packet_queue.cc revision 10423:cc7f3988c5a9
111348Sandreas.sandberg@arm.com/*
211470Sandreas.sandberg@arm.com * Copyright (c) 2012 ARM Limited
311348Sandreas.sandberg@arm.com * All rights reserved.
411348Sandreas.sandberg@arm.com *
511348Sandreas.sandberg@arm.com * The license below extends only to copyright in the software and shall
611348Sandreas.sandberg@arm.com * not be construed as granting a license to any other intellectual
711348Sandreas.sandberg@arm.com * property including but not limited to intellectual property relating
811348Sandreas.sandberg@arm.com * to a hardware implementation of the functionality of the software
911348Sandreas.sandberg@arm.com * licensed hereunder.  You may use the software subject to the license
1011348Sandreas.sandberg@arm.com * terms below provided that you ensure that this notice is replicated
1111348Sandreas.sandberg@arm.com * unmodified and in its entirety in all distributions of the software,
1211348Sandreas.sandberg@arm.com * modified or unmodified, in source code or in binary form.
1311348Sandreas.sandberg@arm.com *
1411348Sandreas.sandberg@arm.com * Copyright (c) 2006 The Regents of The University of Michigan
1511348Sandreas.sandberg@arm.com * All rights reserved.
1611348Sandreas.sandberg@arm.com *
1711348Sandreas.sandberg@arm.com * Redistribution and use in source and binary forms, with or without
1811348Sandreas.sandberg@arm.com * modification, are permitted provided that the following conditions are
1911348Sandreas.sandberg@arm.com * met: redistributions of source code must retain the above copyright
2011348Sandreas.sandberg@arm.com * notice, this list of conditions and the following disclaimer;
2111348Sandreas.sandberg@arm.com * redistributions in binary form must reproduce the above copyright
2211348Sandreas.sandberg@arm.com * notice, this list of conditions and the following disclaimer in the
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2411348Sandreas.sandberg@arm.com * neither the name of the copyright holders nor the names of its
2511348Sandreas.sandberg@arm.com * contributors may be used to endorse or promote products derived from
2611348Sandreas.sandberg@arm.com * this software without specific prior written permission.
2711348Sandreas.sandberg@arm.com *
2811348Sandreas.sandberg@arm.com * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
2911348Sandreas.sandberg@arm.com * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
3011348Sandreas.sandberg@arm.com * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
3111348Sandreas.sandberg@arm.com * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
3211348Sandreas.sandberg@arm.com * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
3311348Sandreas.sandberg@arm.com * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
3411348Sandreas.sandberg@arm.com * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
3511348Sandreas.sandberg@arm.com * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
3611348Sandreas.sandberg@arm.com * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
3711348Sandreas.sandberg@arm.com * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
3811348Sandreas.sandberg@arm.com * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
3911348Sandreas.sandberg@arm.com *
4011348Sandreas.sandberg@arm.com * Authors: Ali Saidi
4111348Sandreas.sandberg@arm.com *          Andreas Hansson
4211348Sandreas.sandberg@arm.com */
4311348Sandreas.sandberg@arm.com
4411348Sandreas.sandberg@arm.com#include "base/trace.hh"
4511348Sandreas.sandberg@arm.com#include "debug/Drain.hh"
4611348Sandreas.sandberg@arm.com#include "debug/PacketQueue.hh"
4711348Sandreas.sandberg@arm.com#include "mem/packet_queue.hh"
4811348Sandreas.sandberg@arm.com
4911348Sandreas.sandberg@arm.comusing namespace std;
5011348Sandreas.sandberg@arm.com
5111348Sandreas.sandberg@arm.comPacketQueue::PacketQueue(EventManager& _em, const std::string& _label)
5211348Sandreas.sandberg@arm.com    : em(_em), sendEvent(this), drainManager(NULL), label(_label),
5311348Sandreas.sandberg@arm.com      waitingOnRetry(false)
5411348Sandreas.sandberg@arm.com{
5511348Sandreas.sandberg@arm.com}
5611348Sandreas.sandberg@arm.com
5711348Sandreas.sandberg@arm.comPacketQueue::~PacketQueue()
5811348Sandreas.sandberg@arm.com{
5911348Sandreas.sandberg@arm.com}
6011348Sandreas.sandberg@arm.com
6111348Sandreas.sandberg@arm.comvoid
6211348Sandreas.sandberg@arm.comPacketQueue::retry()
6311348Sandreas.sandberg@arm.com{
6411348Sandreas.sandberg@arm.com    DPRINTF(PacketQueue, "Queue %s received retry\n", name());
6511348Sandreas.sandberg@arm.com    assert(waitingOnRetry);
6611348Sandreas.sandberg@arm.com    sendDeferredPacket();
6711348Sandreas.sandberg@arm.com}
6811348Sandreas.sandberg@arm.com
6911348Sandreas.sandberg@arm.combool
7011348Sandreas.sandberg@arm.comPacketQueue::checkFunctional(PacketPtr pkt)
7111348Sandreas.sandberg@arm.com{
7211348Sandreas.sandberg@arm.com    pkt->pushLabel(label);
7311348Sandreas.sandberg@arm.com
7411348Sandreas.sandberg@arm.com    auto i = transmitList.begin();
7511348Sandreas.sandberg@arm.com    bool found = false;
7611348Sandreas.sandberg@arm.com
7711348Sandreas.sandberg@arm.com    while (!found && i != transmitList.end()) {
7811348Sandreas.sandberg@arm.com        // If the buffered packet contains data, and it overlaps the
7911348Sandreas.sandberg@arm.com        // current packet, then update data
8011348Sandreas.sandberg@arm.com        found = pkt->checkFunctional(i->pkt);
8111348Sandreas.sandberg@arm.com        ++i;
8211348Sandreas.sandberg@arm.com    }
8311348Sandreas.sandberg@arm.com
8411348Sandreas.sandberg@arm.com    pkt->popLabel();
8511348Sandreas.sandberg@arm.com
8611348Sandreas.sandberg@arm.com    return found;
8711348Sandreas.sandberg@arm.com}
8811348Sandreas.sandberg@arm.com
8911348Sandreas.sandberg@arm.comvoid
9011348Sandreas.sandberg@arm.comPacketQueue::schedSendEvent(Tick when)
9111348Sandreas.sandberg@arm.com{
9211348Sandreas.sandberg@arm.com    // if we are waiting on a retry, do not schedule a send event, and
9311348Sandreas.sandberg@arm.com    // instead rely on retry being called
9411348Sandreas.sandberg@arm.com    if (waitingOnRetry) {
9511348Sandreas.sandberg@arm.com        assert(!sendEvent.scheduled());
9611348Sandreas.sandberg@arm.com        return;
9711348Sandreas.sandberg@arm.com    }
9811348Sandreas.sandberg@arm.com
9911348Sandreas.sandberg@arm.com    if (!sendEvent.scheduled()) {
10011348Sandreas.sandberg@arm.com        em.schedule(&sendEvent, when);
10111348Sandreas.sandberg@arm.com    } else if (sendEvent.when() > when) {
10211348Sandreas.sandberg@arm.com        em.reschedule(&sendEvent, when);
10311348Sandreas.sandberg@arm.com    }
10411348Sandreas.sandberg@arm.com}
10511348Sandreas.sandberg@arm.com
10611348Sandreas.sandberg@arm.comvoid
10711348Sandreas.sandberg@arm.comPacketQueue::schedSendTiming(PacketPtr pkt, Tick when, bool send_as_snoop)
10811348Sandreas.sandberg@arm.com{
10911470Sandreas.sandberg@arm.com    DPRINTF(PacketQueue, "%s for %s address %x size %d\n", __func__,
11011348Sandreas.sandberg@arm.com            pkt->cmdString(), pkt->getAddr(), pkt->getSize());
11112761Sandreas.sandberg@arm.com    // we can still send a packet before the end of this tick
11212761Sandreas.sandberg@arm.com    assert(when >= curTick());
11311348Sandreas.sandberg@arm.com
11411348Sandreas.sandberg@arm.com    // express snoops should never be queued
11511348Sandreas.sandberg@arm.com    assert(!pkt->isExpressSnoop());
11611348Sandreas.sandberg@arm.com
11711348Sandreas.sandberg@arm.com    // add a very basic sanity check on the port to ensure the
11811348Sandreas.sandberg@arm.com    // invisible buffer is not growing beyond reasonable limits
11911348Sandreas.sandberg@arm.com    if (transmitList.size() > 100) {
12011348Sandreas.sandberg@arm.com        panic("Packet queue %s has grown beyond 100 packets\n",
12111348Sandreas.sandberg@arm.com              name());
12211348Sandreas.sandberg@arm.com    }
12311348Sandreas.sandberg@arm.com
12411348Sandreas.sandberg@arm.com    // nothing on the list, or earlier than current front element,
12511348Sandreas.sandberg@arm.com    // schedule an event
12611348Sandreas.sandberg@arm.com    if (transmitList.empty() || when < transmitList.front().tick) {
12711348Sandreas.sandberg@arm.com        // note that currently we ignore a potentially outstanding retry
12811348Sandreas.sandberg@arm.com        // and could in theory put a new packet at the head of the
12911348Sandreas.sandberg@arm.com        // transmit list before retrying the existing packet
13011348Sandreas.sandberg@arm.com        transmitList.push_front(DeferredPacket(when, pkt, send_as_snoop));
13111348Sandreas.sandberg@arm.com        schedSendEvent(when);
13211348Sandreas.sandberg@arm.com        return;
13311348Sandreas.sandberg@arm.com    }
13411348Sandreas.sandberg@arm.com
13512761Sandreas.sandberg@arm.com    // list is non-empty and this belongs at the end
13611348Sandreas.sandberg@arm.com    if (when >= transmitList.back().tick) {
13711348Sandreas.sandberg@arm.com        transmitList.push_back(DeferredPacket(when, pkt, send_as_snoop));
13811348Sandreas.sandberg@arm.com        return;
13912761Sandreas.sandberg@arm.com    }
14012761Sandreas.sandberg@arm.com
14111348Sandreas.sandberg@arm.com    // this belongs in the middle somewhere, insertion sort
14211348Sandreas.sandberg@arm.com    auto i = transmitList.begin();
14311348Sandreas.sandberg@arm.com    ++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::max(std::min(deferredPacketReadyTime(), time),
172                              curTick() + 1);
173
174    if (nextReady != MaxTick) {
175        // if the sendTiming caused someone else to call our
176        // recvTiming we could already have an event scheduled, check
177        if (!sendEvent.scheduled()) {
178            em.schedule(&sendEvent, nextReady);
179        } else if (nextReady < sendEvent.when()) {
180            // if the new time is earlier than when the event
181            // currently is scheduled, move it forward
182            em.reschedule(&sendEvent, nextReady);
183        }
184    } else {
185        // no more to send, so if we're draining, we may be done
186        if (drainManager && transmitList.empty() && !sendEvent.scheduled()) {
187            DPRINTF(Drain, "PacketQueue done draining,"
188                    "processing drain event\n");
189            drainManager->signalDrainDone();
190            drainManager = NULL;
191        }
192    }
193}
194
195void
196PacketQueue::sendDeferredPacket()
197{
198    // try to send what is on the list, this will set waitingOnRetry
199    // accordingly
200    trySendTiming();
201
202    // if we succeeded and are not waiting for a retry, schedule the
203    // next send
204    if (!waitingOnRetry) {
205        scheduleSend();
206    }
207}
208
209void
210PacketQueue::processSendEvent()
211{
212    assert(!waitingOnRetry);
213    sendDeferredPacket();
214}
215
216unsigned int
217PacketQueue::drain(DrainManager *dm)
218{
219    if (transmitList.empty())
220        return 0;
221    DPRINTF(Drain, "PacketQueue not drained\n");
222    drainManager = dm;
223    return 1;
224}
225
226MasterPacketQueue::MasterPacketQueue(EventManager& _em, MasterPort& _masterPort,
227                                     const std::string _label)
228    : PacketQueue(_em, _label), masterPort(_masterPort)
229{
230}
231
232bool
233MasterPacketQueue::sendTiming(PacketPtr pkt, bool send_as_snoop)
234{
235    // attempt to send the packet and return according to the outcome
236    if (!send_as_snoop)
237        return masterPort.sendTimingReq(pkt);
238    else
239        return masterPort.sendTimingSnoopResp(pkt);
240}
241
242SlavePacketQueue::SlavePacketQueue(EventManager& _em, SlavePort& _slavePort,
243                                   const std::string _label)
244    : PacketQueue(_em, _label), slavePort(_slavePort)
245{
246}
247
248bool
249SlavePacketQueue::sendTiming(PacketPtr pkt, bool send_as_snoop)
250{
251    // we should never have queued snoop requests
252    assert(!send_as_snoop);
253    return slavePort.sendTimingResp(pkt);
254}
255