SchedulerStatistics.cpp revision 360784 
1//===--------------------- SchedulerStatistics.cpp --------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8/// \file
9///
10/// This file implements the SchedulerStatistics interface.
11///
12//===----------------------------------------------------------------------===//
13
14#include "Views/SchedulerStatistics.h"
15#include "llvm/Support/Format.h"
16#include "llvm/Support/FormattedStream.h"
17
18namespace llvm {
19namespace mca {
20
21SchedulerStatistics::SchedulerStatistics(const llvm::MCSubtargetInfo &STI)
22    : SM(STI.getSchedModel()), LQResourceID(0), SQResourceID(0), NumIssued(0),
23      NumCycles(0), MostRecentLoadDispatched(~0U),
24      MostRecentStoreDispatched(~0U),
25      Usage(STI.getSchedModel().NumProcResourceKinds, {0, 0, 0}) {
26  if (SM.hasExtraProcessorInfo()) {
27    const MCExtraProcessorInfo &EPI = SM.getExtraProcessorInfo();
28    LQResourceID = EPI.LoadQueueID;
29    SQResourceID = EPI.StoreQueueID;
30  }
31}
32
33// FIXME: This implementation works under the assumption that load/store queue
34// entries are reserved at 'instruction dispatched' stage, and released at
35// 'instruction executed' stage. This currently matches the behavior of LSUnit.
36//
37// The current design minimizes the number of events generated by the
38// Dispatch/Execute stages, at the cost of doing extra bookkeeping in method
39// `onEvent`. However, it introduces a subtle dependency between this view and
40// how the LSUnit works.
41//
42// In future we should add a new "memory queue" event type, so that we stop
43// making assumptions on how LSUnit internally works (See PR39828).
44void SchedulerStatistics::onEvent(const HWInstructionEvent &Event) {
45  if (Event.Type == HWInstructionEvent::Issued) {
46    const Instruction &Inst = *Event.IR.getInstruction();
47    NumIssued += Inst.getDesc().NumMicroOps;
48  } else if (Event.Type == HWInstructionEvent::Dispatched) {
49    const Instruction &Inst = *Event.IR.getInstruction();
50    const unsigned Index = Event.IR.getSourceIndex();
51    if (LQResourceID && Inst.getDesc().MayLoad &&
52        MostRecentLoadDispatched != Index) {
53      Usage[LQResourceID].SlotsInUse++;
54      MostRecentLoadDispatched = Index;
55    }
56    if (SQResourceID && Inst.getDesc().MayStore &&
57        MostRecentStoreDispatched != Index) {
58      Usage[SQResourceID].SlotsInUse++;
59      MostRecentStoreDispatched = Index;
60    }
61  } else if (Event.Type == HWInstructionEvent::Executed) {
62    const Instruction &Inst = *Event.IR.getInstruction();
63    if (LQResourceID && Inst.getDesc().MayLoad) {
64      assert(Usage[LQResourceID].SlotsInUse);
65      Usage[LQResourceID].SlotsInUse--;
66    }
67    if (SQResourceID && Inst.getDesc().MayStore) {
68      assert(Usage[SQResourceID].SlotsInUse);
69      Usage[SQResourceID].SlotsInUse--;
70    }
71  }
72}
73
74void SchedulerStatistics::onReservedBuffers(const InstRef & /* unused */,
75                                            ArrayRef<unsigned> Buffers) {
76  for (const unsigned Buffer : Buffers) {
77    if (Buffer == LQResourceID || Buffer == SQResourceID)
78      continue;
79    Usage[Buffer].SlotsInUse++;
80  }
81}
82
83void SchedulerStatistics::onReleasedBuffers(const InstRef & /* unused */,
84                                            ArrayRef<unsigned> Buffers) {
85  for (const unsigned Buffer : Buffers) {
86    if (Buffer == LQResourceID || Buffer == SQResourceID)
87      continue;
88    Usage[Buffer].SlotsInUse--;
89  }
90}
91
92void SchedulerStatistics::updateHistograms() {
93  for (BufferUsage &BU : Usage) {
94    BU.CumulativeNumUsedSlots += BU.SlotsInUse;
95    BU.MaxUsedSlots = std::max(BU.MaxUsedSlots, BU.SlotsInUse);
96  }
97
98  IssueWidthPerCycle[NumIssued]++;
99  NumIssued = 0;
100}
101
102void SchedulerStatistics::printSchedulerStats(raw_ostream &OS) const {
103  OS << "\n\nSchedulers - "
104     << "number of cycles where we saw N micro opcodes issued:\n";
105  OS << "[# issued], [# cycles]\n";
106
107  bool HasColors = OS.has_colors();
108  const auto It =
109      std::max_element(IssueWidthPerCycle.begin(), IssueWidthPerCycle.end());
110  for (const std::pair<const unsigned, unsigned> &Entry : IssueWidthPerCycle) {
111    unsigned NumIssued = Entry.first;
112    if (NumIssued == It->first && HasColors)
113      OS.changeColor(raw_ostream::SAVEDCOLOR, true, false);
114
115    unsigned IPC = Entry.second;
116    OS << " " << NumIssued << ",          " << IPC << "  ("
117       << format("%.1f", ((double)IPC / NumCycles) * 100) << "%)\n";
118    if (HasColors)
119      OS.resetColor();
120  }
121}
122
123void SchedulerStatistics::printSchedulerUsage(raw_ostream &OS) const {
124  assert(NumCycles && "Unexpected number of cycles!");
125
126  OS << "\nScheduler's queue usage:\n";
127  if (all_of(Usage, [](const BufferUsage &BU) { return !BU.MaxUsedSlots; })) {
128    OS << "No scheduler resources used.\n";
129    return;
130  }
131
132  OS << "[1] Resource name.\n"
133     << "[2] Average number of used buffer entries.\n"
134     << "[3] Maximum number of used buffer entries.\n"
135     << "[4] Total number of buffer entries.\n\n"
136     << " [1]            [2]        [3]        [4]\n";
137
138  formatted_raw_ostream FOS(OS);
139  bool HasColors = FOS.has_colors();
140  for (unsigned I = 0, E = SM.getNumProcResourceKinds(); I < E; ++I) {
141    const MCProcResourceDesc &ProcResource = *SM.getProcResource(I);
142    if (ProcResource.BufferSize <= 0)
143      continue;
144
145    const BufferUsage &BU = Usage[I];
146    double AvgUsage = (double)BU.CumulativeNumUsedSlots / NumCycles;
147    double AlmostFullThreshold = (double)(ProcResource.BufferSize * 4) / 5;
148    unsigned NormalizedAvg = floor((AvgUsage * 10) + 0.5) / 10;
149    unsigned NormalizedThreshold = floor((AlmostFullThreshold * 10) + 0.5) / 10;
150
151    FOS << ProcResource.Name;
152    FOS.PadToColumn(17);
153    if (HasColors && NormalizedAvg >= NormalizedThreshold)
154      FOS.changeColor(raw_ostream::YELLOW, true, false);
155    FOS << NormalizedAvg;
156    if (HasColors)
157      FOS.resetColor();
158    FOS.PadToColumn(28);
159    if (HasColors &&
160        BU.MaxUsedSlots == static_cast<unsigned>(ProcResource.BufferSize))
161      FOS.changeColor(raw_ostream::RED, true, false);
162    FOS << BU.MaxUsedSlots;
163    if (HasColors)
164      FOS.resetColor();
165    FOS.PadToColumn(39);
166    FOS << ProcResource.BufferSize << '\n';
167  }
168
169  FOS.flush();
170}
171
172void SchedulerStatistics::printView(raw_ostream &OS) const {
173  printSchedulerStats(OS);
174  printSchedulerUsage(OS);
175}
176
177} // namespace mca
178} // namespace llvm
179