global_event.cc revision 9983
19983Sstever@gmail.com/* 29983Sstever@gmail.com * Copyright (c) 2011-2013 Advanced Micro Devices, Inc. 39983Sstever@gmail.com * Copyright (c) 2013 Mark D. Hill and David A. Wood 49983Sstever@gmail.com * All rights reserved. 59983Sstever@gmail.com * 69983Sstever@gmail.com * Redistribution and use in source and binary forms, with or without 79983Sstever@gmail.com * modification, are permitted provided that the following conditions are 89983Sstever@gmail.com * met: redistributions of source code must retain the above copyright 99983Sstever@gmail.com * notice, this list of conditions and the following disclaimer; 109983Sstever@gmail.com * redistributions in binary form must reproduce the above copyright 119983Sstever@gmail.com * notice, this list of conditions and the following disclaimer in the 129983Sstever@gmail.com * documentation and/or other materials provided with the distribution; 139983Sstever@gmail.com * neither the name of the copyright holders nor the names of its 149983Sstever@gmail.com * contributors may be used to endorse or promote products derived from 159983Sstever@gmail.com * this software without specific prior written permission. 169983Sstever@gmail.com * 179983Sstever@gmail.com * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 189983Sstever@gmail.com * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 199983Sstever@gmail.com * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 209983Sstever@gmail.com * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 219983Sstever@gmail.com * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 229983Sstever@gmail.com * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 239983Sstever@gmail.com * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 249983Sstever@gmail.com * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 259983Sstever@gmail.com * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 269983Sstever@gmail.com * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 279983Sstever@gmail.com * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 289983Sstever@gmail.com * 299983Sstever@gmail.com * Authors: Steve Reinhardt 309983Sstever@gmail.com */ 319983Sstever@gmail.com 329983Sstever@gmail.com#include "sim/global_event.hh" 339983Sstever@gmail.com 349983Sstever@gmail.comstd::mutex BaseGlobalEvent::globalQMutex; 359983Sstever@gmail.com 369983Sstever@gmail.comBaseGlobalEvent::BaseGlobalEvent(Priority p, Flags f) 379983Sstever@gmail.com{ 389983Sstever@gmail.com barrierEvent.resize(numMainEventQueues); 399983Sstever@gmail.com barrier = new Barrier(numMainEventQueues); 409983Sstever@gmail.com} 419983Sstever@gmail.com 429983Sstever@gmail.com 439983Sstever@gmail.comBaseGlobalEvent::~BaseGlobalEvent() 449983Sstever@gmail.com{ 459983Sstever@gmail.com // see GlobalEvent::BarrierEvent::~BarrierEvent() comments 469983Sstever@gmail.com if (barrierEvent[0] != NULL) { 479983Sstever@gmail.com for (int i = 0; i < numMainEventQueues; ++i) 489983Sstever@gmail.com delete barrierEvent[i]; 499983Sstever@gmail.com } 509983Sstever@gmail.com} 519983Sstever@gmail.com 529983Sstever@gmail.com 539983Sstever@gmail.comvoid BaseGlobalEvent::schedule(Tick when) 549983Sstever@gmail.com{ 559983Sstever@gmail.com // This function is scheduling a global event, which actually is a 569983Sstever@gmail.com // set of local events, one event on each eventq. Global events need 579983Sstever@gmail.com // to have a total order. A thread cannot start executing events that 589983Sstever@gmail.com // follow a global event till all other threads have executed that global 599983Sstever@gmail.com // event as well. If global events were not in a total order, a deadlock 609983Sstever@gmail.com // would occur for there will be two threads who would be waiting for 619983Sstever@gmail.com // each other to execute the global events they themselves have executed. 629983Sstever@gmail.com // 639983Sstever@gmail.com // To ensure this total order, we do two things. 649983Sstever@gmail.com // First, before scheduling any global event, a thread needs to acquire 659983Sstever@gmail.com // the lock globalQMutex. This ensures that only one thread can schedule 669983Sstever@gmail.com // global events at any given time. 679983Sstever@gmail.com // Second, the local events corresponding to a global event are always 689983Sstever@gmail.com // first inserted in to the asyncq, irrespective of whether or not the 699983Sstever@gmail.com // thread scheduling the event owns the eventq on which the event is 709983Sstever@gmail.com // being scheduled. Thus global events have the same order in the asyncq 719983Sstever@gmail.com // of each thread. When they are inserted in the actual eventq, the 729983Sstever@gmail.com // comparators in the Event class ensure that the total order is 739983Sstever@gmail.com // maintained. 749983Sstever@gmail.com 759983Sstever@gmail.com globalQMutex.lock(); 769983Sstever@gmail.com 779983Sstever@gmail.com for (int i = 0; i < numMainEventQueues; ++i) { 789983Sstever@gmail.com mainEventQueue[i]->schedule(barrierEvent[i], when, true); 799983Sstever@gmail.com } 809983Sstever@gmail.com 819983Sstever@gmail.com globalQMutex.unlock(); 829983Sstever@gmail.com} 839983Sstever@gmail.com 849983Sstever@gmail.comvoid BaseGlobalEvent::deschedule() 859983Sstever@gmail.com{ 869983Sstever@gmail.com EventQueue *q = curEventQueue(); 879983Sstever@gmail.com for (uint32_t i = 0; i < numMainEventQueues; ++i) { 889983Sstever@gmail.com if (barrierEvent[i]->scheduled()) { 899983Sstever@gmail.com curEventQueue(mainEventQueue[i]); 909983Sstever@gmail.com mainEventQueue[i]->deschedule(barrierEvent[i]); 919983Sstever@gmail.com } 929983Sstever@gmail.com } 939983Sstever@gmail.com 949983Sstever@gmail.com curEventQueue(q); 959983Sstever@gmail.com} 969983Sstever@gmail.com 979983Sstever@gmail.comvoid BaseGlobalEvent::reschedule(Tick when) 989983Sstever@gmail.com{ 999983Sstever@gmail.com // Read the comment in the schedule() function above. 1009983Sstever@gmail.com globalQMutex.lock(); 1019983Sstever@gmail.com 1029983Sstever@gmail.com for (uint32_t i = 0; i < numMainEventQueues; ++i) { 1039983Sstever@gmail.com if (barrierEvent[i]->scheduled()) 1049983Sstever@gmail.com mainEventQueue[i]->reschedule(barrierEvent[i], when); 1059983Sstever@gmail.com else 1069983Sstever@gmail.com mainEventQueue[i]->schedule(barrierEvent[i], when, true); 1079983Sstever@gmail.com } 1089983Sstever@gmail.com 1099983Sstever@gmail.com globalQMutex.unlock(); 1109983Sstever@gmail.com} 1119983Sstever@gmail.com 1129983Sstever@gmail.comBaseGlobalEvent::BarrierEvent::~BarrierEvent() 1139983Sstever@gmail.com{ 1149983Sstever@gmail.com // if AutoDelete is set, local events will get deleted in event 1159983Sstever@gmail.com // loop, but we need to delete GlobalEvent object too... so let 1169983Sstever@gmail.com // the local event in slot 0 do it 1179983Sstever@gmail.com if (isFlagSet(AutoDelete) && _globalEvent->barrierEvent[0] == this) { 1189983Sstever@gmail.com // set backpointer to NULL so that global event knows not to 1199983Sstever@gmail.com // turn around and recursively delete local events 1209983Sstever@gmail.com _globalEvent->barrierEvent[0] = NULL; 1219983Sstever@gmail.com delete _globalEvent; 1229983Sstever@gmail.com } 1239983Sstever@gmail.com} 1249983Sstever@gmail.com 1259983Sstever@gmail.com 1269983Sstever@gmail.comvoid 1279983Sstever@gmail.comGlobalEvent::BarrierEvent::process() 1289983Sstever@gmail.com{ 1299983Sstever@gmail.com // wait for all queues to arrive at barrier, then process event 1309983Sstever@gmail.com if (globalBarrier()) { 1319983Sstever@gmail.com _globalEvent->process(); 1329983Sstever@gmail.com } 1339983Sstever@gmail.com 1349983Sstever@gmail.com // second barrier to force all queues to wait for event processing 1359983Sstever@gmail.com // to finish before continuing 1369983Sstever@gmail.com globalBarrier(); 1379983Sstever@gmail.com} 1389983Sstever@gmail.com 1399983Sstever@gmail.com 1409983Sstever@gmail.comvoid 1419983Sstever@gmail.comGlobalSyncEvent::BarrierEvent::process() 1429983Sstever@gmail.com{ 1439983Sstever@gmail.com // wait for all queues to arrive at barrier, then process event 1449983Sstever@gmail.com if (globalBarrier()) { 1459983Sstever@gmail.com _globalEvent->process(); 1469983Sstever@gmail.com } 1479983Sstever@gmail.com 1489983Sstever@gmail.com // second barrier to force all queues to wait for event processing 1499983Sstever@gmail.com // to finish before continuing 1509983Sstever@gmail.com globalBarrier(); 1519983Sstever@gmail.com curEventQueue()->handleAsyncInsertions(); 1529983Sstever@gmail.com} 1539983Sstever@gmail.com 1549983Sstever@gmail.comvoid 1559983Sstever@gmail.comGlobalSyncEvent::process() 1569983Sstever@gmail.com{ 1579983Sstever@gmail.com if (repeat) { 1589983Sstever@gmail.com schedule(curTick() + repeat); 1599983Sstever@gmail.com } 1609983Sstever@gmail.com} 1619983Sstever@gmail.com 1629983Sstever@gmail.comconst char * 1639983Sstever@gmail.comGlobalSyncEvent::description() const 1649983Sstever@gmail.com{ 1659983Sstever@gmail.com return "GlobalSyncEvent"; 1669983Sstever@gmail.com} 167