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 DeferredPacketIterator i = transmitList.begin(); 75 DeferredPacketIterator end = transmitList.end(); 76 bool found = false; 77 78 while (!found && i != end) { 79 // If the buffered packet contains data, and it overlaps the 80 // current packet, then update data 81 found = pkt->checkFunctional(i->pkt); 82 ++i; 83 } 84 85 pkt->popLabel(); 86 87 return found; 88} 89 90void 91PacketQueue::schedSendEvent(Tick when) 92{ 93 // if we are waiting on a retry, do not schedule a send event, and 94 // instead rely on retry being called 95 if (waitingOnRetry) { 96 assert(!sendEvent.scheduled()); 97 return; 98 } 99 100 if (!sendEvent.scheduled()) { 101 em.schedule(&sendEvent, when); 102 } else if (sendEvent.when() > when) { 103 em.reschedule(&sendEvent, when); 104 } 105} 106 107void 108PacketQueue::schedSendTiming(PacketPtr pkt, Tick when, bool send_as_snoop) 109{ 110 // we can still send a packet before the end of this tick 111 assert(when >= curTick()); 112 113 // express snoops should never be queued 114 assert(!pkt->isExpressSnoop()); 115
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116 // add a very basic sanity check on the port to ensure the 117 // invisible buffer is not growing beyond reasonable limits 118 if (transmitList.size() > 100) { 119 panic("Packet queue %s has grown beyond 100 packets\n", 120 name()); 121 } 122 |
123 // nothing on the list, or earlier than current front element, 124 // schedule an event 125 if (transmitList.empty() || when < transmitList.front().tick) { 126 // note that currently we ignore a potentially outstanding retry 127 // and could in theory put a new packet at the head of the 128 // transmit list before retrying the existing packet 129 transmitList.push_front(DeferredPacket(when, pkt, send_as_snoop)); 130 schedSendEvent(when); 131 return; 132 } 133 134 // list is non-empty and this belongs at the end 135 if (when >= transmitList.back().tick) { 136 transmitList.push_back(DeferredPacket(when, pkt, send_as_snoop)); 137 return; 138 } 139 140 // this belongs in the middle somewhere, insertion sort 141 DeferredPacketIterator i = transmitList.begin(); 142 ++i; // already checked for insertion at front 143 while (i != transmitList.end() && when >= i->tick) 144 ++i; 145 transmitList.insert(i, DeferredPacket(when, pkt, send_as_snoop)); 146} 147 148void PacketQueue::trySendTiming() 149{ 150 assert(deferredPacketReady()); 151 152 // take the next packet off the list here, as we might return to 153 // ourselves through the sendTiming call below 154 DeferredPacket dp = transmitList.front(); 155 transmitList.pop_front(); 156 157 // use the appropriate implementation of sendTiming based on the 158 // type of port associated with the queue, and whether the packet 159 // is to be sent as a snoop or not 160 waitingOnRetry = !sendTiming(dp.pkt, dp.sendAsSnoop); 161 162 if (waitingOnRetry) { 163 // put the packet back at the front of the list (packet should 164 // not have changed since it wasn't accepted) 165 assert(!sendEvent.scheduled()); 166 transmitList.push_front(dp); 167 } 168} 169 170void 171PacketQueue::scheduleSend(Tick time) 172{ 173 // the next ready time is either determined by the next deferred packet, 174 // or in the cache through the MSHR ready time 175 Tick nextReady = std::min(deferredPacketReadyTime(), time); 176 177 if (nextReady != MaxTick) { 178 // if the sendTiming caused someone else to call our 179 // recvTiming we could already have an event scheduled, check 180 if (!sendEvent.scheduled()) 181 em.schedule(&sendEvent, std::max(nextReady, curTick() + 1)); 182 } else { 183 // no more to send, so if we're draining, we may be done 184 if (drainManager && transmitList.empty() && !sendEvent.scheduled()) { 185 DPRINTF(Drain, "PacketQueue done draining," 186 "processing drain event\n"); 187 drainManager->signalDrainDone(); 188 drainManager = NULL; 189 } 190 } 191} 192 193void 194PacketQueue::sendDeferredPacket() 195{ 196 // try to send what is on the list, this will set waitingOnRetry 197 // accordingly 198 trySendTiming(); 199 200 // if we succeeded and are not waiting for a retry, schedule the 201 // next send 202 if (!waitingOnRetry) { 203 scheduleSend(); 204 } 205} 206 207void 208PacketQueue::processSendEvent() 209{ 210 assert(!waitingOnRetry); 211 sendDeferredPacket(); 212} 213 214unsigned int 215PacketQueue::drain(DrainManager *dm) 216{ 217 if (transmitList.empty() && !sendEvent.scheduled()) 218 return 0; 219 DPRINTF(Drain, "PacketQueue not drained\n"); 220 drainManager = dm; 221 return 1; 222} 223 224MasterPacketQueue::MasterPacketQueue(EventManager& _em, MasterPort& _masterPort, 225 const std::string _label) 226 : PacketQueue(_em, _label), masterPort(_masterPort) 227{ 228} 229 230bool 231MasterPacketQueue::sendTiming(PacketPtr pkt, bool send_as_snoop) 232{ 233 // attempt to send the packet and return according to the outcome 234 if (!send_as_snoop) 235 return masterPort.sendTimingReq(pkt); 236 else 237 return masterPort.sendTimingSnoopResp(pkt); 238} 239 240SlavePacketQueue::SlavePacketQueue(EventManager& _em, SlavePort& _slavePort, 241 const std::string _label) 242 : PacketQueue(_em, _label), slavePort(_slavePort) 243{ 244} 245 246bool 247SlavePacketQueue::sendTiming(PacketPtr pkt, bool send_as_snoop) 248{ 249 // we should never have queued snoop requests 250 assert(!send_as_snoop); 251 return slavePort.sendTimingResp(pkt); 252}
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