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