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,
 * 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: Steve Reinhardt
 */

#ifndef __SIM_GLOBAL_EVENT_HH__
#define __SIM_GLOBAL_EVENT_HH__

#include <mutex>
#include <vector>

#include "base/barrier.hh"
#include "sim/eventq_impl.hh"

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);
    }
};


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);
    }

    void process();

    const char *description() const;

    Tick repeat;
};


#endif // __SIM_GLOBAL_EVENT_HH__