1/*
2 * Copyright (c) 2000-2005 The Regents of The University of Michigan
3 * Copyright (c) 2008 The Hewlett-Packard Development Company
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are
8 * met: redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer;
10 * redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution;
13 * neither the name of the copyright holders nor the names of its
14 * contributors may be used to endorse or promote products derived from
15 * this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * Authors: Steve Reinhardt
30 * Nathan Binkert
31 * Steve Raasch
32 */
33
34#include <cassert>
35#include <iostream>
36#include <string>
37#include <vector>
38
39#include "base/hashmap.hh"
40#include "base/misc.hh"
41#include "base/trace.hh"
42#include "cpu/smt.hh"
43#include "sim/core.hh"
44#include "sim/eventq.hh"
45
46using namespace std;
47
48//
49// Main Event Queue
50//
51// Events on this queue are processed at the *beginning* of each
52// cycle, before the pipeline simulation is performed.
53//
54EventQueue mainEventQueue("Main Event Queue");
55
56#ifndef NDEBUG
57Counter Event::instanceCounter = 0;
58#endif
59
60Event::~Event()
61{
62 assert(!scheduled());
63}
64
65const std::string
66Event::name() const
67{
68#ifndef NDEBUG
69 return csprintf("Event_%d", instance);
70#else
71 return csprintf("Event_%x", (uintptr_t)this);
72#endif
73}
74
75
76Event *
77Event::insertBefore(Event *event, Event *curr)
78{
79 // Either way, event will be the top element in the 'in bin' list
80 // which is the pointer we need in order to look into the list, so
81 // we need to insert that into the bin list.
82 if (!curr || *event < *curr) {
83 // Insert the event before the current list since it is in the future.
84 event->nextBin = curr;
85 event->nextInBin = NULL;
86 } else {
87 // Since we're on the correct list, we need to point to the next list
88 event->nextBin = curr->nextBin; // curr->nextBin can now become stale
89
90 // Insert event at the top of the stack
91 event->nextInBin = curr;
92 }
93
94 return event;
95}
96
97void
98EventQueue::insert(Event *event)
99{
100 // Deal with the head case
101 if (!head || *event <= *head) {
102 head = Event::insertBefore(event, head);
103 return;
104 }
105
106 // Figure out either which 'in bin' list we are on, or where a new list
107 // needs to be inserted
108 Event *prev = head;
109 Event *curr = head->nextBin;
110 while (curr && *curr < *event) {
111 prev = curr;
112 curr = curr->nextBin;
113 }
114
115 // Note: this operation may render all nextBin pointers on the
116 // prev 'in bin' list stale (except for the top one)
117 prev->nextBin = Event::insertBefore(event, curr);
118}
119
120Event *
121Event::removeItem(Event *event, Event *top)
122{
123 Event *curr = top;
124 Event *next = top->nextInBin;
125
126 // if we removed the top item, we need to handle things specially
127 // and just remove the top item, fixing up the next bin pointer of
128 // the new top item
129 if (event == top) {
130 if (!next)
131 return top->nextBin;
132 next->nextBin = top->nextBin;
133 return next;
134 }
135
136 // Since we already checked the current element, we're going to
137 // keep checking event against the next element.
138 while (event != next) {
139 if (!next)
140 panic("event not found!");
141
142 curr = next;
143 next = next->nextInBin;
144 }
145
146 // remove next from the 'in bin' list since it's what we're looking for
147 curr->nextInBin = next->nextInBin;
148 return top;
149}
150
151void
152EventQueue::remove(Event *event)
153{
154 if (head == NULL)
155 panic("event not found!");
156
157 // deal with an event on the head's 'in bin' list (event has the same
158 // time as the head)
159 if (*head == *event) {
160 head = Event::removeItem(event, head);
161 return;
162 }
163
164 // Find the 'in bin' list that this event belongs on
165 Event *prev = head;
166 Event *curr = head->nextBin;
167 while (curr && *curr < *event) {
168 prev = curr;
169 curr = curr->nextBin;
170 }
171
172 if (!curr || *curr != *event)
173 panic("event not found!");
174
175 // curr points to the top item of the the correct 'in bin' list, when
176 // we remove an item, it returns the new top item (which may be
177 // unchanged)
178 prev->nextBin = Event::removeItem(event, curr);
179}
180
181Event *
182EventQueue::serviceOne()
183{
184 Event *event = head;
185 Event *next = head->nextInBin;
186 event->flags.clear(Event::Scheduled);
187
188 if (next) {
189 // update the next bin pointer since it could be stale
190 next->nextBin = head->nextBin;
191
192 // pop the stack
193 head = next;
194 } else {
195 // this was the only element on the 'in bin' list, so get rid of
196 // the 'in bin' list and point to the next bin list
197 head = head->nextBin;
198 }
199
200 // handle action
201 if (!event->squashed()) {
202 event->process();
203 if (event->isExitEvent()) {
204 assert(!event->flags.isSet(Event::AutoDelete)); // would be silly
205 return event;
206 }
207 } else {
208 event->flags.clear(Event::Squashed);
209 }
210
211 if (event->flags.isSet(Event::AutoDelete) && !event->scheduled())
212 delete event;
213
214 return NULL;
215}
216
217void
218Event::serialize(std::ostream &os)
219{
220 SERIALIZE_SCALAR(_when);
221 SERIALIZE_SCALAR(_priority);
222 short _flags = flags;
223 SERIALIZE_SCALAR(_flags);
224}
225
226void
227Event::unserialize(Checkpoint *cp, const string &section)
228{
229 if (scheduled())
230 mainEventQueue.deschedule(this);
231
232 UNSERIALIZE_SCALAR(_when);
233 UNSERIALIZE_SCALAR(_priority);
234
235 // need to see if original event was in a scheduled, unsquashed
236 // state, but don't want to restore those flags in the current
237 // object itself (since they aren't immediately true)
238 short _flags;
239 UNSERIALIZE_SCALAR(_flags);
240 flags = _flags;
241
242 bool wasScheduled = flags.isSet(Scheduled) && !flags.isSet(Squashed);
243 flags.clear(Squashed | Scheduled);
244
245 if (wasScheduled) {
246 DPRINTF(Config, "rescheduling at %d\n", _when);
247 mainEventQueue.schedule(this, _when);
248 }
249}
250
251void
252EventQueue::serialize(ostream &os)
253{
254 std::list<Event *> eventPtrs;
255
256 int numEvents = 0;
257 Event *nextBin = head;
258 while (nextBin) {
259 Event *nextInBin = nextBin;
260
261 while (nextInBin) {
262 if (nextInBin->flags.isSet(Event::AutoSerialize)) {
263 eventPtrs.push_back(nextInBin);
264 paramOut(os, csprintf("event%d", numEvents++),
265 nextInBin->name());
266 }
267 nextInBin = nextInBin->nextInBin;
268 }
269
270 nextBin = nextBin->nextBin;
271 }
272
273 SERIALIZE_SCALAR(numEvents);
274
275 for (std::list<Event *>::iterator it = eventPtrs.begin();
276 it != eventPtrs.end(); ++it) {
277 (*it)->nameOut(os);
278 (*it)->serialize(os);
279 }
280}
281
282void
283EventQueue::unserialize(Checkpoint *cp, const std::string &section)
284{
285 int numEvents;
286 UNSERIALIZE_SCALAR(numEvents);
287
288 std::string eventName;
289 for (int i = 0; i < numEvents; i++) {
290 // get the pointer value associated with the event
291 paramIn(cp, section, csprintf("event%d", i), eventName);
292
293 // create the event based on its pointer value
294 Serializable::create(cp, eventName);
295 }
296}
297
298void
299EventQueue::dump() const
300{
301 cprintf("============================================================\n");
302 cprintf("EventQueue Dump (cycle %d)\n", curTick);
303 cprintf("------------------------------------------------------------\n");
304
305 if (empty())
306 cprintf("<No Events>\n");
307 else {
308 Event *nextBin = head;
309 while (nextBin) {
310 Event *nextInBin = nextBin;
311 while (nextInBin) {
312 nextInBin->dump();
313 nextInBin = nextInBin->nextInBin;
314 }
315
316 nextBin = nextBin->nextBin;
317 }
318 }
319
320 cprintf("============================================================\n");
321}
322
323bool
324EventQueue::debugVerify() const
325{
326 m5::hash_map<long, bool> map;
327
328 Tick time = 0;
329 short priority = 0;
330
331 Event *nextBin = head;
332 while (nextBin) {
333 Event *nextInBin = nextBin;
334 while (nextInBin) {
335 if (nextInBin->when() < time) {
336 cprintf("time goes backwards!");
337 nextInBin->dump();
338 return false;
339 } else if (nextInBin->when() == time &&
340 nextInBin->priority() < priority) {
341 cprintf("priority inverted!");
342 nextInBin->dump();
343 return false;
344 }
345
346 if (map[reinterpret_cast<long>(nextInBin)]) {
347 cprintf("Node already seen");
348 nextInBin->dump();
349 return false;
350 }
351 map[reinterpret_cast<long>(nextInBin)] = true;
352
353 time = nextInBin->when();
354 priority = nextInBin->priority();
355
356 nextInBin = nextInBin->nextInBin;
357 }
358
359 nextBin = nextBin->nextBin;
360 }
361
362 return true;
363}
364
365void
366dumpMainQueue()
367{
368 mainEventQueue.dump();
369}
370
371
372const char *
373Event::description() const
374{
375 return "generic";
376}
377
378void
379Event::trace(const char *action)
380{
381 // This DPRINTF is unconditional because calls to this function
382 // are protected by an 'if (DTRACE(Event))' in the inlined Event
383 // methods.
384 //
385 // This is just a default implementation for derived classes where
386 // it's not worth doing anything special. If you want to put a
387 // more informative message in the trace, override this method on
388 // the particular subclass where you have the information that
389 // needs to be printed.
390 DPRINTFN("%s event %s @ %d\n", description(), action, when());
391}
392
393void
394Event::dump() const
395{
396 cprintf("Event %s (%s)\n", name(), description());
397 cprintf("Flags: %#x\n", flags);
398#ifdef EVENTQ_DEBUG
399 cprintf("Created: %d\n", whenCreated);
400#endif
401 if (scheduled()) {
402#ifdef EVENTQ_DEBUG
403 cprintf("Scheduled at %d\n", whenScheduled);
404#endif
405 cprintf("Scheduled for %d, priority %d\n", when(), _priority);
406 } else {
407 cprintf("Not Scheduled\n");
408 }
409}