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llvm-mirror/lib/Analysis/ProfileSummaryInfo.cpp
Hiroshi Yamauchi 7e568e1e72 [PGO] Enable the working set size scaling under the partial sample PGO.
Summary: Following up D79831.

Reviewers: davidxl

Subscribers: eraman, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D80939
2020-06-04 11:30:54 -07:00

474 lines
18 KiB
C++

//===- ProfileSummaryInfo.cpp - Global profile summary information --------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file contains a pass that provides access to the global profile summary
// information.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/ProfileSummaryInfo.h"
#include "llvm/Analysis/BlockFrequencyInfo.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/ProfileSummary.h"
#include "llvm/InitializePasses.h"
#include "llvm/Support/CommandLine.h"
using namespace llvm;
// The following two parameters determine the threshold for a count to be
// considered hot/cold. These two parameters are percentile values (multiplied
// by 10000). If the counts are sorted in descending order, the minimum count to
// reach ProfileSummaryCutoffHot gives the threshold to determine a hot count.
// Similarly, the minimum count to reach ProfileSummaryCutoffCold gives the
// threshold for determining cold count (everything <= this threshold is
// considered cold).
static cl::opt<int> ProfileSummaryCutoffHot(
"profile-summary-cutoff-hot", cl::Hidden, cl::init(990000), cl::ZeroOrMore,
cl::desc("A count is hot if it exceeds the minimum count to"
" reach this percentile of total counts."));
static cl::opt<int> ProfileSummaryCutoffCold(
"profile-summary-cutoff-cold", cl::Hidden, cl::init(999999), cl::ZeroOrMore,
cl::desc("A count is cold if it is below the minimum count"
" to reach this percentile of total counts."));
static cl::opt<unsigned> ProfileSummaryHugeWorkingSetSizeThreshold(
"profile-summary-huge-working-set-size-threshold", cl::Hidden,
cl::init(15000), cl::ZeroOrMore,
cl::desc("The code working set size is considered huge if the number of"
" blocks required to reach the -profile-summary-cutoff-hot"
" percentile exceeds this count."));
static cl::opt<unsigned> ProfileSummaryLargeWorkingSetSizeThreshold(
"profile-summary-large-working-set-size-threshold", cl::Hidden,
cl::init(12500), cl::ZeroOrMore,
cl::desc("The code working set size is considered large if the number of"
" blocks required to reach the -profile-summary-cutoff-hot"
" percentile exceeds this count."));
// The next two options override the counts derived from summary computation and
// are useful for debugging purposes.
static cl::opt<int> ProfileSummaryHotCount(
"profile-summary-hot-count", cl::ReallyHidden, cl::ZeroOrMore,
cl::desc("A fixed hot count that overrides the count derived from"
" profile-summary-cutoff-hot"));
static cl::opt<int> ProfileSummaryColdCount(
"profile-summary-cold-count", cl::ReallyHidden, cl::ZeroOrMore,
cl::desc("A fixed cold count that overrides the count derived from"
" profile-summary-cutoff-cold"));
static cl::opt<bool> PartialProfile(
"partial-profile", cl::Hidden, cl::init(false),
cl::desc("Specify the current profile is used as a partial profile."));
cl::opt<bool> ScalePartialSampleProfileWorkingSetSize(
"scale-partial-sample-profile-working-set-size", cl::Hidden, cl::init(true),
cl::desc(
"If true, scale the working set size of the partial sample profile "
"by the partial profile ratio to reflect the size of the program "
"being compiled."));
static cl::opt<double> PartialSampleProfileWorkingSetSizeScaleFactor(
"partial-sample-profile-working-set-size-scale-factor", cl::Hidden,
cl::init(0.008),
cl::desc("The scale factor used to scale the working set size of the "
"partial sample profile along with the partial profile ratio. "
"This includes the factor of the profile counter per block "
"and the factor to scale the working set size to use the same "
"shared thresholds as PGO."));
// Find the summary entry for a desired percentile of counts.
static const ProfileSummaryEntry &getEntryForPercentile(SummaryEntryVector &DS,
uint64_t Percentile) {
auto It = partition_point(DS, [=](const ProfileSummaryEntry &Entry) {
return Entry.Cutoff < Percentile;
});
// The required percentile has to be <= one of the percentiles in the
// detailed summary.
if (It == DS.end())
report_fatal_error("Desired percentile exceeds the maximum cutoff");
return *It;
}
// The profile summary metadata may be attached either by the frontend or by
// any backend passes (IR level instrumentation, for example). This method
// checks if the Summary is null and if so checks if the summary metadata is now
// available in the module and parses it to get the Summary object.
void ProfileSummaryInfo::refresh() {
if (hasProfileSummary())
return;
// First try to get context sensitive ProfileSummary.
auto *SummaryMD = M.getProfileSummary(/* IsCS */ true);
if (SummaryMD)
Summary.reset(ProfileSummary::getFromMD(SummaryMD));
if (!hasProfileSummary()) {
// This will actually return PSK_Instr or PSK_Sample summary.
SummaryMD = M.getProfileSummary(/* IsCS */ false);
if (SummaryMD)
Summary.reset(ProfileSummary::getFromMD(SummaryMD));
}
if (!hasProfileSummary())
return;
computeThresholds();
}
Optional<uint64_t> ProfileSummaryInfo::getProfileCount(
const CallBase &Call, BlockFrequencyInfo *BFI, bool AllowSynthetic) const {
assert((isa<CallInst>(Call) || isa<InvokeInst>(Call)) &&
"We can only get profile count for call/invoke instruction.");
if (hasSampleProfile()) {
// In sample PGO mode, check if there is a profile metadata on the
// instruction. If it is present, determine hotness solely based on that,
// since the sampled entry count may not be accurate. If there is no
// annotated on the instruction, return None.
uint64_t TotalCount;
if (Call.extractProfTotalWeight(TotalCount))
return TotalCount;
return None;
}
if (BFI)
return BFI->getBlockProfileCount(Call.getParent(), AllowSynthetic);
return None;
}
/// Returns true if the function's entry is hot. If it returns false, it
/// either means it is not hot or it is unknown whether it is hot or not (for
/// example, no profile data is available).
bool ProfileSummaryInfo::isFunctionEntryHot(const Function *F) const {
if (!F || !hasProfileSummary())
return false;
auto FunctionCount = F->getEntryCount();
// FIXME: The heuristic used below for determining hotness is based on
// preliminary SPEC tuning for inliner. This will eventually be a
// convenience method that calls isHotCount.
return FunctionCount && isHotCount(FunctionCount.getCount());
}
/// Returns true if the function contains hot code. This can include a hot
/// function entry count, hot basic block, or (in the case of Sample PGO)
/// hot total call edge count.
/// If it returns false, it either means it is not hot or it is unknown
/// (for example, no profile data is available).
bool ProfileSummaryInfo::isFunctionHotInCallGraph(
const Function *F, BlockFrequencyInfo &BFI) const {
if (!F || !hasProfileSummary())
return false;
if (auto FunctionCount = F->getEntryCount())
if (isHotCount(FunctionCount.getCount()))
return true;
if (hasSampleProfile()) {
uint64_t TotalCallCount = 0;
for (const auto &BB : *F)
for (const auto &I : BB)
if (isa<CallInst>(I) || isa<InvokeInst>(I))
if (auto CallCount = getProfileCount(cast<CallBase>(I), nullptr))
TotalCallCount += CallCount.getValue();
if (isHotCount(TotalCallCount))
return true;
}
for (const auto &BB : *F)
if (isHotBlock(&BB, &BFI))
return true;
return false;
}
/// Returns true if the function only contains cold code. This means that
/// the function entry and blocks are all cold, and (in the case of Sample PGO)
/// the total call edge count is cold.
/// If it returns false, it either means it is not cold or it is unknown
/// (for example, no profile data is available).
bool ProfileSummaryInfo::isFunctionColdInCallGraph(
const Function *F, BlockFrequencyInfo &BFI) const {
if (!F || !hasProfileSummary())
return false;
if (auto FunctionCount = F->getEntryCount())
if (!isColdCount(FunctionCount.getCount()))
return false;
if (hasSampleProfile()) {
uint64_t TotalCallCount = 0;
for (const auto &BB : *F)
for (const auto &I : BB)
if (isa<CallInst>(I) || isa<InvokeInst>(I))
if (auto CallCount = getProfileCount(cast<CallBase>(I), nullptr))
TotalCallCount += CallCount.getValue();
if (!isColdCount(TotalCallCount))
return false;
}
for (const auto &BB : *F)
if (!isColdBlock(&BB, &BFI))
return false;
return true;
}
bool ProfileSummaryInfo::isFunctionHotnessUnknown(const Function &F) const {
assert(hasPartialSampleProfile() && "Expect partial sample profile");
return !F.getEntryCount().hasValue();
}
template <bool isHot>
bool ProfileSummaryInfo::isFunctionHotOrColdInCallGraphNthPercentile(
int PercentileCutoff, const Function *F, BlockFrequencyInfo &BFI) const {
if (!F || !hasProfileSummary())
return false;
if (auto FunctionCount = F->getEntryCount()) {
if (isHot &&
isHotCountNthPercentile(PercentileCutoff, FunctionCount.getCount()))
return true;
if (!isHot &&
!isColdCountNthPercentile(PercentileCutoff, FunctionCount.getCount()))
return false;
}
if (hasSampleProfile()) {
uint64_t TotalCallCount = 0;
for (const auto &BB : *F)
for (const auto &I : BB)
if (isa<CallInst>(I) || isa<InvokeInst>(I))
if (auto CallCount = getProfileCount(cast<CallBase>(I), nullptr))
TotalCallCount += CallCount.getValue();
if (isHot && isHotCountNthPercentile(PercentileCutoff, TotalCallCount))
return true;
if (!isHot && !isColdCountNthPercentile(PercentileCutoff, TotalCallCount))
return false;
}
for (const auto &BB : *F) {
if (isHot && isHotBlockNthPercentile(PercentileCutoff, &BB, &BFI))
return true;
if (!isHot && !isColdBlockNthPercentile(PercentileCutoff, &BB, &BFI))
return false;
}
return !isHot;
}
// Like isFunctionHotInCallGraph but for a given cutoff.
bool ProfileSummaryInfo::isFunctionHotInCallGraphNthPercentile(
int PercentileCutoff, const Function *F, BlockFrequencyInfo &BFI) const {
return isFunctionHotOrColdInCallGraphNthPercentile<true>(
PercentileCutoff, F, BFI);
}
bool ProfileSummaryInfo::isFunctionColdInCallGraphNthPercentile(
int PercentileCutoff, const Function *F, BlockFrequencyInfo &BFI) const {
return isFunctionHotOrColdInCallGraphNthPercentile<false>(
PercentileCutoff, F, BFI);
}
/// Returns true if the function's entry is a cold. If it returns false, it
/// either means it is not cold or it is unknown whether it is cold or not (for
/// example, no profile data is available).
bool ProfileSummaryInfo::isFunctionEntryCold(const Function *F) const {
if (!F)
return false;
if (F->hasFnAttribute(Attribute::Cold))
return true;
if (!hasProfileSummary())
return false;
auto FunctionCount = F->getEntryCount();
// FIXME: The heuristic used below for determining coldness is based on
// preliminary SPEC tuning for inliner. This will eventually be a
// convenience method that calls isHotCount.
return FunctionCount && isColdCount(FunctionCount.getCount());
}
/// Compute the hot and cold thresholds.
void ProfileSummaryInfo::computeThresholds() {
auto &DetailedSummary = Summary->getDetailedSummary();
auto &HotEntry =
getEntryForPercentile(DetailedSummary, ProfileSummaryCutoffHot);
HotCountThreshold = HotEntry.MinCount;
if (ProfileSummaryHotCount.getNumOccurrences() > 0)
HotCountThreshold = ProfileSummaryHotCount;
auto &ColdEntry =
getEntryForPercentile(DetailedSummary, ProfileSummaryCutoffCold);
ColdCountThreshold = ColdEntry.MinCount;
if (ProfileSummaryColdCount.getNumOccurrences() > 0)
ColdCountThreshold = ProfileSummaryColdCount;
assert(ColdCountThreshold <= HotCountThreshold &&
"Cold count threshold cannot exceed hot count threshold!");
if (!hasPartialSampleProfile() || !ScalePartialSampleProfileWorkingSetSize) {
HasHugeWorkingSetSize =
HotEntry.NumCounts > ProfileSummaryHugeWorkingSetSizeThreshold;
HasLargeWorkingSetSize =
HotEntry.NumCounts > ProfileSummaryLargeWorkingSetSizeThreshold;
} else {
// Scale the working set size of the partial sample profile to reflect the
// size of the program being compiled.
double PartialProfileRatio = Summary->getPartialProfileRatio();
uint64_t ScaledHotEntryNumCounts =
static_cast<uint64_t>(HotEntry.NumCounts * PartialProfileRatio *
PartialSampleProfileWorkingSetSizeScaleFactor);
HasHugeWorkingSetSize =
ScaledHotEntryNumCounts > ProfileSummaryHugeWorkingSetSizeThreshold;
HasLargeWorkingSetSize =
ScaledHotEntryNumCounts > ProfileSummaryLargeWorkingSetSizeThreshold;
}
}
Optional<uint64_t>
ProfileSummaryInfo::computeThreshold(int PercentileCutoff) const {
if (!hasProfileSummary())
return None;
auto iter = ThresholdCache.find(PercentileCutoff);
if (iter != ThresholdCache.end()) {
return iter->second;
}
auto &DetailedSummary = Summary->getDetailedSummary();
auto &Entry =
getEntryForPercentile(DetailedSummary, PercentileCutoff);
uint64_t CountThreshold = Entry.MinCount;
ThresholdCache[PercentileCutoff] = CountThreshold;
return CountThreshold;
}
bool ProfileSummaryInfo::hasHugeWorkingSetSize() const {
return HasHugeWorkingSetSize && HasHugeWorkingSetSize.getValue();
}
bool ProfileSummaryInfo::hasLargeWorkingSetSize() const {
return HasLargeWorkingSetSize && HasLargeWorkingSetSize.getValue();
}
bool ProfileSummaryInfo::isHotCount(uint64_t C) const {
return HotCountThreshold && C >= HotCountThreshold.getValue();
}
bool ProfileSummaryInfo::isColdCount(uint64_t C) const {
return ColdCountThreshold && C <= ColdCountThreshold.getValue();
}
template <bool isHot>
bool ProfileSummaryInfo::isHotOrColdCountNthPercentile(int PercentileCutoff,
uint64_t C) const {
auto CountThreshold = computeThreshold(PercentileCutoff);
if (isHot)
return CountThreshold && C >= CountThreshold.getValue();
else
return CountThreshold && C <= CountThreshold.getValue();
}
bool ProfileSummaryInfo::isHotCountNthPercentile(int PercentileCutoff,
uint64_t C) const {
return isHotOrColdCountNthPercentile<true>(PercentileCutoff, C);
}
bool ProfileSummaryInfo::isColdCountNthPercentile(int PercentileCutoff,
uint64_t C) const {
return isHotOrColdCountNthPercentile<false>(PercentileCutoff, C);
}
uint64_t ProfileSummaryInfo::getOrCompHotCountThreshold() const {
return HotCountThreshold ? HotCountThreshold.getValue() : UINT64_MAX;
}
uint64_t ProfileSummaryInfo::getOrCompColdCountThreshold() const {
return ColdCountThreshold ? ColdCountThreshold.getValue() : 0;
}
bool ProfileSummaryInfo::isHotBlock(const BasicBlock *BB,
BlockFrequencyInfo *BFI) const {
auto Count = BFI->getBlockProfileCount(BB);
return Count && isHotCount(*Count);
}
bool ProfileSummaryInfo::isColdBlock(const BasicBlock *BB,
BlockFrequencyInfo *BFI) const {
auto Count = BFI->getBlockProfileCount(BB);
return Count && isColdCount(*Count);
}
template <bool isHot>
bool ProfileSummaryInfo::isHotOrColdBlockNthPercentile(
int PercentileCutoff, const BasicBlock *BB, BlockFrequencyInfo *BFI) const {
auto Count = BFI->getBlockProfileCount(BB);
if (isHot)
return Count && isHotCountNthPercentile(PercentileCutoff, *Count);
else
return Count && isColdCountNthPercentile(PercentileCutoff, *Count);
}
bool ProfileSummaryInfo::isHotBlockNthPercentile(
int PercentileCutoff, const BasicBlock *BB, BlockFrequencyInfo *BFI) const {
return isHotOrColdBlockNthPercentile<true>(PercentileCutoff, BB, BFI);
}
bool ProfileSummaryInfo::isColdBlockNthPercentile(
int PercentileCutoff, const BasicBlock *BB, BlockFrequencyInfo *BFI) const {
return isHotOrColdBlockNthPercentile<false>(PercentileCutoff, BB, BFI);
}
bool ProfileSummaryInfo::isHotCallSite(const CallBase &CB,
BlockFrequencyInfo *BFI) const {
auto C = getProfileCount(CB, BFI);
return C && isHotCount(*C);
}
bool ProfileSummaryInfo::isColdCallSite(const CallBase &CB,
BlockFrequencyInfo *BFI) const {
auto C = getProfileCount(CB, BFI);
if (C)
return isColdCount(*C);
// In SamplePGO, if the caller has been sampled, and there is no profile
// annotated on the callsite, we consider the callsite as cold.
return hasSampleProfile() && CB.getCaller()->hasProfileData();
}
bool ProfileSummaryInfo::hasPartialSampleProfile() const {
return hasProfileSummary() &&
Summary->getKind() == ProfileSummary::PSK_Sample &&
(PartialProfile || Summary->isPartialProfile());
}
INITIALIZE_PASS(ProfileSummaryInfoWrapperPass, "profile-summary-info",
"Profile summary info", false, true)
ProfileSummaryInfoWrapperPass::ProfileSummaryInfoWrapperPass()
: ImmutablePass(ID) {
initializeProfileSummaryInfoWrapperPassPass(*PassRegistry::getPassRegistry());
}
bool ProfileSummaryInfoWrapperPass::doInitialization(Module &M) {
PSI.reset(new ProfileSummaryInfo(M));
return false;
}
bool ProfileSummaryInfoWrapperPass::doFinalization(Module &M) {
PSI.reset();
return false;
}
AnalysisKey ProfileSummaryAnalysis::Key;
ProfileSummaryInfo ProfileSummaryAnalysis::run(Module &M,
ModuleAnalysisManager &) {
return ProfileSummaryInfo(M);
}
PreservedAnalyses ProfileSummaryPrinterPass::run(Module &M,
ModuleAnalysisManager &AM) {
ProfileSummaryInfo &PSI = AM.getResult<ProfileSummaryAnalysis>(M);
OS << "Functions in " << M.getName() << " with hot/cold annotations: \n";
for (auto &F : M) {
OS << F.getName();
if (PSI.isFunctionEntryHot(&F))
OS << " :hot entry ";
else if (PSI.isFunctionEntryCold(&F))
OS << " :cold entry ";
OS << "\n";
}
return PreservedAnalyses::all();
}
char ProfileSummaryInfoWrapperPass::ID = 0;