41  * @file
  42  *
  43  *  Base classes for ClockedObjects which have evaluate functions to
  44  *  look like clock ticking operations.  TickedObject attaches gem5's event
  45  *  queue to Ticked to apply actual scheduling.
  46  */
  47
  48 #ifndef __SIM_TICKED_OBJECT_HH__
  49 #define __SIM_TICKED_OBJECT_HH__
  50
  51 #include "params/TickedObject.hh"
  52 #include "sim/clocked_object.hh"
  53
  54 /** Ticked attaches gem5's event queue/scheduler to evaluate
  55  *  calls and provides a start/stop interface to ticking.
  56  *
  57  *  Ticked is not a ClockedObject but can be attached to one by
  58  *  inheritance and by calling regStats, serialize/unserialize */
  59 class Ticked
  60 {
  61   protected:
  62     /** An event to call process periodically */
  63     class ClockEvent : public Event
  64     {
  65       public:
  66         Ticked &owner;
  67
  68         ClockEvent(Ticked &owner_, Priority priority) :
  69             Event(priority),
  70             owner(owner_)
  71         { }
  72
  73         /** Evaluate and reschedule */
  74         void
  75         process()
  76         {
  77             ++owner.tickCycles;
  78             ++owner.numCycles;
  79             owner.evaluate();
  80             if (owner.running) {
  81                 owner.object.schedule(this,
  82                     owner.object.clockEdge(Cycles(1)));
  83             }
  84         }
  85     };
  86
  87     friend class ClockEvent;
  88
  89     /** ClockedObject who is responsible for this Ticked's actions/stats */
  90     ClockedObject &object;
  91
  92     /** The single instance of ClockEvent used */
  93     ClockEvent event;
  94
  95     /** Have I been started? and am not stopped */
  96     bool running;
  97
  98     /** Time of last stop event to calculate run time */
  99     Cycles lastStopped;
 100
 101   private:
 102     /** Locally allocated stats */
 103     Stats::Scalar *numCyclesLocal;
 104
 105   protected:
 106     /** Total number of cycles either ticked or spend stopped */
 107     Stats::Scalar &numCycles;
 108
 109     /** Number of cycles ticked */
 110     Stats::Scalar tickCycles;
 111
 112     /** Number of cycles stopped */
 113     Stats::Formula idleCycles;
 114
 115   public:
 116     Ticked(ClockedObject &object_,
 117         Stats::Scalar *imported_num_cycles = NULL,
 118         Event::Priority priority = Event::CPU_Tick_Pri);
 119
 120     virtual ~Ticked() { }
 121
 122     /** Register {num,ticks}Cycles if necessary.  If numCycles is
 123      *  imported, be sure to register it *before* calling this regStats */
 124     void regStats();
 125
 126     /** Start ticking */
 127     void
 128     start()
 129     {
 130         if (!running) {
 131             if (!event.scheduled())
 132                 object.schedule(event, object.clockEdge(Cycles(1)));
 133             running = true;
 134             numCycles += cyclesSinceLastStopped();
 135         }
 136     }
 137
 138     /** How long have we been stopped for? */
 139     Cycles
 140     cyclesSinceLastStopped() const
 141     {
 142         return object.curCycle() - lastStopped;
 143     }
 144
 145     /** Reset stopped time to current time */
 146     void
 147     resetLastStopped()
 148     {
 149         lastStopped = object.curCycle();
 150     }
 151
 152     /** Cancel the next tick event and issue no more */
 153     void
 154     stop()
 155     {
 156         if (running) {
 157             if (event.scheduled())
 158                 object.deschedule(event);
 159             running = false;
 160             resetLastStopped();
 161         }
 162     }
 163
 164     /** Checkpoint lastStopped */
 165     void serialize(std::ostream &os);
 166     void unserialize(Checkpoint *cp, const std::string &section);
 167
 168     /** Action to call on the clock tick */
 169     virtual void evaluate() = 0;
 170 };
 171
 172 /** TickedObject attaches Ticked to ClockedObject and can be used as
 173  *  a base class where ticked operation */
 174 class TickedObject : public ClockedObject, public Ticked
 175 {
 176   public:
 177     TickedObject(TickedObjectParams *params,
 178         Event::Priority priority = Event::CPU_Tick_Pri);
 179
 180     /** Disambiguate to make these functions overload correctly */
 181     using ClockedObject::regStats;
 182     using ClockedObject::serialize;
 183     using ClockedObject::unserialize;
 184
 185     /** Pass on regStats, serialize etc. onto Ticked */
 186     void regStats();
 187     void serialize(std::ostream &os);
 188     void unserialize(Checkpoint *cp, const std::string &section);
 189 };
 190
 191 #endif /* __SIM_TICKED_OBJECT_HH__ */