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/*
* Copyright (c) 2012 ARM Limited
* All rights reserved.
*
* The license below extends only to copyright in the software and shall
* not be construed as granting a license to any other intellectual
* property including but not limited to intellectual property relating
* to a hardware implementation of the functionality of the software
* licensed hereunder. You may use the software subject to the license
* terms below provided that you ensure that this notice is replicated
* unmodified and in its entirety in all distributions of the software,
* modified or unmodified, in source code or in binary form.
*
* Copyright (c) 2006 The Regents of The University of Michigan
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Authors: Ali Saidi
* Andreas Hansson
*/
#include "base/trace.hh"
#include "debug/Drain.hh"
#include "debug/PacketQueue.hh"
#include "mem/packet_queue.hh"
using namespace std;
PacketQueue::PacketQueue(EventManager& _em, const std::string& _label)
: em(_em), sendEvent(this), drainManager(NULL), label(_label),
waitingOnRetry(false)
{
}
PacketQueue::~PacketQueue()
{
}
void
PacketQueue::retry()
{
DPRINTF(PacketQueue, "Queue %s received retry\n", name());
assert(waitingOnRetry);
sendDeferredPacket();
}
bool
PacketQueue::checkFunctional(PacketPtr pkt)
{
pkt->pushLabel(label);
DeferredPacketIterator i = transmitList.begin();
DeferredPacketIterator end = transmitList.end();
bool found = false;
while (!found && i != end) {
// If the buffered packet contains data, and it overlaps the
// current packet, then update data
found = pkt->checkFunctional(i->pkt);
++i;
}
pkt->popLabel();
return found;
}
void
PacketQueue::schedSendEvent(Tick when)
{
// if we are waiting on a retry, do not schedule a send event, and
// instead rely on retry being called
if (waitingOnRetry) {
assert(!sendEvent.scheduled());
return;
}
if (!sendEvent.scheduled()) {
em.schedule(&sendEvent, when);
} else if (sendEvent.when() > when) {
em.reschedule(&sendEvent, when);
}
}
void
PacketQueue::schedSendTiming(PacketPtr pkt, Tick when, bool send_as_snoop)
{
DPRINTF(PacketQueue, "%s for %s address %x size %d\n", __func__,
pkt->cmdString(), pkt->getAddr(), pkt->getSize());
// we can still send a packet before the end of this tick
assert(when >= curTick());
// express snoops should never be queued
assert(!pkt->isExpressSnoop());
// add a very basic sanity check on the port to ensure the
// invisible buffer is not growing beyond reasonable limits
if (transmitList.size() > 100) {
panic("Packet queue %s has grown beyond 100 packets\n",
name());
}
// nothing on the list, or earlier than current front element,
// schedule an event
if (transmitList.empty() || when < transmitList.front().tick) {
// note that currently we ignore a potentially outstanding retry
// and could in theory put a new packet at the head of the
// transmit list before retrying the existing packet
transmitList.push_front(DeferredPacket(when, pkt, send_as_snoop));
schedSendEvent(when);
return;
}
// list is non-empty and this belongs at the end
if (when >= transmitList.back().tick) {
transmitList.push_back(DeferredPacket(when, pkt, send_as_snoop));
return;
}
// this belongs in the middle somewhere, insertion sort
DeferredPacketIterator i = transmitList.begin();
++i; // already checked for insertion at front
while (i != transmitList.end() && when >= i->tick)
++i;
transmitList.insert(i, DeferredPacket(when, pkt, send_as_snoop));
}
void PacketQueue::trySendTiming()
{
assert(deferredPacketReady());
// take the next packet off the list here, as we might return to
// ourselves through the sendTiming call below
DeferredPacket dp = transmitList.front();
transmitList.pop_front();
// use the appropriate implementation of sendTiming based on the
// type of port associated with the queue, and whether the packet
// is to be sent as a snoop or not
waitingOnRetry = !sendTiming(dp.pkt, dp.sendAsSnoop);
if (waitingOnRetry) {
// put the packet back at the front of the list (packet should
// not have changed since it wasn't accepted)
assert(!sendEvent.scheduled());
transmitList.push_front(dp);
}
}
void
PacketQueue::scheduleSend(Tick time)
{
// the next ready time is either determined by the next deferred packet,
// or in the cache through the MSHR ready time
Tick nextReady = std::min(deferredPacketReadyTime(), time);
if (nextReady != MaxTick) {
// if the sendTiming caused someone else to call our
// recvTiming we could already have an event scheduled, check
if (!sendEvent.scheduled())
em.schedule(&sendEvent, std::max(nextReady, curTick() + 1));
} else {
// no more to send, so if we're draining, we may be done
if (drainManager && transmitList.empty() && !sendEvent.scheduled()) {
DPRINTF(Drain, "PacketQueue done draining,"
"processing drain event\n");
drainManager->signalDrainDone();
drainManager = NULL;
}
}
}
void
PacketQueue::sendDeferredPacket()
{
// try to send what is on the list, this will set waitingOnRetry
// accordingly
trySendTiming();
// if we succeeded and are not waiting for a retry, schedule the
// next send
if (!waitingOnRetry) {
scheduleSend();
}
}
void
PacketQueue::processSendEvent()
{
assert(!waitingOnRetry);
sendDeferredPacket();
}
unsigned int
PacketQueue::drain(DrainManager *dm)
{
if (transmitList.empty() && !sendEvent.scheduled())
return 0;
DPRINTF(Drain, "PacketQueue not drained\n");
drainManager = dm;
return 1;
}
MasterPacketQueue::MasterPacketQueue(EventManager& _em, MasterPort& _masterPort,
const std::string _label)
: PacketQueue(_em, _label), masterPort(_masterPort)
{
}
bool
MasterPacketQueue::sendTiming(PacketPtr pkt, bool send_as_snoop)
{
// attempt to send the packet and return according to the outcome
if (!send_as_snoop)
return masterPort.sendTimingReq(pkt);
else
return masterPort.sendTimingSnoopResp(pkt);
}
SlavePacketQueue::SlavePacketQueue(EventManager& _em, SlavePort& _slavePort,
const std::string _label)
: PacketQueue(_em, _label), slavePort(_slavePort)
{
}
bool
SlavePacketQueue::sendTiming(PacketPtr pkt, bool send_as_snoop)
{
// we should never have queued snoop requests
assert(!send_as_snoop);
return slavePort.sendTimingResp(pkt);
}