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47 * Definition of a crossbar object.
50 #include "base/misc.hh"
51 #include "base/trace.hh"
52 #include "debug/AddrRanges.hh"
53 #include "debug/Drain.hh"
54 #include "debug/XBar.hh"
55 #include "mem/xbar.hh"
57 BaseXBar::BaseXBar(const BaseXBarParams
*p
)
59 headerCycles(p
->header_cycles
), width(p
->width
),
60 gotAddrRanges(p
->port_default_connection_count
+
61 p
->port_master_connection_count
, false),
62 gotAllAddrRanges(false), defaultPortID(InvalidPortID
),
63 useDefaultRange(p
->use_default_range
)
68 for (auto m
: masterPorts
)
71 for (auto s
: slavePorts
)
81 BaseXBar::getMasterPort(const std::string
&if_name
, PortID idx
)
83 if (if_name
== "master" && idx
< masterPorts
.size()) {
84 // the master port index translates directly to the vector position
85 return *masterPorts
[idx
];
86 } else if (if_name
== "default") {
87 return *masterPorts
[defaultPortID
];
89 return MemObject::getMasterPort(if_name
, idx
);
94 BaseXBar::getSlavePort(const std::string
&if_name
, PortID idx
)
96 if (if_name
== "slave" && idx
< slavePorts
.size()) {
97 // the slave port index translates directly to the vector position
98 return *slavePorts
[idx
];
100 return MemObject::getSlavePort(if_name
, idx
);
105 BaseXBar::calcPacketTiming(PacketPtr pkt
)
107 // the crossbar will be called at a time that is not necessarily
108 // coinciding with its own clock, so start by determining how long
109 // until the next clock edge (could be zero)
110 Tick offset
= clockEdge() - curTick();
112 // determine how many cycles are needed to send the data
113 unsigned dataCycles
= pkt
->hasData() ? divCeil(pkt
->getSize(), width
) : 0;
115 // before setting the bus delay fields of the packet, ensure that
116 // the delay from any previous crossbar has been accounted for
117 if (pkt
->firstWordDelay
!= 0 || pkt
->lastWordDelay
!= 0)
118 panic("Packet %s already has delay (%d, %d) that should be "
119 "accounted for.\n", pkt
->cmdString(), pkt
->firstWordDelay
,
122 // The first word will be delivered on the cycle after the header.
123 pkt
->firstWordDelay
= (headerCycles
+ 1) * clockPeriod() + offset
;
125 // Note that currently lastWordDelay can be smaller than
126 // firstWordDelay if the packet has no data
127 pkt
->lastWordDelay
= (headerCycles
+ dataCycles
) * clockPeriod() +
131 template <typename SrcType
, typename DstType
>
132 BaseXBar::Layer
<SrcType
,DstType
>::Layer(DstType
& _port
, BaseXBar
& _xbar
,
133 const std::string
& _name
) :
134 port(_port
), xbar(_xbar
), _name(_name
), state(IDLE
), drainManager(NULL
),
135 waitingForPeer(NULL
), releaseEvent(this)
139 template <typename SrcType
, typename DstType
>
140 void BaseXBar::Layer
<SrcType
,DstType
>::occupyLayer(Tick until
)
142 // ensure the state is busy at this point, as the layer should
143 // transition from idle as soon as it has decided to forward the
144 // packet to prevent any follow-on calls to sendTiming seeing an
146 assert(state
== BUSY
);
148 // until should never be 0 as express snoops never occupy the layer
150 xbar
.schedule(releaseEvent
, until
);
152 // account for the occupied ticks
153 occupancy
+= until
- curTick();
155 DPRINTF(BaseXBar
, "The crossbar layer is now busy from tick %d to %d\n",
159 template <typename SrcType
, typename DstType
>
161 BaseXBar::Layer
<SrcType
,DstType
>::tryTiming(SrcType
* src_port
)
163 // if we are in the retry state, we will not see anything but the
164 // retrying port (or in the case of the snoop ports the snoop
165 // response port that mirrors the actual slave port) as we leave
166 // this state again in zero time if the peer does not immediately
167 // call the layer when receiving the retry
169 // first we see if the layer is busy, next we check if the
170 // destination port is already engaged in a transaction waiting
171 // for a retry from the peer
172 if (state
== BUSY
|| waitingForPeer
!= NULL
) {
173 // the port should not be waiting already
174 assert(std::find(waitingForLayer
.begin(), waitingForLayer
.end(),
175 src_port
) == waitingForLayer
.end());
177 // put the port at the end of the retry list waiting for the
178 // layer to be freed up (and in the case of a busy peer, for
179 // that transaction to go through, and then the layer to free
181 waitingForLayer
.push_back(src_port
);
190 template <typename SrcType
, typename DstType
>
192 BaseXBar::Layer
<SrcType
,DstType
>::succeededTiming(Tick busy_time
)
194 // we should have gone from idle or retry to busy in the tryTiming
196 assert(state
== BUSY
);
198 // occupy the layer accordingly
199 occupyLayer(busy_time
);
202 template <typename SrcType
, typename DstType
>
204 BaseXBar::Layer
<SrcType
,DstType
>::failedTiming(SrcType
* src_port
,
207 // ensure no one got in between and tried to send something to
209 assert(waitingForPeer
== NULL
);
211 // if the source port is the current retrying one or not, we have
212 // failed in forwarding and should track that we are now waiting
213 // for the peer to send a retry
214 waitingForPeer
= src_port
;
216 // we should have gone from idle or retry to busy in the tryTiming
218 assert(state
== BUSY
);
220 // occupy the bus accordingly
221 occupyLayer(busy_time
);
224 template <typename SrcType
, typename DstType
>
226 BaseXBar::Layer
<SrcType
,DstType
>::releaseLayer()
228 // releasing the bus means we should now be idle
229 assert(state
== BUSY
);
230 assert(!releaseEvent
.scheduled());
235 // bus layer is now idle, so if someone is waiting we can retry
236 if (!waitingForLayer
.empty()) {
237 // there is no point in sending a retry if someone is still
238 // waiting for the peer
239 if (waitingForPeer
== NULL
)
241 } else if (waitingForPeer
== NULL
&& drainManager
) {
242 DPRINTF(Drain
, "Crossbar done draining, signaling drain manager\n");
243 //If we weren't able to drain before, do it now.
244 drainManager
->signalDrainDone();
245 // Clear the drain event once we're done with it.
250 template <typename SrcType
, typename DstType
>
252 BaseXBar::Layer
<SrcType
,DstType
>::retryWaiting()
254 // this should never be called with no one waiting
255 assert(!waitingForLayer
.empty());
257 // we always go to retrying from idle
258 assert(state
== IDLE
);
263 // set the retrying port to the front of the retry list and pop it
265 SrcType
* retryingPort
= waitingForLayer
.front();
266 waitingForLayer
.pop_front();
268 // tell the port to retry, which in some cases ends up calling the
270 retryingPort
->sendRetry();
272 // If the layer is still in the retry state, sendTiming wasn't
273 // called in zero time (e.g. the cache does this), burn a cycle
274 if (state
== RETRY
) {
275 // update the state to busy and reset the retrying port, we
276 // have done our bit and sent the retry
279 // occupy the crossbar layer until the next cycle ends
280 occupyLayer(xbar
.clockEdge(Cycles(1)));
284 template <typename SrcType
, typename DstType
>
286 BaseXBar::Layer
<SrcType
,DstType
>::recvRetry()
288 // we should never get a retry without having failed to forward
289 // something to this port
290 assert(waitingForPeer
!= NULL
);
292 // add the port where the failed packet originated to the front of
293 // the waiting ports for the layer, this allows us to call retry
294 // on the port immediately if the crossbar layer is idle
295 waitingForLayer
.push_front(waitingForPeer
);
297 // we are no longer waiting for the peer
298 waitingForPeer
= NULL
;
300 // if the layer is idle, retry this port straight away, if we
301 // are busy, then simply let the port wait for its turn
305 assert(state
== BUSY
);
310 BaseXBar::findPort(Addr addr
)
312 // we should never see any address lookups before we've got the
313 // ranges of all connected slave modules
314 assert(gotAllAddrRanges
);
317 PortID dest_id
= checkPortCache(addr
);
318 if (dest_id
!= InvalidPortID
)
321 // Check the address map interval tree
322 auto i
= portMap
.find(addr
);
323 if (i
!= portMap
.end()) {
325 updatePortCache(dest_id
, i
->first
);
329 // Check if this matches the default range
330 if (useDefaultRange
) {
331 if (defaultRange
.contains(addr
)) {
332 DPRINTF(AddrRanges
, " found addr %#llx on default\n",
334 return defaultPortID
;
336 } else if (defaultPortID
!= InvalidPortID
) {
337 DPRINTF(AddrRanges
, "Unable to find destination for addr %#llx, "
338 "will use default port\n", addr
);
339 return defaultPortID
;
342 // we should use the range for the default port and it did not
343 // match, or the default port is not set
344 fatal("Unable to find destination for addr %#llx on %s\n", addr
,
348 /** Function called by the port when the crossbar is receiving a range change.*/
350 BaseXBar::recvRangeChange(PortID master_port_id
)
352 DPRINTF(AddrRanges
, "Received range change from slave port %s\n",
353 masterPorts
[master_port_id
]->getSlavePort().name());
355 // remember that we got a range from this master port and thus the
356 // connected slave module
357 gotAddrRanges
[master_port_id
] = true;
359 // update the global flag
360 if (!gotAllAddrRanges
) {
361 // take a logical AND of all the ports and see if we got
362 // ranges from everyone
363 gotAllAddrRanges
= true;
364 std::vector
<bool>::const_iterator r
= gotAddrRanges
.begin();
365 while (gotAllAddrRanges
&& r
!= gotAddrRanges
.end()) {
366 gotAllAddrRanges
&= *r
++;
368 if (gotAllAddrRanges
)
369 DPRINTF(AddrRanges
, "Got address ranges from all slaves\n");
372 // note that we could get the range from the default port at any
373 // point in time, and we cannot assume that the default range is
374 // set before the other ones are, so we do additional checks once
375 // all ranges are provided
376 if (master_port_id
== defaultPortID
) {
377 // only update if we are indeed checking ranges for the
378 // default port since the port might not have a valid range
380 if (useDefaultRange
) {
381 AddrRangeList ranges
= masterPorts
[master_port_id
]->getAddrRanges();
383 if (ranges
.size() != 1)
384 fatal("Crossbar %s may only have a single default range",
387 defaultRange
= ranges
.front();
390 // the ports are allowed to update their address ranges
391 // dynamically, so remove any existing entries
392 if (gotAddrRanges
[master_port_id
]) {
393 for (auto p
= portMap
.begin(); p
!= portMap
.end(); ) {
394 if (p
->second
== master_port_id
)
395 // erasing invalidates the iterator, so advance it
396 // before the deletion takes place
403 AddrRangeList ranges
= masterPorts
[master_port_id
]->getAddrRanges();
405 for (const auto& r
: ranges
) {
406 DPRINTF(AddrRanges
, "Adding range %s for id %d\n",
407 r
.to_string(), master_port_id
);
408 if (portMap
.insert(r
, master_port_id
) == portMap
.end()) {
409 PortID conflict_id
= portMap
.find(r
)->second
;
410 fatal("%s has two ports with same range:\n\t%s\n\t%s\n",
412 masterPorts
[master_port_id
]->getSlavePort().name(),
413 masterPorts
[conflict_id
]->getSlavePort().name());
418 // if we have received ranges from all our neighbouring slave
419 // modules, go ahead and tell our connected master modules in
420 // turn, this effectively assumes a tree structure of the system
421 if (gotAllAddrRanges
) {
422 DPRINTF(AddrRanges
, "Aggregating address ranges\n");
425 // start out with the default range
426 if (useDefaultRange
) {
427 if (!gotAddrRanges
[defaultPortID
])
428 fatal("Crossbar %s uses default range, but none provided",
431 xbarRanges
.push_back(defaultRange
);
432 DPRINTF(AddrRanges
, "-- Adding default %s\n",
433 defaultRange
.to_string());
436 // merge all interleaved ranges and add any range that is not
437 // a subset of the default range
438 std::vector
<AddrRange
> intlv_ranges
;
439 for (const auto& r
: portMap
) {
440 // if the range is interleaved then save it for now
441 if (r
.first
.interleaved()) {
442 // if we already got interleaved ranges that are not
443 // part of the same range, then first do a merge
444 // before we add the new one
445 if (!intlv_ranges
.empty() &&
446 !intlv_ranges
.back().mergesWith(r
.first
)) {
447 DPRINTF(AddrRanges
, "-- Merging range from %d ranges\n",
448 intlv_ranges
.size());
449 AddrRange
merged_range(intlv_ranges
);
450 // next decide if we keep the merged range or not
451 if (!(useDefaultRange
&&
452 merged_range
.isSubset(defaultRange
))) {
453 xbarRanges
.push_back(merged_range
);
454 DPRINTF(AddrRanges
, "-- Adding merged range %s\n",
455 merged_range
.to_string());
457 intlv_ranges
.clear();
459 intlv_ranges
.push_back(r
.first
);
461 // keep the current range if not a subset of the default
462 if (!(useDefaultRange
&&
463 r
.first
.isSubset(defaultRange
))) {
464 xbarRanges
.push_back(r
.first
);
465 DPRINTF(AddrRanges
, "-- Adding range %s\n",
466 r
.first
.to_string());
471 // if there is still interleaved ranges waiting to be merged,
472 // go ahead and do it
473 if (!intlv_ranges
.empty()) {
474 DPRINTF(AddrRanges
, "-- Merging range from %d ranges\n",
475 intlv_ranges
.size());
476 AddrRange
merged_range(intlv_ranges
);
477 if (!(useDefaultRange
&& merged_range
.isSubset(defaultRange
))) {
478 xbarRanges
.push_back(merged_range
);
479 DPRINTF(AddrRanges
, "-- Adding merged range %s\n",
480 merged_range
.to_string());
484 // also check that no range partially overlaps with the
485 // default range, this has to be done after all ranges are set
486 // as there are no guarantees for when the default range is
487 // update with respect to the other ones
488 if (useDefaultRange
) {
489 for (const auto& r
: xbarRanges
) {
490 // see if the new range is partially
491 // overlapping the default range
492 if (r
.intersects(defaultRange
) &&
493 !r
.isSubset(defaultRange
))
494 fatal("Range %s intersects the " \
495 "default range of %s but is not a " \
496 "subset\n", r
.to_string(), name());
500 // tell all our neighbouring master ports that our address
501 // ranges have changed
502 for (const auto& s
: slavePorts
)
503 s
->sendRangeChange();
510 BaseXBar::getAddrRanges() const
512 // we should never be asked without first having sent a range
513 // change, and the latter is only done once we have all the ranges
514 // of the connected devices
515 assert(gotAllAddrRanges
);
517 // at the moment, this never happens, as there are no cycles in
518 // the range queries and no devices on the master side of a crossbar
519 // (CPU, cache, bridge etc) actually care about the ranges of the
520 // ports they are connected to
522 DPRINTF(AddrRanges
, "Received address range request\n");
530 using namespace Stats
;
533 .init(MemCmd::NUM_MEM_CMDS
)
534 .name(name() + ".trans_dist")
535 .desc("Transaction distribution")
538 // get the string representation of the commands
539 for (int i
= 0; i
< MemCmd::NUM_MEM_CMDS
; i
++) {
541 const std::string
&cstr
= cmd
.toString();
542 transDist
.subname(i
, cstr
);
546 .init(slavePorts
.size(), masterPorts
.size())
547 .name(name() + ".pkt_count")
548 .desc("Packet count per connected master and slave (bytes)")
549 .flags(total
| nozero
| nonan
);
552 .init(slavePorts
.size(), masterPorts
.size())
553 .name(name() + ".pkt_size")
554 .desc("Cumulative packet size per connected master and slave (bytes)")
555 .flags(total
| nozero
| nonan
);
557 // both the packet count and total size are two-dimensional
558 // vectors, indexed by slave port id and master port id, thus the
559 // neighbouring master and slave, they do not differentiate what
560 // came from the master and was forwarded to the slave (requests
561 // and snoop responses) and what came from the slave and was
562 // forwarded to the master (responses and snoop requests)
563 for (int i
= 0; i
< slavePorts
.size(); i
++) {
564 pktCount
.subname(i
, slavePorts
[i
]->getMasterPort().name());
565 pktSize
.subname(i
, slavePorts
[i
]->getMasterPort().name());
566 for (int j
= 0; j
< masterPorts
.size(); j
++) {
567 pktCount
.ysubname(j
, masterPorts
[j
]->getSlavePort().name());
568 pktSize
.ysubname(j
, masterPorts
[j
]->getSlavePort().name());
573 template <typename SrcType
, typename DstType
>
575 BaseXBar::Layer
<SrcType
,DstType
>::drain(DrainManager
*dm
)
577 //We should check that we're not "doing" anything, and that noone is
578 //waiting. We might be idle but have someone waiting if the device we
579 //contacted for a retry didn't actually retry.
581 DPRINTF(Drain
, "Crossbar not drained\n");
588 template <typename SrcType
, typename DstType
>
590 BaseXBar::Layer
<SrcType
,DstType
>::regStats()
592 using namespace Stats
;
595 .name(name() + ".occupancy")
596 .desc("Layer occupancy (ticks)")
600 .name(name() + ".utilization")
601 .desc("Layer utilization (%)")
605 utilization
= 100 * occupancy
/ simTicks
;
609 * Crossbar layer template instantiations. Could be removed with _impl.hh
610 * file, but since there are only two given options (MasterPort and
611 * SlavePort) it seems a bit excessive at this point.
613 template class BaseXBar::Layer
<SlavePort
,MasterPort
>;
614 template class BaseXBar::Layer
<MasterPort
,SlavePort
>;