[heap] Base number of compaction tasks on live memory and compaction speed.

src/heap/gc-tracer.h

Index: src/heap/gc-tracer.h
diff --git a/src/heap/gc-tracer.h b/src/heap/gc-tracer.h
index 1fad040d91e1cc686bcecd37ee0b2fbe8ebb4db2..96e202006b1e8e8099b9d1f54f28d12ce3d5f997 100644
--- a/src/heap/gc-tracer.h
+++ b/src/heap/gc-tracer.h
@@ -178,6 +178,18 @@ class GCTracer {
   };
 
 
+  class CompactionEvent {
+   public:
+    CompactionEvent() : duration(0), live_bytes_compacted(0) {}
+
+    CompactionEvent(double duration, intptr_t live_bytes_compacted)
+        : duration(duration), live_bytes_compacted(live_bytes_compacted) {}
+
+    double duration;
+    intptr_t live_bytes_compacted;
+  };
+
+
   class ContextDisposalEvent {
    public:
     // Default constructor leaves the event uninitialized.
@@ -314,6 +326,8 @@ class GCTracer {
   typedef RingBuffer<ContextDisposalEvent, kRingBufferMaxSize>
       ContextDisposalEventBuffer;
 
+  typedef RingBuffer<CompactionEvent, kRingBufferMaxSize> CompactionEventBuffer;
+
   typedef RingBuffer<SurvivalEvent, kRingBufferMaxSize> SurvivalEventBuffer;
 
   static const int kThroughputTimeFrameMs = 5000;
@@ -336,6 +350,8 @@ class GCTracer {
 
   void AddContextDisposalTime(double time);
 
+  void AddCompactionEvent(double duration, intptr_t live_bytes_compacted);
+
   void AddSurvivalRatio(double survival_ratio);
 
   // Log an incremental marking step.
@@ -406,6 +422,10 @@ class GCTracer {
   intptr_t ScavengeSpeedInBytesPerMillisecond(
       ScavengeSpeedMode mode = kForAllObjects) const;
 
+  // Compute the average compaction speed in bytes/millisecond.
+  // Returns 0 if not enough events have been recorded.
+  intptr_t CompactionSpeedInBytesPerMillisecond() const;
+
   // Compute the average mark-sweep speed in bytes/millisecond.
   // Returns 0 if no events have been recorded.
   intptr_t MarkCompactSpeedInBytesPerMillisecond() const;
@@ -520,6 +540,9 @@ class GCTracer {
   // RingBuffer for context disposal events.
   ContextDisposalEventBuffer context_disposal_events_;
 
+  // RingBuffer for compaction events.
+  CompactionEventBuffer compaction_events_;
+
   // RingBuffer for survival events.
   SurvivalEventBuffer survival_events_;