RPCS3/llvm-mirror
1
0
Fork 0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-23 19:23:23 +01:00
Code Issues Projects Releases Wiki Activity
65e8842f48
llvm-mirror/lib/ProfileData/InstrProfWriter.cpp
Wei Mi 51d4708437 Supplement instr profile with sample profile. 
PGO profile is usually more precise than sample profile. However, PGO profile
needs to be collected from loadtest and loadtest may not be representative
enough to the production workload. Sample profile collected from production
can be used as a supplement -- for functions cold in loadtest but warm/hot
in production, we can scale up the related function in PGO profile if the
function is warm or hot in sample profile.

The implementation contains changes in compiler side and llvm-profdata side.
Given an instr profile and a sample profile, for a function cold in PGO
profile but warm/hot in sample profile, llvm-profdata will either mark
all the counters in the profile to be -1 or scale up the max count in the
function to be above hot threshold, depending on the zero counter ratio in
the profile. The assumption is if there are too many counters being zero
in the function profile, the profile is more likely to cause harm than good,
then llvm-profdata will mark all the counters to be -1 indicating the
function is hot but the profile is unaccountable. In compiler side, if a
function profile with all -1 counters is seen, the function entry count will
be set to be above hot threshold but its internal profile will be dropped.

In the long run, it may be useful to let compiler support using PGO profile
and sample profile at the same time, but that requires more careful design
and more substantial changes to make two profiles work seamlessly. The patch
here serves as a simple intermediate solution.

Differential Revision: https://reviews.llvm.org/D81981
2020-07-27 20:17:40 -07:00

478 lines
16 KiB
C++
Raw Blame History

//===- InstrProfWriter.cpp - Instrumented profiling writer ----------------===//
//
// 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 support for writing profiling data for clang's
// instrumentation based PGO and coverage.
//
//===----------------------------------------------------------------------===//
#include "llvm/ProfileData/InstrProfWriter.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/IR/ProfileSummary.h"
#include "llvm/ProfileData/InstrProf.h"
#include "llvm/ProfileData/ProfileCommon.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/EndianStream.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/OnDiskHashTable.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cstdint>
#include <memory>
#include <string>
#include <tuple>
#include <utility>
#include <vector>
using namespace llvm;
// A struct to define how the data stream should be patched. For Indexed
// profiling, only uint64_t data type is needed.
struct PatchItem {
uint64_t Pos; // Where to patch.
uint64_t *D; // Pointer to an array of source data.
int N; // Number of elements in \c D array.
};
namespace llvm {
// A wrapper class to abstract writer stream with support of bytes
// back patching.
class ProfOStream {
public:
ProfOStream(raw_fd_ostream &FD)
: IsFDOStream(true), OS(FD), LE(FD, support::little) {}
ProfOStream(raw_string_ostream &STR)
: IsFDOStream(false), OS(STR), LE(STR, support::little) {}
uint64_t tell() { return OS.tell(); }
void write(uint64_t V) { LE.write<uint64_t>(V); }
// \c patch can only be called when all data is written and flushed.
// For raw_string_ostream, the patch is done on the target string
// directly and it won't be reflected in the stream's internal buffer.
void patch(PatchItem *P, int NItems) {
using namespace support;
if (IsFDOStream) {
raw_fd_ostream &FDOStream = static_cast<raw_fd_ostream &>(OS);
for (int K = 0; K < NItems; K++) {
FDOStream.seek(P[K].Pos);
for (int I = 0; I < P[K].N; I++)
write(P[K].D[I]);
}
} else {
raw_string_ostream &SOStream = static_cast<raw_string_ostream &>(OS);
std::string &Data = SOStream.str(); // with flush
for (int K = 0; K < NItems; K++) {
for (int I = 0; I < P[K].N; I++) {
uint64_t Bytes = endian::byte_swap<uint64_t, little>(P[K].D[I]);
Data.replace(P[K].Pos + I * sizeof(uint64_t), sizeof(uint64_t),
(const char *)&Bytes, sizeof(uint64_t));
}
}
}
}
// If \c OS is an instance of \c raw_fd_ostream, this field will be
// true. Otherwise, \c OS will be an raw_string_ostream.
bool IsFDOStream;
raw_ostream &OS;
support::endian::Writer LE;
};
class InstrProfRecordWriterTrait {
public:
using key_type = StringRef;
using key_type_ref = StringRef;
using data_type = const InstrProfWriter::ProfilingData *const;
using data_type_ref = const InstrProfWriter::ProfilingData *const;
using hash_value_type = uint64_t;
using offset_type = uint64_t;
support::endianness ValueProfDataEndianness = support::little;
InstrProfSummaryBuilder *SummaryBuilder;
InstrProfSummaryBuilder *CSSummaryBuilder;
InstrProfRecordWriterTrait() = default;
static hash_value_type ComputeHash(key_type_ref K) {
return IndexedInstrProf::ComputeHash(K);
}
static std::pair<offset_type, offset_type>
EmitKeyDataLength(raw_ostream &Out, key_type_ref K, data_type_ref V) {
using namespace support;
endian::Writer LE(Out, little);
offset_type N = K.size();
LE.write<offset_type>(N);
offset_type M = 0;
for (const auto &ProfileData : *V) {
const InstrProfRecord &ProfRecord = ProfileData.second;
M += sizeof(uint64_t); // The function hash
M += sizeof(uint64_t); // The size of the Counts vector
M += ProfRecord.Counts.size() * sizeof(uint64_t);
// Value data
M += ValueProfData::getSize(ProfileData.second);
}
LE.write<offset_type>(M);
return std::make_pair(N, M);
}
void EmitKey(raw_ostream &Out, key_type_ref K, offset_type N) {
Out.write(K.data(), N);
}
void EmitData(raw_ostream &Out, key_type_ref, data_type_ref V, offset_type) {
using namespace support;
endian::Writer LE(Out, little);
for (const auto &ProfileData : *V) {
const InstrProfRecord &ProfRecord = ProfileData.second;
if (NamedInstrProfRecord::hasCSFlagInHash(ProfileData.first))
CSSummaryBuilder->addRecord(ProfRecord);
else
SummaryBuilder->addRecord(ProfRecord);
LE.write<uint64_t>(ProfileData.first); // Function hash
LE.write<uint64_t>(ProfRecord.Counts.size());
for (uint64_t I : ProfRecord.Counts)
LE.write<uint64_t>(I);
// Write value data
std::unique_ptr<ValueProfData> VDataPtr =
ValueProfData::serializeFrom(ProfileData.second);
uint32_t S = VDataPtr->getSize();
VDataPtr->swapBytesFromHost(ValueProfDataEndianness);
Out.write((const char *)VDataPtr.get(), S);
}
}
};
} // end namespace llvm
InstrProfWriter::InstrProfWriter(bool Sparse, bool InstrEntryBBEnabled)
: Sparse(Sparse), InstrEntryBBEnabled(InstrEntryBBEnabled),
InfoObj(new InstrProfRecordWriterTrait()) {}
InstrProfWriter::~InstrProfWriter() { delete InfoObj; }
// Internal interface for testing purpose only.
void InstrProfWriter::setValueProfDataEndianness(
support::endianness Endianness) {
InfoObj->ValueProfDataEndianness = Endianness;
}
void InstrProfWriter::setOutputSparse(bool Sparse) {
this->Sparse = Sparse;
}
void InstrProfWriter::addRecord(NamedInstrProfRecord &&I, uint64_t Weight,
function_ref<void(Error)> Warn) {
auto Name = I.Name;
auto Hash = I.Hash;
addRecord(Name, Hash, std::move(I), Weight, Warn);
}
void InstrProfWriter::overlapRecord(NamedInstrProfRecord &&Other,
OverlapStats &Overlap,
OverlapStats &FuncLevelOverlap,
const OverlapFuncFilters &FuncFilter) {
auto Name = Other.Name;
auto Hash = Other.Hash;
Other.accumulateCounts(FuncLevelOverlap.Test);
if (FunctionData.find(Name) == FunctionData.end()) {
Overlap.addOneUnique(FuncLevelOverlap.Test);
return;
}
if (FuncLevelOverlap.Test.CountSum < 1.0f) {
Overlap.Overlap.NumEntries += 1;
return;
}
auto &ProfileDataMap = FunctionData[Name];
bool NewFunc;
ProfilingData::iterator Where;
std::tie(Where, NewFunc) =
ProfileDataMap.insert(std::make_pair(Hash, InstrProfRecord()));
if (NewFunc) {
Overlap.addOneMismatch(FuncLevelOverlap.Test);
return;
}
InstrProfRecord &Dest = Where->second;
uint64_t ValueCutoff = FuncFilter.ValueCutoff;
if (!FuncFilter.NameFilter.empty() &&
Name.find(FuncFilter.NameFilter) != Name.npos)
ValueCutoff = 0;
Dest.overlap(Other, Overlap, FuncLevelOverlap, ValueCutoff);
}
void InstrProfWriter::addRecord(StringRef Name, uint64_t Hash,
InstrProfRecord &&I, uint64_t Weight,
function_ref<void(Error)> Warn) {
auto &ProfileDataMap = FunctionData[Name];
bool NewFunc;
ProfilingData::iterator Where;
std::tie(Where, NewFunc) =
ProfileDataMap.insert(std::make_pair(Hash, InstrProfRecord()));
InstrProfRecord &Dest = Where->second;
auto MapWarn = [&](instrprof_error E) {
Warn(make_error<InstrProfError>(E));
};
if (NewFunc) {
// We've never seen a function with this name and hash, add it.
Dest = std::move(I);
if (Weight > 1)
Dest.scale(Weight, 1, MapWarn);
} else {
// We're updating a function we've seen before.
Dest.merge(I, Weight, MapWarn);
}
Dest.sortValueData();
}
void InstrProfWriter::mergeRecordsFromWriter(InstrProfWriter &&IPW,
function_ref<void(Error)> Warn) {
for (auto &I : IPW.FunctionData)
for (auto &Func : I.getValue())
addRecord(I.getKey(), Func.first, std::move(Func.second), 1, Warn);
}
bool InstrProfWriter::shouldEncodeData(const ProfilingData &PD) {
if (!Sparse)
return true;
for (const auto &Func : PD) {
const InstrProfRecord &IPR = Func.second;
if (llvm::any_of(IPR.Counts, [](uint64_t Count) { return Count > 0; }))
return true;
}
return false;
}
static void setSummary(IndexedInstrProf::Summary *TheSummary,
ProfileSummary &PS) {
using namespace IndexedInstrProf;
std::vector<ProfileSummaryEntry> &Res = PS.getDetailedSummary();
TheSummary->NumSummaryFields = Summary::NumKinds;
TheSummary->NumCutoffEntries = Res.size();
TheSummary->set(Summary::MaxFunctionCount, PS.getMaxFunctionCount());
TheSummary->set(Summary::MaxBlockCount, PS.getMaxCount());
TheSummary->set(Summary::MaxInternalBlockCount, PS.getMaxInternalCount());
TheSummary->set(Summary::TotalBlockCount, PS.getTotalCount());
TheSummary->set(Summary::TotalNumBlocks, PS.getNumCounts());
TheSummary->set(Summary::TotalNumFunctions, PS.getNumFunctions());
for (unsigned I = 0; I < Res.size(); I++)
TheSummary->setEntry(I, Res[I]);
}
void InstrProfWriter::writeImpl(ProfOStream &OS) {
using namespace IndexedInstrProf;
OnDiskChainedHashTableGenerator<InstrProfRecordWriterTrait> Generator;
InstrProfSummaryBuilder ISB(ProfileSummaryBuilder::DefaultCutoffs);
InfoObj->SummaryBuilder = &ISB;
InstrProfSummaryBuilder CSISB(ProfileSummaryBuilder::DefaultCutoffs);
InfoObj->CSSummaryBuilder = &CSISB;
// Populate the hash table generator.
for (const auto &I : FunctionData)
if (shouldEncodeData(I.getValue()))
Generator.insert(I.getKey(), &I.getValue());
// Write the header.
IndexedInstrProf::Header Header;
Header.Magic = IndexedInstrProf::Magic;
Header.Version = IndexedInstrProf::ProfVersion::CurrentVersion;
if (ProfileKind == PF_IRLevel)
Header.Version |= VARIANT_MASK_IR_PROF;
if (ProfileKind == PF_IRLevelWithCS) {
Header.Version |= VARIANT_MASK_IR_PROF;
Header.Version |= VARIANT_MASK_CSIR_PROF;
}
if (InstrEntryBBEnabled)
Header.Version |= VARIANT_MASK_INSTR_ENTRY;
Header.Unused = 0;
Header.HashType = static_cast<uint64_t>(IndexedInstrProf::HashType);
Header.HashOffset = 0;
int N = sizeof(IndexedInstrProf::Header) / sizeof(uint64_t);
// Only write out all the fields except 'HashOffset'. We need
// to remember the offset of that field to allow back patching
// later.
for (int I = 0; I < N - 1; I++)
OS.write(reinterpret_cast<uint64_t *>(&Header)[I]);
// Save the location of Header.HashOffset field in \c OS.
uint64_t HashTableStartFieldOffset = OS.tell();
// Reserve the space for HashOffset field.
OS.write(0);
// Reserve space to write profile summary data.
uint32_t NumEntries = ProfileSummaryBuilder::DefaultCutoffs.size();
uint32_t SummarySize = Summary::getSize(Summary::NumKinds, NumEntries);
// Remember the summary offset.
uint64_t SummaryOffset = OS.tell();
for (unsigned I = 0; I < SummarySize / sizeof(uint64_t); I++)
OS.write(0);
uint64_t CSSummaryOffset = 0;
uint64_t CSSummarySize = 0;
if (ProfileKind == PF_IRLevelWithCS) {
CSSummaryOffset = OS.tell();
CSSummarySize = SummarySize / sizeof(uint64_t);
for (unsigned I = 0; I < CSSummarySize; I++)
OS.write(0);
}
// Write the hash table.
uint64_t HashTableStart = Generator.Emit(OS.OS, *InfoObj);
// Allocate space for data to be serialized out.
std::unique_ptr<IndexedInstrProf::Summary> TheSummary =
IndexedInstrProf::allocSummary(SummarySize);
// Compute the Summary and copy the data to the data
// structure to be serialized out (to disk or buffer).
std::unique_ptr<ProfileSummary> PS = ISB.getSummary();
setSummary(TheSummary.get(), *PS);
InfoObj->SummaryBuilder = nullptr;
// For Context Sensitive summary.
std::unique_ptr<IndexedInstrProf::Summary> TheCSSummary = nullptr;
if (ProfileKind == PF_IRLevelWithCS) {
TheCSSummary = IndexedInstrProf::allocSummary(SummarySize);
std::unique_ptr<ProfileSummary> CSPS = CSISB.getSummary();
setSummary(TheCSSummary.get(), *CSPS);
}
InfoObj->CSSummaryBuilder = nullptr;
// Now do the final patch:
PatchItem PatchItems[] = {
// Patch the Header.HashOffset field.
{HashTableStartFieldOffset, &HashTableStart, 1},
// Patch the summary data.
{SummaryOffset, reinterpret_cast<uint64_t *>(TheSummary.get()),
(int)(SummarySize / sizeof(uint64_t))},
{CSSummaryOffset, reinterpret_cast<uint64_t *>(TheCSSummary.get()),
(int)CSSummarySize}};
OS.patch(PatchItems, sizeof(PatchItems) / sizeof(*PatchItems));
}
void InstrProfWriter::write(raw_fd_ostream &OS) {
// Write the hash table.
ProfOStream POS(OS);
writeImpl(POS);
}
std::unique_ptr<MemoryBuffer> InstrProfWriter::writeBuffer() {
std::string Data;
raw_string_ostream OS(Data);
ProfOStream POS(OS);
// Write the hash table.
writeImpl(POS);
// Return this in an aligned memory buffer.
return MemoryBuffer::getMemBufferCopy(Data);
}
static const char *ValueProfKindStr[] = {
#define VALUE_PROF_KIND(Enumerator, Value, Descr) #Enumerator,
#include "llvm/ProfileData/InstrProfData.inc"
};
void InstrProfWriter::writeRecordInText(StringRef Name, uint64_t Hash,
const InstrProfRecord &Func,
InstrProfSymtab &Symtab,
raw_fd_ostream &OS) {
OS << Name << "\n";
OS << "# Func Hash:\n" << Hash << "\n";
OS << "# Num Counters:\n" << Func.Counts.size() << "\n";
OS << "# Counter Values:\n";
for (uint64_t Count : Func.Counts)
OS << Count << "\n";
uint32_t NumValueKinds = Func.getNumValueKinds();
if (!NumValueKinds) {
OS << "\n";
return;
}
OS << "# Num Value Kinds:\n" << Func.getNumValueKinds() << "\n";
for (uint32_t VK = 0; VK < IPVK_Last + 1; VK++) {
uint32_t NS = Func.getNumValueSites(VK);
if (!NS)
continue;
OS << "# ValueKind = " << ValueProfKindStr[VK] << ":\n" << VK << "\n";
OS << "# NumValueSites:\n" << NS << "\n";
for (uint32_t S = 0; S < NS; S++) {
uint32_t ND = Func.getNumValueDataForSite(VK, S);
OS << ND << "\n";
std::unique_ptr<InstrProfValueData[]> VD = Func.getValueForSite(VK, S);
for (uint32_t I = 0; I < ND; I++) {
if (VK == IPVK_IndirectCallTarget)
OS << Symtab.getFuncNameOrExternalSymbol(VD[I].Value) << ":"
<< VD[I].Count << "\n";
else
OS << VD[I].Value << ":" << VD[I].Count << "\n";
}
}
}
OS << "\n";
}
Error InstrProfWriter::writeText(raw_fd_ostream &OS) {
if (ProfileKind == PF_IRLevel)
OS << "# IR level Instrumentation Flag\n:ir\n";
else if (ProfileKind == PF_IRLevelWithCS)
OS << "# CSIR level Instrumentation Flag\n:csir\n";
if (InstrEntryBBEnabled)
OS << "# Always instrument the function entry block\n:entry_first\n";
InstrProfSymtab Symtab;
using FuncPair = detail::DenseMapPair<uint64_t, InstrProfRecord>;
using RecordType = std::pair<StringRef, FuncPair>;
SmallVector<RecordType, 4> OrderedFuncData;
for (const auto &I : FunctionData) {
if (shouldEncodeData(I.getValue())) {
if (Error E = Symtab.addFuncName(I.getKey()))
return E;
for (const auto &Func : I.getValue())
OrderedFuncData.push_back(std::make_pair(I.getKey(), Func));
}
}
llvm::sort(OrderedFuncData, [](const RecordType &A, const RecordType &B) {
return std::tie(A.first, A.second.first) <
std::tie(B.first, B.second.first);
});
for (const auto &record : OrderedFuncData) {
const StringRef &Name = record.first;
const FuncPair &Func = record.second;
writeRecordInText(Name, Func.first, Func.second, Symtab, OS);
}
return Error::success();
}
Reference in New Issue View Git Blame Copy Permalink