eventq.cc revision 5501:b1beee9351a4 
1/*
2 * Copyright (c) 2000-2005 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Steve Reinhardt
29 *          Nathan Binkert
30 *          Steve Raasch
31 */
32
33#include <cassert>
34#include <iostream>
35#include <string>
36#include <vector>
37
38#include "base/misc.hh"
39#include "base/trace.hh"
40#include "cpu/smt.hh"
41#include "sim/core.hh"
42#include "sim/eventq.hh"
43
44using namespace std;
45
46//
47// Main Event Queue
48//
49// Events on this queue are processed at the *beginning* of each
50// cycle, before the pipeline simulation is performed.
51//
52EventQueue mainEventQueue("MainEventQueue");
53
54#ifndef NDEBUG
55Counter Event::instanceCounter = 0;
56#endif
57
58void
59EventQueue::insert(Event *event)
60{
61    if (head == NULL || event->when() < head->when() ||
62        (event->when() == head->when() &&
63         event->priority() <= head->priority())) {
64        event->next = head;
65        head = event;
66    } else {
67        Event *prev = head;
68        Event *curr = head->next;
69
70        while (curr) {
71            if (event->when() <= curr->when() &&
72                (event->when() < curr->when() ||
73                 event->priority() <= curr->priority()))
74                break;
75
76            prev = curr;
77            curr = curr->next;
78        }
79
80        event->next = curr;
81        prev->next = event;
82    }
83}
84
85void
86EventQueue::remove(Event *event)
87{
88    if (head == NULL)
89        return;
90
91    if (head == event){
92        head = event->next;
93        return;
94    }
95
96    Event *prev = head;
97    Event *curr = head->next;
98    while (curr && curr != event) {
99        prev = curr;
100        curr = curr->next;
101    }
102
103    if (curr == event)
104        prev->next = curr->next;
105}
106
107Event *
108EventQueue::serviceOne()
109{
110    Event *event = head;
111    event->clearFlags(Event::Scheduled);
112    head = event->next;
113
114    // handle action
115    if (!event->squashed()) {
116        event->process();
117        if (event->isExitEvent()) {
118            assert(!event->getFlags(Event::AutoDelete)); // would be silly
119            return event;
120        }
121    } else {
122        event->clearFlags(Event::Squashed);
123    }
124
125    if (event->getFlags(Event::AutoDelete) && !event->scheduled())
126        delete event;
127
128    return NULL;
129}
130
131
132void
133Event::serialize(std::ostream &os)
134{
135    SERIALIZE_SCALAR(_when);
136    SERIALIZE_SCALAR(_priority);
137    SERIALIZE_ENUM(_flags);
138}
139
140
141void
142Event::unserialize(Checkpoint *cp, const string &section)
143{
144    if (scheduled())
145        deschedule();
146
147    UNSERIALIZE_SCALAR(_when);
148    UNSERIALIZE_SCALAR(_priority);
149
150    // need to see if original event was in a scheduled, unsquashed
151    // state, but don't want to restore those flags in the current
152    // object itself (since they aren't immediately true)
153    UNSERIALIZE_ENUM(_flags);
154    bool wasScheduled = (_flags & Scheduled) && !(_flags & Squashed);
155    _flags &= ~(Squashed | Scheduled);
156
157    if (wasScheduled) {
158        DPRINTF(Config, "rescheduling at %d\n", _when);
159        schedule(_when);
160    }
161}
162
163void
164EventQueue::serialize(ostream &os)
165{
166    std::list<Event *> eventPtrs;
167
168    int numEvents = 0;
169    Event *event = head;
170    while (event) {
171        if (event->getFlags(Event::AutoSerialize)) {
172            eventPtrs.push_back(event);
173            paramOut(os, csprintf("event%d", numEvents++), event->name());
174        }
175        event = event->next;
176    }
177
178    SERIALIZE_SCALAR(numEvents);
179
180    for (std::list<Event *>::iterator it=eventPtrs.begin();
181         it != eventPtrs.end(); ++it) {
182        (*it)->nameOut(os);
183        (*it)->serialize(os);
184    }
185}
186
187void
188EventQueue::unserialize(Checkpoint *cp, const std::string &section)
189{
190    int numEvents;
191    UNSERIALIZE_SCALAR(numEvents);
192
193    std::string eventName;
194    for (int i = 0; i < numEvents; i++) {
195        // get the pointer value associated with the event
196        paramIn(cp, section, csprintf("event%d", i), eventName);
197
198        // create the event based on its pointer value
199        Serializable::create(cp, eventName);
200    }
201}
202
203void
204EventQueue::dump() const
205{
206    cprintf("============================================================\n");
207    cprintf("EventQueue Dump  (cycle %d)\n", curTick);
208    cprintf("------------------------------------------------------------\n");
209
210    if (empty())
211        cprintf("<No Events>\n");
212    else {
213        Event *event = head;
214        while (event) {
215            event->dump();
216            event = event->next;
217        }
218    }
219
220    cprintf("============================================================\n");
221}
222
223void
224dumpMainQueue()
225{
226    mainEventQueue.dump();
227}
228
229
230const char *
231Event::description() const
232{
233    return "generic";
234}
235
236void
237Event::trace(const char *action)
238{
239    // This DPRINTF is unconditional because calls to this function
240    // are protected by an 'if (DTRACE(Event))' in the inlined Event
241    // methods.
242    //
243    // This is just a default implementation for derived classes where
244    // it's not worth doing anything special.  If you want to put a
245    // more informative message in the trace, override this method on
246    // the particular subclass where you have the information that
247    // needs to be printed.
248    DPRINTFN("%s event %s @ %d\n", description(), action, when());
249}
250
251void
252Event::dump() const
253{
254    cprintf("Event %s (%s)\n", name(), description());
255    cprintf("Flags: %#x\n", _flags);
256#ifdef EVENTQ_DEBUG
257    cprintf("Created: %d\n", whenCreated);
258#endif
259    if (scheduled()) {
260#ifdef EVENTQ_DEBUG
261        cprintf("Scheduled at  %d\n", whenScheduled);
262#endif
263        cprintf("Scheduled for %d, priority %d\n", when(), _priority);
264    } else {
265        cprintf("Not Scheduled\n");
266    }
267}
268