| //===-- Analysis.cpp --------------------------------------------*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "Analysis.h" |
| #include "BenchmarkResult.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/MC/MCAsmInfo.h" |
| #include "llvm/Support/FormatVariadic.h" |
| #include <unordered_set> |
| #include <vector> |
| |
| namespace exegesis { |
| |
| static const char kCsvSep = ','; |
| |
| namespace { |
| |
| enum EscapeTag { kEscapeCsv, kEscapeHtml, kEscapeHtmlString }; |
| |
| template <EscapeTag Tag> |
| void writeEscaped(llvm::raw_ostream &OS, const llvm::StringRef S); |
| |
| template <> |
| void writeEscaped<kEscapeCsv>(llvm::raw_ostream &OS, const llvm::StringRef S) { |
| if (std::find(S.begin(), S.end(), kCsvSep) == S.end()) { |
| OS << S; |
| } else { |
| // Needs escaping. |
| OS << '"'; |
| for (const char C : S) { |
| if (C == '"') |
| OS << "\"\""; |
| else |
| OS << C; |
| } |
| OS << '"'; |
| } |
| } |
| |
| template <> |
| void writeEscaped<kEscapeHtml>(llvm::raw_ostream &OS, const llvm::StringRef S) { |
| for (const char C : S) { |
| if (C == '<') |
| OS << "<"; |
| else if (C == '>') |
| OS << ">"; |
| else if (C == '&') |
| OS << "&"; |
| else |
| OS << C; |
| } |
| } |
| |
| template <> |
| void writeEscaped<kEscapeHtmlString>(llvm::raw_ostream &OS, |
| const llvm::StringRef S) { |
| for (const char C : S) { |
| if (C == '"') |
| OS << "\\\""; |
| else |
| OS << C; |
| } |
| } |
| |
| } // namespace |
| |
| template <EscapeTag Tag> |
| static void |
| writeClusterId(llvm::raw_ostream &OS, |
| const InstructionBenchmarkClustering::ClusterId &CID) { |
| if (CID.isNoise()) |
| writeEscaped<Tag>(OS, "[noise]"); |
| else if (CID.isError()) |
| writeEscaped<Tag>(OS, "[error]"); |
| else |
| OS << CID.getId(); |
| } |
| |
| template <EscapeTag Tag> |
| static void writeMeasurementValue(llvm::raw_ostream &OS, const double Value) { |
| writeEscaped<Tag>(OS, llvm::formatv("{0:F}", Value).str()); |
| } |
| |
| template <typename EscapeTag, EscapeTag Tag> |
| void Analysis::writeSnippet(llvm::raw_ostream &OS, |
| llvm::ArrayRef<uint8_t> Bytes, |
| const char *Separator) const { |
| llvm::SmallVector<std::string, 3> Lines; |
| // Parse the asm snippet and print it. |
| while (!Bytes.empty()) { |
| llvm::MCInst MI; |
| uint64_t MISize = 0; |
| if (!Disasm_->getInstruction(MI, MISize, Bytes, 0, llvm::nulls(), |
| llvm::nulls())) { |
| writeEscaped<Tag>(OS, llvm::join(Lines, Separator)); |
| writeEscaped<Tag>(OS, Separator); |
| writeEscaped<Tag>(OS, "[error decoding asm snippet]"); |
| return; |
| } |
| Lines.emplace_back(); |
| std::string &Line = Lines.back(); |
| llvm::raw_string_ostream OSS(Line); |
| InstPrinter_->printInst(&MI, OSS, "", *SubtargetInfo_); |
| Bytes = Bytes.drop_front(MISize); |
| OSS.flush(); |
| Line = llvm::StringRef(Line).trim().str(); |
| } |
| writeEscaped<Tag>(OS, llvm::join(Lines, Separator)); |
| } |
| |
| // Prints a row representing an instruction, along with scheduling info and |
| // point coordinates (measurements). |
| void Analysis::printInstructionRowCsv(const size_t PointId, |
| llvm::raw_ostream &OS) const { |
| const InstructionBenchmark &Point = Clustering_.getPoints()[PointId]; |
| writeClusterId<kEscapeCsv>(OS, Clustering_.getClusterIdForPoint(PointId)); |
| OS << kCsvSep; |
| writeSnippet<EscapeTag, kEscapeCsv>(OS, Point.AssembledSnippet, "; "); |
| OS << kCsvSep; |
| writeEscaped<kEscapeCsv>(OS, Point.Key.Config); |
| OS << kCsvSep; |
| assert(!Point.Key.Instructions.empty()); |
| // FIXME: Resolve variant classes. |
| const unsigned SchedClassId = |
| InstrInfo_->get(Point.Key.Instructions[0].getOpcode()).getSchedClass(); |
| #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) |
| const auto &SchedModel = SubtargetInfo_->getSchedModel(); |
| const llvm::MCSchedClassDesc *const SCDesc = |
| SchedModel.getSchedClassDesc(SchedClassId); |
| writeEscaped<kEscapeCsv>(OS, SCDesc->Name); |
| #else |
| OS << SchedClassId; |
| #endif |
| for (const auto &Measurement : Point.Measurements) { |
| OS << kCsvSep; |
| writeMeasurementValue<kEscapeCsv>(OS, Measurement.Value); |
| } |
| OS << "\n"; |
| } |
| |
| Analysis::Analysis(const llvm::Target &Target, |
| const InstructionBenchmarkClustering &Clustering) |
| : Clustering_(Clustering) { |
| if (Clustering.getPoints().empty()) |
| return; |
| |
| const InstructionBenchmark &FirstPoint = Clustering.getPoints().front(); |
| InstrInfo_.reset(Target.createMCInstrInfo()); |
| RegInfo_.reset(Target.createMCRegInfo(FirstPoint.LLVMTriple)); |
| AsmInfo_.reset(Target.createMCAsmInfo(*RegInfo_, FirstPoint.LLVMTriple)); |
| SubtargetInfo_.reset(Target.createMCSubtargetInfo(FirstPoint.LLVMTriple, |
| FirstPoint.CpuName, "")); |
| InstPrinter_.reset(Target.createMCInstPrinter( |
| llvm::Triple(FirstPoint.LLVMTriple), 0 /*default variant*/, *AsmInfo_, |
| *InstrInfo_, *RegInfo_)); |
| |
| Context_ = llvm::make_unique<llvm::MCContext>(AsmInfo_.get(), RegInfo_.get(), |
| &ObjectFileInfo_); |
| Disasm_.reset(Target.createMCDisassembler(*SubtargetInfo_, *Context_)); |
| assert(Disasm_ && "cannot create MCDisassembler. missing call to " |
| "InitializeXXXTargetDisassembler ?"); |
| } |
| |
| template <> |
| llvm::Error |
| Analysis::run<Analysis::PrintClusters>(llvm::raw_ostream &OS) const { |
| if (Clustering_.getPoints().empty()) |
| return llvm::Error::success(); |
| |
| // Write the header. |
| OS << "cluster_id" << kCsvSep << "opcode_name" << kCsvSep << "config" |
| << kCsvSep << "sched_class"; |
| for (const auto &Measurement : Clustering_.getPoints().front().Measurements) { |
| OS << kCsvSep; |
| writeEscaped<kEscapeCsv>(OS, Measurement.Key); |
| } |
| OS << "\n"; |
| |
| // Write the points. |
| const auto &Clusters = Clustering_.getValidClusters(); |
| for (size_t I = 0, E = Clusters.size(); I < E; ++I) { |
| for (const size_t PointId : Clusters[I].PointIndices) { |
| printInstructionRowCsv(PointId, OS); |
| } |
| OS << "\n\n"; |
| } |
| return llvm::Error::success(); |
| } |
| |
| std::unordered_map<unsigned, std::vector<size_t>> |
| Analysis::makePointsPerSchedClass() const { |
| std::unordered_map<unsigned, std::vector<size_t>> PointsPerSchedClass; |
| const auto &Points = Clustering_.getPoints(); |
| for (size_t PointId = 0, E = Points.size(); PointId < E; ++PointId) { |
| const InstructionBenchmark &Point = Points[PointId]; |
| if (!Point.Error.empty()) |
| continue; |
| assert(!Point.Key.Instructions.empty()); |
| const auto Opcode = Point.Key.Instructions[0].getOpcode(); |
| // FIXME: Resolve variant classes. |
| PointsPerSchedClass[InstrInfo_->get(Opcode).getSchedClass()].push_back( |
| PointId); |
| } |
| return PointsPerSchedClass; |
| } |
| |
| // Uops repeat the same opcode over again. Just show this opcode and show the |
| // whole snippet only on hover. |
| static void writeUopsSnippetHtml(llvm::raw_ostream &OS, |
| const std::vector<llvm::MCInst> &Instructions, |
| const llvm::MCInstrInfo &InstrInfo) { |
| if (Instructions.empty()) |
| return; |
| writeEscaped<kEscapeHtml>(OS, InstrInfo.getName(Instructions[0].getOpcode())); |
| if (Instructions.size() > 1) |
| OS << " (x" << Instructions.size() << ")"; |
| } |
| |
| // Latency tries to find a serial path. Just show the opcode path and show the |
| // whole snippet only on hover. |
| static void |
| writeLatencySnippetHtml(llvm::raw_ostream &OS, |
| const std::vector<llvm::MCInst> &Instructions, |
| const llvm::MCInstrInfo &InstrInfo) { |
| bool First = true; |
| for (const llvm::MCInst &Instr : Instructions) { |
| if (First) |
| First = false; |
| else |
| OS << " → "; |
| writeEscaped<kEscapeHtml>(OS, InstrInfo.getName(Instr.getOpcode())); |
| } |
| } |
| |
| void Analysis::printSchedClassClustersHtml( |
| const std::vector<SchedClassCluster> &Clusters, const SchedClass &SC, |
| llvm::raw_ostream &OS) const { |
| const auto &Points = Clustering_.getPoints(); |
| OS << "<table class=\"sched-class-clusters\">"; |
| OS << "<tr><th>ClusterId</th><th>Opcode/Config</th>"; |
| assert(!Clusters.empty()); |
| for (const auto &Measurement : |
| Points[Clusters[0].getPointIds()[0]].Measurements) { |
| OS << "<th>"; |
| if (Measurement.DebugString.empty()) |
| writeEscaped<kEscapeHtml>(OS, Measurement.Key); |
| else |
| writeEscaped<kEscapeHtml>(OS, Measurement.DebugString); |
| OS << "</th>"; |
| } |
| OS << "</tr>"; |
| for (const SchedClassCluster &Cluster : Clusters) { |
| OS << "<tr class=\"" |
| << (Cluster.measurementsMatch(*SubtargetInfo_, SC, Clustering_) |
| ? "good-cluster" |
| : "bad-cluster") |
| << "\"><td>"; |
| writeClusterId<kEscapeHtml>(OS, Cluster.id()); |
| OS << "</td><td><ul>"; |
| for (const size_t PointId : Cluster.getPointIds()) { |
| const auto &Point = Points[PointId]; |
| OS << "<li><span class=\"mono\" title=\""; |
| writeSnippet<EscapeTag, kEscapeHtmlString>(OS, Point.AssembledSnippet, |
| "\n"); |
| OS << "\">"; |
| switch (Point.Mode) { |
| case InstructionBenchmark::Latency: |
| writeLatencySnippetHtml(OS, Point.Key.Instructions, *InstrInfo_); |
| break; |
| case InstructionBenchmark::Uops: |
| writeUopsSnippetHtml(OS, Point.Key.Instructions, *InstrInfo_); |
| break; |
| default: |
| llvm_unreachable("invalid mode"); |
| } |
| OS << "</span> <span class=\"mono\">"; |
| writeEscaped<kEscapeHtml>(OS, Point.Key.Config); |
| OS << "</span></li>"; |
| } |
| OS << "</ul></td>"; |
| for (const auto &Stats : Cluster.getRepresentative()) { |
| OS << "<td class=\"measurement\">"; |
| writeMeasurementValue<kEscapeHtml>(OS, Stats.avg()); |
| OS << "<br><span class=\"minmax\">["; |
| writeMeasurementValue<kEscapeHtml>(OS, Stats.min()); |
| OS << ";"; |
| writeMeasurementValue<kEscapeHtml>(OS, Stats.max()); |
| OS << "]</span></td>"; |
| } |
| OS << "</tr>"; |
| } |
| OS << "</table>"; |
| } |
| |
| // Return the non-redundant list of WriteProcRes used by the given sched class. |
| // The scheduling model for LLVM is such that each instruction has a certain |
| // number of uops which consume resources which are described by WriteProcRes |
| // entries. Each entry describe how many cycles are spent on a specific ProcRes |
| // kind. |
| // For example, an instruction might have 3 uOps, one dispatching on P0 |
| // (ProcResIdx=1) and two on P06 (ProcResIdx = 7). |
| // Note that LLVM additionally denormalizes resource consumption to include |
| // usage of super resources by subresources. So in practice if there exists a |
| // P016 (ProcResIdx=10), then the cycles consumed by P0 are also consumed by |
| // P06 (ProcResIdx = 7) and P016 (ProcResIdx = 10), and the resources consumed |
| // by P06 are also consumed by P016. In the figure below, parenthesized cycles |
| // denote implied usage of superresources by subresources: |
| // P0 P06 P016 |
| // uOp1 1 (1) (1) |
| // uOp2 1 (1) |
| // uOp3 1 (1) |
| // ============================= |
| // 1 3 3 |
| // Eventually we end up with three entries for the WriteProcRes of the |
| // instruction: |
| // {ProcResIdx=1, Cycles=1} // P0 |
| // {ProcResIdx=7, Cycles=3} // P06 |
| // {ProcResIdx=10, Cycles=3} // P016 |
| // |
| // Note that in this case, P016 does not contribute any cycles, so it would |
| // be removed by this function. |
| // FIXME: Move this to MCSubtargetInfo and use it in llvm-mca. |
| static llvm::SmallVector<llvm::MCWriteProcResEntry, 8> |
| getNonRedundantWriteProcRes(const llvm::MCSchedClassDesc &SCDesc, |
| const llvm::MCSubtargetInfo &STI) { |
| llvm::SmallVector<llvm::MCWriteProcResEntry, 8> Result; |
| const auto &SM = STI.getSchedModel(); |
| const unsigned NumProcRes = SM.getNumProcResourceKinds(); |
| |
| // This assumes that the ProcResDescs are sorted in topological order, which |
| // is guaranteed by the tablegen backend. |
| llvm::SmallVector<float, 32> ProcResUnitUsage(NumProcRes); |
| for (const auto *WPR = STI.getWriteProcResBegin(&SCDesc), |
| *const WPREnd = STI.getWriteProcResEnd(&SCDesc); |
| WPR != WPREnd; ++WPR) { |
| const llvm::MCProcResourceDesc *const ProcResDesc = |
| SM.getProcResource(WPR->ProcResourceIdx); |
| if (ProcResDesc->SubUnitsIdxBegin == nullptr) { |
| // This is a ProcResUnit. |
| Result.push_back({WPR->ProcResourceIdx, WPR->Cycles}); |
| ProcResUnitUsage[WPR->ProcResourceIdx] += WPR->Cycles; |
| } else { |
| // This is a ProcResGroup. First see if it contributes any cycles or if |
| // it has cycles just from subunits. |
| float RemainingCycles = WPR->Cycles; |
| for (const auto *SubResIdx = ProcResDesc->SubUnitsIdxBegin; |
| SubResIdx != ProcResDesc->SubUnitsIdxBegin + ProcResDesc->NumUnits; |
| ++SubResIdx) { |
| RemainingCycles -= ProcResUnitUsage[*SubResIdx]; |
| } |
| if (RemainingCycles < 0.01f) { |
| // The ProcResGroup contributes no cycles of its own. |
| continue; |
| } |
| // The ProcResGroup contributes `RemainingCycles` cycles of its own. |
| Result.push_back({WPR->ProcResourceIdx, |
| static_cast<uint16_t>(std::round(RemainingCycles))}); |
| // Spread the remaining cycles over all subunits. |
| for (const auto *SubResIdx = ProcResDesc->SubUnitsIdxBegin; |
| SubResIdx != ProcResDesc->SubUnitsIdxBegin + ProcResDesc->NumUnits; |
| ++SubResIdx) { |
| ProcResUnitUsage[*SubResIdx] += RemainingCycles / ProcResDesc->NumUnits; |
| } |
| } |
| } |
| return Result; |
| } |
| |
| Analysis::SchedClass::SchedClass(const llvm::MCSchedClassDesc &SD, |
| const llvm::MCSubtargetInfo &STI) |
| : SCDesc(&SD), |
| NonRedundantWriteProcRes(getNonRedundantWriteProcRes(SD, STI)), |
| IdealizedProcResPressure(computeIdealizedProcResPressure( |
| STI.getSchedModel(), NonRedundantWriteProcRes)) {} |
| |
| void Analysis::SchedClassCluster::addPoint( |
| size_t PointId, const InstructionBenchmarkClustering &Clustering) { |
| PointIds.push_back(PointId); |
| const auto &Point = Clustering.getPoints()[PointId]; |
| if (ClusterId.isUndef()) { |
| ClusterId = Clustering.getClusterIdForPoint(PointId); |
| Representative.resize(Point.Measurements.size()); |
| } |
| for (size_t I = 0, E = Point.Measurements.size(); I < E; ++I) { |
| Representative[I].push(Point.Measurements[I]); |
| } |
| assert(ClusterId == Clustering.getClusterIdForPoint(PointId)); |
| } |
| |
| bool Analysis::SchedClassCluster::measurementsMatch( |
| const llvm::MCSubtargetInfo &STI, const SchedClass &SC, |
| const InstructionBenchmarkClustering &Clustering) const { |
| const size_t NumMeasurements = Representative.size(); |
| std::vector<BenchmarkMeasure> ClusterCenterPoint(NumMeasurements); |
| std::vector<BenchmarkMeasure> SchedClassPoint(NumMeasurements); |
| // Latency case. |
| assert(!Clustering.getPoints().empty()); |
| const InstructionBenchmark::ModeE Mode = Clustering.getPoints()[0].Mode; |
| if (Mode == InstructionBenchmark::Latency) { |
| if (NumMeasurements != 1) { |
| llvm::errs() |
| << "invalid number of measurements in latency mode: expected 1, got " |
| << NumMeasurements << "\n"; |
| return false; |
| } |
| // Find the latency. |
| SchedClassPoint[0].Value = 0.0; |
| for (unsigned I = 0; I < SC.SCDesc->NumWriteLatencyEntries; ++I) { |
| const llvm::MCWriteLatencyEntry *const WLE = |
| STI.getWriteLatencyEntry(SC.SCDesc, I); |
| SchedClassPoint[0].Value = |
| std::max<double>(SchedClassPoint[0].Value, WLE->Cycles); |
| } |
| ClusterCenterPoint[0].Value = Representative[0].avg(); |
| } else if (Mode == InstructionBenchmark::Uops) { |
| for (int I = 0, E = Representative.size(); I < E; ++I) { |
| // Find the pressure on ProcResIdx `Key`. |
| uint16_t ProcResIdx = 0; |
| if (!llvm::to_integer(Representative[I].key(), ProcResIdx, 10)) { |
| llvm::errs() << "expected ProcResIdx key, got " |
| << Representative[I].key() << "\n"; |
| return false; |
| } |
| const auto ProcResPressureIt = |
| std::find_if(SC.IdealizedProcResPressure.begin(), |
| SC.IdealizedProcResPressure.end(), |
| [ProcResIdx](const std::pair<uint16_t, float> &WPR) { |
| return WPR.first == ProcResIdx; |
| }); |
| SchedClassPoint[I].Value = |
| ProcResPressureIt == SC.IdealizedProcResPressure.end() |
| ? 0.0 |
| : ProcResPressureIt->second; |
| ClusterCenterPoint[I].Value = Representative[I].avg(); |
| } |
| } else { |
| llvm::errs() << "unimplemented measurement matching for mode " << Mode |
| << "\n"; |
| return false; |
| } |
| return Clustering.isNeighbour(ClusterCenterPoint, SchedClassPoint); |
| } |
| |
| void Analysis::printSchedClassDescHtml(const SchedClass &SC, |
| llvm::raw_ostream &OS) const { |
| OS << "<table class=\"sched-class-desc\">"; |
| OS << "<tr><th>Valid</th><th>Variant</th><th>uOps</th><th>Latency</" |
| "th><th>WriteProcRes</th><th title=\"This is the idealized unit " |
| "resource (port) pressure assuming ideal distribution\">Idealized " |
| "Resource Pressure</th></tr>"; |
| if (SC.SCDesc->isValid()) { |
| const auto &SM = SubtargetInfo_->getSchedModel(); |
| OS << "<tr><td>✔</td>"; |
| OS << "<td>" << (SC.SCDesc->isVariant() ? "✔" : "✕") |
| << "</td>"; |
| OS << "<td>" << SC.SCDesc->NumMicroOps << "</td>"; |
| // Latencies. |
| OS << "<td><ul>"; |
| for (int I = 0, E = SC.SCDesc->NumWriteLatencyEntries; I < E; ++I) { |
| const auto *const Entry = |
| SubtargetInfo_->getWriteLatencyEntry(SC.SCDesc, I); |
| OS << "<li>" << Entry->Cycles; |
| if (SC.SCDesc->NumWriteLatencyEntries > 1) { |
| // Dismabiguate if more than 1 latency. |
| OS << " (WriteResourceID " << Entry->WriteResourceID << ")"; |
| } |
| OS << "</li>"; |
| } |
| OS << "</ul></td>"; |
| // WriteProcRes. |
| OS << "<td><ul>"; |
| for (const auto &WPR : SC.NonRedundantWriteProcRes) { |
| OS << "<li><span class=\"mono\">"; |
| writeEscaped<kEscapeHtml>(OS, |
| SM.getProcResource(WPR.ProcResourceIdx)->Name); |
| OS << "</span>: " << WPR.Cycles << "</li>"; |
| } |
| OS << "</ul></td>"; |
| // Idealized port pressure. |
| OS << "<td><ul>"; |
| for (const auto &Pressure : SC.IdealizedProcResPressure) { |
| OS << "<li><span class=\"mono\">"; |
| writeEscaped<kEscapeHtml>(OS, SubtargetInfo_->getSchedModel() |
| .getProcResource(Pressure.first) |
| ->Name); |
| OS << "</span>: "; |
| writeMeasurementValue<kEscapeHtml>(OS, Pressure.second); |
| OS << "</li>"; |
| } |
| OS << "</ul></td>"; |
| OS << "</tr>"; |
| } else { |
| OS << "<tr><td>✕</td><td></td><td></td></tr>"; |
| } |
| OS << "</table>"; |
| } |
| |
| static constexpr const char kHtmlHead[] = R"( |
| <head> |
| <title>llvm-exegesis Analysis Results</title> |
| <style> |
| body { |
| font-family: sans-serif |
| } |
| span.sched-class-name { |
| font-weight: bold; |
| font-family: monospace; |
| } |
| span.opcode { |
| font-family: monospace; |
| } |
| span.config { |
| font-family: monospace; |
| } |
| div.inconsistency { |
| margin-top: 50px; |
| } |
| table { |
| margin-left: 50px; |
| border-collapse: collapse; |
| } |
| table, table tr,td,th { |
| border: 1px solid #444; |
| } |
| table ul { |
| padding-left: 0px; |
| margin: 0px; |
| list-style-type: none; |
| } |
| table.sched-class-clusters td { |
| padding-left: 10px; |
| padding-right: 10px; |
| padding-top: 10px; |
| padding-bottom: 10px; |
| } |
| table.sched-class-desc td { |
| padding-left: 10px; |
| padding-right: 10px; |
| padding-top: 2px; |
| padding-bottom: 2px; |
| } |
| span.mono { |
| font-family: monospace; |
| } |
| td.measurement { |
| text-align: center; |
| } |
| tr.good-cluster td.measurement { |
| color: #292 |
| } |
| tr.bad-cluster td.measurement { |
| color: #922 |
| } |
| tr.good-cluster td.measurement span.minmax { |
| color: #888; |
| } |
| tr.bad-cluster td.measurement span.minmax { |
| color: #888; |
| } |
| </style> |
| </head> |
| )"; |
| |
| template <> |
| llvm::Error Analysis::run<Analysis::PrintSchedClassInconsistencies>( |
| llvm::raw_ostream &OS) const { |
| const auto &FirstPoint = Clustering_.getPoints()[0]; |
| // Print the header. |
| OS << "<!DOCTYPE html><html>" << kHtmlHead << "<body>"; |
| OS << "<h1><span class=\"mono\">llvm-exegesis</span> Analysis Results</h1>"; |
| OS << "<h3>Triple: <span class=\"mono\">"; |
| writeEscaped<kEscapeHtml>(OS, FirstPoint.LLVMTriple); |
| OS << "</span></h3><h3>Cpu: <span class=\"mono\">"; |
| writeEscaped<kEscapeHtml>(OS, FirstPoint.CpuName); |
| OS << "</span></h3>"; |
| |
| for (const auto &SchedClassAndPoints : makePointsPerSchedClass()) { |
| const auto SchedClassId = SchedClassAndPoints.first; |
| const std::vector<size_t> &SchedClassPoints = SchedClassAndPoints.second; |
| const auto &SchedModel = SubtargetInfo_->getSchedModel(); |
| const llvm::MCSchedClassDesc *const SCDesc = |
| SchedModel.getSchedClassDesc(SchedClassId); |
| if (!SCDesc) |
| continue; |
| const SchedClass SC(*SCDesc, *SubtargetInfo_); |
| |
| // Bucket sched class points into sched class clusters. |
| std::vector<SchedClassCluster> SchedClassClusters; |
| for (const size_t PointId : SchedClassPoints) { |
| const auto &ClusterId = Clustering_.getClusterIdForPoint(PointId); |
| if (!ClusterId.isValid()) |
| continue; // Ignore noise and errors. FIXME: take noise into account ? |
| auto SchedClassClusterIt = |
| std::find_if(SchedClassClusters.begin(), SchedClassClusters.end(), |
| [ClusterId](const SchedClassCluster &C) { |
| return C.id() == ClusterId; |
| }); |
| if (SchedClassClusterIt == SchedClassClusters.end()) { |
| SchedClassClusters.emplace_back(); |
| SchedClassClusterIt = std::prev(SchedClassClusters.end()); |
| } |
| SchedClassClusterIt->addPoint(PointId, Clustering_); |
| } |
| |
| // Print any scheduling class that has at least one cluster that does not |
| // match the checked-in data. |
| if (std::all_of(SchedClassClusters.begin(), SchedClassClusters.end(), |
| [this, &SC](const SchedClassCluster &C) { |
| return C.measurementsMatch(*SubtargetInfo_, SC, |
| Clustering_); |
| })) |
| continue; // Nothing weird. |
| |
| OS << "<div class=\"inconsistency\"><p>Sched Class <span " |
| "class=\"sched-class-name\">"; |
| #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP) |
| writeEscaped<kEscapeHtml>(OS, SCDesc->Name); |
| #else |
| OS << SchedClassId; |
| #endif |
| OS << "</span> contains instructions whose performance characteristics do" |
| " not match that of LLVM:</p>"; |
| printSchedClassClustersHtml(SchedClassClusters, SC, OS); |
| OS << "<p>llvm SchedModel data:</p>"; |
| printSchedClassDescHtml(SC, OS); |
| OS << "</div>"; |
| } |
| |
| OS << "</body></html>"; |
| return llvm::Error::success(); |
| } |
| |
| // Distributes a pressure budget as evenly as possible on the provided subunits |
| // given the already existing port pressure distribution. |
| // |
| // The algorithm is as follows: while there is remaining pressure to |
| // distribute, find the subunits with minimal pressure, and distribute |
| // remaining pressure equally up to the pressure of the unit with |
| // second-to-minimal pressure. |
| // For example, let's assume we want to distribute 2*P1256 |
| // (Subunits = [P1,P2,P5,P6]), and the starting DensePressure is: |
| // DensePressure = P0 P1 P2 P3 P4 P5 P6 P7 |
| // 0.1 0.3 0.2 0.0 0.0 0.5 0.5 0.5 |
| // RemainingPressure = 2.0 |
| // We sort the subunits by pressure: |
| // Subunits = [(P2,p=0.2), (P1,p=0.3), (P5,p=0.5), (P6, p=0.5)] |
| // We'll first start by the subunits with minimal pressure, which are at |
| // the beginning of the sorted array. In this example there is one (P2). |
| // The subunit with second-to-minimal pressure is the next one in the |
| // array (P1). So we distribute 0.1 pressure to P2, and remove 0.1 cycles |
| // from the budget. |
| // Subunits = [(P2,p=0.3), (P1,p=0.3), (P5,p=0.5), (P5,p=0.5)] |
| // RemainingPressure = 1.9 |
| // We repeat this process: distribute 0.2 pressure on each of the minimal |
| // P2 and P1, decrease budget by 2*0.2: |
| // Subunits = [(P2,p=0.5), (P1,p=0.5), (P5,p=0.5), (P5,p=0.5)] |
| // RemainingPressure = 1.5 |
| // There are no second-to-minimal subunits so we just share the remaining |
| // budget (1.5 cycles) equally: |
| // Subunits = [(P2,p=0.875), (P1,p=0.875), (P5,p=0.875), (P5,p=0.875)] |
| // RemainingPressure = 0.0 |
| // We stop as there is no remaining budget to distribute. |
| void distributePressure(float RemainingPressure, |
| llvm::SmallVector<uint16_t, 32> Subunits, |
| llvm::SmallVector<float, 32> &DensePressure) { |
| // Find the number of subunits with minimal pressure (they are at the |
| // front). |
| llvm::sort(Subunits.begin(), Subunits.end(), |
| [&DensePressure](const uint16_t A, const uint16_t B) { |
| return DensePressure[A] < DensePressure[B]; |
| }); |
| const auto getPressureForSubunit = [&DensePressure, |
| &Subunits](size_t I) -> float & { |
| return DensePressure[Subunits[I]]; |
| }; |
| size_t NumMinimalSU = 1; |
| while (NumMinimalSU < Subunits.size() && |
| getPressureForSubunit(NumMinimalSU) == getPressureForSubunit(0)) { |
| ++NumMinimalSU; |
| } |
| while (RemainingPressure > 0.0f) { |
| if (NumMinimalSU == Subunits.size()) { |
| // All units are minimal, just distribute evenly and be done. |
| for (size_t I = 0; I < NumMinimalSU; ++I) { |
| getPressureForSubunit(I) += RemainingPressure / NumMinimalSU; |
| } |
| return; |
| } |
| // Distribute the remaining pressure equally. |
| const float MinimalPressure = getPressureForSubunit(NumMinimalSU - 1); |
| const float SecondToMinimalPressure = getPressureForSubunit(NumMinimalSU); |
| assert(MinimalPressure < SecondToMinimalPressure); |
| const float Increment = SecondToMinimalPressure - MinimalPressure; |
| if (RemainingPressure <= NumMinimalSU * Increment) { |
| // There is not enough remaining pressure. |
| for (size_t I = 0; I < NumMinimalSU; ++I) { |
| getPressureForSubunit(I) += RemainingPressure / NumMinimalSU; |
| } |
| return; |
| } |
| // Bump all minimal pressure subunits to `SecondToMinimalPressure`. |
| for (size_t I = 0; I < NumMinimalSU; ++I) { |
| getPressureForSubunit(I) = SecondToMinimalPressure; |
| RemainingPressure -= SecondToMinimalPressure; |
| } |
| while (NumMinimalSU < Subunits.size() && |
| getPressureForSubunit(NumMinimalSU) == SecondToMinimalPressure) { |
| ++NumMinimalSU; |
| } |
| } |
| } |
| |
| std::vector<std::pair<uint16_t, float>> computeIdealizedProcResPressure( |
| const llvm::MCSchedModel &SM, |
| llvm::SmallVector<llvm::MCWriteProcResEntry, 8> WPRS) { |
| // DensePressure[I] is the port pressure for Proc Resource I. |
| llvm::SmallVector<float, 32> DensePressure(SM.getNumProcResourceKinds()); |
| llvm::sort(WPRS.begin(), WPRS.end(), |
| [](const llvm::MCWriteProcResEntry &A, |
| const llvm::MCWriteProcResEntry &B) { |
| return A.ProcResourceIdx < B.ProcResourceIdx; |
| }); |
| for (const llvm::MCWriteProcResEntry &WPR : WPRS) { |
| // Get units for the entry. |
| const llvm::MCProcResourceDesc *const ProcResDesc = |
| SM.getProcResource(WPR.ProcResourceIdx); |
| if (ProcResDesc->SubUnitsIdxBegin == nullptr) { |
| // This is a ProcResUnit. |
| DensePressure[WPR.ProcResourceIdx] += WPR.Cycles; |
| } else { |
| // This is a ProcResGroup. |
| llvm::SmallVector<uint16_t, 32> Subunits(ProcResDesc->SubUnitsIdxBegin, |
| ProcResDesc->SubUnitsIdxBegin + |
| ProcResDesc->NumUnits); |
| distributePressure(WPR.Cycles, Subunits, DensePressure); |
| } |
| } |
| // Turn dense pressure into sparse pressure by removing zero entries. |
| std::vector<std::pair<uint16_t, float>> Pressure; |
| for (unsigned I = 0, E = SM.getNumProcResourceKinds(); I < E; ++I) { |
| if (DensePressure[I] > 0.0f) |
| Pressure.emplace_back(I, DensePressure[I]); |
| } |
| return Pressure; |
| } |
| |
| } // namespace exegesis |
