gem5/src/sim/eventq.hh
Nilay Vaish daa4c7526a eventq: add a function for replacing head of the queue
This patch adds a function for replacing the event at the head of the queue
with another event. This helps in running a different set of events. Events
already scheduled can processed by replacing the original head event back.
This function has been specifically added to support cache warmup and
cooldown required for creating and restoring checkpoints.

--HG--
extra : rebase_source : ed6e2905720b6bfdefd020fab76235ccf33d28d1
2012-01-05 11:02:56 -06:00

604 lines
17 KiB
C++

/*
* 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/fast_alloc.hh"
#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, public FastAlloc
{
friend class EventQueue;
protected:
typedef 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 (event->flags.isSet(Event::AutoDelete))
delete event;
if (DTRACE(Event))
event->trace("descheduled");
}
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__