Add information about time spent in external callback to...

src/heap.h

 // Copyright 2006-2008 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 1502 matching lines @@
   ~DisableAssertNoAllocation() { }
 };
 
 #endif
 
 // GCTracer collects and prints ONE line after each garbage collector
 // invocation IFF --trace_gc is used.
 
 class GCTracer BASE_EMBEDDED {
  public:
+  // Time spent while in the external scope counts towards the
+  // external time in the tracer and will be reported separately.
+  class ExternalScope BASE_EMBEDDED {
+   public:
+    explicit ExternalScope(GCTracer* tracer) : tracer_(tracer) {
+      start_time_ = OS::TimeCurrentMillis();
+    }
+    ~ExternalScope() {
+      tracer_->external_time_ += OS::TimeCurrentMillis() - start_time_;
+    }
+
+   private:
+    GCTracer* tracer_;
+    double start_time_;
+  };
+
   GCTracer();
-
   ~GCTracer();
 
   // Sets the collector.
   void set_collector(GarbageCollector collector) { collector_ = collector; }
 
   // Sets the GC count.
   void set_gc_count(int count) { gc_count_ = count; }
 
   // Sets the full GC count.
   void set_full_gc_count(int count) { full_gc_count_ = count; }
@@ skipping 13 matching lines @@
 
   // Returns size of object in heap (in MB).
   double SizeOfHeapObjects() {
     return (static_cast<double>(Heap::SizeOfObjects())) / MB;
   }
 
   double start_time_;  // Timestamp set in the constructor.
   double start_size_;  // Size of objects in heap set in constructor.
   GarbageCollector collector_;  // Type of collector.
 
+  // Keep track of the amount of time spent in external callbacks.
+  double external_time_;
+
   // A count (including this one, eg, the first collection is 1) of the
   // number of garbage collections.
   int gc_count_;
 
   // A count (including this one) of the number of full garbage collections.
   int full_gc_count_;
 
   // True if the current GC is a compacting full collection, false
   // otherwise.
   bool is_compacting_;
@@ skipping 139 matching lines @@
 
   // To speed up scavenge collections new space string are kept
   // separate from old space strings.
   static List<Object*> new_space_strings_;
   static List<Object*> old_space_strings_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_HEAP_H_