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44 #include "mem/packet_queue.hh"
46 #include "base/trace.hh"
47 #include "debug/Drain.hh"
48 #include "debug/PacketQueue.hh"
50 PacketQueue::PacketQueue(EventManager
& _em
, const std::string
& _label
,
51 const std::string
& _sendEventName
,
52 bool disable_sanity_check
)
53 : em(_em
), sendEvent([this]{ processSendEvent(); }, _sendEventName
),
54 _disableSanityCheck(disable_sanity_check
),
55 label(_label
), waitingOnRetry(false)
59 PacketQueue::~PacketQueue()
66 DPRINTF(PacketQueue
, "Queue %s received retry\n", name());
67 assert(waitingOnRetry
);
68 waitingOnRetry
= false;
73 PacketQueue::hasAddr(Addr addr
) const
75 // caller is responsible for ensuring that all packets have the
77 for (const auto& p
: transmitList
) {
78 if (p
.pkt
->getAddr() == addr
)
85 PacketQueue::trySatisfyFunctional(PacketPtr pkt
)
87 pkt
->pushLabel(label
);
89 auto i
= transmitList
.begin();
92 while (!found
&& i
!= transmitList
.end()) {
93 // If the buffered packet contains data, and it overlaps the
94 // current packet, then update data
95 found
= pkt
->trySatisfyFunctional(i
->pkt
);
105 PacketQueue::schedSendTiming(PacketPtr pkt
, Tick when
, bool force_order
)
107 DPRINTF(PacketQueue
, "%s for %s address %x size %d when %lu ord: %i\n",
108 __func__
, pkt
->cmdString(), pkt
->getAddr(), pkt
->getSize(), when
,
111 // we can still send a packet before the end of this tick
112 assert(when
>= curTick());
114 // express snoops should never be queued
115 assert(!pkt
->isExpressSnoop());
117 // add a very basic sanity check on the port to ensure the
118 // invisible buffer is not growing beyond reasonable limits
119 if (!_disableSanityCheck
&& transmitList
.size() > 100) {
120 panic("Packet queue %s has grown beyond 100 packets\n",
124 // nothing on the list
125 if (transmitList
.empty()) {
126 transmitList
.emplace_front(when
, pkt
);
127 schedSendEvent(when
);
131 // we should either have an outstanding retry, or a send event
132 // scheduled, but there is an unfortunate corner case where the
133 // x86 page-table walker and timing CPU send out a new request as
134 // part of the receiving of a response (called by
135 // PacketQueue::sendDeferredPacket), in which we end up calling
136 // ourselves again before we had a chance to update waitingOnRetry
137 // assert(waitingOnRetry || sendEvent.scheduled());
139 // this belongs in the middle somewhere, so search from the end to
140 // order by tick; however, if force_order is set, also make sure
141 // not to re-order in front of some existing packet with the same
143 auto i
= transmitList
.end();
145 while (i
!= transmitList
.begin() && when
< i
->tick
&&
146 !(force_order
&& i
->pkt
->getAddr() == pkt
->getAddr()))
149 // emplace inserts the element before the position pointed to by
150 // the iterator, so advance it one step
151 transmitList
.emplace(++i
, when
, pkt
);
155 PacketQueue::schedSendEvent(Tick when
)
157 // if we are waiting on a retry just hold off
158 if (waitingOnRetry
) {
159 DPRINTF(PacketQueue
, "Not scheduling send as waiting for retry\n");
160 assert(!sendEvent
.scheduled());
164 if (when
!= MaxTick
) {
165 // we cannot go back in time, and to be consistent we stick to
166 // one tick in the future
167 when
= std::max(when
, curTick() + 1);
168 // @todo Revisit the +1
170 if (!sendEvent
.scheduled()) {
171 em
.schedule(&sendEvent
, when
);
172 } else if (when
< sendEvent
.when()) {
173 // if the new time is earlier than when the event
174 // currently is scheduled, move it forward
175 em
.reschedule(&sendEvent
, when
);
178 // we get a MaxTick when there is no more to send, so if we're
179 // draining, we may be done at this point
180 if (drainState() == DrainState::Draining
&&
181 transmitList
.empty() && !sendEvent
.scheduled()) {
183 DPRINTF(Drain
, "PacketQueue done draining,"
184 "processing drain event\n");
191 PacketQueue::sendDeferredPacket()
194 assert(!waitingOnRetry
);
195 assert(deferredPacketReady());
197 DeferredPacket dp
= transmitList
.front();
199 // take the packet of the list before sending it, as sending of
200 // the packet in some cases causes a new packet to be enqueued
201 // (most notaly when responding to the timing CPU, leading to a
202 // new request hitting in the L1 icache, leading to a new
204 transmitList
.pop_front();
206 // use the appropriate implementation of sendTiming based on the
208 waitingOnRetry
= !sendTiming(dp
.pkt
);
210 // if we succeeded and are not waiting for a retry, schedule the
212 if (!waitingOnRetry
) {
213 schedSendEvent(deferredPacketReadyTime());
215 // put the packet back at the front of the list
216 transmitList
.emplace_front(dp
);
221 PacketQueue::processSendEvent()
223 assert(!waitingOnRetry
);
224 sendDeferredPacket();
230 if (transmitList
.empty()) {
231 return DrainState::Drained
;
233 DPRINTF(Drain
, "PacketQueue not drained\n");
234 return DrainState::Draining
;
238 ReqPacketQueue::ReqPacketQueue(EventManager
& _em
, MasterPort
& _masterPort
,
239 const std::string _label
)
240 : PacketQueue(_em
, _label
, name(_masterPort
, _label
)),
241 masterPort(_masterPort
)
246 ReqPacketQueue::sendTiming(PacketPtr pkt
)
248 return masterPort
.sendTimingReq(pkt
);
251 SnoopRespPacketQueue::SnoopRespPacketQueue(EventManager
& _em
,
252 MasterPort
& _masterPort
,
253 const std::string _label
)
254 : PacketQueue(_em
, _label
, name(_masterPort
, _label
)),
255 masterPort(_masterPort
)
260 SnoopRespPacketQueue::sendTiming(PacketPtr pkt
)
262 return masterPort
.sendTimingSnoopResp(pkt
);
265 RespPacketQueue::RespPacketQueue(EventManager
& _em
, SlavePort
& _slavePort
,
266 const std::string _label
)
267 : PacketQueue(_em
, _label
, name(_slavePort
, _label
)),
268 slavePort(_slavePort
)
273 RespPacketQueue::sendTiming(PacketPtr pkt
)
275 return slavePort
.sendTimingResp(pkt
);