llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-llvm-analysis Author: Mingming Liu (mingmingl-llvm) <details> <summary>Changes</summary> This PR enhances the `StaticDataProfileInfo::getConstantSectionPrefix` pass to reconcile data hotness information from both PGO counters and data access profiles. When both profiles are available for a global variable, the pass will now use the "hotter" of the two to determine the variable's section placement. This is a follow-up patch of https://github.com/llvm/llvm-project/pull/162388 --- Full diff: https://github.com/llvm/llvm-project/pull/163325.diff 3 Files Affected: - (modified) llvm/include/llvm/Analysis/StaticDataProfileInfo.h (+12-9) - (modified) llvm/lib/Analysis/StaticDataProfileInfo.cpp (+58-1) - (modified) llvm/test/CodeGen/X86/global-variable-partition-with-dap.ll (+93-6) ``````````diff diff --git a/llvm/include/llvm/Analysis/StaticDataProfileInfo.h b/llvm/include/llvm/Analysis/StaticDataProfileInfo.h index 70199a904f320..4a97e3370e451 100644 --- a/llvm/include/llvm/Analysis/StaticDataProfileInfo.h +++ b/llvm/include/llvm/Analysis/StaticDataProfileInfo.h @@ -58,11 +58,18 @@ class StaticDataProfileInfo { LLVM_ABI StaticDataHotness getSectionHotnessUsingProfileCount( const Constant *C, const ProfileSummaryInfo *PSI, uint64_t Count) const; + /// Return the hotness based on section prefix \p SectionPrefix. + LLVM_ABI StaticDataHotness + getSectionHotnessUsingDAP(std::optional<StringRef> SectionPrefix) const; + /// Return the string representation of the hotness enum \p Hotness. LLVM_ABI StringRef hotnessToStr(StaticDataHotness Hotness) const; + bool EnableDataAccessProf = false; + public: - StaticDataProfileInfo() = default; + StaticDataProfileInfo(bool EnableDataAccessProf) + : EnableDataAccessProf(EnableDataAccessProf) {} /// If \p Count is not nullopt, add it to the profile count of the constant \p /// C in a saturating way, and clamp the count to \p getInstrMaxCountValue if @@ -71,14 +78,10 @@ class StaticDataProfileInfo { LLVM_ABI void addConstantProfileCount(const Constant *C, std::optional<uint64_t> Count); - /// Return a section prefix for the constant \p C based on its profile count. - /// - If a constant doesn't have a counter, return an empty string. - /// - Otherwise, - /// - If it has a hot count, return "hot". - /// - If it is seen by unprofiled function, return an empty string. - /// - If it has a cold count, return "unlikely". - /// - Otherwise (e.g. it's used by lukewarm functions), return an empty - /// string. + /// Given a constant \p C, returns a section prefix. + /// If \p C is a global variable, the section prefix is the bigger one + /// between its existing section prefix and its use profile count. Otherwise, + /// the section prefix is based on its use profile count. LLVM_ABI StringRef getConstantSectionPrefix( const Constant *C, const ProfileSummaryInfo *PSI) const; }; diff --git a/llvm/lib/Analysis/StaticDataProfileInfo.cpp b/llvm/lib/Analysis/StaticDataProfileInfo.cpp index 27f8d216454aa..61e1e6779a2b0 100644 --- a/llvm/lib/Analysis/StaticDataProfileInfo.cpp +++ b/llvm/lib/Analysis/StaticDataProfileInfo.cpp @@ -1,10 +1,14 @@ #include "llvm/Analysis/StaticDataProfileInfo.h" #include "llvm/Analysis/ProfileSummaryInfo.h" #include "llvm/IR/Constant.h" +#include "llvm/IR/Constants.h" #include "llvm/IR/GlobalVariable.h" +#include "llvm/IR/Module.h" #include "llvm/InitializePasses.h" #include "llvm/ProfileData/InstrProf.h" +#define DEBUG_TYPE "static-data-profile-info" + using namespace llvm; namespace llvm { @@ -46,6 +50,12 @@ bool IsAnnotationOK(const GlobalVariable &GV) { } // namespace memprof } // namespace llvm +#ifndef NDEBUG +static StringRef debugPrintSectionPrefix(StringRef Prefix) { + return Prefix.empty() ? "<empty>" : Prefix; +} +#endif + void StaticDataProfileInfo::addConstantProfileCount( const Constant *C, std::optional<uint64_t> Count) { if (!Count) { @@ -79,6 +89,18 @@ StaticDataProfileInfo::getSectionHotnessUsingProfileCount( return StaticDataHotness::LukewarmOrUnknown; } +StaticDataProfileInfo::StaticDataHotness +StaticDataProfileInfo::getSectionHotnessUsingDAP( + std::optional<StringRef> MaybeSectionPrefix) const { + if (!MaybeSectionPrefix) + return StaticDataProfileInfo::StaticDataHotness::LukewarmOrUnknown; + StringRef Prefix = *MaybeSectionPrefix; + assert((Prefix == "hot" || Prefix == "unlikely") && + "Expect section_prefix to be one of hot or unlikely"); + return Prefix == "hot" ? StaticDataProfileInfo::StaticDataHotness::Hot + : StaticDataProfileInfo::StaticDataHotness::Cold; +} + StringRef StaticDataProfileInfo::hotnessToStr( StaticDataProfileInfo::StaticDataHotness Hotness) const { switch (Hotness) { @@ -102,13 +124,48 @@ StaticDataProfileInfo::getConstantProfileCount(const Constant *C) const { StringRef StaticDataProfileInfo::getConstantSectionPrefix( const Constant *C, const ProfileSummaryInfo *PSI) const { std::optional<uint64_t> Count = getConstantProfileCount(C); + + if (EnableDataAccessProf) { + // Module flag `HasDataAccessProf` is 1 -> empty section prefix means + // unknown hotness except for string literals. + if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(C); + GV && llvm::memprof::IsAnnotationOK(*GV) && + !GV->getName().starts_with(".str")) { + auto HotnessFromDAP = getSectionHotnessUsingDAP(GV->getSectionPrefix()); + + if (!Count) { + StringRef Prefix = hotnessToStr(HotnessFromDAP); + LLVM_DEBUG(dbgs() << GV->getName() << "has section prefix " + << debugPrintSectionPrefix(Prefix) + << ", solely from data access profiles\n"); + return Prefix; + } + + // Both DAP and PGO counters are available. Use the hotter one. + auto HotnessFromPGO = getSectionHotnessUsingProfileCount(C, PSI, *Count); + StringRef Prefix = hotnessToStr(std::max(HotnessFromDAP, HotnessFromPGO)); + LLVM_DEBUG(dbgs() << GV->getName() << " has section prefix " + << debugPrintSectionPrefix(Prefix) + << ", the max from DAP as " + << debugPrintSectionPrefix(hotnessToStr(HotnessFromDAP)) + << " and PGO counters as " + << debugPrintSectionPrefix(hotnessToStr(HotnessFromPGO)) + << "\n"); + return Prefix; + } + } if (!Count) return ""; + return hotnessToStr(getSectionHotnessUsingProfileCount(C, PSI, *Count)); } bool StaticDataProfileInfoWrapperPass::doInitialization(Module &M) { - Info.reset(new StaticDataProfileInfo()); + bool EnableDataAccessProf = false; + if (auto *MD = mdconst::extract_or_null<ConstantInt>( + M.getModuleFlag("EnableDataAccessProf"))) + EnableDataAccessProf = MD->getZExtValue(); + Info.reset(new StaticDataProfileInfo(EnableDataAccessProf)); return false; } diff --git a/llvm/test/CodeGen/X86/global-variable-partition-with-dap.ll b/llvm/test/CodeGen/X86/global-variable-partition-with-dap.ll index f3950b75a969f..2d3cbaf345f3e 100644 --- a/llvm/test/CodeGen/X86/global-variable-partition-with-dap.ll +++ b/llvm/test/CodeGen/X86/global-variable-partition-with-dap.ll @@ -1,17 +1,102 @@ target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128" target triple = "x86_64-unknown-linux-gnu" -;; A minimal test case. Subsequent PRs will expand on this test case -;; (e.g., with more functions, variables and profiles) and test the hotness -;; reconcillation implementation. +;; Requires asserts for -debug-only. +; REQUIRES: asserts + +; RUN: rm -rf %t && split-file %s %t && cd %t + +; RUN: llc -mtriple=x86_64-unknown-linux-gnu -relocation-model=pic \ +; RUN: -partition-static-data-sections=true \ +; RUN: -debug-only=static-data-profile-info \ +; RUN: -data-sections=true -unique-section-names=false \ +; RUN: input-with-dap-enabled.ll -o - 2>&1 | FileCheck %s --check-prefixes=LOG,IR + ; RUN: llc -mtriple=x86_64-unknown-linux-gnu -relocation-model=pic \ ; RUN: -partition-static-data-sections=true \ +; RUN: -debug-only=static-data-profile-info \ ; RUN: -data-sections=true -unique-section-names=false \ -; RUN: %s -o - 2>&1 | FileCheck %s --check-prefix=IR +; RUN: input-without-dap.ll -o - 2>&1 | FileCheck %s --check-prefixes=NODAP + +; LOG: hot_bss has section prefix hot, the max from DAP as hot and PGO counters as hot +; LOG: data_unknown_hotness has section prefix <empty>, the max from DAP as <empty> and PGO counters as unlikely +; LOG: external_relro_arrayhas section prefix unlikely, solely from data access profiles + +; IR: .type hot_bss,@object +; IR-NEXT: .section .bss.hot.,"aw" +; IR: .type data_unknown_hotness,@object +; IR-NEXT: .section .data,"aw" +; IR: .type external_relro_array,@object +; IR-NEXT: .section .data.rel.ro.unlikely.,"aw" + + +; NODAP: .type hot_bss,@object +; NODAP-NEXT: .section .bss.hot.,"aw" +; NODAP: .type data_unknown_hotness,@object +; NODAP-NEXT: .section .data.unlikely.,"aw" +;; Global variable section prefix metadata is not used when +;; module flag `EnableDataAccessProf` is 0, and @external_relro_array has +;; external linkage, so analysis based on PGO counters doesn't apply. +; NODAP: .type external_relro_array,@object # @external_relro_array +; NODAP: .section .data.rel.ro,"aw" + +;--- input-with-dap-enabled.ll +; Internal vars +@hot_bss = internal global i32 0, !section_prefix !17 +@data_unknown_hotness = internal global i32 1 +; External vars +@external_relro_array = constant [2 x ptr] [ptr @hot_bss, ptr @data_unknown_hotness], !section_prefix !18 + +define void @cold_func() !prof !15 { + %9 = load i32, ptr @data_unknown_hotness + %11 = call i32 (...) @func_taking_arbitrary_param(i32 %9) + ret void +} + +define void @hot_func() !prof !14 { + %9 = load i32, ptr @hot_bss + %11 = call i32 (...) @func_taking_arbitrary_param(i32 %9) + ret void +} + +declare i32 @func_taking_arbitrary_param(...) -; IR: .section .bss.hot.,"aw" +!llvm.module.flags = !{!0, !1} +!0 = !{i32 2, !"EnableDataAccessProf", i32 1} +!1 = !{i32 1, !"ProfileSummary", !2} +!2 = !{!3, !4, !5, !6, !7, !8, !9, !10} +!3 = !{!"ProfileFormat", !"InstrProf"} +!4 = !{!"TotalCount", i64 1460183} +!5 = !{!"MaxCount", i64 849024} +!6 = !{!"MaxInternalCount", i64 32769} +!7 = !{!"MaxFunctionCount", i64 849024} +!8 = !{!"NumCounts", i64 23627} +!9 = !{!"NumFunctions", i64 3271} +!10 = !{!"DetailedSummary", !11} +!11 = !{!12, !13} +!12 = !{i32 990000, i64 166, i32 73} +!13 = !{i32 999999, i64 3, i32 1443} +!14 = !{!"function_entry_count", i64 100000} +!15 = !{!"function_entry_count", i64 1} +!16 = !{!"branch_weights", i32 1, i32 99999} +!17 = !{!"section_prefix", !"hot"} +!18 = !{!"section_prefix", !"unlikely"} + +;--- input-without-dap.ll +; Same as `input-with-dap-enabled.ll` above except that module flag +; `EnableDataAccessProf` has value 0. +; Internal vars @hot_bss = internal global i32 0, !section_prefix !17 +@data_unknown_hotness = internal global i32 1 +; External vars +@external_relro_array = constant [2 x ptr] [ptr @hot_bss, ptr @data_unknown_hotness], !section_prefix !18 + +define void @cold_func() !prof !15 { + %9 = load i32, ptr @data_unknown_hotness + %11 = call i32 (...) @func_taking_arbitrary_param(i32 %9) + ret void +} define void @hot_func() !prof !14 { %9 = load i32, ptr @hot_bss @@ -21,8 +106,9 @@ define void @hot_func() !prof !14 { declare i32 @func_taking_arbitrary_param(...) -!llvm.module.flags = !{!1} +!llvm.module.flags = !{!0, !1} +!0 = !{i32 2, !"EnableDataAccessProf", i32 0} !1 = !{i32 1, !"ProfileSummary", !2} !2 = !{!3, !4, !5, !6, !7, !8, !9, !10} !3 = !{!"ProfileFormat", !"InstrProf"} @@ -40,3 +126,4 @@ declare i32 @func_taking_arbitrary_param(...) !15 = !{!"function_entry_count", i64 1} !16 = !{!"branch_weights", i32 1, i32 99999} !17 = !{!"section_prefix", !"hot"} +!18 = !{!"section_prefix", !"unlikely"} `````````` </details> https://github.com/llvm/llvm-project/pull/163325 _______________________________________________ llvm-branch-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
