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fetch1.cc
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1 /*
2  * Copyright (c) 2013-2014 ARM Limited
3  * All rights reserved
4  *
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24  *
25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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30  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
31  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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35  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36  *
37  * Authors: Andrew Bardsley
38  */
39 
40 #include "cpu/minor/fetch1.hh"
41 
42 #include <cstring>
43 #include <iomanip>
44 #include <sstream>
45 
46 #include "base/cast.hh"
47 #include "cpu/minor/pipeline.hh"
48 #include "debug/Drain.hh"
49 #include "debug/Fetch.hh"
50 #include "debug/MinorTrace.hh"
51 
52 namespace Minor
53 {
54 
55 Fetch1::Fetch1(const std::string &name_,
56  MinorCPU &cpu_,
57  MinorCPUParams &params,
60  Latch<BranchData>::Output prediction_,
61  std::vector<InputBuffer<ForwardLineData>> &next_stage_input_buffer) :
62  Named(name_),
63  cpu(cpu_),
64  inp(inp_),
65  out(out_),
66  prediction(prediction_),
67  nextStageReserve(next_stage_input_buffer),
68  icachePort(name_ + ".icache_port", *this, cpu_),
69  lineSnap(params.fetch1LineSnapWidth),
70  maxLineWidth(params.fetch1LineWidth),
71  fetchLimit(params.fetch1FetchLimit),
72  fetchInfo(params.numThreads),
73  threadPriority(0),
74  requests(name_ + ".requests", "lines", params.fetch1FetchLimit),
75  transfers(name_ + ".transfers", "lines", params.fetch1FetchLimit),
76  icacheState(IcacheRunning),
77  lineSeqNum(InstId::firstLineSeqNum),
78  numFetchesInMemorySystem(0),
79  numFetchesInITLB(0)
80 {
81  if (lineSnap == 0) {
83  DPRINTF(Fetch, "lineSnap set to cache line size of: %d\n",
84  lineSnap);
85  }
86 
87  if (maxLineWidth == 0) {
89  DPRINTF(Fetch, "maxLineWidth set to cache line size of: %d\n",
90  maxLineWidth);
91  }
92 
93  /* These assertions should be copied to the Python config. as well */
94  if ((lineSnap % sizeof(TheISA::MachInst)) != 0) {
95  fatal("%s: fetch1LineSnapWidth must be a multiple "
96  "of sizeof(TheISA::MachInst) (%d)\n", name_,
97  sizeof(TheISA::MachInst));
98  }
99 
100  if (!(maxLineWidth >= lineSnap &&
101  (maxLineWidth % sizeof(TheISA::MachInst)) == 0))
102  {
103  fatal("%s: fetch1LineWidth must be a multiple of"
104  " sizeof(TheISA::MachInst)"
105  " (%d), and >= fetch1LineSnapWidth (%d)\n",
106  name_, sizeof(TheISA::MachInst), lineSnap);
107  }
108 
109  if (fetchLimit < 1) {
110  fatal("%s: fetch1FetchLimit must be >= 1 (%d)\n", name_,
111  fetchLimit);
112  }
113 }
114 
115 inline ThreadID
117 {
118  /* Select thread via policy. */
119  std::vector<ThreadID> priority_list;
120 
121  switch (cpu.threadPolicy) {
122  case Enums::SingleThreaded:
123  priority_list.push_back(0);
124  break;
125  case Enums::RoundRobin:
126  priority_list = cpu.roundRobinPriority(threadPriority);
127  break;
128  case Enums::Random:
129  priority_list = cpu.randomPriority();
130  break;
131  default:
132  panic("Unknown fetch policy");
133  }
134 
135  for (auto tid : priority_list) {
136  if (cpu.getContext(tid)->status() == ThreadContext::Active &&
137  !fetchInfo[tid].blocked &&
138  fetchInfo[tid].state == FetchRunning) {
139  threadPriority = tid;
140  return tid;
141  }
142  }
143 
144  return InvalidThreadID;
145 }
146 
147 void
149 {
150  /* Reference the currently used thread state. */
151  Fetch1ThreadInfo &thread = fetchInfo[tid];
152 
153  /* If line_offset != 0, a request is pushed for the remainder of the
154  * line. */
155  /* Use a lower, sizeof(MachInst) aligned address for the fetch */
156  Addr aligned_pc = thread.pc.instAddr() & ~((Addr) lineSnap - 1);
157  unsigned int line_offset = aligned_pc % lineSnap;
158  unsigned int request_size = maxLineWidth - line_offset;
159 
160  /* Fill in the line's id */
161  InstId request_id(tid,
162  thread.streamSeqNum, thread.predictionSeqNum,
163  lineSeqNum);
164 
165  FetchRequestPtr request = new FetchRequest(*this, request_id, thread.pc);
166 
167  DPRINTF(Fetch, "Inserting fetch into the fetch queue "
168  "%s addr: 0x%x pc: %s line_offset: %d request_size: %d\n",
169  request_id, aligned_pc, thread.pc, line_offset, request_size);
170 
171  request->request->setContext(cpu.threads[tid]->getTC()->contextId());
172  request->request->setVirt(0 /* asid */,
173  aligned_pc, request_size, Request::INST_FETCH, cpu.instMasterId(),
174  /* I've no idea why we need the PC, but give it */
175  thread.pc.instAddr());
176 
177  DPRINTF(Fetch, "Submitting ITLB request\n");
179 
181 
182  /* Reserve space in the queues upstream of requests for results */
183  transfers.reserve();
184  requests.push(request);
185 
186  /* Submit the translation request. The response will come
187  * through finish/markDelayed on this request as it bears
188  * the Translation interface */
189  cpu.threads[request->id.threadId]->itb->translateTiming(
190  request->request,
191  cpu.getContext(request->id.threadId),
192  request, BaseTLB::Execute);
193 
194  lineSeqNum++;
195 
196  /* Step the PC for the next line onto the line aligned next address.
197  * Note that as instructions can span lines, this PC is only a
198  * reliable 'new' PC if the next line has a new stream sequence number. */
199 #if THE_ISA == ALPHA_ISA
200  /* Restore the low bits of the PC used as address space flags */
201  Addr pc_low_bits = thread.pc.instAddr() &
202  ((Addr) (1 << sizeof(TheISA::MachInst)) - 1);
203 
204  thread.pc.set(aligned_pc + request_size + pc_low_bits);
205 #else
206  thread.pc.set(aligned_pc + request_size);
207 #endif
208 }
209 
210 std::ostream &
211 operator <<(std::ostream &os, Fetch1::IcacheState state)
212 {
213  switch (state) {
215  os << "IcacheRunning";
216  break;
218  os << "IcacheNeedsRetry";
219  break;
220  default:
221  os << "IcacheState-" << static_cast<int>(state);
222  break;
223  }
224  return os;
225 }
226 
227 void
229 {
230  /* Make the necessary packet for a memory transaction */
231  packet = new Packet(request, MemCmd::ReadReq);
232  packet->allocate();
233 
234  /* This FetchRequest becomes SenderState to allow the response to be
235  * identified */
236  packet->pushSenderState(this);
237 }
238 
239 void
240 Fetch1::FetchRequest::finish(const Fault &fault_, const RequestPtr &request_,
242 {
243  fault = fault_;
244 
245  state = Translated;
246  fetch.handleTLBResponse(this);
247 
248  /* Let's try and wake up the processor for the next cycle */
249  fetch.cpu.wakeupOnEvent(Pipeline::Fetch1StageId);
250 }
251 
252 void
254 {
256 
257  if (response->fault != NoFault) {
258  DPRINTF(Fetch, "Fault in address ITLB translation: %s, "
259  "paddr: 0x%x, vaddr: 0x%x\n",
260  response->fault->name(),
261  (response->request->hasPaddr() ?
262  response->request->getPaddr() : 0),
263  response->request->getVaddr());
264 
265  if (DTRACE(MinorTrace))
266  minorTraceResponseLine(name(), response);
267  } else {
268  DPRINTF(Fetch, "Got ITLB response\n");
269  }
270 
271  response->state = FetchRequest::Translated;
272 
273  tryToSendToTransfers(response);
274 }
275 
277 {
278  if (packet)
279  delete packet;
280 }
281 
282 void
284 {
285  if (!requests.empty() && requests.front() != request) {
286  DPRINTF(Fetch, "Fetch not at front of requests queue, can't"
287  " issue to memory\n");
288  return;
289  }
290 
291  if (request->state == FetchRequest::InTranslation) {
292  DPRINTF(Fetch, "Fetch still in translation, not issuing to"
293  " memory\n");
294  return;
295  }
296 
297  if (request->isDiscardable() || request->fault != NoFault) {
298  /* Discarded and faulting requests carry on through transfers
299  * as Complete/packet == NULL */
300 
301  request->state = FetchRequest::Complete;
303 
304  /* Wake up the pipeline next cycle as there will be no event
305  * for this queue->queue transfer */
307  } else if (request->state == FetchRequest::Translated) {
308  if (!request->packet)
309  request->makePacket();
310 
311  /* Ensure that the packet won't delete the request */
312  assert(request->packet->needsResponse());
313 
314  if (tryToSend(request))
316  } else {
317  DPRINTF(Fetch, "Not advancing line fetch\n");
318  }
319 }
320 
321 void
323 {
324  assert(!requests.empty() && requests.front() == request);
325 
326  requests.pop();
327  transfers.push(request);
328 }
329 
330 bool
332 {
333  bool ret = false;
334 
335  if (icachePort.sendTimingReq(request->packet)) {
336  /* Invalidate the fetch_requests packet so we don't
337  * accidentally fail to deallocate it (or use it!)
338  * later by overwriting it */
339  request->packet = NULL;
342 
343  ret = true;
344 
345  DPRINTF(Fetch, "Issued fetch request to memory: %s\n",
346  request->id);
347  } else {
348  /* Needs to be resent, wait for that */
350 
351  DPRINTF(Fetch, "Line fetch needs to retry: %s\n",
352  request->id);
353  }
354 
355  return ret;
356 }
357 
358 void
360 {
361  IcacheState old_icache_state = icacheState;
362 
363  switch (icacheState) {
364  case IcacheRunning:
365  /* Move ITLB results on to the memory system */
366  if (!requests.empty()) {
368  }
369  break;
370  case IcacheNeedsRetry:
371  break;
372  }
373 
374  if (icacheState != old_icache_state) {
375  DPRINTF(Fetch, "Step in state %s moving to state %s\n",
376  old_icache_state, icacheState);
377  }
378 }
379 
380 void
382 {
383  if (!queue.empty()) {
384  delete queue.front();
385  queue.pop();
386  }
387 }
388 
389 unsigned int
391 {
392  return requests.occupiedSpace() +
394 }
395 
397 void
399  Fetch1::FetchRequestPtr response) const
400 {
401  const RequestPtr &request M5_VAR_USED = response->request;
402 
403  if (response->packet && response->packet->isError()) {
404  MINORLINE(this, "id=F;%s vaddr=0x%x fault=\"error packet\"\n",
405  response->id, request->getVaddr());
406  } else if (response->fault != NoFault) {
407  MINORLINE(this, "id=F;%s vaddr=0x%x fault=\"%s\"\n",
408  response->id, request->getVaddr(), response->fault->name());
409  } else {
410  MINORLINE(this, "id=%s size=%d vaddr=0x%x paddr=0x%x\n",
411  response->id, request->getSize(),
412  request->getVaddr(), request->getPaddr());
413  }
414 }
415 
416 bool
418 {
419  DPRINTF(Fetch, "recvTimingResp %d\n", numFetchesInMemorySystem);
420 
421  /* Only push the response if we didn't change stream? No, all responses
422  * should hit the responses queue. It's the job of 'step' to throw them
423  * away. */
424  FetchRequestPtr fetch_request = safe_cast<FetchRequestPtr>
425  (response->popSenderState());
426 
427  /* Fixup packet in fetch_request as this may have changed */
428  assert(!fetch_request->packet);
429  fetch_request->packet = response;
430 
432  fetch_request->state = FetchRequest::Complete;
433 
434  if (DTRACE(MinorTrace))
435  minorTraceResponseLine(name(), fetch_request);
436 
437  if (response->isError()) {
438  DPRINTF(Fetch, "Received error response packet: %s\n",
439  fetch_request->id);
440  }
441 
442  /* We go to idle even if there are more things to do on the queues as
443  * it's the job of step to actually step us on to the next transaction */
444 
445  /* Let's try and wake up the processor for the next cycle to move on
446  * queues */
448 
449  /* Never busy */
450  return true;
451 }
452 
453 void
455 {
456  DPRINTF(Fetch, "recvRetry\n");
457  assert(icacheState == IcacheNeedsRetry);
458  assert(!requests.empty());
459 
460  FetchRequestPtr retryRequest = requests.front();
461 
463 
464  if (tryToSend(retryRequest))
465  moveFromRequestsToTransfers(retryRequest);
466 }
467 
468 std::ostream &
469 operator <<(std::ostream &os, Fetch1::FetchState state)
470 {
471  switch (state) {
472  case Fetch1::FetchHalted:
473  os << "FetchHalted";
474  break;
476  os << "FetchWaitingForPC";
477  break;
479  os << "FetchRunning";
480  break;
481  default:
482  os << "FetchState-" << static_cast<int>(state);
483  break;
484  }
485  return os;
486 }
487 
488 void
490 {
491  Fetch1ThreadInfo &thread = fetchInfo[branch.threadId];
492 
493  updateExpectedSeqNums(branch);
494 
495  /* Start fetching again if we were stopped */
496  switch (branch.reason) {
498  {
499  if (thread.wakeupGuard) {
500  DPRINTF(Fetch, "Not suspending fetch due to guard: %s\n",
501  branch);
502  } else {
503  DPRINTF(Fetch, "Suspending fetch: %s\n", branch);
504  thread.state = FetchWaitingForPC;
505  }
506  }
507  break;
509  DPRINTF(Fetch, "Halting fetch\n");
510  thread.state = FetchHalted;
511  break;
512  default:
513  DPRINTF(Fetch, "Changing stream on branch: %s\n", branch);
514  thread.state = FetchRunning;
515  break;
516  }
517  thread.pc = branch.target;
518 }
519 
520 void
522 {
523  Fetch1ThreadInfo &thread = fetchInfo[branch.threadId];
524 
525  DPRINTF(Fetch, "Updating streamSeqNum from: %d to %d,"
526  " predictionSeqNum from: %d to %d\n",
527  thread.streamSeqNum, branch.newStreamSeqNum,
528  thread.predictionSeqNum, branch.newPredictionSeqNum);
529 
530  /* Change the stream */
531  thread.streamSeqNum = branch.newStreamSeqNum;
532  /* Update the prediction. Note that it's possible for this to
533  * actually set the prediction to an *older* value if new
534  * predictions have been discarded by execute */
535  thread.predictionSeqNum = branch.newPredictionSeqNum;
536 }
537 
538 void
540  ForwardLineData &line)
541 {
542  Fetch1ThreadInfo &thread = fetchInfo[response->id.threadId];
543  PacketPtr packet = response->packet;
544 
545  /* Pass the prefetch abort (if any) on to Fetch2 in a ForwardLineData
546  * structure */
547  line.setFault(response->fault);
548  /* Make sequence numbers valid in return */
549  line.id = response->id;
550  /* Set PC to virtual address */
551  line.pc = response->pc;
552  /* Set the lineBase, which is a sizeof(MachInst) aligned address <=
553  * pc.instAddr() */
554  line.lineBaseAddr = response->request->getVaddr();
555 
556  if (response->fault != NoFault) {
557  /* Stop fetching if there was a fault */
558  /* Should probably try to flush the queues as well, but we
559  * can't be sure that this fault will actually reach Execute, and we
560  * can't (currently) selectively remove this stream from the queues */
561  DPRINTF(Fetch, "Stopping line fetch because of fault: %s\n",
562  response->fault->name());
564  } else {
565  line.adoptPacketData(packet);
566  /* Null the response's packet to prevent the response from trying to
567  * deallocate the packet */
568  response->packet = NULL;
569  }
570 }
571 
572 void
574 {
575  const BranchData &execute_branch = *inp.outputWire;
576  const BranchData &fetch2_branch = *prediction.outputWire;
577  ForwardLineData &line_out = *out.inputWire;
578 
579  assert(line_out.isBubble());
580 
581  for (ThreadID tid = 0; tid < cpu.numThreads; tid++)
582  fetchInfo[tid].blocked = !nextStageReserve[tid].canReserve();
583 
585  if (execute_branch.threadId != InvalidThreadID &&
586  execute_branch.threadId == fetch2_branch.threadId) {
587 
588  Fetch1ThreadInfo &thread = fetchInfo[execute_branch.threadId];
589 
590  /* Are we changing stream? Look to the Execute branches first, then
591  * to predicted changes of stream from Fetch2 */
592  if (execute_branch.isStreamChange()) {
593  if (thread.state == FetchHalted) {
594  DPRINTF(Fetch, "Halted, ignoring branch: %s\n", execute_branch);
595  } else {
596  changeStream(execute_branch);
597  }
598 
599  if (!fetch2_branch.isBubble()) {
600  DPRINTF(Fetch, "Ignoring simultaneous prediction: %s\n",
601  fetch2_branch);
602  }
603 
604  /* The streamSeqNum tagging in request/response ->req should handle
605  * discarding those requests when we get to them. */
606  } else if (thread.state != FetchHalted && fetch2_branch.isStreamChange()) {
607  /* Handle branch predictions by changing the instruction source
608  * if we're still processing the same stream (as set by streamSeqNum)
609  * as the one of the prediction.
610  */
611  if (fetch2_branch.newStreamSeqNum != thread.streamSeqNum) {
612  DPRINTF(Fetch, "Not changing stream on prediction: %s,"
613  " streamSeqNum mismatch\n",
614  fetch2_branch);
615  } else {
616  changeStream(fetch2_branch);
617  }
618  }
619  } else {
620  /* Fetch2 and Execute branches are for different threads */
621  if (execute_branch.threadId != InvalidThreadID &&
622  execute_branch.isStreamChange()) {
623 
624  if (fetchInfo[execute_branch.threadId].state == FetchHalted) {
625  DPRINTF(Fetch, "Halted, ignoring branch: %s\n", execute_branch);
626  } else {
627  changeStream(execute_branch);
628  }
629  }
630 
631  if (fetch2_branch.threadId != InvalidThreadID &&
632  fetch2_branch.isStreamChange()) {
633 
634  if (fetchInfo[fetch2_branch.threadId].state == FetchHalted) {
635  DPRINTF(Fetch, "Halted, ignoring branch: %s\n", fetch2_branch);
636  } else if (fetch2_branch.newStreamSeqNum != fetchInfo[fetch2_branch.threadId].streamSeqNum) {
637  DPRINTF(Fetch, "Not changing stream on prediction: %s,"
638  " streamSeqNum mismatch\n", fetch2_branch);
639  } else {
640  changeStream(fetch2_branch);
641  }
642  }
643  }
644 
645  if (numInFlightFetches() < fetchLimit) {
646  ThreadID fetch_tid = getScheduledThread();
647 
648  if (fetch_tid != InvalidThreadID) {
649  DPRINTF(Fetch, "Fetching from thread %d\n", fetch_tid);
650 
651  /* Generate fetch to selected thread */
652  fetchLine(fetch_tid);
653  /* Take up a slot in the fetch queue */
654  nextStageReserve[fetch_tid].reserve();
655  } else {
656  DPRINTF(Fetch, "No active threads available to fetch from\n");
657  }
658  }
659 
660 
661  /* Halting shouldn't prevent fetches in flight from being processed */
662  /* Step fetches through the icachePort queues and memory system */
663  stepQueues();
664 
665  /* As we've thrown away early lines, if there is a line, it must
666  * be from the right stream */
667  if (!transfers.empty() &&
669  {
671 
672  if (response->isDiscardable()) {
673  nextStageReserve[response->id.threadId].freeReservation();
674 
675  DPRINTF(Fetch, "Discarding translated fetch as it's for"
676  " an old stream\n");
677 
678  /* Wake up next cycle just in case there was some other
679  * action to do */
681  } else {
682  DPRINTF(Fetch, "Processing fetched line: %s\n",
683  response->id);
684 
685  processResponse(response, line_out);
686  }
687 
689  }
690 
691  /* If we generated output, and mark the stage as being active
692  * to encourage that output on to the next stage */
693  if (!line_out.isBubble())
695 
696  /* Fetch1 has no inputBuffer so the only activity we can have is to
697  * generate a line output (tested just above) or to initiate a memory
698  * fetch which will signal activity when it returns/needs stepping
699  * between queues */
700 
701 
702  /* This looks hackish. And it is, but there doesn't seem to be a better
703  * way to do this. The signal from commit to suspend fetch takes 1
704  * clock cycle to propagate to fetch. However, a legitimate wakeup
705  * may occur between cycles from the memory system. Thus wakeup guard
706  * prevents us from suspending in that case. */
707 
708  for (auto& thread : fetchInfo) {
709  thread.wakeupGuard = false;
710  }
711 }
712 
713 void
715 {
716  ThreadContext *thread_ctx = cpu.getContext(tid);
717  Fetch1ThreadInfo &thread = fetchInfo[tid];
718  thread.pc = thread_ctx->pcState();
719  thread.state = FetchRunning;
720  thread.wakeupGuard = true;
721  DPRINTF(Fetch, "[tid:%d]: Changing stream wakeup %s\n",
722  tid, thread_ctx->pcState());
723 
725 }
726 
727 bool
729 {
730  bool drained = numInFlightFetches() == 0 && (*out.inputWire).isBubble();
731  for (ThreadID tid = 0; tid < cpu.numThreads; tid++) {
732  Fetch1ThreadInfo &thread = fetchInfo[tid];
733  DPRINTF(Drain, "isDrained[tid:%d]: %s %s%s\n",
734  tid,
735  thread.state == FetchHalted,
736  (numInFlightFetches() == 0 ? "" : "inFlightFetches "),
737  ((*out.inputWire).isBubble() ? "" : "outputtingLine"));
738 
739  drained = drained && (thread.state != FetchRunning);
740  }
741 
742  return drained;
743 }
744 
745 void
747 {
748  os << id;
749 }
750 
752 {
753  Fetch1ThreadInfo &thread = fetch.fetchInfo[id.threadId];
754 
755  /* Can't discard lines in TLB/memory */
756  return state != InTranslation && state != RequestIssuing &&
757  (id.streamSeqNum != thread.streamSeqNum ||
758  id.predictionSeqNum != thread.predictionSeqNum);
759 }
760 
761 void
763 {
764  // TODO: Un-bork minorTrace for THREADS
765  // bork bork bork
766  const Fetch1ThreadInfo &thread = fetchInfo[0];
767 
768  std::ostringstream data;
769 
770  if (thread.blocked)
771  data << 'B';
772  else
773  (*out.inputWire).reportData(data);
774 
775  MINORTRACE("state=%s icacheState=%s in_tlb_mem=%s/%s"
776  " streamSeqNum=%d lines=%s\n", thread.state, icacheState,
778  thread.streamSeqNum, data.str());
781 }
782 
783 }
#define panic(...)
This implements a cprintf based panic() function.
Definition: logging.hh:167
#define DPRINTF(x,...)
Definition: trace.hh:229
ThreadID threadPriority
Definition: fetch1.hh:284
bool isBubble() const
Definition: pipe_data.hh:243
void processResponse(FetchRequestPtr response, ForwardLineData &line)
Convert a response to a ForwardLineData.
Definition: fetch1.cc:539
std::vector< Fetch1ThreadInfo > fetchInfo
Definition: fetch1.hh:283
IcacheState
State of memory access for head instruction fetch.
Definition: fetch1.hh:287
InstSeqNum predictionSeqNum
Prediction sequence number.
Definition: fetch1.hh:274
decltype(nullptr) constexpr NoFault
Definition: types.hh:245
void pop()
Pop the head item.
Definition: buffers.hh:501
#define fatal(...)
This implements a cprintf based fatal() function.
Definition: logging.hh:175
void fetchLine(ThreadID tid)
Insert a line fetch into the requests.
Definition: fetch1.cc:148
Like a Queue but with a restricted interface and a setTail function which, when the queue is empty...
Definition: buffers.hh:567
ThreadID numThreads
Number of threads we&#39;re actually simulating (<= SMT_MAX_THREADS).
Definition: base.hh:378
void stepQueues()
Step requests along between requests and transfers queues.
Definition: fetch1.cc:359
Memory access queuing.
Definition: fetch1.hh:101
bool tryToSend(FetchRequestPtr request)
Try to send (or resend) a memory request&#39;s next/only packet to the memory system. ...
Definition: fetch1.cc:331
Addr lineBaseAddr
First byte address in the line.
Definition: pipe_data.hh:183
virtual TheISA::PCState pcState() const =0
static bool isStreamChange(const BranchData::Reason reason)
Is a request with this reason actually a request to change the PC rather than a bubble or branch pred...
Definition: pipe_data.cc:83
std::vector< InputBuffer< ForwardLineData > > & nextStageReserve
Interface to reserve space in the next stage.
Definition: fetch1.hh:202
ThreadID threadId
ThreadID associated with branch.
Definition: pipe_data.hh:114
unsigned int lineSnap
Line snap size in bytes.
Definition: fetch1.hh:211
bool empty() const
Is the queue empty?
Definition: buffers.hh:504
unsigned int numFetchesInMemorySystem
Count of the number fetches which have left the transfers queue and are in the &#39;wild&#39; in the memory s...
Definition: fetch1.hh:314
InstId id
Identity of the line that this request will generate.
Definition: fetch1.hh:124
std::shared_ptr< Request > RequestPtr
Definition: request.hh:83
void wakeupOnEvent(unsigned int stage_id)
Interface for stages to signal that they have become active after a callback or eventq event where th...
Definition: cpu.cc:298
void popAndDiscard(FetchQueue &queue)
Pop a request from the given queue and correctly deallocate and discard it.
Definition: fetch1.cc:381
void changeStream(const BranchData &branch)
Start fetching from a new address.
Definition: fetch1.cc:489
void updateExpectedSeqNums(const BranchData &branch)
Update streamSeqNum and predictionSeqNum from the given branch (and assume these have changed and dis...
Definition: fetch1.cc:521
void reportData(std::ostream &os) const
Report interface.
Definition: fetch1.cc:746
Line fetch data in the forward direction.
Definition: pipe_data.hh:173
Reason reason
Explanation for this branch.
Definition: pipe_data.hh:111
Stage cycle-by-cycle state.
Definition: fetch1.hh:238
void activity()
Records that there is activity this cycle.
Definition: activity.cc:56
IcacheState icacheState
Retry state of icache_port.
Definition: fetch1.hh:305
unsigned int occupiedSpace() const
Number of slots already occupied in this buffer.
Definition: buffers.hh:471
TheISA::PCState pc
PC to fixup with line address.
Definition: fetch1.hh:136
Id for lines and instructions.
Definition: dyn_inst.hh:70
InstSeqNum newStreamSeqNum
Sequence number of new stream/prediction to be adopted.
Definition: pipe_data.hh:117
TheISA::PCState pc
PC of the first requested inst within this line.
Definition: pipe_data.hh:186
bool sendTimingReq(PacketPtr pkt)
Attempt to send a timing request to the slave port by calling its corresponding receive function...
Definition: port.hh:445
Minor contains all the definitions within the MinorCPU apart from the CPU class itself.
Definition: activity.cc:46
Fetch1(const std::string &name_, MinorCPU &cpu_, MinorCPUParams &params, Latch< BranchData >::Output inp_, Latch< ForwardLineData >::Input out_, Latch< BranchData >::Output prediction_, std::vector< InputBuffer< ForwardLineData >> &next_stage_input_buffer)
Definition: fetch1.cc:55
Latch< BranchData >::Output inp
Input port carrying branch requests from Execute.
Definition: fetch1.hh:195
Bitfield< 4, 0 > mode
ThreadContext is the external interface to all thread state for anything outside of the CPU...
void finish(const Fault &fault_, const RequestPtr &request_, ThreadContext *tc, BaseTLB::Mode mode)
Interface for ITLB responses.
Definition: fetch1.cc:240
Bitfield< 17 > os
Definition: misc.hh:805
STL vector class.
Definition: stl.hh:40
Bitfield< 33 > id
void reserve()
Reserve space in the queue for future pushes.
Definition: buffers.hh:456
void handleTLBResponse(FetchRequestPtr response)
Handle pushing a TLB response onto the right queue.
Definition: fetch1.cc:253
MinorCPU & cpu
Construction-assigned data members.
Definition: fetch1.hh:192
uint32_t MachInst
Definition: types.hh:40
bool blocked
Blocked indication for report.
Definition: fetch1.hh:277
Definition: trace.hh:151
void minorTraceResponseLine(const std::string &name, FetchRequestPtr response) const
Print the appropriate MinorLine line for a fetch response.
Definition: fetch1.cc:398
bool needsResponse() const
Definition: packet.hh:542
#define DTRACE(x)
Definition: trace.hh:227
bool isError() const
Definition: packet.hh:555
ElemType & front()
Head value.
Definition: buffers.hh:496
bool wakeupGuard
Signal to guard against sleeping first cycle of wakeup.
Definition: fetch1.hh:280
std::vector< ThreadID > randomPriority()
Definition: cpu.hh:178
Latch< BranchData >::Output prediction
Input port carrying branch predictions from Fetch2.
Definition: fetch1.hh:199
bool isBubble() const
Definition: pipe_data.hh:150
FetchQueue requests
Queue of address translated requests from Fetch1.
Definition: fetch1.hh:299
void moveFromRequestsToTransfers(FetchRequestPtr request)
Move a request between queues.
Definition: fetch1.cc:322
Minor::MinorActivityRecorder * activityRecorder
Activity recording for pipeline.
Definition: cpu.hh:90
bool isDiscardable() const
Is this line out of date with the current stream/prediction sequence and can it be discarded without ...
Definition: fetch1.cc:751
InstId id
Thread, stream, prediction ...
Definition: pipe_data.hh:197
Latch< ForwardLineData >::Input out
Output port carrying read lines to Fetch2.
Definition: fetch1.hh:197
unsigned int numFetchesInITLB
Number of requests inside the ITLB rather than in the queues.
Definition: fetch1.hh:318
uint64_t Addr
Address type This will probably be moved somewhere else in the near future.
Definition: types.hh:142
unsigned int numInFlightFetches()
Returns the total number of queue occupancy, in-ITLB and in-memory system fetches.
Definition: fetch1.cc:390
void minorTrace() const
Definition: buffers.hh:507
void makePacket()
Make a packet to use with the memory transaction.
Definition: fetch1.cc:228
T safe_cast(U ptr)
Definition: cast.hh:61
InstSeqNum streamSeqNum
Stream sequence number.
Definition: fetch1.hh:268
A Packet is used to encapsulate a transfer between two objects in the memory system (e...
Definition: packet.hh:255
const std::string & name() const
Definition: trace.hh:160
The request was an instruction fetch.
Definition: request.hh:105
FetchState
Cycle-by-cycle state.
Definition: fetch1.hh:226
std::vector< ThreadID > roundRobinPriority(ThreadID priority)
Thread scheduling utility functions.
Definition: cpu.hh:169
Fault fault
Fill in a fault if one happens during fetch, check this by picking apart the response packet...
Definition: fetch1.hh:140
const ThreadID InvalidThreadID
Definition: types.hh:228
Fetch1 is responsible for fetching "lines" from memory and passing them to Fetch2.
unsigned int maxLineWidth
Maximum fetch width in bytes.
Definition: fetch1.hh:217
FetchRequestState state
Definition: fetch1.hh:121
Mode
Definition: tlb.hh:59
friend std::ostream & operator<<(std::ostream &os, Fetch1::FetchState state)
Definition: fetch1.cc:469
RequestPtr request
The underlying request that this fetch represents.
Definition: fetch1.hh:133
int16_t ThreadID
Thread index/ID type.
Definition: types.hh:227
unsigned int cacheLineSize() const
Get the cache line size of the system.
Definition: base.hh:391
Forward data betwen Execute and Fetch1 carrying change-of-address/stream information.
Definition: pipe_data.hh:64
Enums::ThreadPolicy threadPolicy
Thread Scheduling Policy (RoundRobin, Random, etc)
Definition: cpu.hh:114
TheISA::PCState pc
Fetch PC value.
Definition: fetch1.hh:263
bool isComplete() const
Is this a complete read line or fault.
Definition: fetch1.hh:154
virtual bool recvTimingResp(PacketPtr pkt)
Memory interface.
Definition: fetch1.cc:417
virtual ThreadContext * getContext(int tn)
Given a thread num get tho thread context for it.
Definition: base.hh:298
std::vector< Minor::MinorThread * > threads
These are thread state-representing objects for this CPU.
Definition: cpu.hh:95
InstSeqNum newPredictionSeqNum
Definition: pipe_data.hh:118
void push(ElemType &data)
Push an element into the buffer if it isn&#39;t a bubble.
Definition: buffers.hh:428
#define MINORTRACE(...)
DPRINTFN for MinorTrace reporting.
Definition: trace.hh:62
The constructed pipeline.
virtual Status status() const =0
void wakeupFetch(ThreadID tid)
Initiate fetch1 fetching.
Definition: fetch1.cc:714
void tryToSendToTransfers(FetchRequestPtr request)
Try and issue a fetch for a translated request at the head of the requests queue. ...
Definition: fetch1.cc:283
bool isDrained()
Is this stage drained? For Fetch1, draining is initiated by Execute signalling a branch with the reas...
Definition: fetch1.cc:728
SenderState * popSenderState()
Pop the top of the state stack and return a pointer to it.
Definition: packet.cc:327
#define MINORLINE(sim_object,...)
DPRINTFN for MinorTrace MinorLine line reporting.
Definition: trace.hh:70
InstSeqNum lineSeqNum
Sequence number for line fetch used for ordering lines to flush.
Definition: fetch1.hh:308
PacketPtr packet
FetchRequests carry packets while they&#39;re in the requests and transfers responses queues...
Definition: fetch1.hh:130
void setFault(Fault fault_)
Set fault and possible clear the bubble flag.
Definition: pipe_data.cc:165
MinorCPU is an in-order CPU model with four fixed pipeline stages:
Definition: cpu.hh:79
void evaluate()
Pass on input/buffer data to the output if you can.
Definition: fetch1.cc:573
Encapsulate wires on either input or output of the latch.
Definition: buffers.hh:247
static const int NumArgumentRegs M5_VAR_USED
Definition: process.cc:84
TheISA::PCState target
Starting PC of that stream.
Definition: pipe_data.hh:121
void adoptPacketData(Packet *packet)
Use the data from a packet as line instead of allocating new space.
Definition: pipe_data.cc:185
FetchQueue transfers
Queue of in-memory system requests and responses.
Definition: fetch1.hh:302
void minorTrace() const
Definition: fetch1.cc:762
IcachePort icachePort
IcachePort to pass to the CPU.
Definition: fetch1.hh:206
const char data[]
std::shared_ptr< FaultBase > Fault
Definition: types.hh:240
unsigned int fetchLimit
Maximum number of fetches allowed in flight (in queues or memory)
Definition: fetch1.hh:220
ThreadID threadId
The thread to which this line/instruction belongs.
Definition: dyn_inst.hh:83
MasterID instMasterId() const
Reads this CPU&#39;s unique instruction requestor ID.
Definition: base.hh:191
ProbePointArg< PacketInfo > Packet
Packet probe point.
Definition: mem.hh:104
ThreadID getScheduledThread()
Use the current threading policy to determine the next thread to fetch from.
Definition: fetch1.cc:116
virtual void recvReqRetry()
Definition: fetch1.cc:454

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