Bug 1144369 - Add a GC phase to track time spent buffering gray roots; r=sfink, a=RyanVM

js/src/gc/Statistics.cpp

@@ -374,6 +374,7 @@ static const PhaseInfo phases[] = {
     { PHASE_TRACE_HEAP, "Trace Heap", PHASE_NO_PARENT },
         /* PHASE_MARK_ROOTS */
     { PHASE_MARK_ROOTS, "Mark Roots", PHASE_MULTI_PARENTS },
+        { PHASE_BUFFER_GRAY_ROOTS, "Buffer Gray Roots", PHASE_MARK_ROOTS },
         { PHASE_MARK_CCWS, "Mark Cross Compartment Wrappers", PHASE_MARK_ROOTS },
         { PHASE_MARK_ROOTERS, "Mark Rooters", PHASE_MARK_ROOTS },
         { PHASE_MARK_RUNTIME_DATA, "Mark Runtime-wide Data", PHASE_MARK_ROOTS },

js/src/gc/Statistics.h

@@ -75,6 +75,7 @@ enum Phase {
     PHASE_EVICT_NURSERY,
     PHASE_TRACE_HEAP,
     PHASE_MARK_ROOTS,
+    PHASE_BUFFER_GRAY_ROOTS,
     PHASE_MARK_CCWS,
     PHASE_MARK_ROOTERS,
     PHASE_MARK_RUNTIME_DATA,

js/src/jsgc.cpp

@@ -3830,8 +3830,10 @@ GCRuntime::beginMarkPhase(JS::gcreason::Reason reason)
 
     gcstats::AutoPhase ap2(stats, gcstats::PHASE_MARK_ROOTS);
 
-    if (isIncremental)
+    if (isIncremental) {
+        gcstats::AutoPhase ap3(stats, gcstats::PHASE_BUFFER_GRAY_ROOTS);
         bufferGrayRoots();
+    }
 
     /*
      * This code ensures that if a compartment is "dead", then it will be