1 //===- xray-stacks.cpp: XRay Function Call Stack Accounting ---------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file implements stack-based accounting. It takes XRay traces, and
11 // collates statistics across these traces to show a breakdown of time spent
12 // at various points of the stack to provide insight into which functions
13 // spend the most time in terms of a call stack. We provide a few
14 // sorting/filtering options for zero'ing in on the useful stacks.
15 //
16 //===----------------------------------------------------------------------===//
17
18 #include <forward_list>
19 #include <numeric>
20
21 #include "func-id-helper.h"
22 #include "trie-node.h"
23 #include "xray-registry.h"
24 #include "llvm/ADT/StringExtras.h"
25 #include "llvm/Support/CommandLine.h"
26 #include "llvm/Support/Errc.h"
27 #include "llvm/Support/ErrorHandling.h"
28 #include "llvm/Support/FormatAdapters.h"
29 #include "llvm/Support/FormatVariadic.h"
30 #include "llvm/XRay/Graph.h"
31 #include "llvm/XRay/InstrumentationMap.h"
32 #include "llvm/XRay/Trace.h"
33
34 using namespace llvm;
35 using namespace llvm::xray;
36
37 static cl::SubCommand Stack("stack", "Call stack accounting");
38 static cl::list<std::string> StackInputs(cl::Positional,
39 cl::desc("<xray trace>"), cl::Required,
40 cl::sub(Stack), cl::OneOrMore);
41
42 static cl::opt<bool>
43 StackKeepGoing("keep-going", cl::desc("Keep going on errors encountered"),
44 cl::sub(Stack), cl::init(false));
45 static cl::alias StackKeepGoing2("k", cl::aliasopt(StackKeepGoing),
46 cl::desc("Alias for -keep-going"),
47 cl::sub(Stack));
48
49 // TODO: Does there need to be an option to deduce tail or sibling calls?
50
51 static cl::opt<std::string> StacksInstrMap(
52 "instr_map",
53 cl::desc("instrumentation map used to identify function ids. "
54 "Currently supports elf file instrumentation maps."),
55 cl::sub(Stack), cl::init(""));
56 static cl::alias StacksInstrMap2("m", cl::aliasopt(StacksInstrMap),
57 cl::desc("Alias for -instr_map"),
58 cl::sub(Stack));
59
60 static cl::opt<bool>
61 SeparateThreadStacks("per-thread-stacks",
62 cl::desc("Report top stacks within each thread id"),
63 cl::sub(Stack), cl::init(false));
64
65 static cl::opt<bool>
66 AggregateThreads("aggregate-threads",
67 cl::desc("Aggregate stack times across threads"),
68 cl::sub(Stack), cl::init(false));
69
70 static cl::opt<bool>
71 DumpAllStacks("all-stacks",
72 cl::desc("Dump sum of timings for all stacks. "
73 "By default separates stacks per-thread."),
74 cl::sub(Stack), cl::init(false));
75 static cl::alias DumpAllStacksShort("all", cl::aliasopt(DumpAllStacks),
76 cl::desc("Alias for -all-stacks"),
77 cl::sub(Stack));
78
79 // TODO(kpw): Add other interesting formats. Perhaps chrome trace viewer format
80 // possibly with aggregations or just a linear trace of timings.
81 enum StackOutputFormat { HUMAN, FLAMETOOL };
82
83 static cl::opt<StackOutputFormat> StacksOutputFormat(
84 "stack-format",
85 cl::desc("The format that output stacks should be "
86 "output in. Only applies with all-stacks."),
87 cl::values(
88 clEnumValN(HUMAN, "human",
89 "Human readable output. Only valid without -all-stacks."),
90 clEnumValN(FLAMETOOL, "flame",
91 "Format consumable by Brendan Gregg's FlameGraph tool. "
92 "Only valid with -all-stacks.")),
93 cl::sub(Stack), cl::init(HUMAN));
94
95 // Types of values for each stack in a CallTrie.
96 enum class AggregationType {
97 TOTAL_TIME, // The total time spent in a stack and its callees.
98 INVOCATION_COUNT // The number of times the stack was invoked.
99 };
100
101 static cl::opt<AggregationType> RequestedAggregation(
102 "aggregation-type",
103 cl::desc("The type of aggregation to do on call stacks."),
104 cl::values(
105 clEnumValN(
106 AggregationType::TOTAL_TIME, "time",
107 "Capture the total time spent in an all invocations of a stack."),
108 clEnumValN(AggregationType::INVOCATION_COUNT, "count",
109 "Capture the number of times a stack was invoked. "
110 "In flamegraph mode, this count also includes invocations "
111 "of all callees.")),
112 cl::sub(Stack), cl::init(AggregationType::TOTAL_TIME));
113
114 /// A helper struct to work with formatv and XRayRecords. Makes it easier to
115 /// use instrumentation map names or addresses in formatted output.
116 struct format_xray_record : public FormatAdapter<XRayRecord> {
format_xray_recordformat_xray_record117 explicit format_xray_record(XRayRecord record,
118 const FuncIdConversionHelper &conv)
119 : FormatAdapter<XRayRecord>(std::move(record)), Converter(&conv) {}
formatformat_xray_record120 void format(raw_ostream &Stream, StringRef Style) override {
121 Stream << formatv(
122 "{FuncId: \"{0}\", ThreadId: \"{1}\", RecordType: \"{2}\"}",
123 Converter->SymbolOrNumber(Item.FuncId), Item.TId,
124 DecodeRecordType(Item.RecordType));
125 }
126
127 private:
DecodeRecordTypeformat_xray_record128 Twine DecodeRecordType(uint16_t recordType) {
129 switch (recordType) {
130 case 0:
131 return Twine("Fn Entry");
132 case 1:
133 return Twine("Fn Exit");
134 default:
135 // TODO: Add Tail exit when it is added to llvm/XRay/XRayRecord.h
136 return Twine("Unknown");
137 }
138 }
139
140 const FuncIdConversionHelper *Converter;
141 };
142
143 /// The stack command will take a set of XRay traces as arguments, and collects
144 /// information about the stacks of instrumented functions that appear in the
145 /// traces. We track the following pieces of information:
146 ///
147 /// - Total time: amount of time/cycles accounted for in the traces.
148 /// - Stack count: number of times a specific stack appears in the
149 /// traces. Only instrumented functions show up in stacks.
150 /// - Cumulative stack time: amount of time spent in a stack accumulated
151 /// across the invocations in the traces.
152 /// - Cumulative local time: amount of time spent in each instrumented
153 /// function showing up in a specific stack, accumulated across the traces.
154 ///
155 /// Example output for the kind of data we'd like to provide looks like the
156 /// following:
157 ///
158 /// Total time: 3.33234 s
159 /// Stack ID: ...
160 /// Stack Count: 2093
161 /// # Function Local Time (%) Stack Time (%)
162 /// 0 main 2.34 ms 0.07% 3.33234 s 100%
163 /// 1 foo() 3.30000 s 99.02% 3.33 s 99.92%
164 /// 2 bar() 30 ms 0.90% 30 ms 0.90%
165 ///
166 /// We can also show distributions of the function call durations with
167 /// statistics at each level of the stack. This works by doing the following
168 /// algorithm:
169 ///
170 /// 1. When unwinding, record the duration of each unwound function associated
171 /// with the path up to which the unwinding stops. For example:
172 ///
173 /// Step Duration (? means has start time)
174 ///
175 /// push a <start time> a = ?
176 /// push b <start time> a = ?, a->b = ?
177 /// push c <start time> a = ?, a->b = ?, a->b->c = ?
178 /// pop c <end time> a = ?, a->b = ?, emit duration(a->b->c)
179 /// pop b <end time> a = ?, emit duration(a->b)
180 /// push c <start time> a = ?, a->c = ?
181 /// pop c <end time> a = ?, emit duration(a->c)
182 /// pop a <end time> emit duration(a)
183 ///
184 /// 2. We then account for the various stacks we've collected, and for each of
185 /// them will have measurements that look like the following (continuing
186 /// with the above simple example):
187 ///
188 /// c : [<id("a->b->c"), [durations]>, <id("a->c"), [durations]>]
189 /// b : [<id("a->b"), [durations]>]
190 /// a : [<id("a"), [durations]>]
191 ///
192 /// This allows us to compute, for each stack id, and each function that
193 /// shows up in the stack, some important statistics like:
194 ///
195 /// - median
196 /// - 99th percentile
197 /// - mean + stddev
198 /// - count
199 ///
200 /// 3. For cases where we don't have durations for some of the higher levels
201 /// of the stack (perhaps instrumentation wasn't activated when the stack was
202 /// entered), we can mark them appropriately.
203 ///
204 /// Computing this data also allows us to implement lookup by call stack nodes,
205 /// so that we can find functions that show up in multiple stack traces and
206 /// show the statistical properties of that function in various contexts. We
207 /// can compute information similar to the following:
208 ///
209 /// Function: 'c'
210 /// Stacks: 2 / 2
211 /// Stack ID: ...
212 /// Stack Count: ...
213 /// # Function ...
214 /// 0 a ...
215 /// 1 b ...
216 /// 2 c ...
217 ///
218 /// Stack ID: ...
219 /// Stack Count: ...
220 /// # Function ...
221 /// 0 a ...
222 /// 1 c ...
223 /// ----------------...
224 ///
225 /// Function: 'b'
226 /// Stacks: 1 / 2
227 /// Stack ID: ...
228 /// Stack Count: ...
229 /// # Function ...
230 /// 0 a ...
231 /// 1 b ...
232 /// 2 c ...
233 ///
234 ///
235 /// To do this we require a Trie data structure that will allow us to represent
236 /// all the call stacks of instrumented functions in an easily traversible
237 /// manner when we do the aggregations and lookups. For instrumented call
238 /// sequences like the following:
239 ///
240 /// a()
241 /// b()
242 /// c()
243 /// d()
244 /// c()
245 ///
246 /// We will have a representation like so:
247 ///
248 /// a -> b -> c
249 /// | |
250 /// | +--> d
251 /// |
252 /// +--> c
253 ///
254 /// We maintain a sequence of durations on the leaves and in the internal nodes
255 /// as we go through and process every record from the XRay trace. We also
256 /// maintain an index of unique functions, and provide a means of iterating
257 /// through all the instrumented call stacks which we know about.
258
259 struct StackDuration {
260 llvm::SmallVector<int64_t, 4> TerminalDurations;
261 llvm::SmallVector<int64_t, 4> IntermediateDurations;
262 };
263
mergeStackDuration(const StackDuration & Left,const StackDuration & Right)264 StackDuration mergeStackDuration(const StackDuration &Left,
265 const StackDuration &Right) {
266 StackDuration Data{};
267 Data.TerminalDurations.reserve(Left.TerminalDurations.size() +
268 Right.TerminalDurations.size());
269 Data.IntermediateDurations.reserve(Left.IntermediateDurations.size() +
270 Right.IntermediateDurations.size());
271 // Aggregate the durations.
272 for (auto duration : Left.TerminalDurations)
273 Data.TerminalDurations.push_back(duration);
274 for (auto duration : Right.TerminalDurations)
275 Data.TerminalDurations.push_back(duration);
276
277 for (auto duration : Left.IntermediateDurations)
278 Data.IntermediateDurations.push_back(duration);
279 for (auto duration : Right.IntermediateDurations)
280 Data.IntermediateDurations.push_back(duration);
281 return Data;
282 }
283
284 using StackTrieNode = TrieNode<StackDuration>;
285
286 template <AggregationType AggType>
287 std::size_t GetValueForStack(const StackTrieNode *Node);
288
289 // When computing total time spent in a stack, we're adding the timings from
290 // its callees and the timings from when it was a leaf.
291 template <>
292 std::size_t
GetValueForStack(const StackTrieNode * Node)293 GetValueForStack<AggregationType::TOTAL_TIME>(const StackTrieNode *Node) {
294 auto TopSum = std::accumulate(Node->ExtraData.TerminalDurations.begin(),
295 Node->ExtraData.TerminalDurations.end(), 0uLL);
296 return std::accumulate(Node->ExtraData.IntermediateDurations.begin(),
297 Node->ExtraData.IntermediateDurations.end(), TopSum);
298 }
299
300 // Calculates how many times a function was invoked.
301 // TODO: Hook up option to produce stacks
302 template <>
303 std::size_t
GetValueForStack(const StackTrieNode * Node)304 GetValueForStack<AggregationType::INVOCATION_COUNT>(const StackTrieNode *Node) {
305 return Node->ExtraData.TerminalDurations.size() +
306 Node->ExtraData.IntermediateDurations.size();
307 }
308
309 // Make sure there are implementations for each enum value.
310 template <AggregationType T> struct DependentFalseType : std::false_type {};
311
312 template <AggregationType AggType>
GetValueForStack(const StackTrieNode * Node)313 std::size_t GetValueForStack(const StackTrieNode *Node) {
314 static_assert(DependentFalseType<AggType>::value,
315 "No implementation found for aggregation type provided.");
316 return 0;
317 }
318
319 class StackTrie {
320 // Avoid the magic number of 4 propagated through the code with an alias.
321 // We use this SmallVector to track the root nodes in a call graph.
322 using RootVector = SmallVector<StackTrieNode *, 4>;
323
324 // We maintain pointers to the roots of the tries we see.
325 DenseMap<uint32_t, RootVector> Roots;
326
327 // We make sure all the nodes are accounted for in this list.
328 std::forward_list<StackTrieNode> NodeStore;
329
330 // A map of thread ids to pairs call stack trie nodes and their start times.
331 DenseMap<uint32_t, SmallVector<std::pair<StackTrieNode *, uint64_t>, 8>>
332 ThreadStackMap;
333
createTrieNode(uint32_t ThreadId,int32_t FuncId,StackTrieNode * Parent)334 StackTrieNode *createTrieNode(uint32_t ThreadId, int32_t FuncId,
335 StackTrieNode *Parent) {
336 NodeStore.push_front(StackTrieNode{FuncId, Parent, {}, {{}, {}}});
337 auto I = NodeStore.begin();
338 auto *Node = &*I;
339 if (!Parent)
340 Roots[ThreadId].push_back(Node);
341 return Node;
342 }
343
findRootNode(uint32_t ThreadId,int32_t FuncId)344 StackTrieNode *findRootNode(uint32_t ThreadId, int32_t FuncId) {
345 const auto &RootsByThread = Roots[ThreadId];
346 auto I = find_if(RootsByThread,
347 [&](StackTrieNode *N) { return N->FuncId == FuncId; });
348 return (I == RootsByThread.end()) ? nullptr : *I;
349 }
350
351 public:
352 enum class AccountRecordStatus {
353 OK, // Successfully processed
354 ENTRY_NOT_FOUND, // An exit record had no matching call stack entry
355 UNKNOWN_RECORD_TYPE
356 };
357
358 struct AccountRecordState {
359 // We keep track of whether the call stack is currently unwinding.
360 bool wasLastRecordExit;
361
CreateInitialStateStackTrie::AccountRecordState362 static AccountRecordState CreateInitialState() { return {false}; }
363 };
364
accountRecord(const XRayRecord & R,AccountRecordState * state)365 AccountRecordStatus accountRecord(const XRayRecord &R,
366 AccountRecordState *state) {
367 auto &TS = ThreadStackMap[R.TId];
368 switch (R.Type) {
369 case RecordTypes::ENTER:
370 case RecordTypes::ENTER_ARG: {
371 state->wasLastRecordExit = false;
372 // When we encounter a new function entry, we want to record the TSC for
373 // that entry, and the function id. Before doing so we check the top of
374 // the stack to see if there are callees that already represent this
375 // function.
376 if (TS.empty()) {
377 auto *Root = findRootNode(R.TId, R.FuncId);
378 TS.emplace_back(Root ? Root : createTrieNode(R.TId, R.FuncId, nullptr),
379 R.TSC);
380 return AccountRecordStatus::OK;
381 }
382
383 auto &Top = TS.back();
384 auto I = find_if(Top.first->Callees,
385 [&](StackTrieNode *N) { return N->FuncId == R.FuncId; });
386 if (I == Top.first->Callees.end()) {
387 // We didn't find the callee in the stack trie, so we're going to
388 // add to the stack then set up the pointers properly.
389 auto N = createTrieNode(R.TId, R.FuncId, Top.first);
390 Top.first->Callees.emplace_back(N);
391
392 // Top may be invalidated after this statement.
393 TS.emplace_back(N, R.TSC);
394 } else {
395 // We found the callee in the stack trie, so we'll use that pointer
396 // instead, add it to the stack associated with the TSC.
397 TS.emplace_back(*I, R.TSC);
398 }
399 return AccountRecordStatus::OK;
400 }
401 case RecordTypes::EXIT:
402 case RecordTypes::TAIL_EXIT: {
403 bool wasLastRecordExit = state->wasLastRecordExit;
404 state->wasLastRecordExit = true;
405 // The exit case is more interesting, since we want to be able to deduce
406 // missing exit records. To do that properly, we need to look up the stack
407 // and see whether the exit record matches any of the entry records. If it
408 // does match, we attempt to record the durations as we pop the stack to
409 // where we see the parent.
410 if (TS.empty()) {
411 // Short circuit, and say we can't find it.
412
413 return AccountRecordStatus::ENTRY_NOT_FOUND;
414 }
415
416 auto FunctionEntryMatch = find_if(
417 reverse(TS), [&](const std::pair<StackTrieNode *, uint64_t> &E) {
418 return E.first->FuncId == R.FuncId;
419 });
420 auto status = AccountRecordStatus::OK;
421 if (FunctionEntryMatch == TS.rend()) {
422 status = AccountRecordStatus::ENTRY_NOT_FOUND;
423 } else {
424 // Account for offset of 1 between reverse and forward iterators. We
425 // want the forward iterator to include the function that is exited.
426 ++FunctionEntryMatch;
427 }
428 auto I = FunctionEntryMatch.base();
429 for (auto &E : make_range(I, TS.end() - 1))
430 E.first->ExtraData.IntermediateDurations.push_back(
431 std::max(E.second, R.TSC) - std::min(E.second, R.TSC));
432 auto &Deepest = TS.back();
433 if (wasLastRecordExit)
434 Deepest.first->ExtraData.IntermediateDurations.push_back(
435 std::max(Deepest.second, R.TSC) - std::min(Deepest.second, R.TSC));
436 else
437 Deepest.first->ExtraData.TerminalDurations.push_back(
438 std::max(Deepest.second, R.TSC) - std::min(Deepest.second, R.TSC));
439 TS.erase(I, TS.end());
440 return status;
441 }
442 }
443 return AccountRecordStatus::UNKNOWN_RECORD_TYPE;
444 }
445
isEmpty() const446 bool isEmpty() const { return Roots.empty(); }
447
printStack(raw_ostream & OS,const StackTrieNode * Top,FuncIdConversionHelper & FN)448 void printStack(raw_ostream &OS, const StackTrieNode *Top,
449 FuncIdConversionHelper &FN) {
450 // Traverse the pointers up to the parent, noting the sums, then print
451 // in reverse order (callers at top, callees down bottom).
452 SmallVector<const StackTrieNode *, 8> CurrentStack;
453 for (auto *F = Top; F != nullptr; F = F->Parent)
454 CurrentStack.push_back(F);
455 int Level = 0;
456 OS << formatv("{0,-5} {1,-60} {2,+12} {3,+16}\n", "lvl", "function",
457 "count", "sum");
458 for (auto *F :
459 reverse(make_range(CurrentStack.begin() + 1, CurrentStack.end()))) {
460 auto Sum = std::accumulate(F->ExtraData.IntermediateDurations.begin(),
461 F->ExtraData.IntermediateDurations.end(), 0LL);
462 auto FuncId = FN.SymbolOrNumber(F->FuncId);
463 OS << formatv("#{0,-4} {1,-60} {2,+12} {3,+16}\n", Level++,
464 FuncId.size() > 60 ? FuncId.substr(0, 57) + "..." : FuncId,
465 F->ExtraData.IntermediateDurations.size(), Sum);
466 }
467 auto *Leaf = *CurrentStack.begin();
468 auto LeafSum =
469 std::accumulate(Leaf->ExtraData.TerminalDurations.begin(),
470 Leaf->ExtraData.TerminalDurations.end(), 0LL);
471 auto LeafFuncId = FN.SymbolOrNumber(Leaf->FuncId);
472 OS << formatv("#{0,-4} {1,-60} {2,+12} {3,+16}\n", Level++,
473 LeafFuncId.size() > 60 ? LeafFuncId.substr(0, 57) + "..."
474 : LeafFuncId,
475 Leaf->ExtraData.TerminalDurations.size(), LeafSum);
476 OS << "\n";
477 }
478
479 /// Prints top stacks for each thread.
printPerThread(raw_ostream & OS,FuncIdConversionHelper & FN)480 void printPerThread(raw_ostream &OS, FuncIdConversionHelper &FN) {
481 for (auto iter : Roots) {
482 OS << "Thread " << iter.first << ":\n";
483 print(OS, FN, iter.second);
484 OS << "\n";
485 }
486 }
487
488 /// Prints timing sums for each stack in each threads.
489 template <AggregationType AggType>
printAllPerThread(raw_ostream & OS,FuncIdConversionHelper & FN,StackOutputFormat format)490 void printAllPerThread(raw_ostream &OS, FuncIdConversionHelper &FN,
491 StackOutputFormat format) {
492 for (auto iter : Roots) {
493 uint32_t threadId = iter.first;
494 RootVector &perThreadRoots = iter.second;
495 bool reportThreadId = true;
496 printAll<AggType>(OS, FN, perThreadRoots, threadId, reportThreadId);
497 }
498 }
499
500 /// Prints top stacks from looking at all the leaves and ignoring thread IDs.
501 /// Stacks that consist of the same function IDs but were called in different
502 /// thread IDs are not considered unique in this printout.
printIgnoringThreads(raw_ostream & OS,FuncIdConversionHelper & FN)503 void printIgnoringThreads(raw_ostream &OS, FuncIdConversionHelper &FN) {
504 RootVector RootValues;
505
506 // Function to pull the values out of a map iterator.
507 using RootsType = decltype(Roots.begin())::value_type;
508 auto MapValueFn = [](const RootsType &Value) { return Value.second; };
509
510 for (const auto &RootNodeRange :
511 make_range(map_iterator(Roots.begin(), MapValueFn),
512 map_iterator(Roots.end(), MapValueFn))) {
513 for (auto *RootNode : RootNodeRange)
514 RootValues.push_back(RootNode);
515 }
516
517 print(OS, FN, RootValues);
518 }
519
520 /// Creates a merged list of Tries for unique stacks that disregards their
521 /// thread IDs.
mergeAcrossThreads(std::forward_list<StackTrieNode> & NodeStore)522 RootVector mergeAcrossThreads(std::forward_list<StackTrieNode> &NodeStore) {
523 RootVector MergedByThreadRoots;
524 for (auto MapIter : Roots) {
525 const auto &RootNodeVector = MapIter.second;
526 for (auto *Node : RootNodeVector) {
527 auto MaybeFoundIter =
528 find_if(MergedByThreadRoots, [Node](StackTrieNode *elem) {
529 return Node->FuncId == elem->FuncId;
530 });
531 if (MaybeFoundIter == MergedByThreadRoots.end()) {
532 MergedByThreadRoots.push_back(Node);
533 } else {
534 MergedByThreadRoots.push_back(mergeTrieNodes(
535 **MaybeFoundIter, *Node, nullptr, NodeStore, mergeStackDuration));
536 MergedByThreadRoots.erase(MaybeFoundIter);
537 }
538 }
539 }
540 return MergedByThreadRoots;
541 }
542
543 /// Print timing sums for all stacks merged by Thread ID.
544 template <AggregationType AggType>
printAllAggregatingThreads(raw_ostream & OS,FuncIdConversionHelper & FN,StackOutputFormat format)545 void printAllAggregatingThreads(raw_ostream &OS, FuncIdConversionHelper &FN,
546 StackOutputFormat format) {
547 std::forward_list<StackTrieNode> AggregatedNodeStore;
548 RootVector MergedByThreadRoots = mergeAcrossThreads(AggregatedNodeStore);
549 bool reportThreadId = false;
550 printAll<AggType>(OS, FN, MergedByThreadRoots,
551 /*threadId*/ 0, reportThreadId);
552 }
553
554 /// Merges the trie by thread id before printing top stacks.
printAggregatingThreads(raw_ostream & OS,FuncIdConversionHelper & FN)555 void printAggregatingThreads(raw_ostream &OS, FuncIdConversionHelper &FN) {
556 std::forward_list<StackTrieNode> AggregatedNodeStore;
557 RootVector MergedByThreadRoots = mergeAcrossThreads(AggregatedNodeStore);
558 print(OS, FN, MergedByThreadRoots);
559 }
560
561 // TODO: Add a format option when more than one are supported.
562 template <AggregationType AggType>
printAll(raw_ostream & OS,FuncIdConversionHelper & FN,RootVector RootValues,uint32_t ThreadId,bool ReportThread)563 void printAll(raw_ostream &OS, FuncIdConversionHelper &FN,
564 RootVector RootValues, uint32_t ThreadId, bool ReportThread) {
565 SmallVector<const StackTrieNode *, 16> S;
566 for (const auto *N : RootValues) {
567 S.clear();
568 S.push_back(N);
569 while (!S.empty()) {
570 auto *Top = S.pop_back_val();
571 printSingleStack<AggType>(OS, FN, ReportThread, ThreadId, Top);
572 for (const auto *C : Top->Callees)
573 S.push_back(C);
574 }
575 }
576 }
577
578 /// Prints values for stacks in a format consumable for the flamegraph.pl
579 /// tool. This is a line based format that lists each level in the stack
580 /// hierarchy in a semicolon delimited form followed by a space and a numeric
581 /// value. If breaking down by thread, the thread ID will be added as the
582 /// root level of the stack.
583 template <AggregationType AggType>
printSingleStack(raw_ostream & OS,FuncIdConversionHelper & Converter,bool ReportThread,uint32_t ThreadId,const StackTrieNode * Node)584 void printSingleStack(raw_ostream &OS, FuncIdConversionHelper &Converter,
585 bool ReportThread, uint32_t ThreadId,
586 const StackTrieNode *Node) {
587 if (ReportThread)
588 OS << "thread_" << ThreadId << ";";
589 SmallVector<const StackTrieNode *, 5> lineage{};
590 lineage.push_back(Node);
591 while (lineage.back()->Parent != nullptr)
592 lineage.push_back(lineage.back()->Parent);
593 while (!lineage.empty()) {
594 OS << Converter.SymbolOrNumber(lineage.back()->FuncId) << ";";
595 lineage.pop_back();
596 }
597 OS << " " << GetValueForStack<AggType>(Node) << "\n";
598 }
599
print(raw_ostream & OS,FuncIdConversionHelper & FN,RootVector RootValues)600 void print(raw_ostream &OS, FuncIdConversionHelper &FN,
601 RootVector RootValues) {
602 // Go through each of the roots, and traverse the call stack, producing the
603 // aggregates as you go along. Remember these aggregates and stacks, and
604 // show summary statistics about:
605 //
606 // - Total number of unique stacks
607 // - Top 10 stacks by count
608 // - Top 10 stacks by aggregate duration
609 SmallVector<std::pair<const StackTrieNode *, uint64_t>, 11>
610 TopStacksByCount;
611 SmallVector<std::pair<const StackTrieNode *, uint64_t>, 11> TopStacksBySum;
612 auto greater_second =
613 [](const std::pair<const StackTrieNode *, uint64_t> &A,
614 const std::pair<const StackTrieNode *, uint64_t> &B) {
615 return A.second > B.second;
616 };
617 uint64_t UniqueStacks = 0;
618 for (const auto *N : RootValues) {
619 SmallVector<const StackTrieNode *, 16> S;
620 S.emplace_back(N);
621
622 while (!S.empty()) {
623 auto *Top = S.pop_back_val();
624
625 // We only start printing the stack (by walking up the parent pointers)
626 // when we get to a leaf function.
627 if (!Top->ExtraData.TerminalDurations.empty()) {
628 ++UniqueStacks;
629 auto TopSum =
630 std::accumulate(Top->ExtraData.TerminalDurations.begin(),
631 Top->ExtraData.TerminalDurations.end(), 0uLL);
632 {
633 auto E = std::make_pair(Top, TopSum);
634 TopStacksBySum.insert(std::lower_bound(TopStacksBySum.begin(),
635 TopStacksBySum.end(), E,
636 greater_second),
637 E);
638 if (TopStacksBySum.size() == 11)
639 TopStacksBySum.pop_back();
640 }
641 {
642 auto E =
643 std::make_pair(Top, Top->ExtraData.TerminalDurations.size());
644 TopStacksByCount.insert(std::lower_bound(TopStacksByCount.begin(),
645 TopStacksByCount.end(), E,
646 greater_second),
647 E);
648 if (TopStacksByCount.size() == 11)
649 TopStacksByCount.pop_back();
650 }
651 }
652 for (const auto *C : Top->Callees)
653 S.push_back(C);
654 }
655 }
656
657 // Now print the statistics in the end.
658 OS << "\n";
659 OS << "Unique Stacks: " << UniqueStacks << "\n";
660 OS << "Top 10 Stacks by leaf sum:\n\n";
661 for (const auto &P : TopStacksBySum) {
662 OS << "Sum: " << P.second << "\n";
663 printStack(OS, P.first, FN);
664 }
665 OS << "\n";
666 OS << "Top 10 Stacks by leaf count:\n\n";
667 for (const auto &P : TopStacksByCount) {
668 OS << "Count: " << P.second << "\n";
669 printStack(OS, P.first, FN);
670 }
671 OS << "\n";
672 }
673 };
674
CreateErrorMessage(StackTrie::AccountRecordStatus Error,const XRayRecord & Record,const FuncIdConversionHelper & Converter)675 std::string CreateErrorMessage(StackTrie::AccountRecordStatus Error,
676 const XRayRecord &Record,
677 const FuncIdConversionHelper &Converter) {
678 switch (Error) {
679 case StackTrie::AccountRecordStatus::ENTRY_NOT_FOUND:
680 return formatv("Found record {0} with no matching function entry\n",
681 format_xray_record(Record, Converter));
682 default:
683 return formatv("Unknown error type for record {0}\n",
684 format_xray_record(Record, Converter));
685 }
686 }
687
__anon6736a0a20702() 688 static CommandRegistration Unused(&Stack, []() -> Error {
689 // Load each file provided as a command-line argument. For each one of them
690 // account to a single StackTrie, and just print the whole trie for now.
691 StackTrie ST;
692 InstrumentationMap Map;
693 if (!StacksInstrMap.empty()) {
694 auto InstrumentationMapOrError = loadInstrumentationMap(StacksInstrMap);
695 if (!InstrumentationMapOrError)
696 return joinErrors(
697 make_error<StringError>(
698 Twine("Cannot open instrumentation map: ") + StacksInstrMap,
699 std::make_error_code(std::errc::invalid_argument)),
700 InstrumentationMapOrError.takeError());
701 Map = std::move(*InstrumentationMapOrError);
702 }
703
704 if (SeparateThreadStacks && AggregateThreads)
705 return make_error<StringError>(
706 Twine("Can't specify options for per thread reporting and reporting "
707 "that aggregates threads."),
708 std::make_error_code(std::errc::invalid_argument));
709
710 if (!DumpAllStacks && StacksOutputFormat != HUMAN)
711 return make_error<StringError>(
712 Twine("Can't specify a non-human format without -all-stacks."),
713 std::make_error_code(std::errc::invalid_argument));
714
715 if (DumpAllStacks && StacksOutputFormat == HUMAN)
716 return make_error<StringError>(
717 Twine("You must specify a non-human format when reporting with "
718 "-all-stacks."),
719 std::make_error_code(std::errc::invalid_argument));
720
721 symbolize::LLVMSymbolizer::Options Opts(
722 symbolize::FunctionNameKind::LinkageName, true, true, false, "");
723 symbolize::LLVMSymbolizer Symbolizer(Opts);
724 FuncIdConversionHelper FuncIdHelper(StacksInstrMap, Symbolizer,
725 Map.getFunctionAddresses());
726 // TODO: Someday, support output to files instead of just directly to
727 // standard output.
728 for (const auto &Filename : StackInputs) {
729 auto TraceOrErr = loadTraceFile(Filename);
730 if (!TraceOrErr) {
731 if (!StackKeepGoing)
732 return joinErrors(
733 make_error<StringError>(
734 Twine("Failed loading input file '") + Filename + "'",
735 std::make_error_code(std::errc::invalid_argument)),
736 TraceOrErr.takeError());
737 logAllUnhandledErrors(TraceOrErr.takeError(), errs(), "");
738 continue;
739 }
740 auto &T = *TraceOrErr;
741 StackTrie::AccountRecordState AccountRecordState =
742 StackTrie::AccountRecordState::CreateInitialState();
743 for (const auto &Record : T) {
744 auto error = ST.accountRecord(Record, &AccountRecordState);
745 if (error != StackTrie::AccountRecordStatus::OK) {
746 if (!StackKeepGoing)
747 return make_error<StringError>(
748 CreateErrorMessage(error, Record, FuncIdHelper),
749 make_error_code(errc::illegal_byte_sequence));
750 errs() << CreateErrorMessage(error, Record, FuncIdHelper);
751 }
752 }
753 }
754 if (ST.isEmpty()) {
755 return make_error<StringError>(
756 "No instrumented calls were accounted in the input file.",
757 make_error_code(errc::result_out_of_range));
758 }
759
760 // Report the stacks in a long form mode for another tool to analyze.
761 if (DumpAllStacks) {
762 if (AggregateThreads) {
763 switch (RequestedAggregation) {
764 case AggregationType::TOTAL_TIME:
765 ST.printAllAggregatingThreads<AggregationType::TOTAL_TIME>(
766 outs(), FuncIdHelper, StacksOutputFormat);
767 break;
768 case AggregationType::INVOCATION_COUNT:
769 ST.printAllAggregatingThreads<AggregationType::INVOCATION_COUNT>(
770 outs(), FuncIdHelper, StacksOutputFormat);
771 break;
772 }
773 } else {
774 switch (RequestedAggregation) {
775 case AggregationType::TOTAL_TIME:
776 ST.printAllPerThread<AggregationType::TOTAL_TIME>(outs(), FuncIdHelper,
777 StacksOutputFormat);
778 break;
779 case AggregationType::INVOCATION_COUNT:
780 ST.printAllPerThread<AggregationType::INVOCATION_COUNT>(
781 outs(), FuncIdHelper, StacksOutputFormat);
782 break;
783 }
784 }
785 return Error::success();
786 }
787
788 // We're only outputting top stacks.
789 if (AggregateThreads) {
790 ST.printAggregatingThreads(outs(), FuncIdHelper);
791 } else if (SeparateThreadStacks) {
792 ST.printPerThread(outs(), FuncIdHelper);
793 } else {
794 ST.printIgnoringThreads(outs(), FuncIdHelper);
795 }
796 return Error::success();
797 });
798