llvm-bolt/0011-support-D-FOT-addrs-data-parsing-for-optimized-binary.patch

From 525a2d44443547c0349198df18286f594d62d557 Mon Sep 17 00:00:00 2001
From: rfwang07 <wangrufeng5@huawei.com>
Date: Tue, 19 Nov 2024 09:48:40 +0800
Subject: [PATCH] support D-FOT addrs data parsing for optimized binary

---
 bolt/include/bolt/Profile/DataAggregator.h | 31 ++++++++
 bolt/lib/Profile/DataAggregator.cpp        | 86 +++++++++++++++++++++-
 2 files changed, 113 insertions(+), 4 deletions(-)

diff --git a/bolt/include/bolt/Profile/DataAggregator.h b/bolt/include/bolt/Profile/DataAggregator.h
index cc237a6..d352f1b 100644
--- a/bolt/include/bolt/Profile/DataAggregator.h
+++ b/bolt/include/bolt/Profile/DataAggregator.h
@@ -102,6 +102,12 @@ private:
     Type EntryType;
   };
 
+  /// Used for parsing specific libkperf input files.
+  struct LibkperfDataEntry {
+    uint64_t Addr;
+    uint64_t Count;
+  };
+
   struct Trace {
     uint64_t From;
     uint64_t To;
@@ -300,6 +306,9 @@ private:
   /// Parse pre-aggregated LBR samples created by an external tool
   ErrorOr<AggregatedLBREntry> parseAggregatedLBREntry();
 
+  /// Parse libkperf samples created by D-FOT
+  ErrorOr<LibkperfDataEntry> parseLibkperfDataEntry();
+
   /// Parse either buildid:offset or just offset, representing a location in the
   /// binary. Used exclusevely for pre-aggregated LBR samples.
   ErrorOr<Location> parseLocationOrOffset();
@@ -417,10 +426,32 @@ private:
   /// B 4b196f 4b19e0 2 0
   void parsePreAggregated();
 
+  /// Coordinate reading and parsing of libkperf file
+  /// The regular perf2bolt aggregation job is to read perf output directly.
+  /// But in the oeaware framework, sampling is done by libkperf.
+  /// For data collected by sampling the BOLT-optimized binary,
+  /// oeaware can export addrs and counts.
+  /// In perf2bolt, with the help of the BAT section,
+  /// this data is converted to profile that is usable for the original binary.
+  ///
+  /// File format syntax:
+  /// - first line:      <event type>
+  /// - the other lines: <addr> <count>
+  ///
+  /// Example:
+  /// cycles
+  /// 40f544 1
+  /// 40f750 2
+  /// 40f810 53
+  void parseLibkperfFile();
+
   /// Parse the full output of pre-aggregated LBR samples generated by
   /// an external tool.
   std::error_code parsePreAggregatedLBRSamples();
 
+  /// Parse the libkperf samples
+  std::error_code parseLibkperfSamples();
+
   /// Process parsed pre-aggregated data.
   void processPreAggregated();
 
diff --git a/bolt/lib/Profile/DataAggregator.cpp b/bolt/lib/Profile/DataAggregator.cpp
index 24dbe34..509e7c9 100644
--- a/bolt/lib/Profile/DataAggregator.cpp
+++ b/bolt/lib/Profile/DataAggregator.cpp
@@ -85,6 +85,11 @@ cl::opt<bool> ReadPreAggregated(
     "pa", cl::desc("skip perf and read data from a pre-aggregated file format"),
     cl::cat(AggregatorCategory));
 
+cl::opt<bool> ReadLibkperfFile(
+    "libkperf", cl::desc("skip perf and read data from a libkperf file format, "
+                   "only for continuous optimizing with BAT"),
+    cl::cat(AggregatorCategory));
+
 static cl::opt<bool>
 TimeAggregator("time-aggr",
   cl::desc("time BOLT aggregator"),
@@ -157,8 +162,8 @@ void DataAggregator::findPerfExecutable() {
 void DataAggregator::start() {
   outs() << "PERF2BOLT: Starting data aggregation job for " << Filename << "\n";
 
-  // Don't launch perf for pre-aggregated files
-  if (opts::ReadPreAggregated)
+  // Don't launch perf for pre-aggregated files and libkperf files
+  if (opts::ReadPreAggregated || opts::ReadLibkperfFile)
     return;
 
   findPerfExecutable();
@@ -193,7 +198,7 @@ void DataAggregator::start() {
 }
 
 void DataAggregator::abort() {
-  if (opts::ReadPreAggregated)
+  if (opts::ReadPreAggregated || opts::ReadLibkperfFile)
     return;
 
   std::string Error;
@@ -313,6 +318,8 @@ void DataAggregator::processFileBuildID(StringRef FileBuildID) {
 bool DataAggregator::checkPerfDataMagic(StringRef FileName) {
   if (opts::ReadPreAggregated)
     return true;
+  if (opts::ReadLibkperfFile)
+    return true;
 
   Expected<sys::fs::file_t> FD = sys::fs::openNativeFileForRead(FileName);
   if (!FD) {
@@ -359,6 +366,27 @@ void DataAggregator::parsePreAggregated() {
   }
 }
 
+void DataAggregator::parseLibkperfFile() {
+  std::string Error;
+
+  ErrorOr<std::unique_ptr<MemoryBuffer>> MB =
+      MemoryBuffer::getFileOrSTDIN(Filename);
+  if (std::error_code EC = MB.getError()) {
+    errs() << "PERF2BOLT-ERROR: cannot open " << Filename << ": "
+           << EC.message() << "\n";
+    exit(1);
+  }
+
+  FileBuf = std::move(*MB);
+  ParsingBuf = FileBuf->getBuffer();
+  Col = 0;
+  Line = 0;
+  if (parseLibkperfSamples()) {
+    errs() << "PERF2BOLT: failed to parse libkperf samples\n";
+    exit(1);
+  }
+}
+
 std::error_code DataAggregator::writeAutoFDOData(StringRef OutputFilename) {
   outs() << "PERF2BOLT: writing data for autofdo tools...\n";
   NamedRegionTimer T("writeAutoFDO", "Processing branch events", TimerGroupName,
@@ -502,6 +530,11 @@ Error DataAggregator::preprocessProfile(BinaryContext &BC) {
     return Error::success();
   }
 
+  if (opts::ReadLibkperfFile) {
+    parseLibkperfFile();
+    return Error::success();
+  }
+
   if (std::optional<StringRef> FileBuildID = BC.getFileBuildID()) {
     outs() << "BOLT-INFO: binary build-id is:     " << *FileBuildID << "\n";
     processFileBuildID(*FileBuildID);
@@ -608,7 +641,7 @@ bool DataAggregator::mayHaveProfileData(const BinaryFunction &Function) {
 void DataAggregator::processProfile(BinaryContext &BC) {
   if (opts::ReadPreAggregated)
     processPreAggregated();
-  else if (opts::BasicAggregation)
+  else if (opts::BasicAggregation || opts::ReadLibkperfFile)
     processBasicEvents();
   else
     processBranchEvents();
@@ -1206,6 +1239,28 @@ ErrorOr<Location> DataAggregator::parseLocationOrOffset() {
   return Location(true, BuildID.get(), Offset.get());
 }
 
+ErrorOr<DataAggregator::LibkperfDataEntry>
+DataAggregator::parseLibkperfDataEntry() {
+  // <hex addr> <count>
+  while (checkAndConsumeFS()) {
+  }
+  ErrorOr<uint64_t> Addr = parseHexField(FieldSeparator);
+  if (std::error_code EC = Addr.getError())
+    return EC;
+  while (checkAndConsumeFS()) {
+  }
+  ErrorOr<uint64_t> Count = parseNumberField(FieldSeparator, true);
+  if (std::error_code EC = Count.getError())
+    return EC;
+  
+  if (!checkAndConsumeNewLine()) {
+    reportError("expected end of line");
+    return make_error_code(llvm::errc::io_error);
+  }
+
+  return LibkperfDataEntry{Addr.get(), Count.get()};
+}
+
 ErrorOr<DataAggregator::AggregatedLBREntry>
 DataAggregator::parseAggregatedLBREntry() {
   while (checkAndConsumeFS()) {
@@ -1712,6 +1767,29 @@ void DataAggregator::processMemEvents() {
   }
 }
 
+std::error_code DataAggregator::parseLibkperfSamples() {
+  outs() << "PERF2BOLT: parsing libkperf data...\n";
+  NamedRegionTimer T("parseLibkperfData", "Parsing libkperf data",
+                     TimerGroupName, TimerGroupDesc, opts::TimeAggregator);
+  bool FirstLine = true;
+  while (hasData()) {
+    if (FirstLine) {
+      ErrorOr<StringRef> Event = parseString('\n');
+      if (std::error_code EC = Event.getError())
+        return EC;
+      EventNames.insert(Event.get());
+      FirstLine = false;
+    }
+    ErrorOr<LibkperfDataEntry> KperfEntry = parseLibkperfDataEntry();
+    if (std::error_code EC = KperfEntry.getError())
+      return EC;
+    
+    BasicSamples[KperfEntry->Addr] += KperfEntry->Count;
+  }
+
+  return std::error_code();
+}
+
 std::error_code DataAggregator::parsePreAggregatedLBRSamples() {
   outs() << "PERF2BOLT: parsing pre-aggregated profile...\n";
   NamedRegionTimer T("parseAggregated", "Parsing aggregated branch events",
-- 
2.39.5 (Apple Git-154)