| //===-- llvm-exegesis.cpp ---------------------------------------*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| /// |
| /// \file |
| /// Measures execution properties (latencies/uops) of an instruction. |
| /// |
| //===----------------------------------------------------------------------===// |
| |
| #include "lib/Analysis.h" |
| #include "lib/BenchmarkResult.h" |
| #include "lib/BenchmarkRunner.h" |
| #include "lib/Clustering.h" |
| #include "lib/Error.h" |
| #include "lib/LlvmState.h" |
| #include "lib/PerfHelper.h" |
| #include "lib/SnippetFile.h" |
| #include "lib/SnippetRepetitor.h" |
| #include "lib/Target.h" |
| #include "lib/TargetSelect.h" |
| #include "llvm/ADT/StringExtras.h" |
| #include "llvm/ADT/Twine.h" |
| #include "llvm/MC/MCInstBuilder.h" |
| #include "llvm/MC/MCObjectFileInfo.h" |
| #include "llvm/MC/MCParser/MCAsmParser.h" |
| #include "llvm/MC/MCParser/MCTargetAsmParser.h" |
| #include "llvm/MC/MCRegisterInfo.h" |
| #include "llvm/MC/MCSubtargetInfo.h" |
| #include "llvm/MC/TargetRegistry.h" |
| #include "llvm/Object/ObjectFile.h" |
| #include "llvm/Support/CommandLine.h" |
| #include "llvm/Support/FileSystem.h" |
| #include "llvm/Support/Format.h" |
| #include "llvm/Support/Path.h" |
| #include "llvm/Support/SourceMgr.h" |
| #include "llvm/Support/TargetSelect.h" |
| #include <algorithm> |
| #include <string> |
| |
| namespace llvm { |
| namespace exegesis { |
| |
| static cl::OptionCategory Options("llvm-exegesis options"); |
| static cl::OptionCategory BenchmarkOptions("llvm-exegesis benchmark options"); |
| static cl::OptionCategory AnalysisOptions("llvm-exegesis analysis options"); |
| |
| static cl::opt<int> OpcodeIndex( |
| "opcode-index", |
| cl::desc("opcode to measure, by index, or -1 to measure all opcodes"), |
| cl::cat(BenchmarkOptions), cl::init(0)); |
| |
| static cl::opt<std::string> |
| OpcodeNames("opcode-name", |
| cl::desc("comma-separated list of opcodes to measure, by name"), |
| cl::cat(BenchmarkOptions), cl::init("")); |
| |
| static cl::opt<std::string> SnippetsFile("snippets-file", |
| cl::desc("code snippets to measure"), |
| cl::cat(BenchmarkOptions), |
| cl::init("")); |
| |
| static cl::opt<std::string> |
| BenchmarkFile("benchmarks-file", |
| cl::desc("File to read (analysis mode) or write " |
| "(latency/uops/inverse_throughput modes) benchmark " |
| "results. “-” uses stdin/stdout."), |
| cl::cat(Options), cl::init("")); |
| |
| static cl::opt<exegesis::InstructionBenchmark::ModeE> BenchmarkMode( |
| "mode", cl::desc("the mode to run"), cl::cat(Options), |
| cl::values(clEnumValN(exegesis::InstructionBenchmark::Latency, "latency", |
| "Instruction Latency"), |
| clEnumValN(exegesis::InstructionBenchmark::InverseThroughput, |
| "inverse_throughput", |
| "Instruction Inverse Throughput"), |
| clEnumValN(exegesis::InstructionBenchmark::Uops, "uops", |
| "Uop Decomposition"), |
| // When not asking for a specific benchmark mode, |
| // we'll analyse the results. |
| clEnumValN(exegesis::InstructionBenchmark::Unknown, "analysis", |
| "Analysis"))); |
| |
| static cl::opt<exegesis::InstructionBenchmark::ResultAggregationModeE> |
| ResultAggMode( |
| "result-aggregation-mode", |
| cl::desc("How to aggregate multi-values result"), cl::cat(Options), |
| cl::values(clEnumValN(exegesis::InstructionBenchmark::Min, "min", |
| "Keep min reading"), |
| clEnumValN(exegesis::InstructionBenchmark::Max, "max", |
| "Keep max reading"), |
| clEnumValN(exegesis::InstructionBenchmark::Mean, "mean", |
| "Compute mean of all readings"), |
| clEnumValN(exegesis::InstructionBenchmark::MinVariance, |
| "min-variance", |
| "Keep readings set with min-variance")), |
| cl::init(exegesis::InstructionBenchmark::Min)); |
| |
| static cl::opt<exegesis::InstructionBenchmark::RepetitionModeE> RepetitionMode( |
| "repetition-mode", cl::desc("how to repeat the instruction snippet"), |
| cl::cat(BenchmarkOptions), |
| cl::values( |
| clEnumValN(exegesis::InstructionBenchmark::Duplicate, "duplicate", |
| "Duplicate the snippet"), |
| clEnumValN(exegesis::InstructionBenchmark::Loop, "loop", |
| "Loop over the snippet"), |
| clEnumValN(exegesis::InstructionBenchmark::AggregateMin, "min", |
| "All of the above and take the minimum of measurements")), |
| cl::init(exegesis::InstructionBenchmark::Duplicate)); |
| |
| static cl::opt<unsigned> |
| NumRepetitions("num-repetitions", |
| cl::desc("number of time to repeat the asm snippet"), |
| cl::cat(BenchmarkOptions), cl::init(10000)); |
| |
| static cl::opt<unsigned> |
| LoopBodySize("loop-body-size", |
| cl::desc("when repeating the instruction snippet by looping " |
| "over it, duplicate the snippet until the loop body " |
| "contains at least this many instruction"), |
| cl::cat(BenchmarkOptions), cl::init(0)); |
| |
| static cl::opt<unsigned> MaxConfigsPerOpcode( |
| "max-configs-per-opcode", |
| cl::desc( |
| "allow to snippet generator to generate at most that many configs"), |
| cl::cat(BenchmarkOptions), cl::init(1)); |
| |
| static cl::opt<bool> IgnoreInvalidSchedClass( |
| "ignore-invalid-sched-class", |
| cl::desc("ignore instructions that do not define a sched class"), |
| cl::cat(BenchmarkOptions), cl::init(false)); |
| |
| static cl::opt<exegesis::InstructionBenchmarkClustering::ModeE> |
| AnalysisClusteringAlgorithm( |
| "analysis-clustering", cl::desc("the clustering algorithm to use"), |
| cl::cat(AnalysisOptions), |
| cl::values(clEnumValN(exegesis::InstructionBenchmarkClustering::Dbscan, |
| "dbscan", "use DBSCAN/OPTICS algorithm"), |
| clEnumValN(exegesis::InstructionBenchmarkClustering::Naive, |
| "naive", "one cluster per opcode")), |
| cl::init(exegesis::InstructionBenchmarkClustering::Dbscan)); |
| |
| static cl::opt<unsigned> AnalysisDbscanNumPoints( |
| "analysis-numpoints", |
| cl::desc("minimum number of points in an analysis cluster (dbscan only)"), |
| cl::cat(AnalysisOptions), cl::init(3)); |
| |
| static cl::opt<float> AnalysisClusteringEpsilon( |
| "analysis-clustering-epsilon", |
| cl::desc("epsilon for benchmark point clustering"), |
| cl::cat(AnalysisOptions), cl::init(0.1)); |
| |
| static cl::opt<float> AnalysisInconsistencyEpsilon( |
| "analysis-inconsistency-epsilon", |
| cl::desc("epsilon for detection of when the cluster is different from the " |
| "LLVM schedule profile values"), |
| cl::cat(AnalysisOptions), cl::init(0.1)); |
| |
| static cl::opt<std::string> |
| AnalysisClustersOutputFile("analysis-clusters-output-file", cl::desc(""), |
| cl::cat(AnalysisOptions), cl::init("")); |
| static cl::opt<std::string> |
| AnalysisInconsistenciesOutputFile("analysis-inconsistencies-output-file", |
| cl::desc(""), cl::cat(AnalysisOptions), |
| cl::init("")); |
| |
| static cl::opt<bool> AnalysisDisplayUnstableOpcodes( |
| "analysis-display-unstable-clusters", |
| cl::desc("if there is more than one benchmark for an opcode, said " |
| "benchmarks may end up not being clustered into the same cluster " |
| "if the measured performance characteristics are different. by " |
| "default all such opcodes are filtered out. this flag will " |
| "instead show only such unstable opcodes"), |
| cl::cat(AnalysisOptions), cl::init(false)); |
| |
| static cl::opt<std::string> CpuName( |
| "mcpu", |
| cl::desc("cpu name to use for pfm counters, leave empty to autodetect"), |
| cl::cat(Options), cl::init("")); |
| |
| static cl::opt<bool> |
| DumpObjectToDisk("dump-object-to-disk", |
| cl::desc("dumps the generated benchmark object to disk " |
| "and prints a message to access it"), |
| cl::cat(BenchmarkOptions), cl::init(true)); |
| |
| static ExitOnError ExitOnErr("llvm-exegesis error: "); |
| |
| // Helper function that logs the error(s) and exits. |
| template <typename... ArgTs> static void ExitWithError(ArgTs &&... Args) { |
| ExitOnErr(make_error<Failure>(std::forward<ArgTs>(Args)...)); |
| } |
| |
| // Check Err. If it's in a failure state log the file error(s) and exit. |
| static void ExitOnFileError(const Twine &FileName, Error Err) { |
| if (Err) { |
| ExitOnErr(createFileError(FileName, std::move(Err))); |
| } |
| } |
| |
| // Check E. If it's in a success state then return the contained value. |
| // If it's in a failure state log the file error(s) and exit. |
| template <typename T> |
| T ExitOnFileError(const Twine &FileName, Expected<T> &&E) { |
| ExitOnFileError(FileName, E.takeError()); |
| return std::move(*E); |
| } |
| |
| // Checks that only one of OpcodeNames, OpcodeIndex or SnippetsFile is provided, |
| // and returns the opcode indices or {} if snippets should be read from |
| // `SnippetsFile`. |
| static std::vector<unsigned> getOpcodesOrDie(const MCInstrInfo &MCInstrInfo) { |
| const size_t NumSetFlags = (OpcodeNames.empty() ? 0 : 1) + |
| (OpcodeIndex == 0 ? 0 : 1) + |
| (SnippetsFile.empty() ? 0 : 1); |
| if (NumSetFlags != 1) { |
| ExitOnErr.setBanner("llvm-exegesis: "); |
| ExitWithError("please provide one and only one of 'opcode-index', " |
| "'opcode-name' or 'snippets-file'"); |
| } |
| if (!SnippetsFile.empty()) |
| return {}; |
| if (OpcodeIndex > 0) |
| return {static_cast<unsigned>(OpcodeIndex)}; |
| if (OpcodeIndex < 0) { |
| std::vector<unsigned> Result; |
| for (unsigned I = 1, E = MCInstrInfo.getNumOpcodes(); I < E; ++I) |
| Result.push_back(I); |
| return Result; |
| } |
| // Resolve opcode name -> opcode. |
| const auto ResolveName = [&MCInstrInfo](StringRef OpcodeName) -> unsigned { |
| for (unsigned I = 1, E = MCInstrInfo.getNumOpcodes(); I < E; ++I) |
| if (MCInstrInfo.getName(I) == OpcodeName) |
| return I; |
| return 0u; |
| }; |
| SmallVector<StringRef, 2> Pieces; |
| StringRef(OpcodeNames.getValue()) |
| .split(Pieces, ",", /* MaxSplit */ -1, /* KeepEmpty */ false); |
| std::vector<unsigned> Result; |
| for (const StringRef &OpcodeName : Pieces) { |
| if (unsigned Opcode = ResolveName(OpcodeName)) |
| Result.push_back(Opcode); |
| else |
| ExitWithError(Twine("unknown opcode ").concat(OpcodeName)); |
| } |
| return Result; |
| } |
| |
| // Generates code snippets for opcode `Opcode`. |
| static Expected<std::vector<BenchmarkCode>> |
| generateSnippets(const LLVMState &State, unsigned Opcode, |
| const BitVector &ForbiddenRegs) { |
| const Instruction &Instr = State.getIC().getInstr(Opcode); |
| const MCInstrDesc &InstrDesc = Instr.Description; |
| // Ignore instructions that we cannot run. |
| if (InstrDesc.isPseudo() || InstrDesc.usesCustomInsertionHook()) |
| return make_error<Failure>( |
| "Unsupported opcode: isPseudo/usesCustomInserter"); |
| if (InstrDesc.isBranch() || InstrDesc.isIndirectBranch()) |
| return make_error<Failure>("Unsupported opcode: isBranch/isIndirectBranch"); |
| if (InstrDesc.isCall() || InstrDesc.isReturn()) |
| return make_error<Failure>("Unsupported opcode: isCall/isReturn"); |
| |
| const std::vector<InstructionTemplate> InstructionVariants = |
| State.getExegesisTarget().generateInstructionVariants( |
| Instr, MaxConfigsPerOpcode); |
| |
| SnippetGenerator::Options SnippetOptions; |
| SnippetOptions.MaxConfigsPerOpcode = MaxConfigsPerOpcode; |
| const std::unique_ptr<SnippetGenerator> Generator = |
| State.getExegesisTarget().createSnippetGenerator(BenchmarkMode, State, |
| SnippetOptions); |
| if (!Generator) |
| ExitWithError("cannot create snippet generator"); |
| |
| std::vector<BenchmarkCode> Benchmarks; |
| for (const InstructionTemplate &Variant : InstructionVariants) { |
| if (Benchmarks.size() >= MaxConfigsPerOpcode) |
| break; |
| if (auto Err = Generator->generateConfigurations(Variant, Benchmarks, |
| ForbiddenRegs)) |
| return std::move(Err); |
| } |
| return Benchmarks; |
| } |
| |
| void benchmarkMain() { |
| #ifndef HAVE_LIBPFM |
| ExitWithError("benchmarking unavailable, LLVM was built without libpfm."); |
| #endif |
| |
| if (exegesis::pfm::pfmInitialize()) |
| ExitWithError("cannot initialize libpfm"); |
| |
| InitializeNativeTarget(); |
| InitializeNativeTargetAsmPrinter(); |
| InitializeNativeTargetAsmParser(); |
| InitializeNativeExegesisTarget(); |
| |
| const LLVMState State(CpuName); |
| |
| // Preliminary check to ensure features needed for requested |
| // benchmark mode are present on target CPU and/or OS. |
| ExitOnErr(State.getExegesisTarget().checkFeatureSupport()); |
| |
| const std::unique_ptr<BenchmarkRunner> Runner = |
| ExitOnErr(State.getExegesisTarget().createBenchmarkRunner( |
| BenchmarkMode, State, ResultAggMode)); |
| if (!Runner) { |
| ExitWithError("cannot create benchmark runner"); |
| } |
| |
| const auto Opcodes = getOpcodesOrDie(State.getInstrInfo()); |
| |
| SmallVector<std::unique_ptr<const SnippetRepetitor>, 2> Repetitors; |
| if (RepetitionMode != InstructionBenchmark::RepetitionModeE::AggregateMin) |
| Repetitors.emplace_back(SnippetRepetitor::Create(RepetitionMode, State)); |
| else { |
| for (InstructionBenchmark::RepetitionModeE RepMode : |
| {InstructionBenchmark::RepetitionModeE::Duplicate, |
| InstructionBenchmark::RepetitionModeE::Loop}) |
| Repetitors.emplace_back(SnippetRepetitor::Create(RepMode, State)); |
| } |
| |
| BitVector AllReservedRegs; |
| llvm::for_each(Repetitors, |
| [&AllReservedRegs]( |
| const std::unique_ptr<const SnippetRepetitor> &Repetitor) { |
| AllReservedRegs |= Repetitor->getReservedRegs(); |
| }); |
| |
| std::vector<BenchmarkCode> Configurations; |
| if (!Opcodes.empty()) { |
| for (const unsigned Opcode : Opcodes) { |
| // Ignore instructions without a sched class if |
| // -ignore-invalid-sched-class is passed. |
| if (IgnoreInvalidSchedClass && |
| State.getInstrInfo().get(Opcode).getSchedClass() == 0) { |
| errs() << State.getInstrInfo().getName(Opcode) |
| << ": ignoring instruction without sched class\n"; |
| continue; |
| } |
| |
| auto ConfigsForInstr = generateSnippets(State, Opcode, AllReservedRegs); |
| if (!ConfigsForInstr) { |
| logAllUnhandledErrors( |
| ConfigsForInstr.takeError(), errs(), |
| Twine(State.getInstrInfo().getName(Opcode)).concat(": ")); |
| continue; |
| } |
| std::move(ConfigsForInstr->begin(), ConfigsForInstr->end(), |
| std::back_inserter(Configurations)); |
| } |
| } else { |
| Configurations = ExitOnErr(readSnippets(State, SnippetsFile)); |
| } |
| |
| if (NumRepetitions == 0) { |
| ExitOnErr.setBanner("llvm-exegesis: "); |
| ExitWithError("--num-repetitions must be greater than zero"); |
| } |
| |
| // Write to standard output if file is not set. |
| if (BenchmarkFile.empty()) |
| BenchmarkFile = "-"; |
| |
| for (const BenchmarkCode &Conf : Configurations) { |
| InstructionBenchmark Result = ExitOnErr(Runner->runConfiguration( |
| Conf, NumRepetitions, LoopBodySize, Repetitors, DumpObjectToDisk)); |
| ExitOnFileError(BenchmarkFile, Result.writeYaml(State, BenchmarkFile)); |
| } |
| exegesis::pfm::pfmTerminate(); |
| } |
| |
| // Prints the results of running analysis pass `Pass` to file `OutputFilename` |
| // if OutputFilename is non-empty. |
| template <typename Pass> |
| static void maybeRunAnalysis(const Analysis &Analyzer, const std::string &Name, |
| const std::string &OutputFilename) { |
| if (OutputFilename.empty()) |
| return; |
| if (OutputFilename != "-") { |
| errs() << "Printing " << Name << " results to file '" << OutputFilename |
| << "'\n"; |
| } |
| std::error_code ErrorCode; |
| raw_fd_ostream ClustersOS(OutputFilename, ErrorCode, |
| sys::fs::FA_Read | sys::fs::FA_Write); |
| if (ErrorCode) |
| ExitOnFileError(OutputFilename, errorCodeToError(ErrorCode)); |
| if (auto Err = Analyzer.run<Pass>(ClustersOS)) |
| ExitOnFileError(OutputFilename, std::move(Err)); |
| } |
| |
| static void analysisMain() { |
| ExitOnErr.setBanner("llvm-exegesis: "); |
| if (BenchmarkFile.empty()) |
| ExitWithError("--benchmarks-file must be set"); |
| |
| if (AnalysisClustersOutputFile.empty() && |
| AnalysisInconsistenciesOutputFile.empty()) { |
| ExitWithError( |
| "for --mode=analysis: At least one of --analysis-clusters-output-file " |
| "and --analysis-inconsistencies-output-file must be specified"); |
| } |
| |
| InitializeNativeTarget(); |
| InitializeNativeTargetAsmPrinter(); |
| InitializeNativeTargetDisassembler(); |
| |
| // Read benchmarks. |
| const LLVMState State(""); |
| const std::vector<InstructionBenchmark> Points = ExitOnFileError( |
| BenchmarkFile, InstructionBenchmark::readYamls(State, BenchmarkFile)); |
| |
| outs() << "Parsed " << Points.size() << " benchmark points\n"; |
| if (Points.empty()) { |
| errs() << "no benchmarks to analyze\n"; |
| return; |
| } |
| // FIXME: Check that all points have the same triple/cpu. |
| // FIXME: Merge points from several runs (latency and uops). |
| |
| std::string Error; |
| const auto *TheTarget = |
| TargetRegistry::lookupTarget(Points[0].LLVMTriple, Error); |
| if (!TheTarget) { |
| errs() << "unknown target '" << Points[0].LLVMTriple << "'\n"; |
| return; |
| } |
| |
| std::unique_ptr<MCSubtargetInfo> SubtargetInfo( |
| TheTarget->createMCSubtargetInfo(Points[0].LLVMTriple, CpuName, "")); |
| |
| std::unique_ptr<MCInstrInfo> InstrInfo(TheTarget->createMCInstrInfo()); |
| assert(InstrInfo && "Unable to create instruction info!"); |
| |
| const auto Clustering = ExitOnErr(InstructionBenchmarkClustering::create( |
| Points, AnalysisClusteringAlgorithm, AnalysisDbscanNumPoints, |
| AnalysisClusteringEpsilon, SubtargetInfo.get(), InstrInfo.get())); |
| |
| const Analysis Analyzer( |
| *TheTarget, std::move(SubtargetInfo), std::move(InstrInfo), Clustering, |
| AnalysisInconsistencyEpsilon, AnalysisDisplayUnstableOpcodes, CpuName); |
| |
| maybeRunAnalysis<Analysis::PrintClusters>(Analyzer, "analysis clusters", |
| AnalysisClustersOutputFile); |
| maybeRunAnalysis<Analysis::PrintSchedClassInconsistencies>( |
| Analyzer, "sched class consistency analysis", |
| AnalysisInconsistenciesOutputFile); |
| } |
| |
| } // namespace exegesis |
| } // namespace llvm |
| |
| int main(int Argc, char **Argv) { |
| using namespace llvm; |
| cl::ParseCommandLineOptions(Argc, Argv, ""); |
| |
| exegesis::ExitOnErr.setExitCodeMapper([](const Error &Err) { |
| if (Err.isA<exegesis::ClusteringError>()) |
| return EXIT_SUCCESS; |
| return EXIT_FAILURE; |
| }); |
| |
| if (exegesis::BenchmarkMode == exegesis::InstructionBenchmark::Unknown) { |
| exegesis::analysisMain(); |
| } else { |
| exegesis::benchmarkMain(); |
| } |
| return EXIT_SUCCESS; |
| } |
