Bug 1732161 - Add profiler marker for core part of CC r=smaug,gerald

Differential Revision: https://phabricator.services.mozilla.com/D126394

dom/base/CCGCScheduler.cpp

@@ -6,6 +6,7 @@
 
 #include "mozilla/StaticPrefs_javascript.h"
 #include "mozilla/CycleCollectedJSRuntime.h"
+#include "mozilla/ProfilerMarkers.h"
 #include "mozilla/dom/ScriptSettings.h"
 #include "nsRefreshDriver.h"
 
@@ -49,6 +50,52 @@ void CCGCScheduler::NoteGCEnd() {
   }
 }
 
+#ifdef MOZ_GECKO_PROFILER
+struct CCIntervalMarker {
+  static constexpr mozilla::Span<const char> MarkerTypeName() {
+    return mozilla::MakeStringSpan("CC");
+  }
+  static void StreamJSONMarkerData(
+      baseprofiler::SpliceableJSONWriter& aWriter) {}
+  static mozilla::MarkerSchema MarkerTypeDisplay() {
+    using MS = mozilla::MarkerSchema;
+    MS schema{MS::Location::MarkerChart, MS::Location::MarkerTable,
+              MS::Location::TimelineMemory};
+    schema.AddStaticLabelValue(
+        "Description",
+        "Summary data for the core part of a cycle collection, possibly "
+        "encompassing a set of incremental slices. The main thread is not "
+        "blocked for the entire major CC interval, only for the individual "
+        "slices.");
+    return schema;
+  }
+};
+#endif
+
+void CCGCScheduler::NoteCCBegin(TimeStamp aWhen) {
+#ifdef MOZ_GECKO_PROFILER
+  profiler_add_marker("CC", baseprofiler::category::GCCC,
+                      MarkerOptions(MarkerTiming::IntervalStart(aWhen)),
+                      CCIntervalMarker{});
+#endif
+  mIsCollectingCycles = true;
+}
+
+void CCGCScheduler::NoteCCEnd(TimeStamp aWhen) {
+#ifdef MOZ_GECKO_PROFILER
+  profiler_add_marker("CC", baseprofiler::category::GCCC,
+                      MarkerOptions(MarkerTiming::IntervalEnd(aWhen)),
+                      CCIntervalMarker{});
+#endif
+
+  mIsCollectingCycles = false;
+  mLastCCEndTime = aWhen;
+  mNeedsFullCC = false;
+
+  // The GC for this CC has already been requested.
+  mNeedsGCAfterCC = false;
+}
+
 void CCGCScheduler::NoteWontGC() {
   mReadyForMajorGC = false;
   mMajorGCReason = JS::GCReason::NO_REASON;

dom/base/CCGCScheduler.h

@@ -203,6 +203,16 @@ class CCGCScheduler {
   // A timer fired, but then decided not to run a GC.
   void NoteWontGC();
 
+  // This is invoked when we reach the actual cycle collection portion of the
+  // overall cycle collection.
+  void NoteCCBegin(TimeStamp aWhen);
+
+  // This is invoked when the whole process of collection is done -- i.e., CC
+  // preparation (eg ForgetSkippables) in addition to the CC itself. There
+  // really ought to be a separate name for the overall CC as opposed to the
+  // actual cycle collection portion.
+  void NoteCCEnd(TimeStamp aWhen);
+
   void NoteGCSliceEnd(TimeDuration aSliceDuration) {
     if (mMajorGCReason == JS::GCReason::NO_REASON) {
       // Internally-triggered GCs do not wait for the parent's permission to
@@ -261,17 +271,8 @@ class CCGCScheduler {
     mCCollectedZonesWaitingForGC += aResults.mFreedJSZones;
   }
 
-  // This is invoked when the whole process of collection is done -- i.e., CC
-  // preparation (eg ForgetSkippables), the CC itself, and the optional
-  // followup GC. There really ought to be a separate name for the overall CC
-  // as opposed to the actual cycle collection portion.
-  void NoteCCEnd(TimeStamp aWhen) {
-    mLastCCEndTime = aWhen;
-    mNeedsFullCC = false;
-
-    // The GC for this CC has already been requested.
-    mNeedsGCAfterCC = false;
-  }
+  // Test if we are in the NoteCCBegin .. NoteCCEnd interval.
+  bool IsCollectingCycles() const { return mIsCollectingCycles; }
 
   // The CC was abandoned without running a slice, so we only did forget
   // skippables. Prevent running another cycle soon.
@@ -432,6 +433,7 @@ class CCGCScheduler {
   JS::GCReason mMajorGCReason = JS::GCReason::NO_REASON;
 
   bool mIsCompactingOnUserInactive = false;
+  bool mIsCollectingCycles = false;
   bool mUserIsActive = true;
 
  public:

dom/base/nsJSEnvironment.cpp

@@ -1382,6 +1382,11 @@ void nsJSContext::PrepareForCycleCollectionSlice(TimeStamp aDeadline) {
     FinishAnyIncrementalGC();
     afterGCTime = TimeStamp::Now();
   }
+
+  if (!sScheduler.IsCollectingCycles()) {
+    sScheduler.NoteCCBegin(beginTime);
+  }
+
   sCCStats.AfterPrepareForCycleCollectionSlice(aDeadline, beginTime,
                                                afterGCTime);
 }