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author | vitalyisaev <vitalyisaev@yandex-team.com> | 2023-06-29 10:00:50 +0300 |
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committer | vitalyisaev <vitalyisaev@yandex-team.com> | 2023-06-29 10:00:50 +0300 |
commit | 6ffe9e53658409f212834330e13564e4952558f6 (patch) | |
tree | 85b1e00183517648b228aafa7c8fb07f5276f419 /contrib/libs/llvm14/lib/CodeGen/MachineFunctionSplitter.cpp | |
parent | 726057070f9c5a91fc10fde0d5024913d10f1ab9 (diff) | |
download | ydb-6ffe9e53658409f212834330e13564e4952558f6.tar.gz |
YQ Connector: support managed ClickHouse
Со стороны dqrun можно обратиться к инстансу коннектора, который работает на streaming стенде, и извлечь данные из облачного CH.
Diffstat (limited to 'contrib/libs/llvm14/lib/CodeGen/MachineFunctionSplitter.cpp')
-rw-r--r-- | contrib/libs/llvm14/lib/CodeGen/MachineFunctionSplitter.cpp | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/contrib/libs/llvm14/lib/CodeGen/MachineFunctionSplitter.cpp b/contrib/libs/llvm14/lib/CodeGen/MachineFunctionSplitter.cpp new file mode 100644 index 0000000000..0e0eb8b8e0 --- /dev/null +++ b/contrib/libs/llvm14/lib/CodeGen/MachineFunctionSplitter.cpp @@ -0,0 +1,169 @@ +//===-- MachineFunctionSplitter.cpp - Split machine functions //-----------===// +// +// 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 +// Uses profile information to split out cold blocks. +// +// This pass splits out cold machine basic blocks from the parent function. This +// implementation leverages the basic block section framework. Blocks marked +// cold by this pass are grouped together in a separate section prefixed with +// ".text.unlikely.*". The linker can then group these together as a cold +// section. The split part of the function is a contiguous region identified by +// the symbol "foo.cold". Grouping all cold blocks across functions together +// decreases fragmentation and improves icache and itlb utilization. Note that +// the overall changes to the binary size are negligible; only a small number of +// additional jump instructions may be introduced. +// +// For the original RFC of this pass please see +// https://groups.google.com/d/msg/llvm-dev/RUegaMg-iqc/wFAVxa6fCgAJ +//===----------------------------------------------------------------------===// + +#include "llvm/ADT/SmallVector.h" +#include "llvm/ADT/Statistic.h" +#include "llvm/Analysis/ProfileSummaryInfo.h" +#include "llvm/CodeGen/BasicBlockSectionUtils.h" +#include "llvm/CodeGen/MachineBasicBlock.h" +#include "llvm/CodeGen/MachineBlockFrequencyInfo.h" +#include "llvm/CodeGen/MachineFunction.h" +#include "llvm/CodeGen/MachineFunctionPass.h" +#include "llvm/CodeGen/MachineModuleInfo.h" +#include "llvm/CodeGen/Passes.h" +#include "llvm/IR/Function.h" +#include "llvm/IR/Module.h" +#include "llvm/InitializePasses.h" +#include "llvm/Support/CommandLine.h" + +using namespace llvm; + +// FIXME: This cutoff value is CPU dependent and should be moved to +// TargetTransformInfo once we consider enabling this on other platforms. +// The value is expressed as a ProfileSummaryInfo integer percentile cutoff. +// Defaults to 999950, i.e. all blocks colder than 99.995 percentile are split. +// The default was empirically determined to be optimal when considering cutoff +// values between 99%-ile to 100%-ile with respect to iTLB and icache metrics on +// Intel CPUs. +static cl::opt<unsigned> + PercentileCutoff("mfs-psi-cutoff", + cl::desc("Percentile profile summary cutoff used to " + "determine cold blocks. Unused if set to zero."), + cl::init(999950), cl::Hidden); + +static cl::opt<unsigned> ColdCountThreshold( + "mfs-count-threshold", + cl::desc( + "Minimum number of times a block must be executed to be retained."), + cl::init(1), cl::Hidden); + +namespace { + +class MachineFunctionSplitter : public MachineFunctionPass { +public: + static char ID; + MachineFunctionSplitter() : MachineFunctionPass(ID) { + initializeMachineFunctionSplitterPass(*PassRegistry::getPassRegistry()); + } + + StringRef getPassName() const override { + return "Machine Function Splitter Transformation"; + } + + void getAnalysisUsage(AnalysisUsage &AU) const override; + + bool runOnMachineFunction(MachineFunction &F) override; +}; +} // end anonymous namespace + +static bool isColdBlock(const MachineBasicBlock &MBB, + const MachineBlockFrequencyInfo *MBFI, + ProfileSummaryInfo *PSI) { + Optional<uint64_t> Count = MBFI->getBlockProfileCount(&MBB); + if (!Count.hasValue()) + return true; + + if (PercentileCutoff > 0) { + return PSI->isColdCountNthPercentile(PercentileCutoff, *Count); + } + return (*Count < ColdCountThreshold); +} + +bool MachineFunctionSplitter::runOnMachineFunction(MachineFunction &MF) { + // TODO: We only target functions with profile data. Static information may + // also be considered but we don't see performance improvements yet. + if (!MF.getFunction().hasProfileData()) + return false; + + // TODO: We don't split functions where a section attribute has been set + // since the split part may not be placed in a contiguous region. It may also + // be more beneficial to augment the linker to ensure contiguous layout of + // split functions within the same section as specified by the attribute. + if (MF.getFunction().hasSection() || + MF.getFunction().hasFnAttribute("implicit-section-name")) + return false; + + // We don't want to proceed further for cold functions + // or functions of unknown hotness. Lukewarm functions have no prefix. + Optional<StringRef> SectionPrefix = MF.getFunction().getSectionPrefix(); + if (SectionPrefix.hasValue() && + (SectionPrefix.getValue().equals("unlikely") || + SectionPrefix.getValue().equals("unknown"))) { + return false; + } + + // Renumbering blocks here preserves the order of the blocks as + // sortBasicBlocksAndUpdateBranches uses the numeric identifier to sort + // blocks. Preserving the order of blocks is essential to retaining decisions + // made by prior passes such as MachineBlockPlacement. + MF.RenumberBlocks(); + MF.setBBSectionsType(BasicBlockSection::Preset); + auto *MBFI = &getAnalysis<MachineBlockFrequencyInfo>(); + auto *PSI = &getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI(); + + SmallVector<MachineBasicBlock *, 2> LandingPads; + for (auto &MBB : MF) { + if (MBB.isEntryBlock()) + continue; + + if (MBB.isEHPad()) + LandingPads.push_back(&MBB); + else if (isColdBlock(MBB, MBFI, PSI)) + MBB.setSectionID(MBBSectionID::ColdSectionID); + } + + // We only split out eh pads if all of them are cold. + bool HasHotLandingPads = false; + for (const MachineBasicBlock *LP : LandingPads) { + if (!isColdBlock(*LP, MBFI, PSI)) + HasHotLandingPads = true; + } + if (!HasHotLandingPads) { + for (MachineBasicBlock *LP : LandingPads) + LP->setSectionID(MBBSectionID::ColdSectionID); + } + + auto Comparator = [](const MachineBasicBlock &X, const MachineBasicBlock &Y) { + return X.getSectionID().Type < Y.getSectionID().Type; + }; + llvm::sortBasicBlocksAndUpdateBranches(MF, Comparator); + + return true; +} + +void MachineFunctionSplitter::getAnalysisUsage(AnalysisUsage &AU) const { + AU.addRequired<MachineModuleInfoWrapperPass>(); + AU.addRequired<MachineBlockFrequencyInfo>(); + AU.addRequired<ProfileSummaryInfoWrapperPass>(); +} + +char MachineFunctionSplitter::ID = 0; +INITIALIZE_PASS(MachineFunctionSplitter, "machine-function-splitter", + "Split machine functions using profile information", false, + false) + +MachineFunctionPass *llvm::createMachineFunctionSplitterPass() { + return new MachineFunctionSplitter(); +} |