[heap] Rework and improve object stats tracing

- Instead of tracing during marking we can now trace in a separate phase in MC.
  (Heap is iterable.)
- Add more subtypes for fixed arrays, reducing the unknown bucket to around ~8%
  (local run).
- Refactor collection calls to have a single bottleneck.
- Provide JSON-based output format that can be "easily" processed in JS.

BUG=
R=ulan@chromium.org,hpayer@chromium.org

Review-Url: https://codereview.chromium.org/2129173002
Cr-Commit-Position: refs/heads/master@{#37718}

src/heap/heap.cc

@@ -141,7 +141,8 @@ Heap::Heap()
       incremental_marking_(nullptr),
       gc_idle_time_handler_(nullptr),
       memory_reducer_(nullptr),
-      object_stats_(nullptr),
+      live_object_stats_(nullptr),
+      dead_object_stats_(nullptr),
       scavenge_job_(nullptr),
       idle_scavenge_observer_(nullptr),
       full_codegen_bytes_generated_(0),
@@ -5327,8 +5328,10 @@ bool Heap::SetUp() {
 
   memory_reducer_ = new MemoryReducer(this);
 
-  object_stats_ = new ObjectStats(this);
-  object_stats_->ClearObjectStats(true);
+  if (FLAG_track_gc_object_stats) {
+    live_object_stats_ = new ObjectStats(this);
+    dead_object_stats_ = new ObjectStats(this);
+  }
 
   scavenge_job_ = new ScavengeJob();
 
@@ -5486,8 +5489,15 @@ void Heap::TearDown() {
     memory_reducer_ = nullptr;
   }
 
-  delete object_stats_;
-  object_stats_ = nullptr;
+  if (live_object_stats_ != nullptr) {
+    delete live_object_stats_;
+    live_object_stats_ = nullptr;
+  }
+
+  if (dead_object_stats_ != nullptr) {
+    delete dead_object_stats_;
+    dead_object_stats_ = nullptr;
+  }
 
   delete scavenge_job_;
   scavenge_job_ = nullptr;
@@ -6378,14 +6388,16 @@ size_t Heap::NumberOfTrackedHeapObjectTypes() {
 
 
 size_t Heap::ObjectCountAtLastGC(size_t index) {
-  if (index >= ObjectStats::OBJECT_STATS_COUNT) return 0;
-  return object_stats_->object_count_last_gc(index);
+  if (live_object_stats_ == nullptr || index >= ObjectStats::OBJECT_STATS_COUNT)
+    return 0;
+  return live_object_stats_->object_count_last_gc(index);
 }
 
 
 size_t Heap::ObjectSizeAtLastGC(size_t index) {
-  if (index >= ObjectStats::OBJECT_STATS_COUNT) return 0;
-  return object_stats_->object_size_last_gc(index);
+  if (live_object_stats_ == nullptr || index >= ObjectStats::OBJECT_STATS_COUNT)
+    return 0;
+  return live_object_stats_->object_size_last_gc(index);
 }
 
 

src/heap/heap.h

@@ -2201,7 +2201,8 @@ class Heap {
 
   MemoryReducer* memory_reducer_;
 
-  ObjectStats* object_stats_;
+  ObjectStats* live_object_stats_;
+  ObjectStats* dead_object_stats_;
 
   ScavengeJob* scavenge_job_;
 

src/heap/incremental-marking.cc

@@ -213,9 +213,6 @@ class IncrementalMarkingMarkingVisitor
     table_.Register(kVisitFixedArray, &VisitFixedArrayIncremental);
     table_.Register(kVisitNativeContext, &VisitNativeContextIncremental);
     table_.Register(kVisitJSRegExp, &VisitJSRegExp);
-    if (FLAG_track_gc_object_stats) {
-      IncrementalMarkingObjectStatsVisitor::Initialize(&table_);
-    }
   }
 
   static const int kProgressBarScanningChunk = 32 * 1024;

src/heap/mark-compact.cc

@@ -325,7 +325,6 @@ void MarkCompactCollector::ClearInvalidRememberedSetSlots() {
 #endif
 }
 
-
 void MarkCompactCollector::CollectGarbage() {
   // Make sure that Prepare() has been called. The individual steps below will
   // update the state as they proceed.
@@ -1263,10 +1262,6 @@ void MarkCompactMarkingVisitor::Initialize() {
   StaticMarkingVisitor<MarkCompactMarkingVisitor>::Initialize();
 
   table_.Register(kVisitJSRegExp, &VisitRegExpAndFlushCode);
-
-  if (FLAG_track_gc_object_stats) {
-    MarkCompactObjectStatsVisitor::Initialize(&table_);
-  }
 }
 
 
@@ -2243,6 +2238,41 @@ void MarkCompactCollector::RegisterExternallyReferencedObject(Object** object) {
   MarkObject(heap_object, mark_bit);
 }
 
+class MarkCompactCollector::ObjectStatsVisitor
+    : public MarkCompactCollector::HeapObjectVisitor {
+ public:
+  ObjectStatsVisitor(ObjectStats* live_stats, ObjectStats* dead_stats)
+      : live_stats_(live_stats), dead_stats_(dead_stats) {
+    DCHECK_NOT_NULL(live_stats_);
+    DCHECK_NOT_NULL(dead_stats_);
+  }
+
+  bool Visit(HeapObject* obj) override {
+    if (Marking::IsBlack(ObjectMarking::MarkBitFrom(obj))) {
+      ObjectStatsCollector::CollectStatistics(live_stats_, obj);
+    } else {
+      DCHECK(!Marking::IsGrey(ObjectMarking::MarkBitFrom(obj)));
+      ObjectStatsCollector::CollectStatistics(dead_stats_, obj);
+    }
+    return true;
+  }
+
+ private:
+  ObjectStats* live_stats_;
+  ObjectStats* dead_stats_;
+};
+
+void MarkCompactCollector::VisitAllObjects(HeapObjectVisitor* visitor) {
+  SpaceIterator space_it(heap());
+  HeapObject* obj = nullptr;
+  while (space_it.has_next()) {
+    ObjectIterator* it = space_it.next();
+    while ((obj = it->Next()) != nullptr) {
+      visitor->Visit(obj);
+    }
+  }
+}
+
 void MarkCompactCollector::MarkLiveObjects() {
   TRACE_GC(heap()->tracer(), GCTracer::Scope::MC_MARK);
   double start_time = 0.0;
@@ -2262,10 +2292,6 @@ void MarkCompactCollector::MarkLiveObjects() {
     } else {
       // Abort any pending incremental activities e.g. incremental sweeping.
       incremental_marking->Stop();
-      if (FLAG_track_gc_object_stats) {
-        // Clear object stats collected during incremental marking.
-        heap()->object_stats_->ClearObjectStats();
-      }
       if (marking_deque_.in_use()) {
         marking_deque_.Uninitialize(true);
       }
@@ -2347,10 +2373,15 @@ void MarkCompactCollector::MarkLiveObjects() {
                                     start_time);
   }
   if (FLAG_track_gc_object_stats) {
+    ObjectStatsVisitor visitor(heap()->live_object_stats_,
+                               heap()->dead_object_stats_);
+    VisitAllObjects(&visitor);
     if (FLAG_trace_gc_object_stats) {
-      heap()->object_stats_->TraceObjectStats();
+      heap()->live_object_stats_->PrintJSON("live");
+      heap()->dead_object_stats_->PrintJSON("dead");
     }
-    heap()->object_stats_->CheckpointObjectStats();
+    heap()->live_object_stats_->CheckpointObjectStats();
+    heap()->dead_object_stats_->ClearObjectStats();
   }
 }
 

src/heap/mark-compact.h

@@ -501,6 +501,7 @@ class MarkCompactCollector {
   class EvacuateRecordOnlyVisitor;
   class EvacuateVisitorBase;
   class HeapObjectVisitor;
+  class ObjectStatsVisitor;
 
   explicit MarkCompactCollector(Heap* heap);
 
@@ -511,6 +512,8 @@ class MarkCompactCollector {
                                    int* target_fragmentation_percent,
                                    int* max_evacuated_bytes);
 
+  void VisitAllObjects(HeapObjectVisitor* visitor);
+
   // Finishes GC, performs heap verification if enabled.
   void Finish();
 

src/heap/object-stats.h

@@ -14,7 +14,7 @@ namespace internal {
 
 class ObjectStats {
  public:
-  explicit ObjectStats(Heap* heap) : heap_(heap) {}
+  explicit ObjectStats(Heap* heap) : heap_(heap) { ClearObjectStats(); }
 
   // ObjectStats are kept in two arrays, counts and sizes. Related stats are
   // stored in a contiguous linear buffer. Stats groups are stored one after
@@ -30,14 +30,14 @@ class ObjectStats {
 
   void ClearObjectStats(bool clear_last_time_stats = false);
 
-  void TraceObjectStats();
-  void TraceObjectStat(const char* name, int count, int size, double time);
   void CheckpointObjectStats();
+  void PrintJSON(const char* key);
 
   void RecordObjectStats(InstanceType type, size_t size) {
     DCHECK(type <= LAST_TYPE);
     object_counts_[type]++;
     object_sizes_[type] += size;
+    size_histogram_[type][HistogramIndexFromSize(size)]++;
   }
 
   void RecordCodeSubTypeStats(int code_sub_type, int code_age, size_t size) {
@@ -52,12 +52,22 @@ class ObjectStats {
     object_sizes_[code_sub_type_index] += size;
     object_counts_[code_age_index]++;
     object_sizes_[code_age_index] += size;
+    const int idx = HistogramIndexFromSize(size);
+    size_histogram_[code_sub_type_index][idx]++;
+    size_histogram_[code_age_index][idx]++;
   }
 
-  void RecordFixedArraySubTypeStats(int array_sub_type, size_t size) {
+  void RecordFixedArraySubTypeStats(int array_sub_type, size_t size,
+                                    size_t over_allocated) {
     DCHECK(array_sub_type <= LAST_FIXED_ARRAY_SUB_TYPE);
     object_counts_[FIRST_FIXED_ARRAY_SUB_TYPE + array_sub_type]++;
     object_sizes_[FIRST_FIXED_ARRAY_SUB_TYPE + array_sub_type] += size;
+    size_histogram_[FIRST_FIXED_ARRAY_SUB_TYPE + array_sub_type]
+                   [HistogramIndexFromSize(size)]++;
+    over_allocated_[FIRST_FIXED_ARRAY_SUB_TYPE + array_sub_type] +=
+        over_allocated;
+    over_allocated_histogram_[FIRST_FIXED_ARRAY_SUB_TYPE + array_sub_type]
+                             [HistogramIndexFromSize(over_allocated)]++;
   }
 
   size_t object_count_last_gc(size_t index) {
@@ -72,46 +82,49 @@ class ObjectStats {
   Heap* heap() { return heap_; }
 
  private:
-  Heap* heap_;
+  static const int kFirstBucketShift = 5;  // <=32
+  static const int kLastBucketShift = 19;  // >512k
+  static const int kFirstBucket = 1 << kFirstBucketShift;
+  static const int kLastBucket = 1 << kLastBucketShift;
+  static const int kNumberOfBuckets = kLastBucketShift - kFirstBucketShift;
+
+  int HistogramIndexFromSize(size_t size) {
+    if (size == 0) return 0;
+    int idx =
+        static_cast<int>(log2(static_cast<double>(size))) - kFirstBucketShift;
+    return idx < 0 ? 0 : idx;
+  }
 
-  // Object counts and used memory by InstanceType
+  Heap* heap_;
+  // Object counts and used memory by InstanceType.
   size_t object_counts_[OBJECT_STATS_COUNT];
   size_t object_counts_last_time_[OBJECT_STATS_COUNT];
   size_t object_sizes_[OBJECT_STATS_COUNT];
   size_t object_sizes_last_time_[OBJECT_STATS_COUNT];
+  // Approximation of overallocated memory by InstanceType.
+  size_t over_allocated_[OBJECT_STATS_COUNT];
+  // Detailed histograms by InstanceType.
+  size_t size_histogram_[OBJECT_STATS_COUNT][kNumberOfBuckets];
+  size_t over_allocated_histogram_[OBJECT_STATS_COUNT][kNumberOfBuckets];
 };
 
 class ObjectStatsCollector {
  public:
-  static void CollectStatistics(StaticVisitorBase::VisitorId id, Map* map,
-                                HeapObject* obj);
-  static void CollectFixedArrayStatistics(HeapObject* obj);
-
-  static void CountFixedArray(FixedArrayBase* fixed_array,
-                              FixedArraySubInstanceType fast_type,
-                              FixedArraySubInstanceType dictionary_type);
-  static void RecordMapStats(Map* map, HeapObject* obj);
-  static void RecordCodeStats(Map* map, HeapObject* obj);
-  static void RecordSharedFunctionInfoStats(Map* map, HeapObject* obj);
-  static void RecordFixedArrayStats(Map* map, HeapObject* obj);
-};
-
-class MarkCompactObjectStatsVisitor
-    : public StaticMarkingVisitor<MarkCompactObjectStatsVisitor> {
- public:
-  static void Initialize(VisitorDispatchTable<Callback>* original);
+  static void CollectStatistics(ObjectStats* stats, HeapObject* obj);
 
-  template <VisitorId id>
-  static inline void Visit(Map* map, HeapObject* obj);
-};
-
-class IncrementalMarkingObjectStatsVisitor
-    : public StaticMarkingVisitor<IncrementalMarkingObjectStatsVisitor> {
- public:
-  static void Initialize(VisitorDispatchTable<Callback>* original);
+ private:
+  static void RecordMapDetails(ObjectStats* stats, Heap* heap, HeapObject* obj);
+  static void RecordCodeDetails(ObjectStats* stats, Heap* heap,
+                                HeapObject* obj);
+  static void RecordSharedFunctionInfoDetails(ObjectStats* stats, Heap* heap,
+                                              HeapObject* obj);
+  static void RecordFixedArrayDetails(ObjectStats* stats, Heap* heap,
+                                      HeapObject* obj);
 
-  template <VisitorId id>
-  static inline void Visit(Map* map, HeapObject* obj);
+  static void RecordJSObjectDetails(ObjectStats* stats, Heap* heap,
+                                    JSObject* object);
+  static void RecordJSWeakCollectionDetails(ObjectStats* stats, Heap* heap,
+                                            JSWeakCollection* obj);
 };
 
 }  // namespace internal

src/objects-inl.h

@@ -3228,6 +3228,7 @@ CAST_ACCESSOR(JSSet)
 CAST_ACCESSOR(JSSetIterator)
 CAST_ACCESSOR(JSTypedArray)
 CAST_ACCESSOR(JSValue)
+CAST_ACCESSOR(JSWeakCollection)
 CAST_ACCESSOR(JSWeakMap)
 CAST_ACCESSOR(JSWeakSet)
 CAST_ACCESSOR(LayoutDescriptor)

src/objects.h

@@ -777,22 +777,33 @@ STATIC_ASSERT(FOREIGN_TYPE == Internals::kForeignType);
 
 std::ostream& operator<<(std::ostream& os, InstanceType instance_type);
 
-
 #define FIXED_ARRAY_SUB_INSTANCE_TYPE_LIST(V) \
-  V(FAST_ELEMENTS_SUB_TYPE)                   \
+  V(CONTEXT_SUB_TYPE)                         \
+  V(COPY_ON_WRITE_SUB_TYPE)                   \
+  V(DEOPTIMIZATION_DATA_SUB_TYPE)             \
+  V(DESCRIPTOR_ARRAY_SUB_TYPE)                \
+  V(ENUM_CACHE_SUB_TYPE)                      \
+  V(ENUM_INDICES_CACHE_SUB_TYPE)              \
   V(DICTIONARY_ELEMENTS_SUB_TYPE)             \
-  V(FAST_PROPERTIES_SUB_TYPE)                 \
   V(DICTIONARY_PROPERTIES_SUB_TYPE)           \
+  V(FAST_ELEMENTS_SUB_TYPE)                   \
+  V(FAST_PROPERTIES_SUB_TYPE)                 \
+  V(LITERALS_ARRAY_SUB_TYPE)                  \
   V(MAP_CODE_CACHE_SUB_TYPE)                  \
+  V(OBJECT_TO_CODE_SUB_TYPE)                  \
+  V(RELOC_INFO_SUB_TYPE)                      \
   V(SCOPE_INFO_SUB_TYPE)                      \
+  V(SOURCE_POS_SUB_TYPE)                      \
   V(STRING_TABLE_SUB_TYPE)                    \
-  V(DESCRIPTOR_ARRAY_SUB_TYPE)
+  V(TYPE_FEEDBACK_VECTOR_SUB_TYPE)            \
+  V(TYPE_FEEDBACK_METADATA_SUB_TYPE)          \
+  V(WEAK_COLLECTION_SUB_TYPE)
 
 enum FixedArraySubInstanceType {
 #define DEFINE_FIXED_ARRAY_SUB_INSTANCE_TYPE(name) name,
   FIXED_ARRAY_SUB_INSTANCE_TYPE_LIST(DEFINE_FIXED_ARRAY_SUB_INSTANCE_TYPE)
 #undef DEFINE_FIXED_ARRAY_SUB_INSTANCE_TYPE
-      LAST_FIXED_ARRAY_SUB_TYPE = DESCRIPTOR_ARRAY_SUB_TYPE
+      LAST_FIXED_ARRAY_SUB_TYPE = WEAK_COLLECTION_SUB_TYPE
 };
 
 
@@ -10056,6 +10067,8 @@ class JSMapIterator: public OrderedHashTableIterator<JSMapIterator,
 // Base class for both JSWeakMap and JSWeakSet
 class JSWeakCollection: public JSObject {
  public:
+  DECLARE_CAST(JSWeakCollection)
+
   // [table]: the backing hash table mapping keys to values.
   DECL_ACCESSORS(table, Object)