Trace scavenger throughput.

src/heap/gc-tracer.cc

Index: src/heap/gc-tracer.cc
diff --git a/src/heap/gc-tracer.cc b/src/heap/gc-tracer.cc
index 12de0e457e500d47ca8e77b1dffff435b53fd12a..a0f1c464cc26f33d1dae45c36a1f5ac76a606a6c 100644
--- a/src/heap/gc-tracer.cc
+++ b/src/heap/gc-tracer.cc
@@ -103,6 +103,8 @@ void GCTracer::Start(GarbageCollector collector, const char* gc_reason,
   current_.start_object_size = heap_->SizeOfObjects();
   current_.start_memory_size = heap_->isolate()->memory_allocator()->Size();
   current_.start_holes_size = CountTotalHolesSize(heap_);
+  current_.new_space_object_size =
+      heap_->new_space()->top() - heap_->new_space()->bottom();

[Hannes Payer (out of office), 2014/08/19 11:52:59]

The question here is: What is the right size we care about? We have to correlate
the time spent in scavenging with some size.

The Scavenger will process live objects in to space and in from space.
I think we should account for both spaces. WDYT?

 
   current_.cumulative_incremental_marking_steps =
       cumulative_incremental_marking_steps_;
@@ -296,6 +298,8 @@ void GCTracer::PrintNVP() const {
   if (current_.type == Event::SCAVENGER) {
     PrintF("steps_count=%d ", current_.incremental_marking_steps);
     PrintF("steps_took=%.1f ", current_.incremental_marking_duration);
+    PrintF("scavenge_throughput=%" V8_PTR_PREFIX "d ",
+           ScavengeSpeedInBytesPerMillisecond());
   } else {
     PrintF("steps_count=%d ", current_.incremental_marking_steps);
     PrintF("steps_took=%.1f ", current_.incremental_marking_duration);
@@ -398,5 +402,21 @@ intptr_t GCTracer::IncrementalMarkingSpeedInBytesPerMillisecond() const {
 
   return static_cast<intptr_t>(bytes / durations);
 }
+
+
+intptr_t GCTracer::ScavengeSpeedInBytesPerMillisecond() const {
+  intptr_t bytes = 0;
+  double durations = 0.0;
+  EventBuffer::const_iterator iter = scavenger_events_.begin();
+  while (iter != scavenger_events_.end()) {
+    bytes += iter->new_space_object_size;
+    durations += iter->end_time - iter->start_time;
+    ++iter;
+  }
+
+  if (durations == 0.0) return 0;
+
+  return static_cast<intptr_t>(bytes / durations);
+}
 }
 }  // namespace v8::internal