/*
- * Copyright (c) 2012 ARM Limited
+ * Copyright (c) 2012,2015,2018-2020 ARM Limited
* All rights reserved.
*
* The license below extends only to copyright in the software and shall
* 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 "mem/packet_queue.hh"
+
#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(EventManager& _em, const std::string& _label,
+ const std::string& _sendEventName,
+ bool force_order,
+ bool disable_sanity_check)
+ : em(_em), sendEvent([this]{ processSendEvent(); }, _sendEventName),
+ _disableSanityCheck(disable_sanity_check),
+ forceOrder(force_order),
+ label(_label), waitingOnRetry(false)
{
}
{
DPRINTF(PacketQueue, "Queue %s received retry\n", name());
assert(waitingOnRetry);
+ waitingOnRetry = false;
sendDeferredPacket();
}
bool
-PacketQueue::checkFunctional(PacketPtr pkt)
+PacketQueue::checkConflict(const PacketPtr pkt, const int blk_size) const
+{
+ // caller is responsible for ensuring that all packets have the
+ // same alignment
+ for (const auto& p : transmitList) {
+ if (p.pkt->matchBlockAddr(pkt, blk_size))
+ return true;
+ }
+ return false;
+}
+
+bool
+PacketQueue::trySatisfyFunctional(PacketPtr pkt)
{
pkt->pushLabel(label);
- DeferredPacketIterator i = transmitList.begin();
- DeferredPacketIterator end = transmitList.end();
+ auto i = transmitList.begin();
bool found = false;
- while (!found && i != end) {
+ while (!found && i != transmitList.end()) {
// If the buffered packet contains data, and it overlaps the
// current packet, then update data
- found = pkt->checkFunctional(i->pkt);
+ found = pkt->trySatisfyFunctional(i->pkt);
++i;
}
}
void
-PacketQueue::schedSendEvent(Tick when)
+PacketQueue::schedSendTiming(PacketPtr pkt, 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;
- }
+ DPRINTF(PacketQueue, "%s for %s address %x size %d when %lu ord: %i\n",
+ __func__, pkt->cmdString(), pkt->getAddr(), pkt->getSize(), when,
+ forceOrder);
- 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)
-{
// we can still send a packet before the end of this tick
assert(when >= curTick());
// express snoops should never be queued
assert(!pkt->isExpressSnoop());
- // 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;
+ // add a very basic sanity check on the port to ensure the
+ // invisible buffer is not growing beyond reasonable limits
+ if (!_disableSanityCheck && transmitList.size() > 128) {
+ panic("Packet queue %s has grown beyond 128 packets\n",
+ name());
}
- // 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;
- }
+ // we should either have an outstanding retry, or a send event
+ // scheduled, but there is an unfortunate corner case where the
+ // x86 page-table walker and timing CPU send out a new request as
+ // part of the receiving of a response (called by
+ // PacketQueue::sendDeferredPacket), in which we end up calling
+ // ourselves again before we had a chance to update waitingOnRetry
+ // assert(waitingOnRetry || sendEvent.scheduled());
- // 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));
+ // this belongs in the middle somewhere, so search from the end to
+ // order by tick; however, if forceOrder is set, also make sure
+ // not to re-order in front of some existing packet with the same
+ // address
+ auto it = transmitList.end();
+ while (it != transmitList.begin()) {
+ --it;
+ if ((forceOrder && it->pkt->matchAddr(pkt)) || it->tick <= when) {
+ // emplace inserts the element before the position pointed to by
+ // the iterator, so advance it one step
+ transmitList.emplace(++it, when, pkt);
+ return;
+ }
+ }
+ // either the packet list is empty or this has to be inserted
+ // before every other packet
+ transmitList.emplace_front(when, pkt);
+ schedSendEvent(when);
}
-void PacketQueue::trySendTiming()
+void
+PacketQueue::schedSendEvent(Tick when)
{
- 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 we are waiting on a retry just hold off
if (waitingOnRetry) {
- // put the packet back at the front of the list (packet should
- // not have changed since it wasn't accepted)
+ DPRINTF(PacketQueue, "Not scheduling send as waiting for retry\n");
assert(!sendEvent.scheduled());
- transmitList.push_front(dp);
+ return;
}
-}
-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 (when != MaxTick) {
+ // we cannot go back in time, and to be consistent we stick to
+ // one tick in the future
+ when = std::max(when, curTick() + 1);
+ // @todo Revisit the +1
- 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));
+ if (!sendEvent.scheduled()) {
+ em.schedule(&sendEvent, when);
+ } else if (when < sendEvent.when()) {
+ // if the new time is earlier than when the event
+ // currently is scheduled, move it forward
+ em.reschedule(&sendEvent, when);
+ }
} else {
- // no more to send, so if we're draining, we may be done
- if (drainManager && transmitList.empty() && !sendEvent.scheduled()) {
+ // we get a MaxTick when there is no more to send, so if we're
+ // draining, we may be done at this point
+ if (drainState() == DrainState::Draining &&
+ transmitList.empty() && !sendEvent.scheduled()) {
+
DPRINTF(Drain, "PacketQueue done draining,"
"processing drain event\n");
- drainManager->signalDrainDone();
- drainManager = NULL;
+ signalDrainDone();
}
}
}
void
PacketQueue::sendDeferredPacket()
{
- // try to send what is on the list, this will set waitingOnRetry
- // accordingly
- trySendTiming();
+ // sanity checks
+ assert(!waitingOnRetry);
+ assert(deferredPacketReady());
+
+ DeferredPacket dp = transmitList.front();
+
+ // take the packet of the list before sending it, as sending of
+ // the packet in some cases causes a new packet to be enqueued
+ // (most notaly when responding to the timing CPU, leading to a
+ // new request hitting in the L1 icache, leading to a new
+ // response)
+ transmitList.pop_front();
+
+ // use the appropriate implementation of sendTiming based on the
+ // type of queue
+ waitingOnRetry = !sendTiming(dp.pkt);
// if we succeeded and are not waiting for a retry, schedule the
// next send
if (!waitingOnRetry) {
- scheduleSend();
+ schedSendEvent(deferredPacketReadyTime());
+ } else {
+ // put the packet back at the front of the list
+ transmitList.emplace_front(dp);
}
}
sendDeferredPacket();
}
-unsigned int
-PacketQueue::drain(DrainManager *dm)
+DrainState
+PacketQueue::drain()
+{
+ if (transmitList.empty()) {
+ return DrainState::Drained;
+ } else {
+ DPRINTF(Drain, "PacketQueue not drained\n");
+ return DrainState::Draining;
+ }
+}
+
+ReqPacketQueue::ReqPacketQueue(EventManager& _em, RequestPort& _mem_side_port,
+ const std::string _label)
+ : PacketQueue(_em, _label, name(_mem_side_port, _label)),
+ memSidePort(_mem_side_port)
+{
+}
+
+bool
+ReqPacketQueue::sendTiming(PacketPtr pkt)
{
- if (transmitList.empty() && !sendEvent.scheduled())
- return 0;
- DPRINTF(Drain, "PacketQueue not drained\n");
- drainManager = dm;
- return 1;
+ return memSidePort.sendTimingReq(pkt);
}
-MasterPacketQueue::MasterPacketQueue(EventManager& _em, MasterPort& _masterPort,
- const std::string _label)
- : PacketQueue(_em, _label), masterPort(_masterPort)
+SnoopRespPacketQueue::SnoopRespPacketQueue(EventManager& _em,
+ RequestPort& _mem_side_port,
+ bool force_order,
+ const std::string _label)
+ : PacketQueue(_em, _label, name(_mem_side_port, _label), force_order),
+ memSidePort(_mem_side_port)
{
}
bool
-MasterPacketQueue::sendTiming(PacketPtr pkt, bool send_as_snoop)
+SnoopRespPacketQueue::sendTiming(PacketPtr pkt)
{
- // attempt to send the packet and return according to the outcome
- if (!send_as_snoop)
- return masterPort.sendTimingReq(pkt);
- else
- return masterPort.sendTimingSnoopResp(pkt);
+ return memSidePort.sendTimingSnoopResp(pkt);
}
-SlavePacketQueue::SlavePacketQueue(EventManager& _em, SlavePort& _slavePort,
- const std::string _label)
- : PacketQueue(_em, _label), slavePort(_slavePort)
+RespPacketQueue::RespPacketQueue(EventManager& _em,
+ ResponsePort& _cpu_side_port,
+ bool force_order,
+ const std::string _label)
+ : PacketQueue(_em, _label, name(_cpu_side_port, _label), force_order),
+ cpuSidePort(_cpu_side_port)
{
}
bool
-SlavePacketQueue::sendTiming(PacketPtr pkt, bool send_as_snoop)
+RespPacketQueue::sendTiming(PacketPtr pkt)
{
- // we should never have queued snoop requests
- assert(!send_as_snoop);
- return slavePort.sendTimingResp(pkt);
+ return cpuSidePort.sendTimingResp(pkt);
}
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