Add histogram for total heap fragmentation, don't report fragmentation for new space, and report fr…

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index 309d0adf02ae1310cf654b9b261ba7632f1f336f..3b65b7921f710ca723e6e9a083c985183f27cae3 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -447,26 +447,39 @@ void Heap::GarbageCollectionEpilogue() {
   isolate_->counters()->number_of_symbols()->Set(
       symbol_table()->NumberOfElements());
 
+  if (isolate()->memory_allocator()->Size() > 0) {
+    isolate_->counters()->external_fragmentation_total()->AddSample(
+        static_cast<int>(100 -
+            (SizeOfObjects() * 100) / isolate()->memory_allocator()->Size()));
+  }
+
 #define UPDATE_COUNTERS_FOR_SPACE(space)                                     \
   isolate_->counters()->space##_bytes_available()->Set(                      \
       static_cast<int>(space()->Available()));                               \
   isolate_->counters()->space##_bytes_committed()->Set(                      \
       static_cast<int>(space()->CommittedMemory()));                         \
   isolate_->counters()->space##_bytes_used()->Set(                           \
-      static_cast<int>(space()->SizeOfObjects()));                           \
+      static_cast<int>(space()->SizeOfObjects()));
+#define UPDATE_FRAGMENTATION_FOR_SPACE(space)                                \
   if (space()->CommittedMemory() > 0) {                                      \
     isolate_->counters()->external_fragmentation_##space()->AddSample(       \
-        static_cast<int>(                                                    \
+        static_cast<int>(100 -                                               \
             (space()->SizeOfObjects() * 100) / space()->CommittedMemory())); \
   }
+#define UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(space)                   \
+  UPDATE_COUNTERS_FOR_SPACE(space)                                           \
+  UPDATE_FRAGMENTATION_FOR_SPACE(space)
+
   UPDATE_COUNTERS_FOR_SPACE(new_space)
-  UPDATE_COUNTERS_FOR_SPACE(old_pointer_space)
-  UPDATE_COUNTERS_FOR_SPACE(old_data_space)
-  UPDATE_COUNTERS_FOR_SPACE(code_space)
-  UPDATE_COUNTERS_FOR_SPACE(map_space)
-  UPDATE_COUNTERS_FOR_SPACE(cell_space)
-  UPDATE_COUNTERS_FOR_SPACE(lo_space)
+  UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(old_pointer_space)
+  UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(old_data_space)
+  UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(code_space)
+  UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(map_space)
+  UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(cell_space)
+  UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(lo_space)
 #undef UPDATE_COUNTERS_FOR_SPACE
+#undef UPDATE_FRAGMENTATION_FOR_SPACE
+#undef UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE
 
 #if defined(DEBUG)
   ReportStatisticsAfterGC();