Add parallel recompilation time to histogram and plot execution pause times.

src/optimizing-compiler-thread.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 30 matching lines @@
 #ifdef DEBUG
   thread_id_ = ThreadId::Current().ToInteger();
 #endif
   Isolate::SetIsolateThreadLocals(isolate_, NULL);
 
   int64_t epoch = 0;
   if (FLAG_trace_parallel_recompilation) epoch = OS::Ticks();
 
   while (true) {
     input_queue_semaphore_->Wait();
+    Logger::TimerEventScope timer(
+        isolate_->logger(), Logger::TimerEventScope::v8_recompile_parallel);
     if (Acquire_Load(&stop_thread_)) {
       stop_semaphore_->Signal();
       if (FLAG_trace_parallel_recompilation) {
         time_spent_total_ = OS::Ticks() - epoch;
       }
       return;
     }
 
     int64_t compiling_start = 0;
     if (FLAG_trace_parallel_recompilation) compiling_start = OS::Ticks();
@@ skipping 77 matching lines @@
 
 #ifdef DEBUG
 bool OptimizingCompilerThread::IsOptimizerThread() {
   if (!FLAG_parallel_recompilation) return false;
   return ThreadId::Current().ToInteger() == thread_id_;
 }
 #endif
 
 
 } }  // namespace v8::internal