Replacing circular queue by single buffer in CPU Profiler.

src/platform-freebsd.cc

 // Copyright 2012 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 660 matching lines @@
     return;
   }
   if (v8::Locker::IsActive() &&
       !isolate->thread_manager()->IsLockedByCurrentThread()) {
     return;
   }
 
   Sampler* sampler = isolate->logger()->sampler();
   if (sampler == NULL || !sampler->IsActive()) return;
 
-  TickSample sample_obj;
-  TickSample* sample = CpuProfiler::TickSampleEvent(isolate);
-  if (sample == NULL) sample = &sample_obj;
+  TickSample* sample = CpuProfiler::StartTickSampleEvent(isolate);
+  if (sample == NULL) return;
 
   // Extracting the sample from the context is extremely machine dependent.
   ucontext_t* ucontext = reinterpret_cast<ucontext_t*>(context);
   mcontext_t& mcontext = ucontext->uc_mcontext;
   sample->state = isolate->current_vm_state();
 #if V8_HOST_ARCH_IA32
   sample->pc = reinterpret_cast<Address>(mcontext.mc_eip);
   sample->sp = reinterpret_cast<Address>(mcontext.mc_esp);
   sample->fp = reinterpret_cast<Address>(mcontext.mc_ebp);
 #elif V8_HOST_ARCH_X64
   sample->pc = reinterpret_cast<Address>(mcontext.mc_rip);
   sample->sp = reinterpret_cast<Address>(mcontext.mc_rsp);
   sample->fp = reinterpret_cast<Address>(mcontext.mc_rbp);
 #elif V8_HOST_ARCH_ARM
   sample->pc = reinterpret_cast<Address>(mcontext.mc_r15);
   sample->sp = reinterpret_cast<Address>(mcontext.mc_r13);
   sample->fp = reinterpret_cast<Address>(mcontext.mc_r11);
 #endif
   sampler->SampleStack(sample);
   sampler->Tick(sample);
+  CpuProfiler::FinishTickSampleEvent(isolate);
 }
 
 
 class SignalSender : public Thread {
  public:
   enum SleepInterval {
     HALF_INTERVAL,
     FULL_INTERVAL
   };
 
@@ skipping 183 matching lines @@
 
 
 void Sampler::Stop() {
   ASSERT(IsActive());
   SignalSender::RemoveActiveSampler(this);
   SetActive(false);
 }
 
 
 } }  // namespace v8::internal