eventq.cc revision 5502
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("MainEventQueue"); 55 56#ifndef NDEBUG 57Counter Event::instanceCounter = 0; 58#endif 59 60inline void 61insertBefore(Event *event, Event *curr) 62{ 63 // Either way, event will be the last element in the 'in bin' list 64 // which is the pointer we need in order to look into the list, so 65 // we need to insert that into the bin list. 66 if (!curr || *event < *curr) { 67 // Insert the event before the current list since it is in the future. 68 event->nextBin = curr; 69 70 // We need to create a new 'in bin' list 71 event->nextInBin = event; 72 } else { 73 // Since we're on the correct list, we need to point to the next list 74 event->nextBin = curr->nextBin; // curr->nextBin can now become stale 75 76 // Insert event at the end of the 'nextInBin' curr is the last 77 // element on the 'in bin' list and curr->nextInBin is the first 78 79 event->nextInBin = curr->nextInBin; // event->nextInBin needs to 80 // point to the first 81 curr->nextInBin = event; // curr->nextInBin is now second to last 82 } 83} 84 85void 86EventQueue::insert(Event *event) 87{ 88 // Deal with the head case 89 if (!head || *event <= *head) { 90 insertBefore(event, head); 91 head = event; 92 return; 93 } 94 95 // Figure out either which 'in bin' list we are on, or where a new list 96 // needs to be inserted 97 Event *curr = head; 98 Event *next = head->nextBin; 99 while (next && *next < *event) { 100 curr = next; 101 next = next->nextBin; 102 } 103 104 insertBefore(event, next); 105 curr->nextBin = event; // all nextBin pointers on the curr 106 // 'in bin' list are now stale 107} 108 109inline Event * 110removeItem(Event *event, Event *last) 111{ 112 Event *prev = last; 113 Event *curr = last->nextInBin; 114 115 while (event != curr) { 116 if (curr == last) 117 panic("event not found!"); 118 119 prev = curr; 120 curr = curr->nextInBin; 121 } 122 123 // If this was the only item in this list, we're done. 124 if (prev == curr) 125 return NULL; 126 127 // remove curr from the 'in bin' list since it's what we're looking for 128 prev->nextInBin = curr->nextInBin; 129 130 // If we didn't remove the last item, we're done 131 if (curr != last) 132 return last; 133 134 // if we removed the last item, the new last item is prev 135 // fix it up since it might be stale and return it 136 prev->nextBin = last->nextBin; 137 return prev; 138} 139 140void 141EventQueue::remove(Event *event) 142{ 143 if (head == NULL) 144 panic("event not found!"); 145 146 // deal with an event on the head's 'in bin' list (event has the same 147 // time as the head) 148 if (*head == *event) { 149 head = removeItem(event, head); 150 if (!head) 151 head = event->nextBin; 152 return; 153 } 154 155 // Find the 'in bin' list that this event belongs on 156 Event *prev = head; 157 Event *curr = head->nextBin; 158 while (curr && *curr < *event) { 159 prev = curr; 160 curr = curr->nextBin; 161 } 162 163 if (!curr || *curr != *event) 164 panic("event not found!"); 165 166 // curr points to the last item of the the correct 'in bin' list, when 167 // we remove an item, it returns the new last item (which may be 168 // unchanged) 169 Event *last = removeItem(event, curr); 170 if (!last) { 171 // The current item was removed, so we need to fix the bin list 172 prev->nextBin = curr->nextBin; 173 } else if (last != curr) { 174 // We have a new last item, so we need to update the bin list 175 prev->nextBin = last; 176 } 177} 178 179Event * 180EventQueue::serviceOne() 181{ 182 // grab the first element 183 Event *event = head->nextInBin; 184 event->clearFlags(Event::Scheduled); 185 186 if (head == event) { 187 // this was the only element on the 'in bin' list, so get rid of 188 // the 'in bin' list and point to the next bin list 189 head = event->nextBin; 190 } else { 191 // maintain head->nextInBin as the first element 192 head->nextInBin = event->nextInBin; 193 } 194 195 // handle action 196 if (!event->squashed()) { 197 event->process(); 198 if (event->isExitEvent()) { 199 assert(!event->getFlags(Event::AutoDelete)); // would be silly 200 return event; 201 } 202 } else { 203 event->clearFlags(Event::Squashed); 204 } 205 206 if (event->getFlags(Event::AutoDelete) && !event->scheduled()) 207 delete event; 208 209 return NULL; 210} 211 212void 213Event::serialize(std::ostream &os) 214{ 215 SERIALIZE_SCALAR(_when); 216 SERIALIZE_SCALAR(_priority); 217 SERIALIZE_ENUM(_flags); 218} 219 220void 221Event::unserialize(Checkpoint *cp, const string §ion) 222{ 223 if (scheduled()) 224 deschedule(); 225 226 UNSERIALIZE_SCALAR(_when); 227 UNSERIALIZE_SCALAR(_priority); 228 229 // need to see if original event was in a scheduled, unsquashed 230 // state, but don't want to restore those flags in the current 231 // object itself (since they aren't immediately true) 232 UNSERIALIZE_ENUM(_flags); 233 bool wasScheduled = (_flags & Scheduled) && !(_flags & Squashed); 234 _flags &= ~(Squashed | Scheduled); 235 236 if (wasScheduled) { 237 DPRINTF(Config, "rescheduling at %d\n", _when); 238 schedule(_when); 239 } 240} 241 242void 243EventQueue::serialize(ostream &os) 244{ 245 std::list<Event *> eventPtrs; 246 247 int numEvents = 0; 248 Event *nextBin = head; 249 while (nextBin) { 250 Event *nextInBin = nextBin->nextInBin; 251 252 do { 253 if (nextInBin->getFlags(Event::AutoSerialize)) { 254 eventPtrs.push_back(nextInBin); 255 paramOut(os, csprintf("event%d", numEvents++), 256 nextInBin->name()); 257 } 258 nextInBin = nextInBin->nextInBin; 259 } while (nextInBin != nextBin); 260 261 nextBin = nextBin->nextBin; 262 } 263 264 SERIALIZE_SCALAR(numEvents); 265 266 for (std::list<Event *>::iterator it = eventPtrs.begin(); 267 it != eventPtrs.end(); ++it) { 268 (*it)->nameOut(os); 269 (*it)->serialize(os); 270 } 271} 272 273void 274EventQueue::unserialize(Checkpoint *cp, const std::string §ion) 275{ 276 int numEvents; 277 UNSERIALIZE_SCALAR(numEvents); 278 279 std::string eventName; 280 for (int i = 0; i < numEvents; i++) { 281 // get the pointer value associated with the event 282 paramIn(cp, section, csprintf("event%d", i), eventName); 283 284 // create the event based on its pointer value 285 Serializable::create(cp, eventName); 286 } 287} 288 289void 290EventQueue::dump() const 291{ 292 cprintf("============================================================\n"); 293 cprintf("EventQueue Dump (cycle %d)\n", curTick); 294 cprintf("------------------------------------------------------------\n"); 295 296 m5::hash_map<long, bool> map; 297 298 if (empty()) 299 cprintf("<No Events>\n"); 300 else { 301 Event *nextBin = head; 302 while (nextBin) { 303 Event *nextInBin = nextBin; 304 if (map[reinterpret_cast<long>(nextInBin)]) 305 break; 306 map[reinterpret_cast<long>(nextInBin)] = true; 307 do { 308 nextInBin = nextInBin->nextInBin; 309 nextInBin->dump(); 310 } while (nextInBin != nextBin); 311 312 nextBin = nextBin->nextBin; 313 } 314 } 315 316 cprintf("============================================================\n"); 317} 318 319bool 320EventQueue::debugVerify() const 321{ 322 m5::hash_map<long, bool> map; 323 324 Tick time = 0; 325 short priority = 0; 326 327 Event *nextBin = head; 328 while (nextBin) { 329 Event *nextInBin = nextBin->nextInBin; 330 do { 331 if (nextInBin->when() < time) { 332 cprintf("time goes backwards!"); 333 nextInBin->dump(); 334 return false; 335 } else if (nextInBin->when() == time && 336 nextInBin->priority() < priority) { 337 cprintf("priority inverted!"); 338 nextInBin->dump(); 339 return false; 340 } 341 342 if (map[reinterpret_cast<long>(nextInBin)]) { 343 cprintf("Node already seen"); 344 nextInBin->dump(); 345 return false; 346 } 347 map[reinterpret_cast<long>(nextInBin)] = true; 348 349 time = nextInBin->when(); 350 priority = nextInBin->priority(); 351 352 nextInBin = nextInBin->nextInBin; 353 } while (nextInBin != nextBin); 354 355 nextBin = nextBin->nextBin; 356 } 357 358 return true; 359} 360 361void 362dumpMainQueue() 363{ 364 mainEventQueue.dump(); 365} 366 367 368const char * 369Event::description() const 370{ 371 return "generic"; 372} 373 374void 375Event::trace(const char *action) 376{ 377 // This DPRINTF is unconditional because calls to this function 378 // are protected by an 'if (DTRACE(Event))' in the inlined Event 379 // methods. 380 // 381 // This is just a default implementation for derived classes where 382 // it's not worth doing anything special. If you want to put a 383 // more informative message in the trace, override this method on 384 // the particular subclass where you have the information that 385 // needs to be printed. 386 DPRINTFN("%s event %s @ %d\n", description(), action, when()); 387} 388 389void 390Event::dump() const 391{ 392 cprintf("Event %s (%s)\n", name(), description()); 393 cprintf("Flags: %#x\n", _flags); 394#ifdef EVENTQ_DEBUG 395 cprintf("Created: %d\n", whenCreated); 396#endif 397 if (scheduled()) { 398#ifdef EVENTQ_DEBUG 399 cprintf("Scheduled at %d\n", whenScheduled); 400#endif 401 cprintf("Scheduled for %d, priority %d\n", when(), _priority); 402 } else { 403 cprintf("Not Scheduled\n"); 404 } 405} 406