llvm/tools/llvm-mca/Views/ResourcePressureView.cpp

   1 //===--------------------- ResourcePressureView.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 methods in the ResourcePressureView interface.
  11 ///
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "Views/ResourcePressureView.h"
  15 #include "llvm/Support/FormattedStream.h"
  16 #include "llvm/Support/raw_ostream.h"
  17
  18 namespace llvm {
  19 namespace mca {
  20
  21 ResourcePressureView::ResourcePressureView(const llvm::MCSubtargetInfo &sti,
  22                                            MCInstPrinter &Printer,
  23                                            ArrayRef<MCInst> S)
  24     : InstructionView(sti, Printer, S), LastInstructionIdx(0) {
  25   // Populate the map of resource descriptors.
  26   unsigned R2VIndex = 0;
  27   const MCSchedModel &SM = getSubTargetInfo().getSchedModel();
  28   for (unsigned I = 0, E = SM.getNumProcResourceKinds(); I < E; ++I) {
  29     const MCProcResourceDesc &ProcResource = *SM.getProcResource(I);
  30     unsigned NumUnits = ProcResource.NumUnits;
  31     // Skip groups and invalid resources with zero units.
  32     if (ProcResource.SubUnitsIdxBegin || !NumUnits)
  33       continue;
  34
  35     Resource2VecIndex.insert(std::pair<unsigned, unsigned>(I, R2VIndex));
  36     R2VIndex += ProcResource.NumUnits;
  37   }
  38
  39   NumResourceUnits = R2VIndex;
  40   ResourceUsage.resize(NumResourceUnits * (getSource().size() + 1));
  41   std::fill(ResourceUsage.begin(), ResourceUsage.end(), 0.0);
  42 }
  43
  44 void ResourcePressureView::onEvent(const HWInstructionEvent &Event) {
  45   if (Event.Type == HWInstructionEvent::Dispatched) {
  46     LastInstructionIdx = Event.IR.getSourceIndex();
  47     return;
  48   }
  49
  50   // We're only interested in Issue events.
  51   if (Event.Type != HWInstructionEvent::Issued)
  52     return;
  53
  54   const auto &IssueEvent = static_cast<const HWInstructionIssuedEvent &>(Event);
  55   ArrayRef<llvm::MCInst> Source = getSource();
  56   const unsigned SourceIdx = Event.IR.getSourceIndex() % Source.size();
  57   for (const std::pair<ResourceRef, ReleaseAtCycles> &Use :
  58        IssueEvent.UsedResources) {
  59     const ResourceRef &RR = Use.first;
  60     assert(Resource2VecIndex.contains(RR.first));
  61     unsigned R2VIndex = Resource2VecIndex[RR.first];
  62     R2VIndex += llvm::countr_zero(RR.second);
  63     ResourceUsage[R2VIndex + NumResourceUnits * SourceIdx] += Use.second;
  64     ResourceUsage[R2VIndex + NumResourceUnits * Source.size()] += Use.second;
  65   }
  66 }
  67
  68 static void printColumnNames(formatted_raw_ostream &OS,
  69                              const MCSchedModel &SM) {
  70   unsigned Column = OS.getColumn();
  71   for (unsigned I = 1, ResourceIndex = 0, E = SM.getNumProcResourceKinds();
  72        I < E; ++I) {
  73     const MCProcResourceDesc &ProcResource = *SM.getProcResource(I);
  74     unsigned NumUnits = ProcResource.NumUnits;
  75     // Skip groups and invalid resources with zero units.
  76     if (ProcResource.SubUnitsIdxBegin || !NumUnits)
  77       continue;
  78
  79     for (unsigned J = 0; J < NumUnits; ++J) {
  80       Column += 7;
  81       OS << "[" << ResourceIndex;
  82       if (NumUnits > 1)
  83         OS << '.' << J;
  84       OS << ']';
  85       OS.PadToColumn(Column);
  86     }
  87
  88     ResourceIndex++;
  89   }
  90 }
  91
  92 static void printResourcePressure(formatted_raw_ostream &OS, double Pressure,
  93                                   unsigned Col) {
  94   if (!Pressure || Pressure < 0.005) {
  95     OS << " - ";
  96   } else {
  97     // Round to the value to the nearest hundredth and then print it.
  98     OS << format("%.2f", floor((Pressure * 100) + 0.5) / 100);
  99   }
 100   OS.PadToColumn(Col);
 101 }
 102
 103 void ResourcePressureView::printResourcePressurePerIter(raw_ostream &OS) const {
 104   std::string Buffer;
 105   raw_string_ostream TempStream(Buffer);
 106   formatted_raw_ostream FOS(TempStream);
 107
 108   FOS << "\n\nResources:\n";
 109   const MCSchedModel &SM = getSubTargetInfo().getSchedModel();
 110   for (unsigned I = 1, ResourceIndex = 0, E = SM.getNumProcResourceKinds();
 111        I < E; ++I) {
 112     const MCProcResourceDesc &ProcResource = *SM.getProcResource(I);
 113     unsigned NumUnits = ProcResource.NumUnits;
 114     // Skip groups and invalid resources with zero units.
 115     if (ProcResource.SubUnitsIdxBegin || !NumUnits)
 116       continue;
 117
 118     for (unsigned J = 0; J < NumUnits; ++J) {
 119       FOS << '[' << ResourceIndex;
 120       if (NumUnits > 1)
 121         FOS << '.' << J;
 122       FOS << ']';
 123       FOS.PadToColumn(6);
 124       FOS << "- " << ProcResource.Name << '\n';
 125     }
 126
 127     ResourceIndex++;
 128   }
 129
 130   FOS << "\n\nResource pressure per iteration:\n";
 131   FOS.flush();
 132   printColumnNames(FOS, SM);
 133   FOS << '\n';
 134   FOS.flush();
 135
 136   ArrayRef<llvm::MCInst> Source = getSource();
 137   const unsigned Executions = LastInstructionIdx / Source.size() + 1;
 138   for (unsigned I = 0, E = NumResourceUnits; I < E; ++I) {
 139     double Usage = ResourceUsage[I + Source.size() * E];
 140     printResourcePressure(FOS, Usage / Executions, (I + 1) * 7);
 141   }
 142
 143   FOS.flush();
 144   OS << Buffer;
 145 }
 146
 147 void ResourcePressureView::printResourcePressurePerInst(raw_ostream &OS) const {
 148   std::string Buffer;
 149   raw_string_ostream TempStream(Buffer);
 150   formatted_raw_ostream FOS(TempStream);
 151
 152   FOS << "\n\nResource pressure by instruction:\n";
 153   printColumnNames(FOS, getSubTargetInfo().getSchedModel());
 154   FOS << "Instructions:\n";
 155
 156   unsigned InstrIndex = 0;
 157   ArrayRef<llvm::MCInst> Source = getSource();
 158   const unsigned Executions = LastInstructionIdx / Source.size() + 1;
 159   for (const MCInst &MCI : Source) {
 160     unsigned BaseEltIdx = InstrIndex * NumResourceUnits;
 161     for (unsigned J = 0; J < NumResourceUnits; ++J) {
 162       double Usage = ResourceUsage[J + BaseEltIdx];
 163       printResourcePressure(FOS, Usage / Executions, (J + 1) * 7);
 164     }
 165
 166     FOS << printInstructionString(MCI) << '\n';
 167     FOS.flush();
 168     OS << Buffer;
 169     Buffer = "";
 170
 171     ++InstrIndex;
 172   }
 173 }
 174
 175 json::Value ResourcePressureView::toJSON() const {
 176   // We're dumping the instructions and the ResourceUsage array.
 177   json::Array ResourcePressureInfo;
 178
 179   // The ResourceUsage matrix is sparse, so we only consider
 180   // non-zero values.
 181   ArrayRef<llvm::MCInst> Source = getSource();
 182   const unsigned Executions = LastInstructionIdx / Source.size() + 1;
 183   for (const auto &R : enumerate(ResourceUsage)) {
 184     const ReleaseAtCycles &RU = R.value();
 185     if (RU.getNumerator() == 0)
 186       continue;
 187     unsigned InstructionIndex = R.index() / NumResourceUnits;
 188     unsigned ResourceIndex = R.index() % NumResourceUnits;
 189     double Usage = RU / Executions;
 190     ResourcePressureInfo.push_back(
 191         json::Object({{"InstructionIndex", InstructionIndex},
 192                       {"ResourceIndex", ResourceIndex},
 193                       {"ResourceUsage", Usage}}));
 194   }
 195
 196   json::Object JO({{"ResourcePressureInfo", std::move(ResourcePressureInfo)}});
 197   return JO;
 198 }
 199 } // namespace mca
 200 } // namespace llvm