Adding gem5 source to svn.

git-svn-id: https://www4.informatik.uni-erlangen.de/i4svn/danceos/trunk/devel/fail@1819 8c4709b5-6ec9-48aa-a5cd-a96041d1645a

simulators/gem5/src/sim/eventq.hh

@@ -0,0 +1,603 @@
+/*
+ * Copyright (c) 2000-2005 The Regents of The University of Michigan
+ * 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
+ *          Nathan Binkert
+ */
+
+/* @file
+ * EventQueue interfaces
+ */
+
+#ifndef __SIM_EVENTQ_HH__
+#define __SIM_EVENTQ_HH__
+
+#include <algorithm>
+#include <cassert>
+#include <climits>
+#include <iosfwd>
+#include <string>
+
+#include "base/flags.hh"
+#include "base/misc.hh"
+#include "base/trace.hh"
+#include "base/types.hh"
+#include "debug/Event.hh"
+#include "sim/serialize.hh"
+
+class EventQueue;       // forward declaration
+
+extern EventQueue mainEventQueue;
+
+/*
+ * An item on an event queue.  The action caused by a given
+ * event is specified by deriving a subclass and overriding the
+ * process() member function.
+ *
+ * Caution, the order of members is chosen to maximize data packing.
+ */
+class Event : public Serializable
+{
+    friend class EventQueue;
+
+  protected:   
+    typedef unsigned short FlagsType;
+    typedef ::Flags<FlagsType> Flags;
+
+    static const FlagsType PublicRead    = 0x003f; // public readable flags
+    static const FlagsType PublicWrite   = 0x001d; // public writable flags
+    static const FlagsType Squashed      = 0x0001; // has been squashed
+    static const FlagsType Scheduled     = 0x0002; // has been scheduled
+    static const FlagsType AutoDelete    = 0x0004; // delete after dispatch
+    static const FlagsType AutoSerialize = 0x0008; // must be serialized
+    static const FlagsType IsExitEvent   = 0x0010; // special exit event
+    static const FlagsType IsMainQueue   = 0x0020; // on main event queue
+    static const FlagsType Initialized   = 0x7a40; // somewhat random bits
+    static const FlagsType InitMask      = 0xffc0; // mask for init bits
+
+    bool
+    initialized() const
+    {
+        return this && (flags & InitMask) == Initialized;
+    }
+
+  public:
+    typedef int8_t Priority;
+
+  private:
+    // The event queue is now a linked list of linked lists.  The
+    // 'nextBin' pointer is to find the bin, where a bin is defined as
+    // when+priority.  All events in the same bin will be stored in a
+    // second linked list (a stack) maintained by the 'nextInBin'
+    // pointer.  The list will be accessed in LIFO order.  The end
+    // result is that the insert/removal in 'nextBin' is
+    // linear/constant, and the lookup/removal in 'nextInBin' is
+    // constant/constant.  Hopefully this is a significant improvement
+    // over the current fully linear insertion.
+    Event *nextBin;
+    Event *nextInBin;
+
+    static Event *insertBefore(Event *event, Event *curr);
+    static Event *removeItem(Event *event, Event *last);
+
+    Tick _when;         //!< timestamp when event should be processed
+    Priority _priority; //!< event priority
+    Flags flags;
+
+#ifndef NDEBUG
+    /// Global counter to generate unique IDs for Event instances
+    static Counter instanceCounter;
+
+    /// This event's unique ID.  We can also use pointer values for
+    /// this but they're not consistent across runs making debugging
+    /// more difficult.  Thus we use a global counter value when
+    /// debugging.
+    Counter instance;
+
+    /// queue to which this event belongs (though it may or may not be
+    /// scheduled on this queue yet)
+    EventQueue *queue;
+#endif
+
+#ifdef EVENTQ_DEBUG
+    Tick whenCreated;   //!< time created
+    Tick whenScheduled; //!< time scheduled
+#endif
+
+    void
+    setWhen(Tick when, EventQueue *q)
+    {
+        _when = when;
+#ifndef NDEBUG
+        queue = q;
+#endif
+#ifdef EVENTQ_DEBUG
+        whenScheduled = curTick();
+#endif
+    }
+
+  protected:
+    /// Accessor for flags.
+    Flags
+    getFlags() const
+    {
+        return flags & PublicRead;
+    }
+
+    bool
+    isFlagSet(Flags _flags) const
+    {
+        assert(_flags.noneSet(~PublicRead));
+        return flags.isSet(_flags);
+    }
+
+    /// Accessor for flags.
+    void
+    setFlags(Flags _flags)
+    {
+        assert(_flags.noneSet(~PublicWrite));
+        flags.set(_flags);
+    }
+
+    void
+    clearFlags(Flags _flags)
+    {
+        assert(_flags.noneSet(~PublicWrite));
+        flags.clear(_flags);
+    }
+
+    void
+    clearFlags()
+    {
+        flags.clear(PublicWrite);
+    }
+
+    // This function isn't really useful if TRACING_ON is not defined
+    virtual void trace(const char *action);     //!< trace event activity
+
+  public:
+    /// Event priorities, to provide tie-breakers for events scheduled
+    /// at the same cycle.  Most events are scheduled at the default
+    /// priority; these values are used to control events that need to
+    /// be ordered within a cycle.
+
+    /// Minimum priority
+    static const Priority Minimum_Pri =          SCHAR_MIN;
+
+    /// If we enable tracing on a particular cycle, do that as the
+    /// very first thing so we don't miss any of the events on
+    /// that cycle (even if we enter the debugger).
+    static const Priority Trace_Enable_Pri =          -101;
+
+    /// Breakpoints should happen before anything else (except
+    /// enabling trace output), so we don't miss any action when
+    /// debugging.
+    static const Priority Debug_Break_Pri =           -100;
+
+    /// CPU switches schedule the new CPU's tick event for the
+    /// same cycle (after unscheduling the old CPU's tick event).
+    /// The switch needs to come before any tick events to make
+    /// sure we don't tick both CPUs in the same cycle.
+    static const Priority CPU_Switch_Pri =             -31;
+
+    /// For some reason "delayed" inter-cluster writebacks are
+    /// scheduled before regular writebacks (which have default
+    /// priority).  Steve?
+    static const Priority Delayed_Writeback_Pri =       -1;
+
+    /// Default is zero for historical reasons.
+    static const Priority Default_Pri =                  0;
+
+    /// Serailization needs to occur before tick events also, so
+    /// that a serialize/unserialize is identical to an on-line
+    /// CPU switch.
+    static const Priority Serialize_Pri =               32;
+
+    /// CPU ticks must come after other associated CPU events
+    /// (such as writebacks).
+    static const Priority CPU_Tick_Pri =                50;
+
+    /// Statistics events (dump, reset, etc.) come after
+    /// everything else, but before exit.
+    static const Priority Stat_Event_Pri =              90;
+
+    /// Progress events come at the end.
+    static const Priority Progress_Event_Pri =          95;
+
+    /// If we want to exit on this cycle, it's the very last thing
+    /// we do.
+    static const Priority Sim_Exit_Pri =               100;
+
+    /// Maximum priority
+    static const Priority Maximum_Pri =          SCHAR_MAX;
+
+    /*
+     * Event constructor
+     * @param queue that the event gets scheduled on
+     */
+    Event(Priority p = Default_Pri, Flags f = 0)
+        : nextBin(NULL), nextInBin(NULL), _priority(p),
+          flags(Initialized | f)
+    {
+        assert(f.noneSet(~PublicWrite));
+#ifndef NDEBUG
+        instance = ++instanceCounter;
+        queue = NULL;
+#endif
+#ifdef EVENTQ_DEBUG
+        whenCreated = curTick();
+        whenScheduled = 0;
+#endif
+    }
+
+    virtual ~Event();
+    virtual const std::string name() const;
+
+    /// Return a C string describing the event.  This string should
+    /// *not* be dynamically allocated; just a const char array
+    /// describing the event class.
+    virtual const char *description() const;
+
+    /// Dump the current event data
+    void dump() const;
+
+  public:
+    /*
+     * This member function is invoked when the event is processed
+     * (occurs).  There is no default implementation; each subclass
+     * must provide its own implementation.  The event is not
+     * automatically deleted after it is processed (to allow for
+     * statically allocated event objects).
+     *
+     * If the AutoDestroy flag is set, the object is deleted once it
+     * is processed.
+     */
+    virtual void process() = 0;
+
+    /// Determine if the current event is scheduled
+    bool scheduled() const { return flags.isSet(Scheduled); }
+
+    /// Squash the current event
+    void squash() { flags.set(Squashed); }
+
+    /// Check whether the event is squashed
+    bool squashed() const { return flags.isSet(Squashed); }
+
+    /// See if this is a SimExitEvent (without resorting to RTTI)
+    bool isExitEvent() const { return flags.isSet(IsExitEvent); }
+
+    /// Get the time that the event is scheduled
+    Tick when() const { return _when; }
+
+    /// Get the event priority
+    Priority priority() const { return _priority; }
+
+#ifndef SWIG
+    struct priority_compare
+        : public std::binary_function<Event *, Event *, bool>
+    {
+        bool
+        operator()(const Event *l, const Event *r) const
+        {
+            return l->when() >= r->when() || l->priority() >= r->priority();
+        }
+    };
+
+    virtual void serialize(std::ostream &os);
+    virtual void unserialize(Checkpoint *cp, const std::string &section);
+#endif
+};
+
+#ifndef SWIG
+inline bool
+operator<(const Event &l, const Event &r)
+{
+    return l.when() < r.when() ||
+        (l.when() == r.when() && l.priority() < r.priority());
+}
+
+inline bool
+operator>(const Event &l, const Event &r)
+{
+    return l.when() > r.when() ||
+        (l.when() == r.when() && l.priority() > r.priority());
+}
+
+inline bool
+operator<=(const Event &l, const Event &r)
+{
+    return l.when() < r.when() ||
+        (l.when() == r.when() && l.priority() <= r.priority());
+}
+inline bool
+operator>=(const Event &l, const Event &r)
+{
+    return l.when() > r.when() ||
+        (l.when() == r.when() && l.priority() >= r.priority());
+}
+
+inline bool
+operator==(const Event &l, const Event &r)
+{
+    return l.when() == r.when() && l.priority() == r.priority();
+}
+
+inline bool
+operator!=(const Event &l, const Event &r)
+{
+    return l.when() != r.when() || l.priority() != r.priority();
+}
+#endif
+
+/*
+ * Queue of events sorted in time order
+ */
+class EventQueue : public Serializable
+{
+  private:
+    std::string objName;
+    Event *head;
+
+    void insert(Event *event);
+    void remove(Event *event);
+
+    EventQueue(const EventQueue &);
+    const EventQueue &operator=(const EventQueue &);
+
+  public:
+    EventQueue(const std::string &n);
+
+    virtual const std::string name() const { return objName; }
+
+    // schedule the given event on this queue
+    void schedule(Event *event, Tick when);
+    void deschedule(Event *event);
+    void reschedule(Event *event, Tick when, bool always = false);
+
+    Tick nextTick() const { return head->when(); }
+    Event *serviceOne();
+
+    // process all events up to the given timestamp.  we inline a
+    // quick test to see if there are any events to process; if so,
+    // call the internal out-of-line version to process them all.
+    void
+    serviceEvents(Tick when)
+    {
+        while (!empty()) {
+            if (nextTick() > when)
+                break;
+
+            /**
+             * @todo this assert is a good bug catcher.  I need to
+             * make it true again.
+             */
+            //assert(head->when() >= when && "event scheduled in the past");
+            serviceOne();
+        }
+    }
+
+    // return true if no events are queued
+    bool empty() const { return head == NULL; }
+
+    void dump() const;
+
+    bool debugVerify() const;
+
+    /**
+     *  function for replacing the head of the event queue, so that a
+     *  different set of events can run without disturbing events that have
+     *  already been scheduled. Already scheduled events can be processed
+     *  by replacing the original head back.
+     *  USING THIS FUNCTION CAN BE DANGEROUS TO THE HEALTH OF THE SIMULATOR.
+     *  NOT RECOMMENDED FOR USE.
+     */
+    Event* replaceHead(Event* s);
+
+#ifndef SWIG
+    virtual void serialize(std::ostream &os);
+    virtual void unserialize(Checkpoint *cp, const std::string &section);
+#endif
+};
+
+#ifndef SWIG
+class EventManager
+{
+  protected:
+    /** A pointer to this object's event queue */
+    EventQueue *eventq;
+
+  public:
+    EventManager(EventManager &em) : eventq(em.queue()) {}
+    EventManager(EventManager *em) : eventq(em ? em->queue() : NULL) {}
+    EventManager(EventQueue *eq) : eventq(eq) {}
+
+    EventQueue *
+    queue() const
+    {
+        return eventq;
+    }
+
+    operator EventQueue *() const
+    {
+        return eventq;
+    }
+
+    void
+    schedule(Event &event, Tick when)
+    {
+        eventq->schedule(&event, when);
+    }
+
+    void
+    deschedule(Event &event)
+    {
+        eventq->deschedule(&event);
+    }
+
+    void
+    reschedule(Event &event, Tick when, bool always = false)
+    {
+        eventq->reschedule(&event, when, always);
+    }
+
+    void
+    schedule(Event *event, Tick when)
+    {
+        eventq->schedule(event, when);
+    }
+
+    void
+    deschedule(Event *event)
+    {
+        eventq->deschedule(event);
+    }
+
+    void
+    reschedule(Event *event, Tick when, bool always = false)
+    {
+        eventq->reschedule(event, when, always);
+    }
+};
+
+inline void
+EventQueue::schedule(Event *event, Tick when)
+{
+    // Typecasting Tick->Utick here since gcc
+    // complains about signed overflow
+    assert((UTick)when >= (UTick)curTick());
+    assert(!event->scheduled());
+    assert(event->initialized());
+
+    event->setWhen(when, this);
+    insert(event);
+    event->flags.set(Event::Scheduled);
+    if (this == &mainEventQueue)
+        event->flags.set(Event::IsMainQueue);
+    else
+        event->flags.clear(Event::IsMainQueue);
+
+    if (DTRACE(Event))
+        event->trace("scheduled");
+}
+
+inline void
+EventQueue::deschedule(Event *event)
+{
+    assert(event->scheduled());
+    assert(event->initialized());
+
+    remove(event);
+
+    event->flags.clear(Event::Squashed);
+    event->flags.clear(Event::Scheduled);
+
+    if (DTRACE(Event))
+        event->trace("descheduled");
+
+    if (event->flags.isSet(Event::AutoDelete))
+        delete event;
+}
+
+inline void
+EventQueue::reschedule(Event *event, Tick when, bool always)
+{
+    // Typecasting Tick->Utick here since gcc
+    // complains about signed overflow
+    assert((UTick)when >= (UTick)curTick());
+    assert(always || event->scheduled());
+    assert(event->initialized());
+
+    if (event->scheduled())
+        remove(event);
+            
+    event->setWhen(when, this);
+    insert(event);
+    event->flags.clear(Event::Squashed);
+    event->flags.set(Event::Scheduled);
+    if (this == &mainEventQueue)
+        event->flags.set(Event::IsMainQueue);
+    else
+        event->flags.clear(Event::IsMainQueue);
+
+    if (DTRACE(Event))
+        event->trace("rescheduled");
+}
+
+template <class T, void (T::* F)()>
+void
+DelayFunction(EventQueue *eventq, Tick when, T *object)
+{
+    class DelayEvent : public Event
+    {
+      private:
+        T *object;
+
+      public:
+        DelayEvent(T *o)
+            : Event(Default_Pri, AutoDelete), object(o)
+        { }
+        void process() { (object->*F)(); }
+        const char *description() const { return "delay"; }
+    };
+
+    eventq->schedule(new DelayEvent(object), when);
+}
+
+template <class T, void (T::* F)()>
+class EventWrapper : public Event
+{
+  private:
+    T *object;
+
+  public:
+    EventWrapper(T *obj, bool del = false, Priority p = Default_Pri)
+        : Event(p), object(obj)
+    {
+        if (del)
+            setFlags(AutoDelete);
+    }
+
+    EventWrapper(T &obj, bool del = false, Priority p = Default_Pri)
+        : Event(p), object(&obj)
+    {
+        if (del)
+            setFlags(AutoDelete);
+    }
+
+    void process() { (object->*F)(); }
+
+    const std::string
+    name() const
+    {
+        return object->name() + ".wrapped_event";
+    }
+
+    const char *description() const { return "EventWrapped"; }
+};
+#endif
+
+#endif // __SIM_EVENTQ_HH__