Replacing circular queue by single buffer in CPU Profiler.

src/cpu-profiler-inl.h

 // 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.
 
 #ifndef V8_CPU_PROFILER_INL_H_
 #define V8_CPU_PROFILER_INL_H_
 
 #include "cpu-profiler.h"
 
 #include <new>
-#include "circular-queue-inl.h"
 #include "profile-generator-inl.h"
 #include "unbound-queue-inl.h"
 
 namespace v8 {
 namespace internal {
 
 void CodeCreateEventRecord::UpdateCodeMap(CodeMap* code_map) {
   code_map->AddCode(start, entry, size);
   if (shared != NULL) {
     entry->set_shared_id(code_map->GetSharedId(shared));
   }
 }
 
 
 void CodeMoveEventRecord::UpdateCodeMap(CodeMap* code_map) {
   code_map->MoveCode(from, to);
 }
 
 
 void SharedFunctionInfoMoveEventRecord::UpdateCodeMap(CodeMap* code_map) {
   code_map->MoveCode(from, to);
 }
 
 
-TickSample* ProfilerEventsProcessor::TickSampleEvent() {
+TickSample* ProfilerEventsProcessor::StartTickSampleEvent() {
+  if (!ticks_buffer_is_empty_)
+    return NULL;

[Jakob Kummerow, 2012/09/04 11:25:18]

Please either move this onto the same line as the "if", or put {} around it. (V8
differs from Chromium style here, we don't omit the {} unless everything is on
the same line.)

   generator_->Tick();
-  TickSampleEventRecord* evt =
-      new(ticks_buffer_.Enqueue()) TickSampleEventRecord(enqueue_order_);
-  return &evt->sample;
+  ticks_buffer_ = TickSampleEventRecord(enqueue_order_);
+  return &ticks_buffer_.sample;
 }
 
 
 bool ProfilerEventsProcessor::FilterOutCodeCreateEvent(
     Logger::LogEventsAndTags tag) {
   return FLAG_prof_browser_mode
       && (tag != Logger::CALLBACK_TAG
           && tag != Logger::FUNCTION_TAG
           && tag != Logger::LAZY_COMPILE_TAG
           && tag != Logger::REG_EXP_TAG
           && tag != Logger::SCRIPT_TAG);
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_CPU_PROFILER_INL_H_