Limit rate of full garbage collections triggered by idle notification.

src/heap/gc-idle-time-handler.cc

Index: src/heap/gc-idle-time-handler.cc
diff --git a/src/heap/gc-idle-time-handler.cc b/src/heap/gc-idle-time-handler.cc
index c74b46ea9b6d126b0770df551a830593198d63ef..8b8f306b7ffbd6d84167872562670b222e6f45e0 100644
--- a/src/heap/gc-idle-time-handler.cc
+++ b/src/heap/gc-idle-time-handler.cc
@@ -17,6 +17,7 @@ const int GCIdleTimeHandler::kMaxMarkCompactsInIdleRound = 7;
 const int GCIdleTimeHandler::kIdleScavengeThreshold = 5;
 const double GCIdleTimeHandler::kHighContextDisposalRate = 100;
 const size_t GCIdleTimeHandler::kMinTimeForOverApproximatingWeakClosureInMs = 1;
+const double GCIdleTimeHandler::kMinMillisecondsInBetweenMarkCompact = 1000;
 
 
 void GCIdleTimeAction::Print() {
@@ -152,10 +153,15 @@ bool GCIdleTimeHandler::ShouldDoScavenge(
 
 bool GCIdleTimeHandler::ShouldDoMarkCompact(
     size_t idle_time_in_ms, size_t size_of_objects,
-    size_t mark_compact_speed_in_bytes_per_ms) {
-  return idle_time_in_ms >=
-         EstimateMarkCompactTime(size_of_objects,
-                                 mark_compact_speed_in_bytes_per_ms);
+    size_t mark_compact_speed_in_bytes_per_ms, double last_mark_compact_time,
+    double current_time) {
+  bool mark_compact_rate_high =
+      current_time <
+      last_mark_compact_time + kMinMillisecondsInBetweenMarkCompact;

[jochen (gone - plz use gerrit), 2015/03/20 12:41:52]

you're adding seconds + milliseconds here as far as I can tell

[Hannes Payer (out of office), 2015/03/20 14:20:39]

yeah, found it when I run the experiment. already removed.

+  return !mark_compact_rate_high &&
+         idle_time_in_ms >=
+             EstimateMarkCompactTime(size_of_objects,
+                                     mark_compact_speed_in_bytes_per_ms);
 }
 
 
@@ -204,6 +210,7 @@ GCIdleTimeAction GCIdleTimeHandler::Compute(double idle_time_in_ms,
                                             HeapState heap_state) {
   if (static_cast<int>(idle_time_in_ms) <= 0) {
     if (heap_state.contexts_disposed > 0) {
+      printf("start idle round, contexts disposed\n");

[jochen (gone - plz use gerrit), 2015/03/20 12:41:52]

debug code?

[Hannes Payer (out of office), 2015/03/20 14:20:39]

Done.

       StartIdleRound();
     }
     if (heap_state.incremental_marking_stopped) {
@@ -226,6 +233,7 @@ GCIdleTimeAction GCIdleTimeHandler::Compute(double idle_time_in_ms,
 
   if (IsMarkCompactIdleRoundFinished()) {
     if (EnoughGarbageSinceLastIdleRound()) {
+      printf("start idle round, enough garbage\n");
       StartIdleRound();
     } else {
       return GCIdleTimeAction::Done();
@@ -233,9 +241,10 @@ GCIdleTimeAction GCIdleTimeHandler::Compute(double idle_time_in_ms,
   }
 
   if (heap_state.incremental_marking_stopped) {
-    if (ShouldDoMarkCompact(static_cast<size_t>(idle_time_in_ms),
-                            heap_state.size_of_objects,
-                            heap_state.mark_compact_speed_in_bytes_per_ms)) {
+    if (ShouldDoMarkCompact(
+            static_cast<size_t>(idle_time_in_ms), heap_state.size_of_objects,
+            heap_state.mark_compact_speed_in_bytes_per_ms,
+            heap_state.last_mark_compact_time, heap_state.current_time)) {
       // If there are no more than two GCs left in this idle round and we are
       // allowed to do a full GC, then make those GCs full in order to compact
       // the code space.