[NOT FOR LANDING] Patch for experiments: V8

src/heap/heap.cc

 // 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.
 
 #include "src/heap/heap.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/ast/context-slot-cache.h"
 #include "src/base/bits.h"
@@ skipping 796 matching lines @@
   TRACE_EVENT0("v8", "V8.GCIncrementalMarkingFinalize");
   TRACE_GC(tracer(), GCTracer::Scope::MC_INCREMENTAL_FINALIZE);
 
   {
     GCCallbacksScope scope(this);
     if (scope.CheckReenter()) {
       AllowHeapAllocation allow_allocation;
       TRACE_GC(tracer(), GCTracer::Scope::MC_INCREMENTAL_EXTERNAL_PROLOGUE);
       VMState<EXTERNAL> state(isolate_);
       HandleScope handle_scope(isolate_);
-      CallGCPrologueCallbacks(kGCTypeIncrementalMarking, kNoGCCallbackFlags);
+      CallGCPrologueCallbacks(kGCTypeIncrementalMarking,
+          FLAG_object_grouping_in_incremental_finalization
+              ? kNoGCCallbackFlags
+              : kGCCallbackFlagDisableObjectGrouping);
     }
   }
   incremental_marking()->FinalizeIncrementally();
   {
     GCCallbacksScope scope(this);
     if (scope.CheckReenter()) {
       AllowHeapAllocation allow_allocation;
       TRACE_GC(tracer(), GCTracer::Scope::MC_INCREMENTAL_EXTERNAL_EPILOGUE);
       VMState<EXTERNAL> state(isolate_);
       HandleScope handle_scope(isolate_);
@@ skipping 4576 matching lines @@
              isolate()->LoadStartTimeMs() + kMaxLoadTimeMs;
 }
 
 // This predicate is called when an old generation space cannot allocated from
 // the free list and is about to add a new page. Returning false will cause a
 // major GC. It happens when the old generation allocation limit is reached and
 // - either we need to optimize for memory usage,
 // - or the incremental marking is not in progress and we cannot start it.
 bool Heap::ShouldExpandOldGenerationOnSlowAllocation() {
   if (always_allocate() || OldGenerationSpaceAvailable() > 0) return true;
-  // We reached the old generation allocation limit.

[ulan, 2017/03/30 16:24:30]

This changes reduce noise in scheduling mark-compact GCs.

-
-  if (ShouldOptimizeForMemoryUsage()) return false;
-
-  if (ShouldOptimizeForLoadTime()) return true;
-
-  if (incremental_marking()->NeedsFinalization()) {
-    return !AllocationLimitOvershotByLargeMargin();
-  }
-
   if (incremental_marking()->IsStopped() &&
       IncrementalMarkingLimitReached() == IncrementalMarkingLimit::kNoLimit) {
     // We cannot start incremental marking.
     return false;
   }
   return true;
 }
 
 // This function returns either kNoLimit, kSoftLimit, or kHardLimit.
 // The kNoLimit means that either incremental marking is disabled or it is too
@@ skipping 10 matching lines @@
   if ((FLAG_stress_compaction && (gc_count_ & 1) != 0) ||
       HighMemoryPressure()) {
     // If there is high memory pressure or stress testing is enabled, then
     // start marking immediately.
     return IncrementalMarkingLimit::kHardLimit;
   }
   size_t old_generation_space_available = OldGenerationSpaceAvailable();
   if (old_generation_space_available > new_space_->Capacity()) {
     return IncrementalMarkingLimit::kNoLimit;
   }
-  if (ShouldOptimizeForMemoryUsage()) {

[ulan, 2017/03/30 16:24:30]

This changes reduce noise in scheduling mark-compact GCs.

-    return IncrementalMarkingLimit::kHardLimit;
-  }
-  if (ShouldOptimizeForLoadTime()) {
-    return IncrementalMarkingLimit::kNoLimit;
-  }
   if (old_generation_space_available == 0) {
     return IncrementalMarkingLimit::kHardLimit;
   }
   return IncrementalMarkingLimit::kSoftLimit;
 }
 
 void Heap::EnableInlineAllocation() {
   if (!inline_allocation_disabled_) return;
   inline_allocation_disabled_ = false;
 
@@ skipping 1116 matching lines @@
 }
 
 
 // static
 int Heap::GetStaticVisitorIdForMap(Map* map) {
   return StaticVisitorBase::GetVisitorId(map);
 }
 
 }  // namespace internal
 }  // namespace v8