eventq.cc revision 5768
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} 63 64const std::string 65Event::name() const 66{ 67#ifndef NDEBUG 68 return csprintf("Event_%d", instance); 69#else 70 return csprintf("Event_%x", (uintptr_t)this); 71#endif 72} 73 74 75Event * 76Event::insertBefore(Event *event, Event *curr) 77{ 78 // Either way, event will be the top element in the 'in bin' list 79 // which is the pointer we need in order to look into the list, so 80 // we need to insert that into the bin list. 81 if (!curr || *event < *curr) { 82 // Insert the event before the current list since it is in the future. 83 event->nextBin = curr; 84 event->nextInBin = NULL; 85 } else { 86 // Since we're on the correct list, we need to point to the next list 87 event->nextBin = curr->nextBin; // curr->nextBin can now become stale 88 89 // Insert event at the top of the stack 90 event->nextInBin = curr; 91 } 92 93 return event; 94} 95 96void 97EventQueue::insert(Event *event) 98{ 99 // Deal with the head case 100 if (!head || *event <= *head) { 101 head = Event::insertBefore(event, head); 102 return; 103 } 104 105 // Figure out either which 'in bin' list we are on, or where a new list 106 // needs to be inserted 107 Event *prev = head; 108 Event *curr = head->nextBin; 109 while (curr && *curr < *event) { 110 prev = curr; 111 curr = curr->nextBin; 112 } 113 114 // Note: this operation may render all nextBin pointers on the 115 // prev 'in bin' list stale (except for the top one) 116 prev->nextBin = Event::insertBefore(event, curr); 117} 118 119Event * 120Event::removeItem(Event *event, Event *top) 121{ 122 Event *curr = top; 123 Event *next = top->nextInBin; 124 125 // if we removed the top item, we need to handle things specially 126 // and just remove the top item, fixing up the next bin pointer of 127 // the new top item 128 if (event == top) { 129 if (!next) 130 return top->nextBin; 131 next->nextBin = top->nextBin; 132 return next; 133 } 134 135 // Since we already checked the current element, we're going to 136 // keep checking event against the next element. 137 while (event != next) { 138 if (!next) 139 panic("event not found!"); 140 141 curr = next; 142 next = next->nextInBin; 143 } 144 145 // remove next from the 'in bin' list since it's what we're looking for 146 curr->nextInBin = next->nextInBin; 147 return top; 148} 149 150void 151EventQueue::remove(Event *event) 152{ 153 if (head == NULL) 154 panic("event not found!"); 155 156 // deal with an event on the head's 'in bin' list (event has the same 157 // time as the head) 158 if (*head == *event) { 159 head = Event::removeItem(event, head); 160 return; 161 } 162 163 // Find the 'in bin' list that this event belongs on 164 Event *prev = head; 165 Event *curr = head->nextBin; 166 while (curr && *curr < *event) { 167 prev = curr; 168 curr = curr->nextBin; 169 } 170 171 if (!curr || *curr != *event) 172 panic("event not found!"); 173 174 // curr points to the top item of the the correct 'in bin' list, when 175 // we remove an item, it returns the new top item (which may be 176 // unchanged) 177 prev->nextBin = Event::removeItem(event, curr); 178} 179 180Event * 181EventQueue::serviceOne() 182{ 183 Event *event = head; 184 Event *next = head->nextInBin; 185 event->clearFlags(Event::Scheduled); 186 187 if (next) { 188 // update the next bin pointer since it could be stale 189 next->nextBin = head->nextBin; 190 191 // pop the stack 192 head = next; 193 } else { 194 // this was the only element on the 'in bin' list, so get rid of 195 // the 'in bin' list and point to the next bin list 196 head = head->nextBin; 197 } 198 199 // handle action 200 if (!event->squashed()) { 201 event->process(); 202 if (event->isExitEvent()) { 203 assert(!event->getFlags(Event::AutoDelete)); // would be silly 204 return event; 205 } 206 } else { 207 event->clearFlags(Event::Squashed); 208 } 209 210 if (event->getFlags(Event::AutoDelete) && !event->scheduled()) 211 delete event; 212 213 return NULL; 214} 215 216void 217Event::serialize(std::ostream &os) 218{ 219 SERIALIZE_SCALAR(_when); 220 SERIALIZE_SCALAR(_priority); 221 SERIALIZE_ENUM(_flags); 222} 223 224void 225Event::unserialize(Checkpoint *cp, const string §ion) 226{ 227 if (scheduled()) 228 mainEventQueue.deschedule(this); 229 230 UNSERIALIZE_SCALAR(_when); 231 UNSERIALIZE_SCALAR(_priority); 232 233 // need to see if original event was in a scheduled, unsquashed 234 // state, but don't want to restore those flags in the current 235 // object itself (since they aren't immediately true) 236 UNSERIALIZE_ENUM(_flags); 237 bool wasScheduled = (_flags & Scheduled) && !(_flags & Squashed); 238 _flags &= ~(Squashed | Scheduled); 239 240 if (wasScheduled) { 241 DPRINTF(Config, "rescheduling at %d\n", _when); 242 mainEventQueue.schedule(this, _when); 243 } 244} 245 246void 247EventQueue::serialize(ostream &os) 248{ 249 std::list<Event *> eventPtrs; 250 251 int numEvents = 0; 252 Event *nextBin = head; 253 while (nextBin) { 254 Event *nextInBin = nextBin; 255 256 while (nextInBin) { 257 if (nextInBin->getFlags(Event::AutoSerialize)) { 258 eventPtrs.push_back(nextInBin); 259 paramOut(os, csprintf("event%d", numEvents++), 260 nextInBin->name()); 261 } 262 nextInBin = nextInBin->nextInBin; 263 } 264 265 nextBin = nextBin->nextBin; 266 } 267 268 SERIALIZE_SCALAR(numEvents); 269 270 for (std::list<Event *>::iterator it = eventPtrs.begin(); 271 it != eventPtrs.end(); ++it) { 272 (*it)->nameOut(os); 273 (*it)->serialize(os); 274 } 275} 276 277void 278EventQueue::unserialize(Checkpoint *cp, const std::string §ion) 279{ 280 int numEvents; 281 UNSERIALIZE_SCALAR(numEvents); 282 283 std::string eventName; 284 for (int i = 0; i < numEvents; i++) { 285 // get the pointer value associated with the event 286 paramIn(cp, section, csprintf("event%d", i), eventName); 287 288 // create the event based on its pointer value 289 Serializable::create(cp, eventName); 290 } 291} 292 293void 294EventQueue::dump() const 295{ 296 cprintf("============================================================\n"); 297 cprintf("EventQueue Dump (cycle %d)\n", curTick); 298 cprintf("------------------------------------------------------------\n"); 299 300 if (empty()) 301 cprintf("<No Events>\n"); 302 else { 303 Event *nextBin = head; 304 while (nextBin) { 305 Event *nextInBin = nextBin; 306 while (nextInBin) { 307 nextInBin->dump(); 308 nextInBin = nextInBin->nextInBin; 309 } 310 311 nextBin = nextBin->nextBin; 312 } 313 } 314 315 cprintf("============================================================\n"); 316} 317 318bool 319EventQueue::debugVerify() const 320{ 321 m5::hash_map<long, bool> map; 322 323 Tick time = 0; 324 short priority = 0; 325 326 Event *nextBin = head; 327 while (nextBin) { 328 Event *nextInBin = nextBin; 329 while (nextInBin) { 330 if (nextInBin->when() < time) { 331 cprintf("time goes backwards!"); 332 nextInBin->dump(); 333 return false; 334 } else if (nextInBin->when() == time && 335 nextInBin->priority() < priority) { 336 cprintf("priority inverted!"); 337 nextInBin->dump(); 338 return false; 339 } 340 341 if (map[reinterpret_cast<long>(nextInBin)]) { 342 cprintf("Node already seen"); 343 nextInBin->dump(); 344 return false; 345 } 346 map[reinterpret_cast<long>(nextInBin)] = true; 347 348 time = nextInBin->when(); 349 priority = nextInBin->priority(); 350 351 nextInBin = nextInBin->nextInBin; 352 } 353 354 nextBin = nextBin->nextBin; 355 } 356 357 return true; 358} 359 360void 361dumpMainQueue() 362{ 363 mainEventQueue.dump(); 364} 365 366 367const char * 368Event::description() const 369{ 370 return "generic"; 371} 372 373void 374Event::trace(const char *action) 375{ 376 // This DPRINTF is unconditional because calls to this function 377 // are protected by an 'if (DTRACE(Event))' in the inlined Event 378 // methods. 379 // 380 // This is just a default implementation for derived classes where 381 // it's not worth doing anything special. If you want to put a 382 // more informative message in the trace, override this method on 383 // the particular subclass where you have the information that 384 // needs to be printed. 385 DPRINTFN("%s event %s @ %d\n", description(), action, when()); 386} 387 388void 389Event::dump() const 390{ 391 cprintf("Event %s (%s)\n", name(), description()); 392 cprintf("Flags: %#x\n", _flags); 393#ifdef EVENTQ_DEBUG 394 cprintf("Created: %d\n", whenCreated); 395#endif 396 if (scheduled()) { 397#ifdef EVENTQ_DEBUG 398 cprintf("Scheduled at %d\n", whenScheduled); 399#endif 400 cprintf("Scheduled for %d, priority %d\n", when(), _priority); 401 } else { 402 cprintf("Not Scheduled\n"); 403 } 404} 405