1 //===- xray-account.h - XRay Function Call Accounting ---------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file implements basic function call accounting from an XRay trace. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include <algorithm> 14 #include <cassert> 15 #include <numeric> 16 #include <system_error> 17 #include <utility> 18 19 #include "xray-account.h" 20 #include "xray-registry.h" 21 #include "llvm/Support/ErrorHandling.h" 22 #include "llvm/Support/FormatVariadic.h" 23 #include "llvm/XRay/InstrumentationMap.h" 24 #include "llvm/XRay/Trace.h" 25 26 using namespace llvm; 27 using namespace llvm::xray; 28 29 static cl::SubCommand Account("account", "Function call accounting"); 30 static cl::opt<std::string> AccountInput(cl::Positional, 31 cl::desc("<xray log file>"), 32 cl::Required, cl::sub(Account)); 33 static cl::opt<bool> 34 AccountKeepGoing("keep-going", cl::desc("Keep going on errors encountered"), 35 cl::sub(Account), cl::init(false)); 36 static cl::alias AccountKeepGoing2("k", cl::aliasopt(AccountKeepGoing), 37 cl::desc("Alias for -keep_going")); 38 static cl::opt<bool> AccountRecursiveCallsOnly( 39 "recursive-calls-only", cl::desc("Only count the calls that are recursive"), 40 cl::sub(Account), cl::init(false)); 41 static cl::opt<bool> AccountDeduceSiblingCalls( 42 "deduce-sibling-calls", 43 cl::desc("Deduce sibling calls when unrolling function call stacks"), 44 cl::sub(Account), cl::init(false)); 45 static cl::alias 46 AccountDeduceSiblingCalls2("d", cl::aliasopt(AccountDeduceSiblingCalls), 47 cl::desc("Alias for -deduce_sibling_calls")); 48 static cl::opt<std::string> 49 AccountOutput("output", cl::value_desc("output file"), cl::init("-"), 50 cl::desc("output file; use '-' for stdout"), 51 cl::sub(Account)); 52 static cl::alias AccountOutput2("o", cl::aliasopt(AccountOutput), 53 cl::desc("Alias for -output")); 54 enum class AccountOutputFormats { TEXT, CSV }; 55 static cl::opt<AccountOutputFormats> 56 AccountOutputFormat("format", cl::desc("output format"), 57 cl::values(clEnumValN(AccountOutputFormats::TEXT, 58 "text", "report stats in text"), 59 clEnumValN(AccountOutputFormats::CSV, "csv", 60 "report stats in csv")), 61 cl::sub(Account)); 62 static cl::alias AccountOutputFormat2("f", cl::desc("Alias of -format"), 63 cl::aliasopt(AccountOutputFormat)); 64 65 enum class SortField { 66 FUNCID, 67 COUNT, 68 MIN, 69 MED, 70 PCT90, 71 PCT99, 72 MAX, 73 SUM, 74 FUNC, 75 }; 76 77 static cl::opt<SortField> AccountSortOutput( 78 "sort", cl::desc("sort output by this field"), cl::value_desc("field"), 79 cl::sub(Account), cl::init(SortField::FUNCID), 80 cl::values(clEnumValN(SortField::FUNCID, "funcid", "function id"), 81 clEnumValN(SortField::COUNT, "count", "funciton call counts"), 82 clEnumValN(SortField::MIN, "min", "minimum function durations"), 83 clEnumValN(SortField::MED, "med", "median function durations"), 84 clEnumValN(SortField::PCT90, "90p", "90th percentile durations"), 85 clEnumValN(SortField::PCT99, "99p", "99th percentile durations"), 86 clEnumValN(SortField::MAX, "max", "maximum function durations"), 87 clEnumValN(SortField::SUM, "sum", "sum of call durations"), 88 clEnumValN(SortField::FUNC, "func", "function names"))); 89 static cl::alias AccountSortOutput2("s", cl::aliasopt(AccountSortOutput), 90 cl::desc("Alias for -sort")); 91 92 enum class SortDirection { 93 ASCENDING, 94 DESCENDING, 95 }; 96 static cl::opt<SortDirection> AccountSortOrder( 97 "sortorder", cl::desc("sort ordering"), cl::init(SortDirection::ASCENDING), 98 cl::values(clEnumValN(SortDirection::ASCENDING, "asc", "ascending"), 99 clEnumValN(SortDirection::DESCENDING, "dsc", "descending")), 100 cl::sub(Account)); 101 static cl::alias AccountSortOrder2("r", cl::aliasopt(AccountSortOrder), 102 cl::desc("Alias for -sortorder")); 103 104 static cl::opt<int> AccountTop("top", cl::desc("only show the top N results"), 105 cl::value_desc("N"), cl::sub(Account), 106 cl::init(-1)); 107 static cl::alias AccountTop2("p", cl::desc("Alias for -top"), 108 cl::aliasopt(AccountTop)); 109 110 static cl::opt<std::string> 111 AccountInstrMap("instr_map", 112 cl::desc("binary with the instrumentation map, or " 113 "a separate instrumentation map"), 114 cl::value_desc("binary with xray_instr_map"), 115 cl::sub(Account), cl::init("")); 116 static cl::alias AccountInstrMap2("m", cl::aliasopt(AccountInstrMap), 117 cl::desc("Alias for -instr_map")); 118 119 namespace { 120 121 template <class T, class U> void setMinMax(std::pair<T, T> &MM, U &&V) { 122 if (MM.first == 0 || MM.second == 0) 123 MM = std::make_pair(std::forward<U>(V), std::forward<U>(V)); 124 else 125 MM = std::make_pair(std::min(MM.first, V), std::max(MM.second, V)); 126 } 127 128 template <class T> T diff(T L, T R) { return std::max(L, R) - std::min(L, R); } 129 130 } // namespace 131 132 using RecursionStatus = LatencyAccountant::FunctionStack::RecursionStatus; 133 RecursionStatus &RecursionStatus::operator++() { 134 auto Depth = Bitfield::get<RecursionStatus::Depth>(Storage); 135 assert(Depth >= 0 && Depth < std::numeric_limits<decltype(Depth)>::max()); 136 ++Depth; 137 Bitfield::set<RecursionStatus::Depth>(Storage, Depth); // ++Storage 138 // Did this function just (maybe indirectly) call itself the first time? 139 if (!isRecursive() && Depth == 2) // Storage == 2 / Storage s> 1 140 Bitfield::set<RecursionStatus::IsRecursive>(Storage, 141 true); // Storage |= INT_MIN 142 return *this; 143 } 144 RecursionStatus &RecursionStatus::operator--() { 145 auto Depth = Bitfield::get<RecursionStatus::Depth>(Storage); 146 assert(Depth > 0); 147 --Depth; 148 Bitfield::set<RecursionStatus::Depth>(Storage, Depth); // --Storage 149 // Did we leave a function that previouly (maybe indirectly) called itself? 150 if (isRecursive() && Depth == 0) // Storage == INT_MIN 151 Bitfield::set<RecursionStatus::IsRecursive>(Storage, false); // Storage = 0 152 return *this; 153 } 154 bool RecursionStatus::isRecursive() const { 155 return Bitfield::get<RecursionStatus::IsRecursive>(Storage); // Storage s< 0 156 } 157 158 bool LatencyAccountant::accountRecord(const XRayRecord &Record) { 159 setMinMax(PerThreadMinMaxTSC[Record.TId], Record.TSC); 160 setMinMax(PerCPUMinMaxTSC[Record.CPU], Record.TSC); 161 162 if (CurrentMaxTSC == 0) 163 CurrentMaxTSC = Record.TSC; 164 165 if (Record.TSC < CurrentMaxTSC) 166 return false; 167 168 auto &ThreadStack = PerThreadFunctionStack[Record.TId]; 169 if (RecursiveCallsOnly && !ThreadStack.RecursionDepth) 170 ThreadStack.RecursionDepth.emplace(); 171 switch (Record.Type) { 172 case RecordTypes::CUSTOM_EVENT: 173 case RecordTypes::TYPED_EVENT: 174 // TODO: Support custom and typed event accounting in the future. 175 return true; 176 case RecordTypes::ENTER: 177 case RecordTypes::ENTER_ARG: { 178 ThreadStack.Stack.emplace_back(Record.FuncId, Record.TSC); 179 if (ThreadStack.RecursionDepth) 180 ++(*ThreadStack.RecursionDepth)[Record.FuncId]; 181 break; 182 } 183 case RecordTypes::EXIT: 184 case RecordTypes::TAIL_EXIT: { 185 if (ThreadStack.Stack.empty()) 186 return false; 187 188 if (ThreadStack.Stack.back().first == Record.FuncId) { 189 const auto &Top = ThreadStack.Stack.back(); 190 if (!ThreadStack.RecursionDepth || 191 (*ThreadStack.RecursionDepth)[Top.first].isRecursive()) 192 recordLatency(Top.first, diff(Top.second, Record.TSC)); 193 if (ThreadStack.RecursionDepth) 194 --(*ThreadStack.RecursionDepth)[Top.first]; 195 ThreadStack.Stack.pop_back(); 196 break; 197 } 198 199 if (!DeduceSiblingCalls) 200 return false; 201 202 // Look for the parent up the stack. 203 auto Parent = 204 std::find_if(ThreadStack.Stack.rbegin(), ThreadStack.Stack.rend(), 205 [&](const std::pair<const int32_t, uint64_t> &E) { 206 return E.first == Record.FuncId; 207 }); 208 if (Parent == ThreadStack.Stack.rend()) 209 return false; 210 211 // Account time for this apparently sibling call exit up the stack. 212 // Considering the following case: 213 // 214 // f() 215 // g() 216 // h() 217 // 218 // We might only ever see the following entries: 219 // 220 // -> f() 221 // -> g() 222 // -> h() 223 // <- h() 224 // <- f() 225 // 226 // Now we don't see the exit to g() because some older version of the XRay 227 // runtime wasn't instrumenting tail exits. If we don't deduce tail calls, 228 // we may potentially never account time for g() -- and this code would have 229 // already bailed out, because `<- f()` doesn't match the current "top" of 230 // stack where we're waiting for the exit to `g()` instead. This is not 231 // ideal and brittle -- so instead we provide a potentially inaccurate 232 // accounting of g() instead, computing it from the exit of f(). 233 // 234 // While it might be better that we account the time between `-> g()` and 235 // `-> h()` as the proper accounting of time for g() here, this introduces 236 // complexity to do correctly (need to backtrack, etc.). 237 // 238 // FIXME: Potentially implement the more complex deduction algorithm? 239 auto R = make_range(std::next(Parent).base(), ThreadStack.Stack.end()); 240 for (auto &E : R) { 241 if (!ThreadStack.RecursionDepth || 242 (*ThreadStack.RecursionDepth)[E.first].isRecursive()) 243 recordLatency(E.first, diff(E.second, Record.TSC)); 244 } 245 for (auto &Top : reverse(R)) { 246 if (ThreadStack.RecursionDepth) 247 --(*ThreadStack.RecursionDepth)[Top.first]; 248 ThreadStack.Stack.pop_back(); 249 } 250 break; 251 } 252 } 253 254 return true; 255 } 256 257 namespace { 258 259 // We consolidate the data into a struct which we can output in various forms. 260 struct ResultRow { 261 uint64_t Count; 262 double Min; 263 double Median; 264 double Pct90; 265 double Pct99; 266 double Max; 267 double Sum; 268 std::string DebugInfo; 269 std::string Function; 270 }; 271 272 ResultRow getStats(MutableArrayRef<uint64_t> Timings) { 273 assert(!Timings.empty()); 274 ResultRow R; 275 R.Sum = std::accumulate(Timings.begin(), Timings.end(), 0.0); 276 auto MinMax = std::minmax_element(Timings.begin(), Timings.end()); 277 R.Min = *MinMax.first; 278 R.Max = *MinMax.second; 279 R.Count = Timings.size(); 280 281 auto MedianOff = Timings.size() / 2; 282 std::nth_element(Timings.begin(), Timings.begin() + MedianOff, Timings.end()); 283 R.Median = Timings[MedianOff]; 284 285 auto Pct90Off = std::floor(Timings.size() * 0.9); 286 std::nth_element(Timings.begin(), Timings.begin() + (uint64_t)Pct90Off, 287 Timings.end()); 288 R.Pct90 = Timings[Pct90Off]; 289 290 auto Pct99Off = std::floor(Timings.size() * 0.99); 291 std::nth_element(Timings.begin(), Timings.begin() + (uint64_t)Pct99Off, 292 Timings.end()); 293 R.Pct99 = Timings[Pct99Off]; 294 return R; 295 } 296 297 } // namespace 298 299 using TupleType = std::tuple<int32_t, uint64_t, ResultRow>; 300 301 template <typename F> 302 static void sortByKey(std::vector<TupleType> &Results, F Fn) { 303 bool ASC = AccountSortOrder == SortDirection::ASCENDING; 304 llvm::sort(Results, [=](const TupleType &L, const TupleType &R) { 305 return ASC ? Fn(L) < Fn(R) : Fn(L) > Fn(R); 306 }); 307 } 308 309 template <class F> 310 void LatencyAccountant::exportStats(const XRayFileHeader &Header, F Fn) const { 311 std::vector<TupleType> Results; 312 Results.reserve(FunctionLatencies.size()); 313 for (auto FT : FunctionLatencies) { 314 const auto &FuncId = FT.first; 315 auto &Timings = FT.second; 316 Results.emplace_back(FuncId, Timings.size(), getStats(Timings)); 317 auto &Row = std::get<2>(Results.back()); 318 if (Header.CycleFrequency) { 319 double CycleFrequency = Header.CycleFrequency; 320 Row.Min /= CycleFrequency; 321 Row.Median /= CycleFrequency; 322 Row.Pct90 /= CycleFrequency; 323 Row.Pct99 /= CycleFrequency; 324 Row.Max /= CycleFrequency; 325 Row.Sum /= CycleFrequency; 326 } 327 328 Row.Function = FuncIdHelper.SymbolOrNumber(FuncId); 329 Row.DebugInfo = FuncIdHelper.FileLineAndColumn(FuncId); 330 } 331 332 // Sort the data according to user-provided flags. 333 switch (AccountSortOutput) { 334 case SortField::FUNCID: 335 sortByKey(Results, [](const TupleType &X) { return std::get<0>(X); }); 336 break; 337 case SortField::COUNT: 338 sortByKey(Results, [](const TupleType &X) { return std::get<1>(X); }); 339 break; 340 case SortField::MIN: 341 sortByKey(Results, [](const TupleType &X) { return std::get<2>(X).Min; }); 342 break; 343 case SortField::MED: 344 sortByKey(Results, [](const TupleType &X) { return std::get<2>(X).Median; }); 345 break; 346 case SortField::PCT90: 347 sortByKey(Results, [](const TupleType &X) { return std::get<2>(X).Pct90; }); 348 break; 349 case SortField::PCT99: 350 sortByKey(Results, [](const TupleType &X) { return std::get<2>(X).Pct99; }); 351 break; 352 case SortField::MAX: 353 sortByKey(Results, [](const TupleType &X) { return std::get<2>(X).Max; }); 354 break; 355 case SortField::SUM: 356 sortByKey(Results, [](const TupleType &X) { return std::get<2>(X).Sum; }); 357 break; 358 case SortField::FUNC: 359 llvm_unreachable("Not implemented"); 360 } 361 362 if (AccountTop > 0) { 363 auto MaxTop = 364 std::min(AccountTop.getValue(), static_cast<int>(Results.size())); 365 Results.erase(Results.begin() + MaxTop, Results.end()); 366 } 367 368 for (const auto &R : Results) 369 Fn(std::get<0>(R), std::get<1>(R), std::get<2>(R)); 370 } 371 372 void LatencyAccountant::exportStatsAsText(raw_ostream &OS, 373 const XRayFileHeader &Header) const { 374 OS << "Functions with latencies: " << FunctionLatencies.size() << "\n"; 375 376 // We spend some effort to make the text output more readable, so we do the 377 // following formatting decisions for each of the fields: 378 // 379 // - funcid: 32-bit, but we can determine the largest number and be 380 // between 381 // a minimum of 5 characters, up to 9 characters, right aligned. 382 // - count: 64-bit, but we can determine the largest number and be 383 // between 384 // a minimum of 5 characters, up to 9 characters, right aligned. 385 // - min, median, 90pct, 99pct, max: double precision, but we want to keep 386 // the values in seconds, with microsecond precision (0.000'001), so we 387 // have at most 6 significant digits, with the whole number part to be 388 // at 389 // least 1 character. For readability we'll right-align, with full 9 390 // characters each. 391 // - debug info, function name: we format this as a concatenation of the 392 // debug info and the function name. 393 // 394 static constexpr char StatsHeaderFormat[] = 395 "{0,+9} {1,+10} [{2,+9}, {3,+9}, {4,+9}, {5,+9}, {6,+9}] {7,+9}"; 396 static constexpr char StatsFormat[] = 397 R"({0,+9} {1,+10} [{2,+9:f6}, {3,+9:f6}, {4,+9:f6}, {5,+9:f6}, {6,+9:f6}] {7,+9:f6})"; 398 OS << llvm::formatv(StatsHeaderFormat, "funcid", "count", "min", "med", "90p", 399 "99p", "max", "sum") 400 << llvm::formatv(" {0,-12}\n", "function"); 401 exportStats(Header, [&](int32_t FuncId, size_t Count, const ResultRow &Row) { 402 OS << llvm::formatv(StatsFormat, FuncId, Count, Row.Min, Row.Median, 403 Row.Pct90, Row.Pct99, Row.Max, Row.Sum) 404 << " " << Row.DebugInfo << ": " << Row.Function << "\n"; 405 }); 406 } 407 408 void LatencyAccountant::exportStatsAsCSV(raw_ostream &OS, 409 const XRayFileHeader &Header) const { 410 OS << "funcid,count,min,median,90%ile,99%ile,max,sum,debug,function\n"; 411 exportStats(Header, [&](int32_t FuncId, size_t Count, const ResultRow &Row) { 412 OS << FuncId << ',' << Count << ',' << Row.Min << ',' << Row.Median << ',' 413 << Row.Pct90 << ',' << Row.Pct99 << ',' << Row.Max << "," << Row.Sum 414 << ",\"" << Row.DebugInfo << "\",\"" << Row.Function << "\"\n"; 415 }); 416 } 417 418 using namespace llvm::xray; 419 420 namespace llvm { 421 template <> struct format_provider<llvm::xray::RecordTypes> { 422 static void format(const llvm::xray::RecordTypes &T, raw_ostream &Stream, 423 StringRef Style) { 424 switch (T) { 425 case RecordTypes::ENTER: 426 Stream << "enter"; 427 break; 428 case RecordTypes::ENTER_ARG: 429 Stream << "enter-arg"; 430 break; 431 case RecordTypes::EXIT: 432 Stream << "exit"; 433 break; 434 case RecordTypes::TAIL_EXIT: 435 Stream << "tail-exit"; 436 break; 437 case RecordTypes::CUSTOM_EVENT: 438 Stream << "custom-event"; 439 break; 440 case RecordTypes::TYPED_EVENT: 441 Stream << "typed-event"; 442 break; 443 } 444 } 445 }; 446 } // namespace llvm 447 448 static CommandRegistration Unused(&Account, []() -> Error { 449 InstrumentationMap Map; 450 if (!AccountInstrMap.empty()) { 451 auto InstrumentationMapOrError = loadInstrumentationMap(AccountInstrMap); 452 if (!InstrumentationMapOrError) 453 return joinErrors(make_error<StringError>( 454 Twine("Cannot open instrumentation map '") + 455 AccountInstrMap + "'", 456 std::make_error_code(std::errc::invalid_argument)), 457 InstrumentationMapOrError.takeError()); 458 Map = std::move(*InstrumentationMapOrError); 459 } 460 461 std::error_code EC; 462 raw_fd_ostream OS(AccountOutput, EC, sys::fs::OpenFlags::OF_TextWithCRLF); 463 if (EC) 464 return make_error<StringError>( 465 Twine("Cannot open file '") + AccountOutput + "' for writing.", EC); 466 467 const auto &FunctionAddresses = Map.getFunctionAddresses(); 468 symbolize::LLVMSymbolizer Symbolizer; 469 llvm::xray::FuncIdConversionHelper FuncIdHelper(AccountInstrMap, Symbolizer, 470 FunctionAddresses); 471 xray::LatencyAccountant FCA(FuncIdHelper, AccountRecursiveCallsOnly, 472 AccountDeduceSiblingCalls); 473 auto TraceOrErr = loadTraceFile(AccountInput); 474 if (!TraceOrErr) 475 return joinErrors( 476 make_error<StringError>( 477 Twine("Failed loading input file '") + AccountInput + "'", 478 std::make_error_code(std::errc::executable_format_error)), 479 TraceOrErr.takeError()); 480 481 auto &T = *TraceOrErr; 482 for (const auto &Record : T) { 483 if (FCA.accountRecord(Record)) 484 continue; 485 errs() 486 << "Error processing record: " 487 << llvm::formatv( 488 R"({{type: {0}; cpu: {1}; record-type: {2}; function-id: {3}; tsc: {4}; thread-id: {5}; process-id: {6}}})", 489 Record.RecordType, Record.CPU, Record.Type, Record.FuncId, 490 Record.TSC, Record.TId, Record.PId) 491 << '\n'; 492 for (const auto &ThreadStack : FCA.getPerThreadFunctionStack()) { 493 errs() << "Thread ID: " << ThreadStack.first << "\n"; 494 if (ThreadStack.second.Stack.empty()) { 495 errs() << " (empty stack)\n"; 496 continue; 497 } 498 auto Level = ThreadStack.second.Stack.size(); 499 for (const auto &Entry : llvm::reverse(ThreadStack.second.Stack)) 500 errs() << " #" << Level-- << "\t" 501 << FuncIdHelper.SymbolOrNumber(Entry.first) << '\n'; 502 } 503 if (!AccountKeepGoing) 504 return make_error<StringError>( 505 Twine("Failed accounting function calls in file '") + AccountInput + 506 "'.", 507 std::make_error_code(std::errc::executable_format_error)); 508 } 509 switch (AccountOutputFormat) { 510 case AccountOutputFormats::TEXT: 511 FCA.exportStatsAsText(OS, T.getFileHeader()); 512 break; 513 case AccountOutputFormats::CSV: 514 FCA.exportStatsAsCSV(OS, T.getFileHeader()); 515 break; 516 } 517 518 return Error::success(); 519 }); 520