trace.cc revision 9fb1ab1f6bb58bdaccef78bc81b3202d0121e2ed 
1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "trace.h"
18
19#include <sys/uio.h>
20#include <unistd.h>
21
22#include "android-base/stringprintf.h"
23
24#include "art_method-inl.h"
25#include "base/casts.h"
26#include "base/enums.h"
27#include "base/stl_util.h"
28#include "base/systrace.h"
29#include "base/time_utils.h"
30#include "base/unix_file/fd_file.h"
31#include "class_linker.h"
32#include "common_throws.h"
33#include "debugger.h"
34#include "dex_file-inl.h"
35#include "entrypoints/quick/quick_entrypoints.h"
36#include "gc/scoped_gc_critical_section.h"
37#include "instrumentation.h"
38#include "mirror/class-inl.h"
39#include "mirror/dex_cache-inl.h"
40#include "mirror/object-inl.h"
41#include "mirror/object_array-inl.h"
42#include "nativehelper/ScopedLocalRef.h"
43#include "os.h"
44#include "scoped_thread_state_change-inl.h"
45#include "stack.h"
46#include "thread.h"
47#include "thread_list.h"
48#include "utils.h"
49
50namespace art {
51
52using android::base::StringPrintf;
53
54static constexpr size_t TraceActionBits = MinimumBitsToStore(
55    static_cast<size_t>(kTraceMethodActionMask));
56static constexpr uint8_t kOpNewMethod = 1U;
57static constexpr uint8_t kOpNewThread = 2U;
58static constexpr uint8_t kOpTraceSummary = 3U;
59
60class BuildStackTraceVisitor : public StackVisitor {
61 public:
62  explicit BuildStackTraceVisitor(Thread* thread)
63      : StackVisitor(thread, nullptr, StackVisitor::StackWalkKind::kIncludeInlinedFrames),
64        method_trace_(Trace::AllocStackTrace()) {}
65
66  bool VisitFrame() REQUIRES_SHARED(Locks::mutator_lock_) {
67    ArtMethod* m = GetMethod();
68    // Ignore runtime frames (in particular callee save).
69    if (!m->IsRuntimeMethod()) {
70      method_trace_->push_back(m);
71    }
72    return true;
73  }
74
75  // Returns a stack trace where the topmost frame corresponds with the first element of the vector.
76  std::vector<ArtMethod*>* GetStackTrace() const {
77    return method_trace_;
78  }
79
80 private:
81  std::vector<ArtMethod*>* const method_trace_;
82
83  DISALLOW_COPY_AND_ASSIGN(BuildStackTraceVisitor);
84};
85
86static const char     kTraceTokenChar             = '*';
87static const uint16_t kTraceHeaderLength          = 32;
88static const uint32_t kTraceMagicValue            = 0x574f4c53;
89static const uint16_t kTraceVersionSingleClock    = 2;
90static const uint16_t kTraceVersionDualClock      = 3;
91static const uint16_t kTraceRecordSizeSingleClock = 10;  // using v2
92static const uint16_t kTraceRecordSizeDualClock   = 14;  // using v3 with two timestamps
93
94TraceClockSource Trace::default_clock_source_ = kDefaultTraceClockSource;
95
96Trace* volatile Trace::the_trace_ = nullptr;
97pthread_t Trace::sampling_pthread_ = 0U;
98std::unique_ptr<std::vector<ArtMethod*>> Trace::temp_stack_trace_;
99
100// The key identifying the tracer to update instrumentation.
101static constexpr const char* kTracerInstrumentationKey = "Tracer";
102
103static TraceAction DecodeTraceAction(uint32_t tmid) {
104  return static_cast<TraceAction>(tmid & kTraceMethodActionMask);
105}
106
107ArtMethod* Trace::DecodeTraceMethod(uint32_t tmid) {
108  MutexLock mu(Thread::Current(), *unique_methods_lock_);
109  return unique_methods_[tmid >> TraceActionBits];
110}
111
112uint32_t Trace::EncodeTraceMethod(ArtMethod* method) {
113  MutexLock mu(Thread::Current(), *unique_methods_lock_);
114  uint32_t idx;
115  auto it = art_method_id_map_.find(method);
116  if (it != art_method_id_map_.end()) {
117    idx = it->second;
118  } else {
119    unique_methods_.push_back(method);
120    idx = unique_methods_.size() - 1;
121    art_method_id_map_.emplace(method, idx);
122  }
123  DCHECK_LT(idx, unique_methods_.size());
124  DCHECK_EQ(unique_methods_[idx], method);
125  return idx;
126}
127
128uint32_t Trace::EncodeTraceMethodAndAction(ArtMethod* method, TraceAction action) {
129  uint32_t tmid = (EncodeTraceMethod(method) << TraceActionBits) | action;
130  DCHECK_EQ(method, DecodeTraceMethod(tmid));
131  return tmid;
132}
133
134std::vector<ArtMethod*>* Trace::AllocStackTrace() {
135  return (temp_stack_trace_.get() != nullptr)  ? temp_stack_trace_.release() :
136      new std::vector<ArtMethod*>();
137}
138
139void Trace::FreeStackTrace(std::vector<ArtMethod*>* stack_trace) {
140  stack_trace->clear();
141  temp_stack_trace_.reset(stack_trace);
142}
143
144void Trace::SetDefaultClockSource(TraceClockSource clock_source) {
145#if defined(__linux__)
146  default_clock_source_ = clock_source;
147#else
148  if (clock_source != TraceClockSource::kWall) {
149    LOG(WARNING) << "Ignoring tracing request to use CPU time.";
150  }
151#endif
152}
153
154static uint16_t GetTraceVersion(TraceClockSource clock_source) {
155  return (clock_source == TraceClockSource::kDual) ? kTraceVersionDualClock
156                                                    : kTraceVersionSingleClock;
157}
158
159static uint16_t GetRecordSize(TraceClockSource clock_source) {
160  return (clock_source == TraceClockSource::kDual) ? kTraceRecordSizeDualClock
161                                                    : kTraceRecordSizeSingleClock;
162}
163
164bool Trace::UseThreadCpuClock() {
165  return (clock_source_ == TraceClockSource::kThreadCpu) ||
166      (clock_source_ == TraceClockSource::kDual);
167}
168
169bool Trace::UseWallClock() {
170  return (clock_source_ == TraceClockSource::kWall) ||
171      (clock_source_ == TraceClockSource::kDual);
172}
173
174void Trace::MeasureClockOverhead() {
175  if (UseThreadCpuClock()) {
176    Thread::Current()->GetCpuMicroTime();
177  }
178  if (UseWallClock()) {
179    MicroTime();
180  }
181}
182
183// Compute an average time taken to measure clocks.
184uint32_t Trace::GetClockOverheadNanoSeconds() {
185  Thread* self = Thread::Current();
186  uint64_t start = self->GetCpuMicroTime();
187
188  for (int i = 4000; i > 0; i--) {
189    MeasureClockOverhead();
190    MeasureClockOverhead();
191    MeasureClockOverhead();
192    MeasureClockOverhead();
193    MeasureClockOverhead();
194    MeasureClockOverhead();
195    MeasureClockOverhead();
196    MeasureClockOverhead();
197  }
198
199  uint64_t elapsed_us = self->GetCpuMicroTime() - start;
200  return static_cast<uint32_t>(elapsed_us / 32);
201}
202
203// TODO: put this somewhere with the big-endian equivalent used by JDWP.
204static void Append2LE(uint8_t* buf, uint16_t val) {
205  *buf++ = static_cast<uint8_t>(val);
206  *buf++ = static_cast<uint8_t>(val >> 8);
207}
208
209// TODO: put this somewhere with the big-endian equivalent used by JDWP.
210static void Append4LE(uint8_t* buf, uint32_t val) {
211  *buf++ = static_cast<uint8_t>(val);
212  *buf++ = static_cast<uint8_t>(val >> 8);
213  *buf++ = static_cast<uint8_t>(val >> 16);
214  *buf++ = static_cast<uint8_t>(val >> 24);
215}
216
217// TODO: put this somewhere with the big-endian equivalent used by JDWP.
218static void Append8LE(uint8_t* buf, uint64_t val) {
219  *buf++ = static_cast<uint8_t>(val);
220  *buf++ = static_cast<uint8_t>(val >> 8);
221  *buf++ = static_cast<uint8_t>(val >> 16);
222  *buf++ = static_cast<uint8_t>(val >> 24);
223  *buf++ = static_cast<uint8_t>(val >> 32);
224  *buf++ = static_cast<uint8_t>(val >> 40);
225  *buf++ = static_cast<uint8_t>(val >> 48);
226  *buf++ = static_cast<uint8_t>(val >> 56);
227}
228
229static void GetSample(Thread* thread, void* arg) REQUIRES_SHARED(Locks::mutator_lock_) {
230  BuildStackTraceVisitor build_trace_visitor(thread);
231  build_trace_visitor.WalkStack();
232  std::vector<ArtMethod*>* stack_trace = build_trace_visitor.GetStackTrace();
233  Trace* the_trace = reinterpret_cast<Trace*>(arg);
234  the_trace->CompareAndUpdateStackTrace(thread, stack_trace);
235}
236
237static void ClearThreadStackTraceAndClockBase(Thread* thread, void* arg ATTRIBUTE_UNUSED) {
238  thread->SetTraceClockBase(0);
239  std::vector<ArtMethod*>* stack_trace = thread->GetStackTraceSample();
240  thread->SetStackTraceSample(nullptr);
241  delete stack_trace;
242}
243
244void Trace::CompareAndUpdateStackTrace(Thread* thread,
245                                       std::vector<ArtMethod*>* stack_trace) {
246  CHECK_EQ(pthread_self(), sampling_pthread_);
247  std::vector<ArtMethod*>* old_stack_trace = thread->GetStackTraceSample();
248  // Update the thread's stack trace sample.
249  thread->SetStackTraceSample(stack_trace);
250  // Read timer clocks to use for all events in this trace.
251  uint32_t thread_clock_diff = 0;
252  uint32_t wall_clock_diff = 0;
253  ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
254  if (old_stack_trace == nullptr) {
255    // If there's no previous stack trace sample for this thread, log an entry event for all
256    // methods in the trace.
257    for (auto rit = stack_trace->rbegin(); rit != stack_trace->rend(); ++rit) {
258      LogMethodTraceEvent(thread, *rit, instrumentation::Instrumentation::kMethodEntered,
259                          thread_clock_diff, wall_clock_diff);
260    }
261  } else {
262    // If there's a previous stack trace for this thread, diff the traces and emit entry and exit
263    // events accordingly.
264    auto old_rit = old_stack_trace->rbegin();
265    auto rit = stack_trace->rbegin();
266    // Iterate bottom-up over both traces until there's a difference between them.
267    while (old_rit != old_stack_trace->rend() && rit != stack_trace->rend() && *old_rit == *rit) {
268      old_rit++;
269      rit++;
270    }
271    // Iterate top-down over the old trace until the point where they differ, emitting exit events.
272    for (auto old_it = old_stack_trace->begin(); old_it != old_rit.base(); ++old_it) {
273      LogMethodTraceEvent(thread, *old_it, instrumentation::Instrumentation::kMethodExited,
274                          thread_clock_diff, wall_clock_diff);
275    }
276    // Iterate bottom-up over the new trace from the point where they differ, emitting entry events.
277    for (; rit != stack_trace->rend(); ++rit) {
278      LogMethodTraceEvent(thread, *rit, instrumentation::Instrumentation::kMethodEntered,
279                          thread_clock_diff, wall_clock_diff);
280    }
281    FreeStackTrace(old_stack_trace);
282  }
283}
284
285void* Trace::RunSamplingThread(void* arg) {
286  Runtime* runtime = Runtime::Current();
287  intptr_t interval_us = reinterpret_cast<intptr_t>(arg);
288  CHECK_GE(interval_us, 0);
289  CHECK(runtime->AttachCurrentThread("Sampling Profiler", true, runtime->GetSystemThreadGroup(),
290                                     !runtime->IsAotCompiler()));
291
292  while (true) {
293    usleep(interval_us);
294    ScopedTrace trace("Profile sampling");
295    Thread* self = Thread::Current();
296    Trace* the_trace;
297    {
298      MutexLock mu(self, *Locks::trace_lock_);
299      the_trace = the_trace_;
300      if (the_trace == nullptr) {
301        break;
302      }
303    }
304    {
305      ScopedSuspendAll ssa(__FUNCTION__);
306      MutexLock mu(self, *Locks::thread_list_lock_);
307      runtime->GetThreadList()->ForEach(GetSample, the_trace);
308    }
309  }
310
311  runtime->DetachCurrentThread();
312  return nullptr;
313}
314
315void Trace::Start(const char* trace_filename, int trace_fd, size_t buffer_size, int flags,
316                  TraceOutputMode output_mode, TraceMode trace_mode, int interval_us) {
317  Thread* self = Thread::Current();
318  {
319    MutexLock mu(self, *Locks::trace_lock_);
320    if (the_trace_ != nullptr) {
321      LOG(ERROR) << "Trace already in progress, ignoring this request";
322      return;
323    }
324  }
325
326  // Check interval if sampling is enabled
327  if (trace_mode == TraceMode::kSampling && interval_us <= 0) {
328    LOG(ERROR) << "Invalid sampling interval: " << interval_us;
329    ScopedObjectAccess soa(self);
330    ThrowRuntimeException("Invalid sampling interval: %d", interval_us);
331    return;
332  }
333
334  // Open trace file if not going directly to ddms.
335  std::unique_ptr<File> trace_file;
336  if (output_mode != TraceOutputMode::kDDMS) {
337    if (trace_fd < 0) {
338      trace_file.reset(OS::CreateEmptyFileWriteOnly(trace_filename));
339    } else {
340      trace_file.reset(new File(trace_fd, "tracefile"));
341      trace_file->DisableAutoClose();
342    }
343    if (trace_file.get() == nullptr) {
344      PLOG(ERROR) << "Unable to open trace file '" << trace_filename << "'";
345      ScopedObjectAccess soa(self);
346      ThrowRuntimeException("Unable to open trace file '%s'", trace_filename);
347      return;
348    }
349  }
350
351  Runtime* runtime = Runtime::Current();
352
353  // Enable count of allocs if specified in the flags.
354  bool enable_stats = false;
355
356  // Create Trace object.
357  {
358    // Required since EnableMethodTracing calls ConfigureStubs which visits class linker classes.
359    gc::ScopedGCCriticalSection gcs(self,
360                                    gc::kGcCauseInstrumentation,
361                                    gc::kCollectorTypeInstrumentation);
362    ScopedSuspendAll ssa(__FUNCTION__);
363    MutexLock mu(self, *Locks::trace_lock_);
364    if (the_trace_ != nullptr) {
365      LOG(ERROR) << "Trace already in progress, ignoring this request";
366    } else {
367      enable_stats = (flags && kTraceCountAllocs) != 0;
368      the_trace_ = new Trace(trace_file.release(), trace_filename, buffer_size, flags, output_mode,
369                             trace_mode);
370      if (trace_mode == TraceMode::kSampling) {
371        CHECK_PTHREAD_CALL(pthread_create, (&sampling_pthread_, nullptr, &RunSamplingThread,
372                                            reinterpret_cast<void*>(interval_us)),
373                                            "Sampling profiler thread");
374        the_trace_->interval_us_ = interval_us;
375      } else {
376        runtime->GetInstrumentation()->AddListener(the_trace_,
377                                                   instrumentation::Instrumentation::kMethodEntered |
378                                                   instrumentation::Instrumentation::kMethodExited |
379                                                   instrumentation::Instrumentation::kMethodUnwind);
380        // TODO: In full-PIC mode, we don't need to fully deopt.
381        runtime->GetInstrumentation()->EnableMethodTracing(kTracerInstrumentationKey);
382      }
383    }
384  }
385
386  // Can't call this when holding the mutator lock.
387  if (enable_stats) {
388    runtime->SetStatsEnabled(true);
389  }
390}
391
392void Trace::StopTracing(bool finish_tracing, bool flush_file) {
393  bool stop_alloc_counting = false;
394  Runtime* const runtime = Runtime::Current();
395  Trace* the_trace = nullptr;
396  Thread* const self = Thread::Current();
397  pthread_t sampling_pthread = 0U;
398  {
399    MutexLock mu(self, *Locks::trace_lock_);
400    if (the_trace_ == nullptr) {
401      LOG(ERROR) << "Trace stop requested, but no trace currently running";
402    } else {
403      the_trace = the_trace_;
404      the_trace_ = nullptr;
405      sampling_pthread = sampling_pthread_;
406    }
407  }
408  // Make sure that we join before we delete the trace since we don't want to have
409  // the sampling thread access a stale pointer. This finishes since the sampling thread exits when
410  // the_trace_ is null.
411  if (sampling_pthread != 0U) {
412    CHECK_PTHREAD_CALL(pthread_join, (sampling_pthread, nullptr), "sampling thread shutdown");
413    sampling_pthread_ = 0U;
414  }
415
416  {
417    gc::ScopedGCCriticalSection gcs(self,
418                                    gc::kGcCauseInstrumentation,
419                                    gc::kCollectorTypeInstrumentation);
420    ScopedSuspendAll ssa(__FUNCTION__);
421    if (the_trace != nullptr) {
422      stop_alloc_counting = (the_trace->flags_ & Trace::kTraceCountAllocs) != 0;
423      if (finish_tracing) {
424        the_trace->FinishTracing();
425      }
426
427      if (the_trace->trace_mode_ == TraceMode::kSampling) {
428        MutexLock mu(self, *Locks::thread_list_lock_);
429        runtime->GetThreadList()->ForEach(ClearThreadStackTraceAndClockBase, nullptr);
430      } else {
431        runtime->GetInstrumentation()->DisableMethodTracing(kTracerInstrumentationKey);
432        runtime->GetInstrumentation()->RemoveListener(
433            the_trace, instrumentation::Instrumentation::kMethodEntered |
434            instrumentation::Instrumentation::kMethodExited |
435            instrumentation::Instrumentation::kMethodUnwind);
436      }
437      if (the_trace->trace_file_.get() != nullptr) {
438        // Do not try to erase, so flush and close explicitly.
439        if (flush_file) {
440          if (the_trace->trace_file_->Flush() != 0) {
441            PLOG(WARNING) << "Could not flush trace file.";
442          }
443        } else {
444          the_trace->trace_file_->MarkUnchecked();  // Do not trigger guard.
445        }
446        if (the_trace->trace_file_->Close() != 0) {
447          PLOG(ERROR) << "Could not close trace file.";
448        }
449      }
450      delete the_trace;
451    }
452  }
453  if (stop_alloc_counting) {
454    // Can be racy since SetStatsEnabled is not guarded by any locks.
455    runtime->SetStatsEnabled(false);
456  }
457}
458
459void Trace::Abort() {
460  // Do not write anything anymore.
461  StopTracing(false, false);
462}
463
464void Trace::Stop() {
465  // Finish writing.
466  StopTracing(true, true);
467}
468
469void Trace::Shutdown() {
470  if (GetMethodTracingMode() != kTracingInactive) {
471    Stop();
472  }
473}
474
475void Trace::Pause() {
476  bool stop_alloc_counting = false;
477  Runtime* runtime = Runtime::Current();
478  Trace* the_trace = nullptr;
479
480  Thread* const self = Thread::Current();
481  pthread_t sampling_pthread = 0U;
482  {
483    MutexLock mu(self, *Locks::trace_lock_);
484    if (the_trace_ == nullptr) {
485      LOG(ERROR) << "Trace pause requested, but no trace currently running";
486      return;
487    } else {
488      the_trace = the_trace_;
489      sampling_pthread = sampling_pthread_;
490    }
491  }
492
493  if (sampling_pthread != 0U) {
494    {
495      MutexLock mu(self, *Locks::trace_lock_);
496      the_trace_ = nullptr;
497    }
498    CHECK_PTHREAD_CALL(pthread_join, (sampling_pthread, nullptr), "sampling thread shutdown");
499    sampling_pthread_ = 0U;
500    {
501      MutexLock mu(self, *Locks::trace_lock_);
502      the_trace_ = the_trace;
503    }
504  }
505
506  if (the_trace != nullptr) {
507    gc::ScopedGCCriticalSection gcs(self,
508                                    gc::kGcCauseInstrumentation,
509                                    gc::kCollectorTypeInstrumentation);
510    ScopedSuspendAll ssa(__FUNCTION__);
511    stop_alloc_counting = (the_trace->flags_ & Trace::kTraceCountAllocs) != 0;
512
513    if (the_trace->trace_mode_ == TraceMode::kSampling) {
514      MutexLock mu(self, *Locks::thread_list_lock_);
515      runtime->GetThreadList()->ForEach(ClearThreadStackTraceAndClockBase, nullptr);
516    } else {
517      runtime->GetInstrumentation()->DisableMethodTracing(kTracerInstrumentationKey);
518      runtime->GetInstrumentation()->RemoveListener(
519          the_trace,
520          instrumentation::Instrumentation::kMethodEntered |
521          instrumentation::Instrumentation::kMethodExited |
522          instrumentation::Instrumentation::kMethodUnwind);
523    }
524  }
525
526  if (stop_alloc_counting) {
527    // Can be racy since SetStatsEnabled is not guarded by any locks.
528    Runtime::Current()->SetStatsEnabled(false);
529  }
530}
531
532void Trace::Resume() {
533  Thread* self = Thread::Current();
534  Trace* the_trace;
535  {
536    MutexLock mu(self, *Locks::trace_lock_);
537    if (the_trace_ == nullptr) {
538      LOG(ERROR) << "No trace to resume (or sampling mode), ignoring this request";
539      return;
540    }
541    the_trace = the_trace_;
542  }
543
544  Runtime* runtime = Runtime::Current();
545
546  // Enable count of allocs if specified in the flags.
547  bool enable_stats = (the_trace->flags_ && kTraceCountAllocs) != 0;
548
549  {
550    gc::ScopedGCCriticalSection gcs(self,
551                                    gc::kGcCauseInstrumentation,
552                                    gc::kCollectorTypeInstrumentation);
553    ScopedSuspendAll ssa(__FUNCTION__);
554
555    // Reenable.
556    if (the_trace->trace_mode_ == TraceMode::kSampling) {
557      CHECK_PTHREAD_CALL(pthread_create, (&sampling_pthread_, nullptr, &RunSamplingThread,
558          reinterpret_cast<void*>(the_trace->interval_us_)), "Sampling profiler thread");
559    } else {
560      runtime->GetInstrumentation()->AddListener(the_trace,
561                                                 instrumentation::Instrumentation::kMethodEntered |
562                                                 instrumentation::Instrumentation::kMethodExited |
563                                                 instrumentation::Instrumentation::kMethodUnwind);
564      // TODO: In full-PIC mode, we don't need to fully deopt.
565      runtime->GetInstrumentation()->EnableMethodTracing(kTracerInstrumentationKey);
566    }
567  }
568
569  // Can't call this when holding the mutator lock.
570  if (enable_stats) {
571    runtime->SetStatsEnabled(true);
572  }
573}
574
575TracingMode Trace::GetMethodTracingMode() {
576  MutexLock mu(Thread::Current(), *Locks::trace_lock_);
577  if (the_trace_ == nullptr) {
578    return kTracingInactive;
579  } else {
580    switch (the_trace_->trace_mode_) {
581      case TraceMode::kSampling:
582        return kSampleProfilingActive;
583      case TraceMode::kMethodTracing:
584        return kMethodTracingActive;
585    }
586    LOG(FATAL) << "Unreachable";
587    UNREACHABLE();
588  }
589}
590
591static constexpr size_t kMinBufSize = 18U;  // Trace header is up to 18B.
592
593Trace::Trace(File* trace_file, const char* trace_name, size_t buffer_size, int flags,
594             TraceOutputMode output_mode, TraceMode trace_mode)
595    : trace_file_(trace_file),
596      buf_(new uint8_t[std::max(kMinBufSize, buffer_size)]()),
597      flags_(flags), trace_output_mode_(output_mode), trace_mode_(trace_mode),
598      clock_source_(default_clock_source_),
599      buffer_size_(std::max(kMinBufSize, buffer_size)),
600      start_time_(MicroTime()), clock_overhead_ns_(GetClockOverheadNanoSeconds()), cur_offset_(0),
601      overflow_(false), interval_us_(0), streaming_lock_(nullptr),
602      unique_methods_lock_(new Mutex("unique methods lock", kTracingUniqueMethodsLock)) {
603  uint16_t trace_version = GetTraceVersion(clock_source_);
604  if (output_mode == TraceOutputMode::kStreaming) {
605    trace_version |= 0xF0U;
606  }
607  // Set up the beginning of the trace.
608  memset(buf_.get(), 0, kTraceHeaderLength);
609  Append4LE(buf_.get(), kTraceMagicValue);
610  Append2LE(buf_.get() + 4, trace_version);
611  Append2LE(buf_.get() + 6, kTraceHeaderLength);
612  Append8LE(buf_.get() + 8, start_time_);
613  if (trace_version >= kTraceVersionDualClock) {
614    uint16_t record_size = GetRecordSize(clock_source_);
615    Append2LE(buf_.get() + 16, record_size);
616  }
617  static_assert(18 <= kMinBufSize, "Minimum buffer size not large enough for trace header");
618
619  // Update current offset.
620  cur_offset_.StoreRelaxed(kTraceHeaderLength);
621
622  if (output_mode == TraceOutputMode::kStreaming) {
623    streaming_file_name_ = trace_name;
624    streaming_lock_ = new Mutex("tracing lock", LockLevel::kTracingStreamingLock);
625    seen_threads_.reset(new ThreadIDBitSet());
626  }
627}
628
629Trace::~Trace() {
630  delete streaming_lock_;
631  delete unique_methods_lock_;
632}
633
634static uint64_t ReadBytes(uint8_t* buf, size_t bytes) {
635  uint64_t ret = 0;
636  for (size_t i = 0; i < bytes; ++i) {
637    ret |= static_cast<uint64_t>(buf[i]) << (i * 8);
638  }
639  return ret;
640}
641
642void Trace::DumpBuf(uint8_t* buf, size_t buf_size, TraceClockSource clock_source) {
643  uint8_t* ptr = buf + kTraceHeaderLength;
644  uint8_t* end = buf + buf_size;
645
646  while (ptr < end) {
647    uint32_t tmid = ReadBytes(ptr + 2, sizeof(tmid));
648    ArtMethod* method = DecodeTraceMethod(tmid);
649    TraceAction action = DecodeTraceAction(tmid);
650    LOG(INFO) << ArtMethod::PrettyMethod(method) << " " << static_cast<int>(action);
651    ptr += GetRecordSize(clock_source);
652  }
653}
654
655void Trace::FinishTracing() {
656  size_t final_offset = 0;
657
658  std::set<ArtMethod*> visited_methods;
659  if (trace_output_mode_ == TraceOutputMode::kStreaming) {
660    // Clean up.
661    STLDeleteValues(&seen_methods_);
662  } else {
663    final_offset = cur_offset_.LoadRelaxed();
664    GetVisitedMethods(final_offset, &visited_methods);
665  }
666
667  // Compute elapsed time.
668  uint64_t elapsed = MicroTime() - start_time_;
669
670  std::ostringstream os;
671
672  os << StringPrintf("%cversion\n", kTraceTokenChar);
673  os << StringPrintf("%d\n", GetTraceVersion(clock_source_));
674  os << StringPrintf("data-file-overflow=%s\n", overflow_ ? "true" : "false");
675  if (UseThreadCpuClock()) {
676    if (UseWallClock()) {
677      os << StringPrintf("clock=dual\n");
678    } else {
679      os << StringPrintf("clock=thread-cpu\n");
680    }
681  } else {
682    os << StringPrintf("clock=wall\n");
683  }
684  os << StringPrintf("elapsed-time-usec=%" PRIu64 "\n", elapsed);
685  if (trace_output_mode_ != TraceOutputMode::kStreaming) {
686    size_t num_records = (final_offset - kTraceHeaderLength) / GetRecordSize(clock_source_);
687    os << StringPrintf("num-method-calls=%zd\n", num_records);
688  }
689  os << StringPrintf("clock-call-overhead-nsec=%d\n", clock_overhead_ns_);
690  os << StringPrintf("vm=art\n");
691  os << StringPrintf("pid=%d\n", getpid());
692  if ((flags_ & kTraceCountAllocs) != 0) {
693    os << StringPrintf("alloc-count=%d\n", Runtime::Current()->GetStat(KIND_ALLOCATED_OBJECTS));
694    os << StringPrintf("alloc-size=%d\n", Runtime::Current()->GetStat(KIND_ALLOCATED_BYTES));
695    os << StringPrintf("gc-count=%d\n", Runtime::Current()->GetStat(KIND_GC_INVOCATIONS));
696  }
697  os << StringPrintf("%cthreads\n", kTraceTokenChar);
698  DumpThreadList(os);
699  os << StringPrintf("%cmethods\n", kTraceTokenChar);
700  DumpMethodList(os, visited_methods);
701  os << StringPrintf("%cend\n", kTraceTokenChar);
702  std::string header(os.str());
703
704  if (trace_output_mode_ == TraceOutputMode::kStreaming) {
705    MutexLock mu(Thread::Current(), *streaming_lock_);  // To serialize writing.
706    // Write a special token to mark the end of trace records and the start of
707    // trace summary.
708    uint8_t buf[7];
709    Append2LE(buf, 0);
710    buf[2] = kOpTraceSummary;
711    Append4LE(buf + 3, static_cast<uint32_t>(header.length()));
712    WriteToBuf(buf, sizeof(buf));
713    // Write the trace summary. The summary is identical to the file header when
714    // the output mode is not streaming (except for methods).
715    WriteToBuf(reinterpret_cast<const uint8_t*>(header.c_str()), header.length());
716    // Flush the buffer, which may include some trace records before the summary.
717    FlushBuf();
718  } else {
719    if (trace_file_.get() == nullptr) {
720      iovec iov[2];
721      iov[0].iov_base = reinterpret_cast<void*>(const_cast<char*>(header.c_str()));
722      iov[0].iov_len = header.length();
723      iov[1].iov_base = buf_.get();
724      iov[1].iov_len = final_offset;
725      Dbg::DdmSendChunkV(CHUNK_TYPE("MPSE"), iov, 2);
726      const bool kDumpTraceInfo = false;
727      if (kDumpTraceInfo) {
728        LOG(INFO) << "Trace sent:\n" << header;
729        DumpBuf(buf_.get(), final_offset, clock_source_);
730      }
731    } else {
732      if (!trace_file_->WriteFully(header.c_str(), header.length()) ||
733          !trace_file_->WriteFully(buf_.get(), final_offset)) {
734        std::string detail(StringPrintf("Trace data write failed: %s", strerror(errno)));
735        PLOG(ERROR) << detail;
736        ThrowRuntimeException("%s", detail.c_str());
737      }
738    }
739  }
740}
741
742void Trace::DexPcMoved(Thread* thread ATTRIBUTE_UNUSED,
743                       Handle<mirror::Object> this_object ATTRIBUTE_UNUSED,
744                       ArtMethod* method,
745                       uint32_t new_dex_pc) {
746  // We're not recorded to listen to this kind of event, so complain.
747  LOG(ERROR) << "Unexpected dex PC event in tracing " << ArtMethod::PrettyMethod(method)
748             << " " << new_dex_pc;
749}
750
751void Trace::FieldRead(Thread* thread ATTRIBUTE_UNUSED,
752                      Handle<mirror::Object> this_object ATTRIBUTE_UNUSED,
753                      ArtMethod* method,
754                      uint32_t dex_pc,
755                      ArtField* field ATTRIBUTE_UNUSED)
756    REQUIRES_SHARED(Locks::mutator_lock_) {
757  // We're not recorded to listen to this kind of event, so complain.
758  LOG(ERROR) << "Unexpected field read event in tracing " << ArtMethod::PrettyMethod(method)
759             << " " << dex_pc;
760}
761
762void Trace::FieldWritten(Thread* thread ATTRIBUTE_UNUSED,
763                         Handle<mirror::Object> this_object ATTRIBUTE_UNUSED,
764                         ArtMethod* method,
765                         uint32_t dex_pc,
766                         ArtField* field ATTRIBUTE_UNUSED,
767                         const JValue& field_value ATTRIBUTE_UNUSED)
768    REQUIRES_SHARED(Locks::mutator_lock_) {
769  // We're not recorded to listen to this kind of event, so complain.
770  LOG(ERROR) << "Unexpected field write event in tracing " << ArtMethod::PrettyMethod(method)
771             << " " << dex_pc;
772}
773
774void Trace::MethodEntered(Thread* thread,
775                          Handle<mirror::Object> this_object ATTRIBUTE_UNUSED,
776                          ArtMethod* method,
777                          uint32_t dex_pc ATTRIBUTE_UNUSED) {
778  uint32_t thread_clock_diff = 0;
779  uint32_t wall_clock_diff = 0;
780  ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
781  LogMethodTraceEvent(thread, method, instrumentation::Instrumentation::kMethodEntered,
782                      thread_clock_diff, wall_clock_diff);
783}
784
785void Trace::MethodExited(Thread* thread,
786                         Handle<mirror::Object> this_object ATTRIBUTE_UNUSED,
787                         ArtMethod* method,
788                         uint32_t dex_pc ATTRIBUTE_UNUSED,
789                         const JValue& return_value ATTRIBUTE_UNUSED) {
790  uint32_t thread_clock_diff = 0;
791  uint32_t wall_clock_diff = 0;
792  ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
793  LogMethodTraceEvent(thread, method, instrumentation::Instrumentation::kMethodExited,
794                      thread_clock_diff, wall_clock_diff);
795}
796
797void Trace::MethodUnwind(Thread* thread,
798                         Handle<mirror::Object> this_object ATTRIBUTE_UNUSED,
799                         ArtMethod* method,
800                         uint32_t dex_pc ATTRIBUTE_UNUSED) {
801  uint32_t thread_clock_diff = 0;
802  uint32_t wall_clock_diff = 0;
803  ReadClocks(thread, &thread_clock_diff, &wall_clock_diff);
804  LogMethodTraceEvent(thread, method, instrumentation::Instrumentation::kMethodUnwind,
805                      thread_clock_diff, wall_clock_diff);
806}
807
808void Trace::ExceptionThrown(Thread* thread ATTRIBUTE_UNUSED,
809                            Handle<mirror::Throwable> exception_object ATTRIBUTE_UNUSED)
810    REQUIRES_SHARED(Locks::mutator_lock_) {
811  LOG(ERROR) << "Unexpected exception thrown event in tracing";
812}
813
814void Trace::ExceptionHandled(Thread* thread ATTRIBUTE_UNUSED,
815                             Handle<mirror::Throwable> exception_object ATTRIBUTE_UNUSED)
816    REQUIRES_SHARED(Locks::mutator_lock_) {
817  LOG(ERROR) << "Unexpected exception thrown event in tracing";
818}
819
820void Trace::Branch(Thread* /*thread*/, ArtMethod* method,
821                   uint32_t /*dex_pc*/, int32_t /*dex_pc_offset*/)
822      REQUIRES_SHARED(Locks::mutator_lock_) {
823  LOG(ERROR) << "Unexpected branch event in tracing" << ArtMethod::PrettyMethod(method);
824}
825
826void Trace::InvokeVirtualOrInterface(Thread*,
827                                     Handle<mirror::Object>,
828                                     ArtMethod* method,
829                                     uint32_t dex_pc,
830                                     ArtMethod*) {
831  LOG(ERROR) << "Unexpected invoke event in tracing" << ArtMethod::PrettyMethod(method)
832             << " " << dex_pc;
833}
834
835void Trace::ReadClocks(Thread* thread, uint32_t* thread_clock_diff, uint32_t* wall_clock_diff) {
836  if (UseThreadCpuClock()) {
837    uint64_t clock_base = thread->GetTraceClockBase();
838    if (UNLIKELY(clock_base == 0)) {
839      // First event, record the base time in the map.
840      uint64_t time = thread->GetCpuMicroTime();
841      thread->SetTraceClockBase(time);
842    } else {
843      *thread_clock_diff = thread->GetCpuMicroTime() - clock_base;
844    }
845  }
846  if (UseWallClock()) {
847    *wall_clock_diff = MicroTime() - start_time_;
848  }
849}
850
851bool Trace::RegisterMethod(ArtMethod* method) {
852  mirror::DexCache* dex_cache = method->GetDexCache();
853  const DexFile* dex_file = dex_cache->GetDexFile();
854  if (seen_methods_.find(dex_file) == seen_methods_.end()) {
855    seen_methods_.insert(std::make_pair(dex_file, new DexIndexBitSet()));
856  }
857  DexIndexBitSet* bit_set = seen_methods_.find(dex_file)->second;
858  if (!(*bit_set)[method->GetDexMethodIndex()]) {
859    bit_set->set(method->GetDexMethodIndex());
860    return true;
861  }
862  return false;
863}
864
865bool Trace::RegisterThread(Thread* thread) {
866  pid_t tid = thread->GetTid();
867  CHECK_LT(0U, static_cast<uint32_t>(tid));
868  CHECK_LT(static_cast<uint32_t>(tid), kMaxThreadIdNumber);
869
870  if (!(*seen_threads_)[tid]) {
871    seen_threads_->set(tid);
872    return true;
873  }
874  return false;
875}
876
877std::string Trace::GetMethodLine(ArtMethod* method) {
878  method = method->GetInterfaceMethodIfProxy(kRuntimePointerSize);
879  return StringPrintf("%#x\t%s\t%s\t%s\t%s\n", (EncodeTraceMethod(method) << TraceActionBits),
880      PrettyDescriptor(method->GetDeclaringClassDescriptor()).c_str(), method->GetName(),
881      method->GetSignature().ToString().c_str(), method->GetDeclaringClassSourceFile());
882}
883
884void Trace::WriteToBuf(const uint8_t* src, size_t src_size) {
885  int32_t old_offset = cur_offset_.LoadRelaxed();
886  int32_t new_offset = old_offset + static_cast<int32_t>(src_size);
887  if (dchecked_integral_cast<size_t>(new_offset) > buffer_size_) {
888    // Flush buffer.
889    if (!trace_file_->WriteFully(buf_.get(), old_offset)) {
890      PLOG(WARNING) << "Failed streaming a tracing event.";
891    }
892
893    // Check whether the data is too large for the buffer, then write immediately.
894    if (src_size >= buffer_size_) {
895      if (!trace_file_->WriteFully(src, src_size)) {
896        PLOG(WARNING) << "Failed streaming a tracing event.";
897      }
898      cur_offset_.StoreRelease(0);  // Buffer is empty now.
899      return;
900    }
901
902    old_offset = 0;
903    new_offset = static_cast<int32_t>(src_size);
904  }
905  cur_offset_.StoreRelease(new_offset);
906  // Fill in data.
907  memcpy(buf_.get() + old_offset, src, src_size);
908}
909
910void Trace::FlushBuf() {
911  int32_t offset = cur_offset_.LoadRelaxed();
912  if (!trace_file_->WriteFully(buf_.get(), offset)) {
913    PLOG(WARNING) << "Failed flush the remaining data in streaming.";
914  }
915  cur_offset_.StoreRelease(0);
916}
917
918void Trace::LogMethodTraceEvent(Thread* thread, ArtMethod* method,
919                                instrumentation::Instrumentation::InstrumentationEvent event,
920                                uint32_t thread_clock_diff, uint32_t wall_clock_diff) {
921  // Ensure we always use the non-obsolete version of the method so that entry/exit events have the
922  // same pointer value.
923  method = method->GetNonObsoleteMethod();
924  // Advance cur_offset_ atomically.
925  int32_t new_offset;
926  int32_t old_offset = 0;
927
928  // We do a busy loop here trying to acquire the next offset.
929  if (trace_output_mode_ != TraceOutputMode::kStreaming) {
930    do {
931      old_offset = cur_offset_.LoadRelaxed();
932      new_offset = old_offset + GetRecordSize(clock_source_);
933      if (static_cast<size_t>(new_offset) > buffer_size_) {
934        overflow_ = true;
935        return;
936      }
937    } while (!cur_offset_.CompareExchangeWeakSequentiallyConsistent(old_offset, new_offset));
938  }
939
940  TraceAction action = kTraceMethodEnter;
941  switch (event) {
942    case instrumentation::Instrumentation::kMethodEntered:
943      action = kTraceMethodEnter;
944      break;
945    case instrumentation::Instrumentation::kMethodExited:
946      action = kTraceMethodExit;
947      break;
948    case instrumentation::Instrumentation::kMethodUnwind:
949      action = kTraceUnroll;
950      break;
951    default:
952      UNIMPLEMENTED(FATAL) << "Unexpected event: " << event;
953  }
954
955  uint32_t method_value = EncodeTraceMethodAndAction(method, action);
956
957  // Write data
958  uint8_t* ptr;
959  static constexpr size_t kPacketSize = 14U;  // The maximum size of data in a packet.
960  uint8_t stack_buf[kPacketSize];             // Space to store a packet when in streaming mode.
961  if (trace_output_mode_ == TraceOutputMode::kStreaming) {
962    ptr = stack_buf;
963  } else {
964    ptr = buf_.get() + old_offset;
965  }
966
967  Append2LE(ptr, thread->GetTid());
968  Append4LE(ptr + 2, method_value);
969  ptr += 6;
970
971  if (UseThreadCpuClock()) {
972    Append4LE(ptr, thread_clock_diff);
973    ptr += 4;
974  }
975  if (UseWallClock()) {
976    Append4LE(ptr, wall_clock_diff);
977  }
978  static_assert(kPacketSize == 2 + 4 + 4 + 4, "Packet size incorrect.");
979
980  if (trace_output_mode_ == TraceOutputMode::kStreaming) {
981    MutexLock mu(Thread::Current(), *streaming_lock_);  // To serialize writing.
982    if (RegisterMethod(method)) {
983      // Write a special block with the name.
984      std::string method_line(GetMethodLine(method));
985      uint8_t buf2[5];
986      Append2LE(buf2, 0);
987      buf2[2] = kOpNewMethod;
988      Append2LE(buf2 + 3, static_cast<uint16_t>(method_line.length()));
989      WriteToBuf(buf2, sizeof(buf2));
990      WriteToBuf(reinterpret_cast<const uint8_t*>(method_line.c_str()), method_line.length());
991    }
992    if (RegisterThread(thread)) {
993      // It might be better to postpone this. Threads might not have received names...
994      std::string thread_name;
995      thread->GetThreadName(thread_name);
996      uint8_t buf2[7];
997      Append2LE(buf2, 0);
998      buf2[2] = kOpNewThread;
999      Append2LE(buf2 + 3, static_cast<uint16_t>(thread->GetTid()));
1000      Append2LE(buf2 + 5, static_cast<uint16_t>(thread_name.length()));
1001      WriteToBuf(buf2, sizeof(buf2));
1002      WriteToBuf(reinterpret_cast<const uint8_t*>(thread_name.c_str()), thread_name.length());
1003    }
1004    WriteToBuf(stack_buf, sizeof(stack_buf));
1005  }
1006}
1007
1008void Trace::GetVisitedMethods(size_t buf_size,
1009                              std::set<ArtMethod*>* visited_methods) {
1010  uint8_t* ptr = buf_.get() + kTraceHeaderLength;
1011  uint8_t* end = buf_.get() + buf_size;
1012
1013  while (ptr < end) {
1014    uint32_t tmid = ReadBytes(ptr + 2, sizeof(tmid));
1015    ArtMethod* method = DecodeTraceMethod(tmid);
1016    visited_methods->insert(method);
1017    ptr += GetRecordSize(clock_source_);
1018  }
1019}
1020
1021void Trace::DumpMethodList(std::ostream& os, const std::set<ArtMethod*>& visited_methods) {
1022  for (const auto& method : visited_methods) {
1023    os << GetMethodLine(method);
1024  }
1025}
1026
1027static void DumpThread(Thread* t, void* arg) {
1028  std::ostream& os = *reinterpret_cast<std::ostream*>(arg);
1029  std::string name;
1030  t->GetThreadName(name);
1031  os << t->GetTid() << "\t" << name << "\n";
1032}
1033
1034void Trace::DumpThreadList(std::ostream& os) {
1035  Thread* self = Thread::Current();
1036  for (auto it : exited_threads_) {
1037    os << it.first << "\t" << it.second << "\n";
1038  }
1039  Locks::thread_list_lock_->AssertNotHeld(self);
1040  MutexLock mu(self, *Locks::thread_list_lock_);
1041  Runtime::Current()->GetThreadList()->ForEach(DumpThread, &os);
1042}
1043
1044void Trace::StoreExitingThreadInfo(Thread* thread) {
1045  MutexLock mu(thread, *Locks::trace_lock_);
1046  if (the_trace_ != nullptr) {
1047    std::string name;
1048    thread->GetThreadName(name);
1049    // The same thread/tid may be used multiple times. As SafeMap::Put does not allow to override
1050    // a previous mapping, use SafeMap::Overwrite.
1051    the_trace_->exited_threads_.Overwrite(thread->GetTid(), name);
1052  }
1053}
1054
1055Trace::TraceOutputMode Trace::GetOutputMode() {
1056  MutexLock mu(Thread::Current(), *Locks::trace_lock_);
1057  CHECK(the_trace_ != nullptr) << "Trace output mode requested, but no trace currently running";
1058  return the_trace_->trace_output_mode_;
1059}
1060
1061Trace::TraceMode Trace::GetMode() {
1062  MutexLock mu(Thread::Current(), *Locks::trace_lock_);
1063  CHECK(the_trace_ != nullptr) << "Trace mode requested, but no trace currently running";
1064  return the_trace_->trace_mode_;
1065}
1066
1067size_t Trace::GetBufferSize() {
1068  MutexLock mu(Thread::Current(), *Locks::trace_lock_);
1069  CHECK(the_trace_ != nullptr) << "Trace mode requested, but no trace currently running";
1070  return the_trace_->buffer_size_;
1071}
1072
1073bool Trace::IsTracingEnabled() {
1074  MutexLock mu(Thread::Current(), *Locks::trace_lock_);
1075  return the_trace_ != nullptr;
1076}
1077
1078}  // namespace art
1079