274 lines
8.5 KiB
C++
274 lines
8.5 KiB
C++
/*
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* Copyright (c) 2012,2015 ARM Limited
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* All rights reserved.
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*
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* The license below extends only to copyright in the software and shall
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* not be construed as granting a license to any other intellectual
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* property including but not limited to intellectual property relating
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* to a hardware implementation of the functionality of the software
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* licensed hereunder. You may use the software subject to the license
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* terms below provided that you ensure that this notice is replicated
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* unmodified and in its entirety in all distributions of the software,
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* modified or unmodified, in source code or in binary form.
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*
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* Copyright (c) 2006 The Regents of The University of Michigan
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* Authors: Ali Saidi
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* Andreas Hansson
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*/
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#include "mem/packet_queue.hh"
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#include "base/trace.hh"
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#include "debug/Drain.hh"
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#include "debug/PacketQueue.hh"
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using namespace std;
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PacketQueue::PacketQueue(EventManager& _em, const std::string& _label,
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bool disable_sanity_check)
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: em(_em), sendEvent(this), _disableSanityCheck(disable_sanity_check),
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label(_label), waitingOnRetry(false)
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{
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}
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PacketQueue::~PacketQueue()
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{
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}
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void
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PacketQueue::retry()
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{
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DPRINTF(PacketQueue, "Queue %s received retry\n", name());
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assert(waitingOnRetry);
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waitingOnRetry = false;
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sendDeferredPacket();
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}
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bool
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PacketQueue::hasAddr(Addr addr) const
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{
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// caller is responsible for ensuring that all packets have the
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// same alignment
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for (const auto& p : transmitList) {
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if (p.pkt->getAddr() == addr)
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return true;
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}
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return false;
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}
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bool
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PacketQueue::checkFunctional(PacketPtr pkt)
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{
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pkt->pushLabel(label);
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auto i = transmitList.begin();
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bool found = false;
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while (!found && i != transmitList.end()) {
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// If the buffered packet contains data, and it overlaps the
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// current packet, then update data
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found = pkt->checkFunctional(i->pkt);
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++i;
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}
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pkt->popLabel();
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return found;
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}
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void
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PacketQueue::schedSendTiming(PacketPtr pkt, Tick when, bool force_order)
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{
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DPRINTF(PacketQueue, "%s for %s address %x size %d when %lu ord: %i\n",
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__func__, pkt->cmdString(), pkt->getAddr(), pkt->getSize(), when,
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force_order);
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// we can still send a packet before the end of this tick
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assert(when >= curTick());
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// express snoops should never be queued
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assert(!pkt->isExpressSnoop());
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// add a very basic sanity check on the port to ensure the
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// invisible buffer is not growing beyond reasonable limits
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if (!_disableSanityCheck && transmitList.size() > 100) {
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panic("Packet queue %s has grown beyond 100 packets\n",
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name());
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}
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// nothing on the list
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if (transmitList.empty()) {
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transmitList.emplace_front(when, pkt);
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schedSendEvent(when);
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return;
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}
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// we should either have an outstanding retry, or a send event
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// scheduled, but there is an unfortunate corner case where the
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// x86 page-table walker and timing CPU send out a new request as
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// part of the receiving of a response (called by
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// PacketQueue::sendDeferredPacket), in which we end up calling
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// ourselves again before we had a chance to update waitingOnRetry
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// assert(waitingOnRetry || sendEvent.scheduled());
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// this belongs in the middle somewhere, so search from the end to
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// order by tick; however, if force_order is set, also make sure
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// not to re-order in front of some existing packet with the same
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// address
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auto i = transmitList.end();
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--i;
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while (i != transmitList.begin() && when < i->tick &&
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!(force_order && i->pkt->getAddr() == pkt->getAddr()))
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--i;
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// emplace inserts the element before the position pointed to by
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// the iterator, so advance it one step
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transmitList.emplace(++i, when, pkt);
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}
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void
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PacketQueue::schedSendEvent(Tick when)
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{
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// if we are waiting on a retry just hold off
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if (waitingOnRetry) {
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DPRINTF(PacketQueue, "Not scheduling send as waiting for retry\n");
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assert(!sendEvent.scheduled());
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return;
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}
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if (when != MaxTick) {
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// we cannot go back in time, and to be consistent we stick to
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// one tick in the future
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when = std::max(when, curTick() + 1);
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// @todo Revisit the +1
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if (!sendEvent.scheduled()) {
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em.schedule(&sendEvent, when);
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} else if (when < sendEvent.when()) {
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// if the new time is earlier than when the event
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// currently is scheduled, move it forward
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em.reschedule(&sendEvent, when);
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}
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} else {
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// we get a MaxTick when there is no more to send, so if we're
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// draining, we may be done at this point
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if (drainState() == DrainState::Draining &&
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transmitList.empty() && !sendEvent.scheduled()) {
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DPRINTF(Drain, "PacketQueue done draining,"
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"processing drain event\n");
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signalDrainDone();
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}
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}
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}
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void
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PacketQueue::sendDeferredPacket()
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{
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// sanity checks
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assert(!waitingOnRetry);
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assert(deferredPacketReady());
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DeferredPacket dp = transmitList.front();
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// take the packet of the list before sending it, as sending of
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// the packet in some cases causes a new packet to be enqueued
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// (most notaly when responding to the timing CPU, leading to a
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// new request hitting in the L1 icache, leading to a new
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// response)
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transmitList.pop_front();
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// use the appropriate implementation of sendTiming based on the
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// type of queue
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waitingOnRetry = !sendTiming(dp.pkt);
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// if we succeeded and are not waiting for a retry, schedule the
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// next send
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if (!waitingOnRetry) {
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schedSendEvent(deferredPacketReadyTime());
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} else {
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// put the packet back at the front of the list
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transmitList.emplace_front(dp);
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}
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}
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void
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PacketQueue::processSendEvent()
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{
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assert(!waitingOnRetry);
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sendDeferredPacket();
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}
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DrainState
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PacketQueue::drain()
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{
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if (transmitList.empty()) {
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return DrainState::Drained;
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} else {
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DPRINTF(Drain, "PacketQueue not drained\n");
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return DrainState::Draining;
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}
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}
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ReqPacketQueue::ReqPacketQueue(EventManager& _em, MasterPort& _masterPort,
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const std::string _label)
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: PacketQueue(_em, _label), masterPort(_masterPort)
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{
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}
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bool
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ReqPacketQueue::sendTiming(PacketPtr pkt)
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{
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return masterPort.sendTimingReq(pkt);
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}
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SnoopRespPacketQueue::SnoopRespPacketQueue(EventManager& _em,
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MasterPort& _masterPort,
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const std::string _label)
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: PacketQueue(_em, _label), masterPort(_masterPort)
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{
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}
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bool
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SnoopRespPacketQueue::sendTiming(PacketPtr pkt)
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{
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return masterPort.sendTimingSnoopResp(pkt);
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}
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RespPacketQueue::RespPacketQueue(EventManager& _em, SlavePort& _slavePort,
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const std::string _label)
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: PacketQueue(_em, _label), slavePort(_slavePort)
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{
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}
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bool
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RespPacketQueue::sendTiming(PacketPtr pkt)
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{
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return slavePort.sendTimingResp(pkt);
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}
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