[heap] New heuristics for incremental marking step size.

This patch simplifies code for speeding up marking and
removes write barrier counter.

The step size is now computed based in two parts:
- bytes to mark in order to keep up with allocation,
- bytes to mark in order to make progress.

BUG=chromium:616434, chromium:646139, chromium:644819
LOG=NO

Review-Url: https://codereview.chromium.org/2359903002
Cr-Commit-Position: refs/heads/master@{#39827}

src/arm/code-stubs-arm.cc

@@ -3238,16 +3238,6 @@ void RecordWriteStub::CheckNeedsToInformIncrementalMarker(
   Label need_incremental;
   Label need_incremental_pop_scratch;
 
-  __ and_(regs_.scratch0(), regs_.object(), Operand(~Page::kPageAlignmentMask));
-  __ ldr(regs_.scratch1(),
-         MemOperand(regs_.scratch0(),
-                    MemoryChunk::kWriteBarrierCounterOffset));
-  __ sub(regs_.scratch1(), regs_.scratch1(), Operand(1), SetCC);
-  __ str(regs_.scratch1(),
-         MemOperand(regs_.scratch0(),
-                    MemoryChunk::kWriteBarrierCounterOffset));
-  __ b(mi, &need_incremental);
-
   // Let's look at the color of the object:  If it is not black we don't have
   // to inform the incremental marker.
   __ JumpIfBlack(regs_.object(), regs_.scratch0(), regs_.scratch1(), &on_black);

src/arm64/code-stubs-arm64.cc

@@ -3155,16 +3155,6 @@ void RecordWriteStub::CheckNeedsToInformIncrementalMarker(
   Label need_incremental;
   Label need_incremental_pop_scratch;
 
-  Register mem_chunk = regs_.scratch0();
-  Register counter = regs_.scratch1();
-  __ Bic(mem_chunk, regs_.object(), Page::kPageAlignmentMask);
-  __ Ldr(counter,
-         MemOperand(mem_chunk, MemoryChunk::kWriteBarrierCounterOffset));
-  __ Subs(counter, counter, 1);
-  __ Str(counter,
-         MemOperand(mem_chunk, MemoryChunk::kWriteBarrierCounterOffset));
-  __ B(mi, &need_incremental);
-
   // If the object is not black we don't have to inform the incremental marker.
   __ JumpIfBlack(regs_.object(), regs_.scratch0(), regs_.scratch1(), &on_black);
 

src/heap/heap.cc

@@ -115,7 +115,6 @@ Heap::Heap()
       inline_allocation_disabled_(false),
       total_regexp_code_generated_(0),
       tracer_(nullptr),
-      high_survival_rate_period_length_(0),
       promoted_objects_size_(0),
       promotion_ratio_(0),
       semi_space_copied_object_size_(0),
@@ -141,7 +140,7 @@ Heap::Heap()
       full_codegen_bytes_generated_(0),
       crankshaft_codegen_bytes_generated_(0),
       new_space_allocation_counter_(0),
-      old_generation_allocation_counter_(0),
+      old_generation_allocation_counter_at_last_gc_(0),
       old_generation_size_at_last_gc_(0),
       gcs_since_last_deopt_(0),
       global_pretenuring_feedback_(nullptr),
@@ -1269,11 +1268,6 @@ void Heap::UpdateSurvivalStatistics(int start_new_space_size) {
 
   double survival_rate = promotion_ratio_ + semi_space_copied_rate_;
   tracer()->AddSurvivalRatio(survival_rate);
-  if (survival_rate > kYoungSurvivalRateHighThreshold) {
-    high_survival_rate_period_length_++;
-  } else {
-    high_survival_rate_period_length_ = 0;
-  }
 }
 
 bool Heap::PerformGarbageCollection(
@@ -1310,13 +1304,6 @@ bool Heap::PerformGarbageCollection(
 
   int start_new_space_size = static_cast<int>(Heap::new_space()->Size());
 
-  if (IsHighSurvivalRate()) {
-    // We speed up the incremental marker if it is running so that it
-    // does not fall behind the rate of promotion, which would cause a
-    // constantly growing old space.
-    incremental_marking()->NotifyOfHighPromotionRate();
-  }
-
   {
     Heap::PretenuringScope pretenuring_scope(this);
 
@@ -1327,7 +1314,7 @@ bool Heap::PerformGarbageCollection(
       old_generation_size_configured_ = true;
       // This should be updated before PostGarbageCollectionProcessing, which
       // can cause another GC. Take into account the objects promoted during GC.
-      old_generation_allocation_counter_ +=
+      old_generation_allocation_counter_at_last_gc_ +=
           static_cast<size_t>(promoted_objects_size_);
       old_generation_size_at_last_gc_ = PromotedSpaceSizeOfObjects();
     } else {

src/heap/heap.h

@@ -1387,16 +1387,18 @@ class Heap {
   }
 
   void UpdateOldGenerationAllocationCounter() {
-    old_generation_allocation_counter_ = OldGenerationAllocationCounter();
+    old_generation_allocation_counter_at_last_gc_ =
+        OldGenerationAllocationCounter();
   }
 
   size_t OldGenerationAllocationCounter() {
-    return old_generation_allocation_counter_ + PromotedSinceLastGC();
+    return old_generation_allocation_counter_at_last_gc_ +
+           PromotedSinceLastGC();
   }
 
   // This should be used only for testing.
-  void set_old_generation_allocation_counter(size_t new_value) {
-    old_generation_allocation_counter_ = new_value;
+  void set_old_generation_allocation_counter_at_last_gc(size_t new_value) {
+    old_generation_allocation_counter_at_last_gc_ = new_value;
   }
 
   size_t PromotedSinceLastGC() {
@@ -1723,10 +1725,6 @@ class Heap {
   // Flush the number to string cache.
   void FlushNumberStringCache();
 
-  // TODO(hpayer): Allocation site pretenuring may make this method obsolete.
-  // Re-visit incremental marking heuristics.
-  bool IsHighSurvivalRate() { return high_survival_rate_period_length_ > 0; }
-
   void ConfigureInitialOldGenerationSize();
 
   bool HasLowYoungGenerationAllocationRate();
@@ -2201,7 +2199,6 @@ class Heap {
 
   GCTracer* tracer_;
 
-  int high_survival_rate_period_length_;
   intptr_t promoted_objects_size_;
   double promotion_ratio_;
   double promotion_rate_;
@@ -2260,7 +2257,7 @@ class Heap {
   // This counter is increased before each GC and never reset. To
   // account for the bytes allocated since the last GC, use the
   // OldGenerationAllocationCounter() function.
-  size_t old_generation_allocation_counter_;
+  size_t old_generation_allocation_counter_at_last_gc_;
 
   // The size of objects in old generation after the last MarkCompact GC.
   size_t old_generation_size_at_last_gc_;

src/heap/incremental-marking.h

@@ -108,31 +108,19 @@ class IncrementalMarking {
   // 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 intptr_t kStepSizeInMs = 1;
+  static const size_t kAllocatedThreshold = 64 * KB;
+
+  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();
 
@@ -175,8 +163,6 @@ class IncrementalMarking {
 
   void ActivateGeneratedStub(Code* stub);
 
-  void NotifyOfHighPromotionRate();
-
   void NotifyIncompleteScanOfObject(int unscanned_bytes) {
     unscanned_bytes_of_large_object_ = unscanned_bytes;
   }
@@ -235,7 +221,7 @@ class IncrementalMarking {
           incremental_marking_(incremental_marking) {}
 
     void Step(int bytes_allocated, Address, size_t) override {
-      incremental_marking_.NotifyAllocatedBytes(bytes_allocated);
+      incremental_marking_.AdvanceIncrementalMarkingOnAllocation();
     }
 
    private:
@@ -244,10 +230,6 @@ class IncrementalMarking {
 
   int64_t SpaceLeftInOldSpace();
 
-  void SpeedUp();
-
-  void ResetStepCounters();
-
   void StartMarking();
 
   void StartBlackAllocation();
@@ -283,38 +265,36 @@ class IncrementalMarking {
 
   void IncrementIdleMarkingDelayCounter();
 
-  Heap* heap_;
+  void AdvanceIncrementalMarkingOnAllocation();
+
+  size_t StepSizeToKeepUpWithAllocations();
+  size_t StepSizeToMakeProgress();
 
-  Observer observer_;
+  Heap* heap_;
 
   State state_;
-  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_;
+  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 unscanned_bytes_of_large_object_;
+  int idle_marking_delay_counter_;
+  int incremental_marking_finalization_rounds_;
 
+  bool is_compacting_;
+  bool should_hurry_;
   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);
 };

src/ia32/code-stubs-ia32.cc

@@ -3190,17 +3190,6 @@ void RecordWriteStub::CheckNeedsToInformIncrementalMarker(
     Mode mode) {
   Label object_is_black, need_incremental, need_incremental_pop_object;
 
-  __ mov(regs_.scratch0(), Immediate(~Page::kPageAlignmentMask));
-  __ and_(regs_.scratch0(), regs_.object());
-  __ mov(regs_.scratch1(),
-         Operand(regs_.scratch0(),
-                 MemoryChunk::kWriteBarrierCounterOffset));
-  __ sub(regs_.scratch1(), Immediate(1));
-  __ mov(Operand(regs_.scratch0(),
-                 MemoryChunk::kWriteBarrierCounterOffset),
-         regs_.scratch1());
-  __ j(negative, &need_incremental);
-
   // Let's look at the color of the object:  If it is not black we don't have
   // to inform the incremental marker.
   __ JumpIfBlack(regs_.object(),

src/x64/code-stubs-x64.cc

@@ -3129,17 +3129,6 @@ void RecordWriteStub::CheckNeedsToInformIncrementalMarker(
   Label need_incremental;
   Label need_incremental_pop_object;
 
-  __ movp(regs_.scratch0(), Immediate(~Page::kPageAlignmentMask));
-  __ andp(regs_.scratch0(), regs_.object());
-  __ movp(regs_.scratch1(),
-         Operand(regs_.scratch0(),
-                 MemoryChunk::kWriteBarrierCounterOffset));
-  __ subp(regs_.scratch1(), Immediate(1));
-  __ movp(Operand(regs_.scratch0(),
-                 MemoryChunk::kWriteBarrierCounterOffset),
-         regs_.scratch1());
-  __ j(negative, &need_incremental);
-
   // Let's look at the color of the object:  If it is not black we don't have
   // to inform the incremental marker.
   __ JumpIfBlack(regs_.object(),

test/cctest/heap/test-heap.cc

@@ -6209,7 +6209,8 @@ TEST(OldSpaceAllocationCounter) {
   CHECK_LE(kSize, counter4 - counter3);
   // Test counter overflow.
   size_t max_counter = -1;
-  heap->set_old_generation_allocation_counter(max_counter - 10 * kSize);
+  heap->set_old_generation_allocation_counter_at_last_gc(max_counter -
+                                                         10 * kSize);
   size_t start = heap->OldGenerationAllocationCounter();
   for (int i = 0; i < 20; i++) {
     AllocateInSpace(isolate, kSize, OLD_SPACE);