[heap] New heuristics for incremental marking step size.

src/heap/incremental-marking.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_INCREMENTAL_MARKING_H_
 #define V8_HEAP_INCREMENTAL_MARKING_H_
 
 #include "src/cancelable-task.h"
 #include "src/execution.h"
 #include "src/heap/heap.h"
@@ skipping 90 matching lines @@
                                    CompletionAction completion_action,
                                    ForceCompletionAction force_completion,
                                    StepOrigin step_origin);
 
   // It's hard to know how much work the incremental marker should do to make
   // progress in the face of the mutator creating new work for it.  We start
   // of at a moderate rate of work and gradually increase the speed of the
   // incremental marker until it completes.
   // Do some marking every time this much memory has been allocated or that many
   // heavy (color-checking) write barriers have been invoked.
-  static const intptr_t kAllocatedThreshold = 65536;
-  static const intptr_t kWriteBarriersInvokedThreshold = 32768;
-  // Start off by marking this many times more memory than has been allocated.
-  static const intptr_t kInitialMarkingSpeed = 1;
-  // But if we are promoting a lot of data we need to mark faster to keep up
-  // with the data that is entering the old space through promotion.
-  static const intptr_t kFastMarking = 3;
-  // After this many steps we increase the marking/allocating factor.
-  static const intptr_t kMarkingSpeedAccellerationInterval = 1024;
-  // This is how much we increase the marking/allocating factor by.
-  static const intptr_t kMarkingSpeedAccelleration = 2;
-  static const intptr_t kMaxMarkingSpeed = 1000;
+  static const size_t kAllocatedThreshold = 64 * KB;
 
-  static const intptr_t kStepSizeInMs = 1;
+  static const int kStepSizeInMs = 1;
+  static const int kMaxStepSizeInMs = 5;
 
   // This is the upper bound for how many times we allow finalization of
   // incremental marking to be postponed.
-  static const size_t kMaxIdleMarkingDelayCounter = 3;
+  static const int kMaxIdleMarkingDelayCounter = 3;
 
   void FinalizeSweeping();
 
-  void NotifyAllocatedBytes(intptr_t allocated_bytes);
-
-  void Step(intptr_t bytes_to_process, CompletionAction action,
-            ForceCompletionAction completion, StepOrigin origin);
+  size_t Step(size_t bytes_to_process, CompletionAction action,
+              ForceCompletionAction completion, StepOrigin step_origin);
 
   inline void RestartIfNotMarking();
 
   static void RecordWriteFromCode(HeapObject* obj, Object** slot,
                                   Isolate* isolate);
 
   static void RecordWriteOfCodeEntryFromCode(JSFunction* host, Object** slot,
                                              Isolate* isolate);
 
   // Record a slot for compaction.  Returns false for objects that are
@@ skipping 22 matching lines @@
   }
 
   inline void SetNewSpacePageFlags(Page* chunk) {
     SetNewSpacePageFlags(chunk, IsMarking());
   }
 
   bool IsCompacting() { return IsMarking() && is_compacting_; }
 
   void ActivateGeneratedStub(Code* stub);
 
-  void NotifyOfHighPromotionRate();
-
   void NotifyIncompleteScanOfObject(int unscanned_bytes) {
     unscanned_bytes_of_large_object_ = unscanned_bytes;
   }
 
   void ClearIdleMarkingDelayCounter();
 
   bool IsIdleMarkingDelayCounterLimitReached();
 
   static void MarkGrey(Heap* heap, HeapObject* object);
 
@@ skipping 38 matching lines @@
   void AbortBlackAllocation();
 
  private:
   class Observer : public AllocationObserver {
    public:
     Observer(IncrementalMarking& incremental_marking, intptr_t step_size)
         : AllocationObserver(step_size),
           incremental_marking_(incremental_marking) {}
 
     void Step(int bytes_allocated, Address, size_t) override {
-      incremental_marking_.NotifyAllocatedBytes(bytes_allocated);
+      incremental_marking_.AdvanceIncrementalMarkingOnAllocation();
     }
 
    private:
     IncrementalMarking& incremental_marking_;
   };
 
   int64_t SpaceLeftInOldSpace();
 
-  void SpeedUp();
-
-  void ResetStepCounters();
-
   void StartMarking();
 
   void StartBlackAllocation();
   void FinishBlackAllocation();
 
   void MarkRoots();
   void MarkObjectGroups();
   void ProcessWeakCells();
   // Retain dying maps for <FLAG_retain_maps_for_n_gc> garbage collections to
   // increase chances of reusing of map transition tree in future.
@@ skipping 15 matching lines @@
   INLINE(void ProcessMarkingDeque());
 
   INLINE(intptr_t ProcessMarkingDeque(
       intptr_t bytes_to_process,
       ForceCompletionAction completion = DO_NOT_FORCE_COMPLETION));
 
   INLINE(void VisitObject(Map* map, HeapObject* obj, int size));
 
   void IncrementIdleMarkingDelayCounter();
 
+  void AdvanceIncrementalMarkingOnAllocation();
+
+  size_t StepSizeToKeepUpWithAllocations();
+  size_t StepSizeToMakeProgress();
+
   Heap* heap_;
 
-  Observer observer_;
+  State state_;
 
-  State state_;
+  double start_time_ms_;
+  size_t initial_old_generation_size_;
+  size_t old_generation_allocation_counter_;
+  size_t bytes_allocated_;
+  size_t bytes_marked_ahead_of_schedule_;
+  size_t unscanned_bytes_of_large_object_;
+
+  int idle_marking_delay_counter_;
+  int incremental_marking_finalization_rounds_;
+
   bool is_compacting_;
-
-  int steps_count_;
-  int64_t old_generation_space_available_at_start_of_incremental_;
-  int64_t old_generation_space_used_at_start_of_incremental_;
-  int64_t bytes_rescanned_;
   bool should_hurry_;
-  int marking_speed_;
-  intptr_t bytes_scanned_;
-  intptr_t allocated_;
-  intptr_t write_barriers_invoked_since_last_step_;
-  intptr_t bytes_marked_ahead_of_schedule_;
-  size_t idle_marking_delay_counter_;
-
-  int unscanned_bytes_of_large_object_;
-
   bool was_activated_;
-
   bool black_allocation_;
-
   bool finalize_marking_completed_;
 
-  int incremental_marking_finalization_rounds_;
-
   GCRequestType request_type_;
 
   IncrementalMarkingJob incremental_marking_job_;
+  Observer new_generation_observer_;
+  Observer old_generation_observer_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(IncrementalMarking);
 };
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_INCREMENTAL_MARKING_H_