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llvm-project/llvm/tools/llvm-xray/xray-account.cpp

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//===- xray-account.h - XRay Function Call Accounting ---------------------===//
//
// 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 implements basic function call accounting from an XRay trace.
//
//===----------------------------------------------------------------------===//
#include <algorithm>
#include <cassert>
#include <numeric>
#include <system_error>
#include <utility>
#include "xray-account.h"
#include "xray-registry.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/XRay/InstrumentationMap.h"
#include "llvm/XRay/Trace.h"
using namespace llvm;
using namespace llvm::xray;
static cl::SubCommand Account("account", "Function call accounting");
static cl::opt<std::string> AccountInput(cl::Positional,
cl::desc("<xray log file>"),
cl::Required, cl::sub(Account));
static cl::opt<bool>
AccountKeepGoing("keep-going", cl::desc("Keep going on errors encountered"),
cl::sub(Account), cl::init(false));
static cl::alias AccountKeepGoing2("k", cl::aliasopt(AccountKeepGoing),
cl::desc("Alias for -keep_going"));
static cl::opt<bool> AccountRecursiveCallsOnly(
"recursive-calls-only", cl::desc("Only count the calls that are recursive"),
cl::sub(Account), cl::init(false));
static cl::opt<bool> AccountDeduceSiblingCalls(
"deduce-sibling-calls",
cl::desc("Deduce sibling calls when unrolling function call stacks"),
cl::sub(Account), cl::init(false));
static cl::alias
AccountDeduceSiblingCalls2("d", cl::aliasopt(AccountDeduceSiblingCalls),
cl::desc("Alias for -deduce_sibling_calls"));
static cl::opt<std::string>
AccountOutput("output", cl::value_desc("output file"), cl::init("-"),
cl::desc("output file; use '-' for stdout"),
cl::sub(Account));
static cl::alias AccountOutput2("o", cl::aliasopt(AccountOutput),
cl::desc("Alias for -output"));
enum class AccountOutputFormats { TEXT, CSV };
static cl::opt<AccountOutputFormats>
AccountOutputFormat("format", cl::desc("output format"),
cl::values(clEnumValN(AccountOutputFormats::TEXT,
"text", "report stats in text"),
clEnumValN(AccountOutputFormats::CSV, "csv",
"report stats in csv")),
cl::sub(Account));
static cl::alias AccountOutputFormat2("f", cl::desc("Alias of -format"),
cl::aliasopt(AccountOutputFormat));
enum class SortField {
FUNCID,
COUNT,
MIN,
MED,
PCT90,
PCT99,
MAX,
SUM,
FUNC,
};
static cl::opt<SortField> AccountSortOutput(
"sort", cl::desc("sort output by this field"), cl::value_desc("field"),
cl::sub(Account), cl::init(SortField::FUNCID),
cl::values(clEnumValN(SortField::FUNCID, "funcid", "function id"),
clEnumValN(SortField::COUNT, "count", "funciton call counts"),
clEnumValN(SortField::MIN, "min", "minimum function durations"),
clEnumValN(SortField::MED, "med", "median function durations"),
clEnumValN(SortField::PCT90, "90p", "90th percentile durations"),
clEnumValN(SortField::PCT99, "99p", "99th percentile durations"),
clEnumValN(SortField::MAX, "max", "maximum function durations"),
clEnumValN(SortField::SUM, "sum", "sum of call durations"),
clEnumValN(SortField::FUNC, "func", "function names")));
static cl::alias AccountSortOutput2("s", cl::aliasopt(AccountSortOutput),
cl::desc("Alias for -sort"));
enum class SortDirection {
ASCENDING,
DESCENDING,
};
static cl::opt<SortDirection> AccountSortOrder(
"sortorder", cl::desc("sort ordering"), cl::init(SortDirection::ASCENDING),
cl::values(clEnumValN(SortDirection::ASCENDING, "asc", "ascending"),
clEnumValN(SortDirection::DESCENDING, "dsc", "descending")),
cl::sub(Account));
static cl::alias AccountSortOrder2("r", cl::aliasopt(AccountSortOrder),
cl::desc("Alias for -sortorder"));
static cl::opt<int> AccountTop("top", cl::desc("only show the top N results"),
cl::value_desc("N"), cl::sub(Account),
cl::init(-1));
static cl::alias AccountTop2("p", cl::desc("Alias for -top"),
cl::aliasopt(AccountTop));
static cl::opt<std::string>
AccountInstrMap("instr_map",
cl::desc("binary with the instrumentation map, or "
"a separate instrumentation map"),
cl::value_desc("binary with xray_instr_map"),
cl::sub(Account), cl::init(""));
static cl::alias AccountInstrMap2("m", cl::aliasopt(AccountInstrMap),
cl::desc("Alias for -instr_map"));
namespace {
template <class T, class U> void setMinMax(std::pair<T, T> &MM, U &&V) {
if (MM.first == 0 || MM.second == 0)
MM = std::make_pair(std::forward<U>(V), std::forward<U>(V));
else
MM = std::make_pair(std::min(MM.first, V), std::max(MM.second, V));
}
template <class T> T diff(T L, T R) { return std::max(L, R) - std::min(L, R); }
} // namespace
using RecursionStatus = LatencyAccountant::FunctionStack::RecursionStatus;
RecursionStatus &RecursionStatus::operator++() {
auto Depth = Bitfield::get<RecursionStatus::Depth>(Storage);
assert(Depth >= 0 && Depth < std::numeric_limits<decltype(Depth)>::max());
++Depth;
Bitfield::set<RecursionStatus::Depth>(Storage, Depth); // ++Storage
// Did this function just (maybe indirectly) call itself the first time?
if (!isRecursive() && Depth == 2) // Storage == 2 / Storage s> 1
Bitfield::set<RecursionStatus::IsRecursive>(Storage,
true); // Storage |= INT_MIN
return *this;
}
RecursionStatus &RecursionStatus::operator--() {
auto Depth = Bitfield::get<RecursionStatus::Depth>(Storage);
assert(Depth > 0);
--Depth;
Bitfield::set<RecursionStatus::Depth>(Storage, Depth); // --Storage
// Did we leave a function that previouly (maybe indirectly) called itself?
if (isRecursive() && Depth == 0) // Storage == INT_MIN
Bitfield::set<RecursionStatus::IsRecursive>(Storage, false); // Storage = 0
return *this;
}
bool RecursionStatus::isRecursive() const {
return Bitfield::get<RecursionStatus::IsRecursive>(Storage); // Storage s< 0
}
bool LatencyAccountant::accountRecord(const XRayRecord &Record) {
setMinMax(PerThreadMinMaxTSC[Record.TId], Record.TSC);
setMinMax(PerCPUMinMaxTSC[Record.CPU], Record.TSC);
if (CurrentMaxTSC == 0)
CurrentMaxTSC = Record.TSC;
if (Record.TSC < CurrentMaxTSC)
return false;
auto &ThreadStack = PerThreadFunctionStack[Record.TId];
if (RecursiveCallsOnly && !ThreadStack.RecursionDepth)
ThreadStack.RecursionDepth.emplace();
switch (Record.Type) {
case RecordTypes::CUSTOM_EVENT:
case RecordTypes::TYPED_EVENT:
// TODO: Support custom and typed event accounting in the future.
return true;
case RecordTypes::ENTER:
case RecordTypes::ENTER_ARG: {
ThreadStack.Stack.emplace_back(Record.FuncId, Record.TSC);
if (ThreadStack.RecursionDepth)
++(*ThreadStack.RecursionDepth)[Record.FuncId];
break;
}
case RecordTypes::EXIT:
case RecordTypes::TAIL_EXIT: {
if (ThreadStack.Stack.empty())
return false;
if (ThreadStack.Stack.back().first == Record.FuncId) {
const auto &Top = ThreadStack.Stack.back();
if (!ThreadStack.RecursionDepth ||
(*ThreadStack.RecursionDepth)[Top.first].isRecursive())
recordLatency(Top.first, diff(Top.second, Record.TSC));
if (ThreadStack.RecursionDepth)
--(*ThreadStack.RecursionDepth)[Top.first];
ThreadStack.Stack.pop_back();
break;
}
if (!DeduceSiblingCalls)
return false;
// Look for the parent up the stack.
auto Parent =
std::find_if(ThreadStack.Stack.rbegin(), ThreadStack.Stack.rend(),
[&](const std::pair<const int32_t, uint64_t> &E) {
return E.first == Record.FuncId;
});
if (Parent == ThreadStack.Stack.rend())
return false;
// Account time for this apparently sibling call exit up the stack.
// Considering the following case:
//
// f()
// g()
// h()
//
// We might only ever see the following entries:
//
// -> f()
// -> g()
// -> h()
// <- h()
// <- f()
//
// Now we don't see the exit to g() because some older version of the XRay
// runtime wasn't instrumenting tail exits. If we don't deduce tail calls,
// we may potentially never account time for g() -- and this code would have
// already bailed out, because `<- f()` doesn't match the current "top" of
// stack where we're waiting for the exit to `g()` instead. This is not
// ideal and brittle -- so instead we provide a potentially inaccurate
// accounting of g() instead, computing it from the exit of f().
//
// While it might be better that we account the time between `-> g()` and
// `-> h()` as the proper accounting of time for g() here, this introduces
// complexity to do correctly (need to backtrack, etc.).
//
// FIXME: Potentially implement the more complex deduction algorithm?
auto R = make_range(std::next(Parent).base(), ThreadStack.Stack.end());
for (auto &E : R) {
if (!ThreadStack.RecursionDepth ||
(*ThreadStack.RecursionDepth)[E.first].isRecursive())
recordLatency(E.first, diff(E.second, Record.TSC));
}
for (auto &Top : reverse(R)) {
if (ThreadStack.RecursionDepth)
--(*ThreadStack.RecursionDepth)[Top.first];
ThreadStack.Stack.pop_back();
}
break;
}
}
return true;
}
namespace {
// We consolidate the data into a struct which we can output in various forms.
struct ResultRow {
uint64_t Count;
double Min;
double Median;
double Pct90;
double Pct99;
double Max;
double Sum;
std::string DebugInfo;
std::string Function;
};
ResultRow getStats(MutableArrayRef<uint64_t> Timings) {
assert(!Timings.empty());
ResultRow R;
R.Sum = std::accumulate(Timings.begin(), Timings.end(), 0.0);
auto MinMax = std::minmax_element(Timings.begin(), Timings.end());
R.Min = *MinMax.first;
R.Max = *MinMax.second;
R.Count = Timings.size();
auto MedianOff = Timings.size() / 2;
std::nth_element(Timings.begin(), Timings.begin() + MedianOff, Timings.end());
R.Median = Timings[MedianOff];
auto Pct90Off = std::floor(Timings.size() * 0.9);
std::nth_element(Timings.begin(), Timings.begin() + (uint64_t)Pct90Off,
Timings.end());
R.Pct90 = Timings[Pct90Off];
auto Pct99Off = std::floor(Timings.size() * 0.99);
std::nth_element(Timings.begin(), Timings.begin() + (uint64_t)Pct99Off,
Timings.end());
R.Pct99 = Timings[Pct99Off];
return R;
}
} // namespace
using TupleType = std::tuple<int32_t, uint64_t, ResultRow>;
template <typename F>
static void sortByKey(std::vector<TupleType> &Results, F Fn) {
bool ASC = AccountSortOrder == SortDirection::ASCENDING;
llvm::sort(Results, [=](const TupleType &L, const TupleType &R) {
return ASC ? Fn(L) < Fn(R) : Fn(L) > Fn(R);
});
}
template <class F>
void LatencyAccountant::exportStats(const XRayFileHeader &Header, F Fn) const {
std::vector<TupleType> Results;
Results.reserve(FunctionLatencies.size());
for (auto FT : FunctionLatencies) {
const auto &FuncId = FT.first;
auto &Timings = FT.second;
Results.emplace_back(FuncId, Timings.size(), getStats(Timings));
auto &Row = std::get<2>(Results.back());
if (Header.CycleFrequency) {
double CycleFrequency = Header.CycleFrequency;
Row.Min /= CycleFrequency;
Row.Median /= CycleFrequency;
Row.Pct90 /= CycleFrequency;
Row.Pct99 /= CycleFrequency;
Row.Max /= CycleFrequency;
Row.Sum /= CycleFrequency;
}
Row.Function = FuncIdHelper.SymbolOrNumber(FuncId);
Row.DebugInfo = FuncIdHelper.FileLineAndColumn(FuncId);
}
// Sort the data according to user-provided flags.
switch (AccountSortOutput) {
case SortField::FUNCID:
sortByKey(Results, [](const TupleType &X) { return std::get<0>(X); });
break;
case SortField::COUNT:
sortByKey(Results, [](const TupleType &X) { return std::get<1>(X); });
break;
case SortField::MIN:
sortByKey(Results, [](const TupleType &X) { return std::get<2>(X).Min; });
break;
case SortField::MED:
sortByKey(Results, [](const TupleType &X) { return std::get<2>(X).Median; });
break;
case SortField::PCT90:
sortByKey(Results, [](const TupleType &X) { return std::get<2>(X).Pct90; });
break;
case SortField::PCT99:
sortByKey(Results, [](const TupleType &X) { return std::get<2>(X).Pct99; });
break;
case SortField::MAX:
sortByKey(Results, [](const TupleType &X) { return std::get<2>(X).Max; });
break;
case SortField::SUM:
sortByKey(Results, [](const TupleType &X) { return std::get<2>(X).Sum; });
break;
case SortField::FUNC:
llvm_unreachable("Not implemented");
}
if (AccountTop > 0) {
auto MaxTop =
std::min(AccountTop.getValue(), static_cast<int>(Results.size()));
Results.erase(Results.begin() + MaxTop, Results.end());
}
for (const auto &R : Results)
Fn(std::get<0>(R), std::get<1>(R), std::get<2>(R));
}
void LatencyAccountant::exportStatsAsText(raw_ostream &OS,
const XRayFileHeader &Header) const {
OS << "Functions with latencies: " << FunctionLatencies.size() << "\n";
// We spend some effort to make the text output more readable, so we do the
// following formatting decisions for each of the fields:
//
// - funcid: 32-bit, but we can determine the largest number and be
// between
// a minimum of 5 characters, up to 9 characters, right aligned.
// - count: 64-bit, but we can determine the largest number and be
// between
// a minimum of 5 characters, up to 9 characters, right aligned.
// - min, median, 90pct, 99pct, max: double precision, but we want to keep
// the values in seconds, with microsecond precision (0.000'001), so we
// have at most 6 significant digits, with the whole number part to be
// at
// least 1 character. For readability we'll right-align, with full 9
// characters each.
// - debug info, function name: we format this as a concatenation of the
// debug info and the function name.
//
static constexpr char StatsHeaderFormat[] =
"{0,+9} {1,+10} [{2,+9}, {3,+9}, {4,+9}, {5,+9}, {6,+9}] {7,+9}";
static constexpr char StatsFormat[] =
R"({0,+9} {1,+10} [{2,+9:f6}, {3,+9:f6}, {4,+9:f6}, {5,+9:f6}, {6,+9:f6}] {7,+9:f6})";
OS << llvm::formatv(StatsHeaderFormat, "funcid", "count", "min", "med", "90p",
"99p", "max", "sum")
<< llvm::formatv(" {0,-12}\n", "function");
exportStats(Header, [&](int32_t FuncId, size_t Count, const ResultRow &Row) {
OS << llvm::formatv(StatsFormat, FuncId, Count, Row.Min, Row.Median,
Row.Pct90, Row.Pct99, Row.Max, Row.Sum)
<< " " << Row.DebugInfo << ": " << Row.Function << "\n";
});
}
void LatencyAccountant::exportStatsAsCSV(raw_ostream &OS,
const XRayFileHeader &Header) const {
OS << "funcid,count,min,median,90%ile,99%ile,max,sum,debug,function\n";
exportStats(Header, [&](int32_t FuncId, size_t Count, const ResultRow &Row) {
OS << FuncId << ',' << Count << ',' << Row.Min << ',' << Row.Median << ','
<< Row.Pct90 << ',' << Row.Pct99 << ',' << Row.Max << "," << Row.Sum
<< ",\"" << Row.DebugInfo << "\",\"" << Row.Function << "\"\n";
});
}
using namespace llvm::xray;
namespace llvm {
template <> struct format_provider<llvm::xray::RecordTypes> {
static void format(const llvm::xray::RecordTypes &T, raw_ostream &Stream,
StringRef Style) {
switch (T) {
case RecordTypes::ENTER:
Stream << "enter";
break;
case RecordTypes::ENTER_ARG:
Stream << "enter-arg";
break;
case RecordTypes::EXIT:
Stream << "exit";
break;
case RecordTypes::TAIL_EXIT:
Stream << "tail-exit";
break;
case RecordTypes::CUSTOM_EVENT:
Stream << "custom-event";
break;
case RecordTypes::TYPED_EVENT:
Stream << "typed-event";
break;
}
}
};
} // namespace llvm
static CommandRegistration Unused(&Account, []() -> Error {
InstrumentationMap Map;
if (!AccountInstrMap.empty()) {
auto InstrumentationMapOrError = loadInstrumentationMap(AccountInstrMap);
if (!InstrumentationMapOrError)
return joinErrors(make_error<StringError>(
Twine("Cannot open instrumentation map '") +
AccountInstrMap + "'",
std::make_error_code(std::errc::invalid_argument)),
InstrumentationMapOrError.takeError());
Map = std::move(*InstrumentationMapOrError);
}
std::error_code EC;
raw_fd_ostream OS(AccountOutput, EC, sys::fs::OpenFlags::OF_Text);
if (EC)
return make_error<StringError>(
Twine("Cannot open file '") + AccountOutput + "' for writing.", EC);
const auto &FunctionAddresses = Map.getFunctionAddresses();
symbolize::LLVMSymbolizer Symbolizer;
llvm::xray::FuncIdConversionHelper FuncIdHelper(AccountInstrMap, Symbolizer,
FunctionAddresses);
xray::LatencyAccountant FCA(FuncIdHelper, AccountRecursiveCallsOnly,
AccountDeduceSiblingCalls);
auto TraceOrErr = loadTraceFile(AccountInput);
if (!TraceOrErr)
return joinErrors(
make_error<StringError>(
Twine("Failed loading input file '") + AccountInput + "'",
std::make_error_code(std::errc::executable_format_error)),
TraceOrErr.takeError());
auto &T = *TraceOrErr;
for (const auto &Record : T) {
if (FCA.accountRecord(Record))
continue;
errs()
<< "Error processing record: "
<< llvm::formatv(
R"({{type: {0}; cpu: {1}; record-type: {2}; function-id: {3}; tsc: {4}; thread-id: {5}; process-id: {6}}})",
Record.RecordType, Record.CPU, Record.Type, Record.FuncId,
Record.TSC, Record.TId, Record.PId)
<< '\n';
for (const auto &ThreadStack : FCA.getPerThreadFunctionStack()) {
errs() << "Thread ID: " << ThreadStack.first << "\n";
if (ThreadStack.second.Stack.empty()) {
errs() << " (empty stack)\n";
continue;
}
auto Level = ThreadStack.second.Stack.size();
for (const auto &Entry : llvm::reverse(ThreadStack.second.Stack))
errs() << " #" << Level-- << "\t"
<< FuncIdHelper.SymbolOrNumber(Entry.first) << '\n';
}
if (!AccountKeepGoing)
return make_error<StringError>(
Twine("Failed accounting function calls in file '") + AccountInput +
"'.",
std::make_error_code(std::errc::executable_format_error));
}
switch (AccountOutputFormat) {
case AccountOutputFormats::TEXT:
FCA.exportStatsAsText(OS, T.getFileHeader());
break;
case AccountOutputFormats::CSV:
FCA.exportStatsAsCSV(OS, T.getFileHeader());
break;
}
return Error::success();
});
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