packet_queue.cc revision 10322:7f4059e4f2d5
1/* 2 * Copyright (c) 2012 ARM Limited 3 * All rights reserved. 4 * 5 * The license below extends only to copyright in the software and shall 6 * not be construed as granting a license to any other intellectual 7 * property including but not limited to intellectual property relating 8 * to a hardware implementation of the functionality of the software 9 * licensed hereunder. You may use the software subject to the license 10 * terms below provided that you ensure that this notice is replicated 11 * unmodified and in its entirety in all distributions of the software, 12 * modified or unmodified, in source code or in binary form. 13 * 14 * Copyright (c) 2006 The Regents of The University of Michigan 15 * All rights reserved. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions are 19 * met: redistributions of source code must retain the above copyright 20 * notice, this list of conditions and the following disclaimer; 21 * redistributions in binary form must reproduce the above copyright 22 * notice, this list of conditions and the following disclaimer in the 23 * documentation and/or other materials provided with the distribution; 24 * neither the name of the copyright holders nor the names of its 25 * contributors may be used to endorse or promote products derived from 26 * this software without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 39 * 40 * Authors: Ali Saidi 41 * Andreas Hansson 42 */ 43 44#include "base/trace.hh" 45#include "debug/Drain.hh" 46#include "debug/PacketQueue.hh" 47#include "mem/packet_queue.hh" 48 49using namespace std; 50 51PacketQueue::PacketQueue(EventManager& _em, const std::string& _label) 52 : em(_em), sendEvent(this), drainManager(NULL), label(_label), 53 waitingOnRetry(false) 54{ 55} 56 57PacketQueue::~PacketQueue() 58{ 59} 60 61void 62PacketQueue::retry() 63{ 64 DPRINTF(PacketQueue, "Queue %s received retry\n", name()); 65 assert(waitingOnRetry); 66 sendDeferredPacket(); 67} 68 69bool 70PacketQueue::checkFunctional(PacketPtr pkt) 71{ 72 pkt->pushLabel(label); 73 74 auto i = transmitList.begin(); 75 bool found = false; 76 77 while (!found && i != transmitList.end()) { 78 // If the buffered packet contains data, and it overlaps the 79 // current packet, then update data 80 found = pkt->checkFunctional(i->pkt); 81 ++i; 82 } 83 84 pkt->popLabel(); 85 86 return found; 87} 88 89void 90PacketQueue::schedSendEvent(Tick when) 91{ 92 // if we are waiting on a retry, do not schedule a send event, and 93 // instead rely on retry being called 94 if (waitingOnRetry) { 95 assert(!sendEvent.scheduled()); 96 return; 97 } 98 99 if (!sendEvent.scheduled()) { 100 em.schedule(&sendEvent, when); 101 } else if (sendEvent.when() > when) { 102 em.reschedule(&sendEvent, when); 103 } 104} 105 106void 107PacketQueue::schedSendTiming(PacketPtr pkt, Tick when, bool send_as_snoop) 108{ 109 DPRINTF(PacketQueue, "%s for %s address %x size %d\n", __func__, 110 pkt->cmdString(), pkt->getAddr(), pkt->getSize()); 111 // we can still send a packet before the end of this tick 112 assert(when >= curTick()); 113 114 // express snoops should never be queued 115 assert(!pkt->isExpressSnoop()); 116 117 // add a very basic sanity check on the port to ensure the 118 // invisible buffer is not growing beyond reasonable limits 119 if (transmitList.size() > 100) { 120 panic("Packet queue %s has grown beyond 100 packets\n", 121 name()); 122 } 123 124 // nothing on the list, or earlier than current front element, 125 // schedule an event 126 if (transmitList.empty() || when < transmitList.front().tick) { 127 // note that currently we ignore a potentially outstanding retry 128 // and could in theory put a new packet at the head of the 129 // transmit list before retrying the existing packet 130 transmitList.push_front(DeferredPacket(when, pkt, send_as_snoop)); 131 schedSendEvent(when); 132 return; 133 } 134 135 // list is non-empty and this belongs at the end 136 if (when >= transmitList.back().tick) { 137 transmitList.push_back(DeferredPacket(when, pkt, send_as_snoop)); 138 return; 139 } 140 141 // this belongs in the middle somewhere, insertion sort 142 auto i = transmitList.begin(); 143 ++i; // already checked for insertion at front 144 while (i != transmitList.end() && when >= i->tick) 145 ++i; 146 transmitList.insert(i, DeferredPacket(when, pkt, send_as_snoop)); 147} 148 149void PacketQueue::trySendTiming() 150{ 151 assert(deferredPacketReady()); 152 153 DeferredPacket dp = transmitList.front(); 154 155 // use the appropriate implementation of sendTiming based on the 156 // type of port associated with the queue, and whether the packet 157 // is to be sent as a snoop or not 158 waitingOnRetry = !sendTiming(dp.pkt, dp.sendAsSnoop); 159 160 if (!waitingOnRetry) { 161 // take the packet off the list 162 transmitList.pop_front(); 163 } 164} 165 166void 167PacketQueue::scheduleSend(Tick time) 168{ 169 // the next ready time is either determined by the next deferred packet, 170 // or in the cache through the MSHR ready time 171 Tick nextReady = std::min(deferredPacketReadyTime(), time); 172 173 if (nextReady != MaxTick) { 174 // if the sendTiming caused someone else to call our 175 // recvTiming we could already have an event scheduled, check 176 if (!sendEvent.scheduled()) 177 em.schedule(&sendEvent, std::max(nextReady, curTick() + 1)); 178 } else { 179 // no more to send, so if we're draining, we may be done 180 if (drainManager && transmitList.empty() && !sendEvent.scheduled()) { 181 DPRINTF(Drain, "PacketQueue done draining," 182 "processing drain event\n"); 183 drainManager->signalDrainDone(); 184 drainManager = NULL; 185 } 186 } 187} 188 189void 190PacketQueue::sendDeferredPacket() 191{ 192 // try to send what is on the list, this will set waitingOnRetry 193 // accordingly 194 trySendTiming(); 195 196 // if we succeeded and are not waiting for a retry, schedule the 197 // next send 198 if (!waitingOnRetry) { 199 scheduleSend(); 200 } 201} 202 203void 204PacketQueue::processSendEvent() 205{ 206 assert(!waitingOnRetry); 207 sendDeferredPacket(); 208} 209 210unsigned int 211PacketQueue::drain(DrainManager *dm) 212{ 213 if (transmitList.empty()) 214 return 0; 215 DPRINTF(Drain, "PacketQueue not drained\n"); 216 drainManager = dm; 217 return 1; 218} 219 220MasterPacketQueue::MasterPacketQueue(EventManager& _em, MasterPort& _masterPort, 221 const std::string _label) 222 : PacketQueue(_em, _label), masterPort(_masterPort) 223{ 224} 225 226bool 227MasterPacketQueue::sendTiming(PacketPtr pkt, bool send_as_snoop) 228{ 229 // attempt to send the packet and return according to the outcome 230 if (!send_as_snoop) 231 return masterPort.sendTimingReq(pkt); 232 else 233 return masterPort.sendTimingSnoopResp(pkt); 234} 235 236SlavePacketQueue::SlavePacketQueue(EventManager& _em, SlavePort& _slavePort, 237 const std::string _label) 238 : PacketQueue(_em, _label), slavePort(_slavePort) 239{ 240} 241 242bool 243SlavePacketQueue::sendTiming(PacketPtr pkt, bool send_as_snoop) 244{ 245 // we should never have queued snoop requests 246 assert(!send_as_snoop); 247 return slavePort.sendTimingResp(pkt); 248} 249