[heap] Add GC sum counters

Adds reporting for
- V8.GCMarkCompactor as sum of V8 mark-compact events

Bug: chromium:843903
Change-Id: I5e8a80c8d1a9c5bf696635b54659ac56403f52d5
Reviewed-on: https://chromium-review.googlesource.com/c/1256764
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56750}

src/counters.h

@@ -1180,6 +1180,7 @@ class RuntimeCallTimerScope {
   HR(gc_finalize_sweep, V8.GCFinalizeMC.Sweep, 0, 10000, 101)                  \
   HR(gc_scavenger_scavenge_main, V8.GCScavenger.ScavengeMain, 0, 10000, 101)   \
   HR(gc_scavenger_scavenge_roots, V8.GCScavenger.ScavengeRoots, 0, 10000, 101) \
+  HR(gc_mark_compactor, V8.GCMarkCompactor, 0, 10000, 101)                     \
   HR(scavenge_reason, V8.GCScavengeReason, 0, 21, 22)                          \
   HR(young_generation_handling, V8.GCYoungGenerationHandling, 0, 2, 3)         \
   /* Asm/Wasm. */                                                              \

src/heap/gc-tracer.cc

@@ -326,6 +326,7 @@ void GCTracer::Stop(GarbageCollector collector) {
                                     current_.incremental_marking_duration);
       recorded_incremental_mark_compacts_.Push(
           MakeBytesAndDuration(current_.start_object_size, duration));
+      RecordGCSumCounters(duration);
       ResetIncrementalMarkingCounters();
       combined_mark_compact_speed_cache_ = 0.0;
       FetchBackgroundMarkCompactCounters();
@@ -337,6 +338,7 @@ void GCTracer::Stop(GarbageCollector collector) {
           current_.end_time, duration + current_.incremental_marking_duration);
       recorded_mark_compacts_.Push(
           MakeBytesAndDuration(current_.start_object_size, duration));
+      RecordGCSumCounters(duration);
       ResetIncrementalMarkingCounters();
       combined_mark_compact_speed_cache_ = 0.0;
       FetchBackgroundMarkCompactCounters();
@@ -1120,5 +1122,25 @@ void GCTracer::RecordGCPhasesHistograms(HistogramTimer* gc_timer) {
   }
 }
 
+void GCTracer::RecordGCSumCounters(double atomic_pause_duration) {
+  // Emit UMA counters.
+  const double overall_duration =
+      current_.incremental_marking_scopes[Scope::MC_INCREMENTAL_START]
+          .duration +
+      current_.incremental_marking_scopes[Scope::MC_INCREMENTAL_SWEEPING]
+          .duration +
+      incremental_marking_duration_ +
+      current_.incremental_marking_scopes[Scope::MC_INCREMENTAL_FINALIZE]
+          .duration +
+      atomic_pause_duration;
+  heap_->isolate()->counters()->gc_mark_compactor()->AddSample(
+      static_cast<int>(overall_duration));
+
+  // Emit trace event counters.
+  TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("v8.gc"),
+                       "V8.GCMarkCompactorSummary", TRACE_EVENT_SCOPE_THREAD,
+                       "duration", overall_duration);
+}
+
 }  // namespace internal
 }  // namespace v8

src/heap/gc-tracer.h

@@ -338,6 +338,7 @@ class V8_EXPORT_PRIVATE GCTracer {
   FRIEND_TEST(GCTracerTest, IncrementalScope);
   FRIEND_TEST(GCTracerTest, IncrementalMarkingSpeed);
   FRIEND_TEST(GCTracerTest, MutatorUtilization);
+  FRIEND_TEST(GCTracerTest, RecordGCSumHistograms);
   FRIEND_TEST(GCTracerTest, RecordMarkCompactHistograms);
   FRIEND_TEST(GCTracerTest, RecordScavengerHistograms);
 
@@ -359,6 +360,11 @@ class V8_EXPORT_PRIVATE GCTracer {
   void RecordMutatorUtilization(double mark_compactor_end_time,
                                 double mark_compactor_duration);
 
+  // Overall time spent in mark compact within a given GC cycle. Exact
+  // accounting of events within a GC is not necessary which is why the
+  // recording takes place at the end of the atomic pause.
+  void RecordGCSumCounters(double atomic_pause_duration);
+
   // Print one detailed trace line in name=value format.
   // TODO(ernstm): Move to Heap.
   void PrintNVP() const;

test/unittests/heap/gc-tracer-unittest.cc

@@ -468,7 +468,7 @@ class GcHistogram {
 
   static void CleanUp() { histograms_.clear(); }
 
-  int Total() {
+  int Total() const {
     int result = 0;
     for (int i : samples_) {
       result += i;
@@ -476,7 +476,7 @@ class GcHistogram {
     return result;
   }
 
-  int Count() { return static_cast<int>(samples_.size()); }
+  int Count() const { return static_cast<int>(samples_.size()); }
 
  private:
   std::vector<int> samples_;
@@ -524,5 +524,27 @@ TEST_F(GCTracerTest, RecordScavengerHistograms) {
   GcHistogram::CleanUp();
 }
 
+TEST_F(GCTracerTest, RecordGCSumHistograms) {
+  if (FLAG_stress_incremental_marking) return;
+  isolate()->SetCreateHistogramFunction(&GcHistogram::CreateHistogram);
+  isolate()->SetAddHistogramSampleFunction(&GcHistogram::AddHistogramSample);
+  GCTracer* tracer = i_isolate()->heap()->tracer();
+  tracer->ResetForTesting();
+  tracer->current_
+      .incremental_marking_scopes[GCTracer::Scope::MC_INCREMENTAL_START]
+      .duration = 1;
+  tracer->current_
+      .incremental_marking_scopes[GCTracer::Scope::MC_INCREMENTAL_SWEEPING]
+      .duration = 2;
+  tracer->AddIncrementalMarkingStep(3.0, 1024);
+  tracer->current_
+      .incremental_marking_scopes[GCTracer::Scope::MC_INCREMENTAL_FINALIZE]
+      .duration = 4;
+  const double atomic_pause_duration = 5.0;
+  tracer->RecordGCSumCounters(atomic_pause_duration);
+  EXPECT_EQ(15, GcHistogram::Get("V8.GCMarkCompactor")->Total());
+  GcHistogram::CleanUp();
+}
+
 }  // namespace internal
 }  // namespace v8