Heap profiling: add logging of heap memory stats (capacity, used) under 'log-gc' flag.

src/log.cc

 // Copyright 2009 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 825 matching lines @@
   msg.Append('\n');
   msg.WriteToLogFile();
 #endif
 }
 
 
 void Logger::HeapSampleBeginEvent(const char* space, const char* kind) {
 #ifdef ENABLE_LOGGING_AND_PROFILING
   if (!Log::IsEnabled() || !FLAG_log_gc) return;
   LogMessageBuilder msg;
-  msg.Append("heap-sample-begin,\"%s\",\"%s\"", space, kind);
-  uint32_t sec, usec;
-  if (OS::GetUserTime(&sec, &usec) != -1) {
-    msg.Append(",%d,%d", sec, usec);
-  }
-  msg.Append('\n');
+  // Using non-relative system time in order to be able to synchronize with
+  // external memory profiling events (e.g. DOM memory size).
+  msg.Append("heap-sample-begin,\"%s\",\"%s\",%.0f\n",
+             space, kind, OS::TimeCurrentMillis());
   msg.WriteToLogFile();
 #endif
 }
+
+
+void Logger::HeapSampleStats(const char* space, const char* kind,
+                             int capacity, int used) {
+#ifdef ENABLE_LOGGING_AND_PROFILING
+  if (!Log::IsEnabled() || !FLAG_log_gc) return;
+  LogMessageBuilder msg;
+  msg.Append("heap-sample-stats,\"%s\",\"%s\",%d,%d\n",
+             space, kind, capacity, used);
+  msg.WriteToLogFile();
+#endif
+}
 
 
 void Logger::HeapSampleEndEvent(const char* space, const char* kind) {
 #ifdef ENABLE_LOGGING_AND_PROFILING
   if (!Log::IsEnabled() || !FLAG_log_gc) return;
   LogMessageBuilder msg;
   msg.Append("heap-sample-end,\"%s\",\"%s\"\n", space, kind);
   msg.WriteToLogFile();
 #endif
 }
@@ skipping 335 matching lines @@
   // Otherwise, if the sliding state window computation has not been
   // started we do it now.
   if (sliding_state_window_ == NULL) {
     sliding_state_window_ = new SlidingStateWindow();
   }
 #endif
 }
 
 
 } }  // namespace v8::internal