global_event.hh

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/*
 * Copyright (c) 2011-2013 Advanced Micro Devices, Inc.
 * Copyright (c) 2013 Mark D. Hill and David A. Wood
 * 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,
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
#ifndef __SIM_GLOBAL_EVENT_HH__
#define __SIM_GLOBAL_EVENT_HH__
 
#include <mutex>
#include <vector>
 
#include "base/barrier.hh"
#include "sim/eventq.hh"
 
namespace gem5
{


class BaseGlobalEvent : public EventBase
{
  private:
      static std::mutex globalQMutex;
 
  protected:

    class BarrierEvent : public Event
    {
      protected:
        BaseGlobalEvent *_globalEvent;
 
        BarrierEvent(BaseGlobalEvent *global_event, Priority p, Flags f)
            : Event(p, f), _globalEvent(global_event)
        {
        }
 
        ~BarrierEvent();
 
        friend class BaseGlobalEvent;
 
        bool globalBarrier()
        {
            // This method will be called from the process() method in
            // the local barrier events
            // (GlobalSyncEvent::BarrierEvent).  The local event
            // queues are always locked when servicing events (calling
            // the process() method), which means that it will be
            // locked when entering this method. We need to unlock it
            // while waiting on the barrier to prevent deadlocks if
            // another thread wants to lock the event queue.
            EventQueue::ScopedRelease release(curEventQueue());
            return _globalEvent->barrier.wait();
        }
 
      public:
        virtual BaseGlobalEvent *globalEvent() { return _globalEvent; }
    };

    Barrier barrier;

    std::vector<BarrierEvent *> barrierEvent;
 
  public:
    BaseGlobalEvent(Priority p, Flags f);
 
    virtual ~BaseGlobalEvent();
 
    virtual void process() = 0;
 
    virtual const char *description() const = 0;
 
    void schedule(Tick when);
 
    bool scheduled() const
    {
        bool sched = false;
        for (uint32_t i = 0; i < numMainEventQueues; ++i) {
            sched = sched || barrierEvent[i]->scheduled();
        }
 
        return sched;
    }
 
    Tick when() const
    {
        assert(numMainEventQueues > 0);
        return barrierEvent[0]->when();
    }
 
    void deschedule();
    void reschedule(Tick when);
};
 

template <class Derived>
class BaseGlobalEventTemplate : public BaseGlobalEvent
{
  protected:
    BaseGlobalEventTemplate(Priority p, Flags f)
        : BaseGlobalEvent(p, f)
    {
        for (int i = 0; i < numMainEventQueues; ++i)
            barrierEvent[i] = new typename Derived::BarrierEvent(this, p, f);
    }
 
    virtual ~BaseGlobalEventTemplate(){}
};
 

class GlobalEvent : public BaseGlobalEventTemplate<GlobalEvent>
{
  public:
    typedef BaseGlobalEventTemplate<GlobalEvent> Base;
 
    class BarrierEvent : public Base::BarrierEvent
    {
      public:
        void process();
        BarrierEvent(Base *global_event, Priority p, Flags f)
            : Base::BarrierEvent(global_event, p, f)
        { }
    };
 
    GlobalEvent(Priority p, Flags f)
        : Base(p, f)
    { }
 
    GlobalEvent(Tick when, Priority p, Flags f)
        : Base(p, f)
    {
        schedule(when);
    }
 
    virtual void process() = 0;
};

class GlobalSyncEvent : public BaseGlobalEventTemplate<GlobalSyncEvent>
{
  public:
    typedef BaseGlobalEventTemplate<GlobalSyncEvent> Base;
 
    class BarrierEvent : public Base::BarrierEvent
    {
      public:
        void process();
        BarrierEvent(Base *global_event, Priority p, Flags f)
            : Base::BarrierEvent(global_event, p, f)
        { }
    };
 
    GlobalSyncEvent(Priority p, Flags f)
        : Base(p, f), repeat(0)
    { }
 
    GlobalSyncEvent(Tick when, Tick _repeat, Priority p, Flags f)
        : Base(p, f), repeat(_repeat)
    {
        schedule(when);
    }
 
    virtual ~GlobalSyncEvent (){}
 
    void process();
 
    const char *description() const;
 
    Tick repeat;
};
 
} // namespace gem5
 
#endif // __SIM_GLOBAL_EVENT_HH__