eventq.cc revision 5695
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 * 61Event::insertBefore(Event *event, Event *curr) 62{ 63 // Either way, event will be the top 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 event->nextInBin = NULL; 70 } else { 71 // Since we're on the correct list, we need to point to the next list 72 event->nextBin = curr->nextBin; // curr->nextBin can now become stale 73 74 // Insert event at the top of the stack 75 event->nextInBin = curr; 76 } 77 78 return event; 79} 80 81void 82EventQueue::insert(Event *event) 83{ 84 // Deal with the head case 85 if (!head || *event <= *head) { 86 head = Event::insertBefore(event, head); 87 return; 88 } 89 90 // Figure out either which 'in bin' list we are on, or where a new list 91 // needs to be inserted 92 Event *prev = head; 93 Event *curr = head->nextBin; 94 while (curr && *curr < *event) { 95 prev = curr; 96 curr = curr->nextBin; 97 } 98 99 // Note: this operation may render all nextBin pointers on the 100 // prev 'in bin' list stale (except for the top one) 101 prev->nextBin = Event::insertBefore(event, curr); 102} 103 104Event * 105Event::removeItem(Event *event, Event *top) 106{ 107 Event *curr = top; 108 Event *next = top->nextInBin; 109 110 // if we removed the top item, we need to handle things specially 111 // and just remove the top item, fixing up the next bin pointer of 112 // the new top item 113 if (event == top) { 114 if (!next) 115 return top->nextBin; 116 next->nextBin = top->nextBin; 117 return next; 118 } 119 120 // Since we already checked the current element, we're going to 121 // keep checking event against the next element. 122 while (event != next) { 123 if (!next) 124 panic("event not found!"); 125 126 curr = next; 127 next = next->nextInBin; 128 } 129 130 // remove next from the 'in bin' list since it's what we're looking for 131 curr->nextInBin = next->nextInBin; 132 return top; 133} 134 135void 136EventQueue::remove(Event *event) 137{ 138 if (head == NULL) 139 panic("event not found!"); 140 141 // deal with an event on the head's 'in bin' list (event has the same 142 // time as the head) 143 if (*head == *event) { 144 head = Event::removeItem(event, head); 145 return; 146 } 147 148 // Find the 'in bin' list that this event belongs on 149 Event *prev = head; 150 Event *curr = head->nextBin; 151 while (curr && *curr < *event) { 152 prev = curr; 153 curr = curr->nextBin; 154 } 155 156 if (!curr || *curr != *event) 157 panic("event not found!"); 158 159 // curr points to the top item of the the correct 'in bin' list, when 160 // we remove an item, it returns the new top item (which may be 161 // unchanged) 162 prev->nextBin = Event::removeItem(event, curr); 163} 164 165Event * 166EventQueue::serviceOne() 167{ 168 Event *event = head; 169 Event *next = head->nextInBin; 170 event->clearFlags(Event::Scheduled); 171 172 if (next) { 173 // update the next bin pointer since it could be stale 174 next->nextBin = head->nextBin; 175 176 // pop the stack 177 head = next; 178 } else { 179 // this was the only element on the 'in bin' list, so get rid of 180 // the 'in bin' list and point to the next bin list 181 head = head->nextBin; 182 } 183 184 // handle action 185 if (!event->squashed()) { 186 event->process(); 187 if (event->isExitEvent()) { 188 assert(!event->getFlags(Event::AutoDelete)); // would be silly 189 return event; 190 } 191 } else { 192 event->clearFlags(Event::Squashed); 193 } 194 195 if (event->getFlags(Event::AutoDelete) && !event->scheduled()) 196 delete event; 197 198 return NULL; 199} 200 201void 202Event::serialize(std::ostream &os) 203{ 204 SERIALIZE_SCALAR(_when); 205 SERIALIZE_SCALAR(_priority); 206 SERIALIZE_ENUM(_flags); 207} 208 209void 210Event::unserialize(Checkpoint *cp, const string §ion) 211{ 212 if (scheduled()) 213 mainEventQueue.deschedule(this); 214 215 UNSERIALIZE_SCALAR(_when); 216 UNSERIALIZE_SCALAR(_priority); 217 218 // need to see if original event was in a scheduled, unsquashed 219 // state, but don't want to restore those flags in the current 220 // object itself (since they aren't immediately true) 221 UNSERIALIZE_ENUM(_flags); 222 bool wasScheduled = (_flags & Scheduled) && !(_flags & Squashed); 223 _flags &= ~(Squashed | Scheduled); 224 225 if (wasScheduled) { 226 DPRINTF(Config, "rescheduling at %d\n", _when); 227 mainEventQueue.schedule(this, _when); 228 } 229} 230 231void 232EventQueue::serialize(ostream &os) 233{ 234 std::list<Event *> eventPtrs; 235 236 int numEvents = 0; 237 Event *nextBin = head; 238 while (nextBin) { 239 Event *nextInBin = nextBin; 240 241 while (nextInBin) { 242 if (nextInBin->getFlags(Event::AutoSerialize)) { 243 eventPtrs.push_back(nextInBin); 244 paramOut(os, csprintf("event%d", numEvents++), 245 nextInBin->name()); 246 } 247 nextInBin = nextInBin->nextInBin; 248 } 249 250 nextBin = nextBin->nextBin; 251 } 252 253 SERIALIZE_SCALAR(numEvents); 254 255 for (std::list<Event *>::iterator it = eventPtrs.begin(); 256 it != eventPtrs.end(); ++it) { 257 (*it)->nameOut(os); 258 (*it)->serialize(os); 259 } 260} 261 262void 263EventQueue::unserialize(Checkpoint *cp, const std::string §ion) 264{ 265 int numEvents; 266 UNSERIALIZE_SCALAR(numEvents); 267 268 std::string eventName; 269 for (int i = 0; i < numEvents; i++) { 270 // get the pointer value associated with the event 271 paramIn(cp, section, csprintf("event%d", i), eventName); 272 273 // create the event based on its pointer value 274 Serializable::create(cp, eventName); 275 } 276} 277 278void 279EventQueue::dump() const 280{ 281 cprintf("============================================================\n"); 282 cprintf("EventQueue Dump (cycle %d)\n", curTick); 283 cprintf("------------------------------------------------------------\n"); 284 285 if (empty()) 286 cprintf("<No Events>\n"); 287 else { 288 Event *nextBin = head; 289 while (nextBin) { 290 Event *nextInBin = nextBin; 291 while (nextInBin) { 292 nextInBin->dump(); 293 nextInBin = nextInBin->nextInBin; 294 } 295 296 nextBin = nextBin->nextBin; 297 } 298 } 299 300 cprintf("============================================================\n"); 301} 302 303bool 304EventQueue::debugVerify() const 305{ 306 m5::hash_map<long, bool> map; 307 308 Tick time = 0; 309 short priority = 0; 310 311 Event *nextBin = head; 312 while (nextBin) { 313 Event *nextInBin = nextBin; 314 while (nextInBin) { 315 if (nextInBin->when() < time) { 316 cprintf("time goes backwards!"); 317 nextInBin->dump(); 318 return false; 319 } else if (nextInBin->when() == time && 320 nextInBin->priority() < priority) { 321 cprintf("priority inverted!"); 322 nextInBin->dump(); 323 return false; 324 } 325 326 if (map[reinterpret_cast<long>(nextInBin)]) { 327 cprintf("Node already seen"); 328 nextInBin->dump(); 329 return false; 330 } 331 map[reinterpret_cast<long>(nextInBin)] = true; 332 333 time = nextInBin->when(); 334 priority = nextInBin->priority(); 335 336 nextInBin = nextInBin->nextInBin; 337 } 338 339 nextBin = nextBin->nextBin; 340 } 341 342 return true; 343} 344 345void 346dumpMainQueue() 347{ 348 mainEventQueue.dump(); 349} 350 351 352const char * 353Event::description() const 354{ 355 return "generic"; 356} 357 358void 359Event::trace(const char *action) 360{ 361 // This DPRINTF is unconditional because calls to this function 362 // are protected by an 'if (DTRACE(Event))' in the inlined Event 363 // methods. 364 // 365 // This is just a default implementation for derived classes where 366 // it's not worth doing anything special. If you want to put a 367 // more informative message in the trace, override this method on 368 // the particular subclass where you have the information that 369 // needs to be printed. 370 DPRINTFN("%s event %s @ %d\n", description(), action, when()); 371} 372 373void 374Event::dump() const 375{ 376 cprintf("Event %s (%s)\n", name(), description()); 377 cprintf("Flags: %#x\n", _flags); 378#ifdef EVENTQ_DEBUG 379 cprintf("Created: %d\n", whenCreated); 380#endif 381 if (scheduled()) { 382#ifdef EVENTQ_DEBUG 383 cprintf("Scheduled at %d\n", whenScheduled); 384#endif 385 cprintf("Scheduled for %d, priority %d\n", when(), _priority); 386 } else { 387 cprintf("Not Scheduled\n"); 388 } 389} 390