CPU profiler: sample call stack on profiling start.

src/cpu-profiler.cc

 // Copyright 2010 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 13 matching lines @@
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include "v8.h"
 
 #include "cpu-profiler-inl.h"
 
 #ifdef ENABLE_LOGGING_AND_PROFILING
 
+#include "frames-inl.h"
 #include "log-inl.h"
 
 #include "../include/v8-profiler.h"
 
 namespace v8 {
 namespace internal {
 
 static const int kEventsBufferSize = 256*KB;
 static const int kTickSamplesBufferChunkSize = 64*KB;
 static const int kTickSamplesBufferChunksCount = 16;
 
 
 ProfilerEventsProcessor::ProfilerEventsProcessor(ProfileGenerator* generator)
     : generator_(generator),
       running_(false),
       ticks_buffer_(sizeof(TickSampleEventRecord),
                     kTickSamplesBufferChunkSize,
                     kTickSamplesBufferChunksCount),
-      enqueue_order_(0) { }
+      enqueue_order_(0) {
+}
 
 
 void ProfilerEventsProcessor::CallbackCreateEvent(Logger::LogEventsAndTags tag,
                                                   const char* prefix,
                                                   String* name,
                                                   Address start) {
   if (FilterOutCodeCreateEvent(tag)) return;
   CodeEventsContainer evt_rec;
   CodeCreateEventRecord* rec = &evt_rec.CodeCreateEventRecord_;
   rec->type = CodeEventRecord::CODE_CREATION;
@@ skipping 111 matching lines @@
   CodeCreateEventRecord* rec = &evt_rec.CodeCreateEventRecord_;
   rec->type = CodeEventRecord::CODE_CREATION;
   rec->order = ++enqueue_order_;
   rec->start = start;
   rec->entry = generator_->NewCodeEntry(tag, prefix, name);
   rec->size = size;
   events_buffer_.Enqueue(evt_rec);
 }
 
 
+void ProfilerEventsProcessor::AddCurrentStack() {
+  TickSampleEventRecord record;
+  TickSample* sample = &record.sample;
+  sample->state = VMState::current_state();
+  sample->pc = reinterpret_cast<Address>(sample);  // Not NULL.
+  sample->frames_count = 0;
+  for (StackTraceFrameIterator it;
+       !it.done() && sample->frames_count < TickSample::kMaxFramesCount;
+       it.Advance()) {
+    JavaScriptFrame* frame = it.frame();
+    sample->stack[sample->frames_count++] =
+        reinterpret_cast<Address>(frame->function());
+  }
+  record.order = enqueue_order_;
+  ticks_from_vm_buffer_.Enqueue(record);
+}
+
+
 bool ProfilerEventsProcessor::ProcessCodeEvent(unsigned* dequeue_order) {
   if (!events_buffer_.IsEmpty()) {
     CodeEventsContainer record;
     events_buffer_.Dequeue(&record);
     switch (record.generic.type) {
 #define PROFILER_TYPE_CASE(type, clss)                          \
       case CodeEventRecord::type:                               \
         record.clss##_.UpdateCodeMap(generator_->code_map());   \
         break;
 
       CODE_EVENTS_TYPE_LIST(PROFILER_TYPE_CASE)
 
 #undef PROFILER_TYPE_CASE
       default: return true;  // Skip record.
     }
     *dequeue_order = record.generic.order;
     return true;
   }
   return false;
 }
 
 
 bool ProfilerEventsProcessor::ProcessTicks(unsigned dequeue_order) {
   while (true) {
+    if (!ticks_from_vm_buffer_.IsEmpty()
+        && ticks_from_vm_buffer_.Peek()->order == dequeue_order) {
+      TickSampleEventRecord record;
+      ticks_from_vm_buffer_.Dequeue(&record);
+      generator_->RecordTickSample(record.sample);
+    }
+
     const TickSampleEventRecord* rec =
         TickSampleEventRecord::cast(ticks_buffer_.StartDequeue());
-    if (rec == NULL) return false;
+    if (rec == NULL) return !ticks_from_vm_buffer_.IsEmpty();
     if (rec->order == dequeue_order) {
       generator_->RecordTickSample(rec->sample);
       ticks_buffer_.FinishDequeue();
     } else {
       return true;
     }
   }
 }
 
 
@@ skipping 188 matching lines @@
 CpuProfiler::~CpuProfiler() {
   delete token_enumerator_;
   delete profiles_;
 }
 
 
 void CpuProfiler::StartCollectingProfile(const char* title) {
   if (profiles_->StartProfiling(title, next_profile_uid_++)) {
     StartProcessorIfNotStarted();
   }
+  processor_->AddCurrentStack();
 }
 
 
 void CpuProfiler::StartCollectingProfile(String* title) {
-  if (profiles_->StartProfiling(title, next_profile_uid_++)) {
-    StartProcessorIfNotStarted();
-  }
+  StartCollectingProfile(profiles_->GetName(title));
 }
 
 
 void CpuProfiler::StartProcessorIfNotStarted() {
   if (processor_ == NULL) {
     // Disable logging when using the new implementation.
     saved_logging_nesting_ = Logger::logging_nesting_;
     Logger::logging_nesting_ = 0;
     generator_ = new ProfileGenerator(profiles_);
     processor_ = new ProfilerEventsProcessor(generator_);
     processor_->Start();
-    // Enable stack sampling.
-    // It is important to have it started prior to logging, see issue 683:
-    // http://code.google.com/p/v8/issues/detail?id=683
-    reinterpret_cast<Sampler*>(Logger::ticker_)->Start();
     // Enumerate stuff we already have in the heap.
     if (Heap::HasBeenSetup()) {
       Logger::LogCodeObjects();
       Logger::LogCompiledFunctions();
       Logger::LogFunctionObjects();
       Logger::LogAccessorCallbacks();
     }
+    // Enable stack sampling.
+    reinterpret_cast<Sampler*>(Logger::ticker_)->Start();
   }
 }
 
 
 CpuProfile* CpuProfiler::StopCollectingProfile(const char* title) {
   const double actual_sampling_rate = generator_->actual_sampling_rate();
   StopProcessorIfLastProfile();
   CpuProfile* result = profiles_->StopProfiling(CodeEntry::kNoSecurityToken,
                                                 title,
                                                 actual_sampling_rate);
@@ skipping 45 matching lines @@
 void CpuProfiler::TearDown() {
 #ifdef ENABLE_LOGGING_AND_PROFILING
   if (singleton_ != NULL) {
     delete singleton_;
   }
   singleton_ = NULL;
 #endif
 }
 
 } }  // namespace v8::internal