Use deadline in IdleNotification.

src/heap/heap.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/bits.h"
 #include "src/base/once.h"
@@ skipping 4374 matching lines @@
 }
 
 
 bool Heap::WorthActivatingIncrementalMarking() {
   return incremental_marking()->IsStopped() &&
          incremental_marking()->WorthActivating() && NextGCIsLikelyToBeFull();
 }
 
 
 bool Heap::IdleNotification(int idle_time_in_ms) {
-  base::ElapsedTimer timer;
-  timer.Start();
-  isolate()->counters()->gc_idle_time_allotted_in_ms()->AddSample(
-      idle_time_in_ms);
+  return IdleNotification(
+      V8::GetCurrentPlatform()->MonotonicallyIncreasingTime() +
+      static_cast<double>(idle_time_in_ms));
+}
+
+
+bool Heap::IdleNotification(double deadline) {
   HistogramTimerScope idle_notification_scope(
       isolate_->counters()->gc_idle_notification());
 
   GCIdleTimeHandler::HeapState heap_state;
   heap_state.contexts_disposed = contexts_disposed_;
   heap_state.contexts_disposal_rate =
       tracer()->ContextDisposalRateInMilliseconds();
   heap_state.size_of_objects = static_cast<size_t>(SizeOfObjects());
   heap_state.incremental_marking_stopped = incremental_marking()->IsStopped();
   // TODO(ulan): Start incremental marking only for large heaps.
   heap_state.can_start_incremental_marking =
       incremental_marking()->ShouldActivate() && FLAG_incremental_marking;
   heap_state.sweeping_in_progress =
       mark_compact_collector()->sweeping_in_progress();
   heap_state.mark_compact_speed_in_bytes_per_ms =
       static_cast<size_t>(tracer()->MarkCompactSpeedInBytesPerMillisecond());
   heap_state.incremental_marking_speed_in_bytes_per_ms = static_cast<size_t>(
       tracer()->IncrementalMarkingSpeedInBytesPerMillisecond());
   heap_state.scavenge_speed_in_bytes_per_ms =
       static_cast<size_t>(tracer()->ScavengeSpeedInBytesPerMillisecond());
   heap_state.used_new_space_size = new_space_.Size();
   heap_state.new_space_capacity = new_space_.Capacity();
   heap_state.new_space_allocation_throughput_in_bytes_per_ms =
       static_cast<size_t>(
           tracer()->NewSpaceAllocationThroughputInBytesPerMillisecond());
 
+  double idle_time =
+      deadline - V8::GetCurrentPlatform()->MonotonicallyIncreasingTime();

[rmcilroy, 2014/11/25 10:35:41]

Both deadline and MonotonicallyIncreasingTime() return time in seconds, not ms. 
Probably better to rename the arguments to deadline_seconds to avoid this
confusion in the future.  Actually, it might be even better to translate to
base::TimeTicks / base::TimeDelta initially to avoid issues (I would have
returned base::TimeTicks for MonotonicallyIncreasingTime() if it was available
in Blink, but unfortunately it's not).

[Hannes Payer (out of office), 2014/11/25 12:28:59]

I am using now seconds granularity on the api level and internally I convert it
to milliseconds.

   GCIdleTimeAction action =
-      gc_idle_time_handler_.Compute(idle_time_in_ms, heap_state);
+      gc_idle_time_handler_.Compute(idle_time, heap_state);
+  isolate()->counters()->gc_idle_time_allotted_in_ms()->AddSample(
+      static_cast<int>(idle_time));
 
   bool result = false;
-  int actual_time_in_ms = 0;
   switch (action.type) {
     case DONE:
       result = true;
       break;
     case DO_INCREMENTAL_MARKING: {
       if (incremental_marking()->IsStopped()) {
         incremental_marking()->Start();
       }
       incremental_marking()->Step(action.parameter,
                                   IncrementalMarking::NO_GC_VIA_STACK_GUARD,
                                   IncrementalMarking::FORCE_MARKING,
                                   IncrementalMarking::DO_NOT_FORCE_COMPLETION);
-      actual_time_in_ms = static_cast<int>(timer.Elapsed().InMilliseconds());
-      int remaining_idle_time_in_ms = idle_time_in_ms - actual_time_in_ms;
-      if (remaining_idle_time_in_ms > 0) {
+      double remaining_idle_time_in_ms =
+          deadline - V8::GetCurrentPlatform()->MonotonicallyIncreasingTime();
+      if (remaining_idle_time_in_ms > 0.0) {
         TryFinalizeIdleIncrementalMarking(
-            remaining_idle_time_in_ms, heap_state.size_of_objects,
+            static_cast<size_t>(remaining_idle_time_in_ms),
+            heap_state.size_of_objects,
             heap_state.mark_compact_speed_in_bytes_per_ms);
       }
       break;
     }
     case DO_FULL_GC: {
       HistogramTimerScope scope(isolate_->counters()->gc_context());
       if (contexts_disposed_) {
         CollectAllGarbage(kNoGCFlags, "idle notification: contexts disposed");
         gc_idle_time_handler_.NotifyIdleMarkCompact();
         gc_count_at_last_idle_gc_ = gc_count_;
       } else {
         IdleMarkCompact("idle notification: finalize idle round");
       }
       break;
     }
     case DO_SCAVENGE:
       CollectGarbage(NEW_SPACE, "idle notification: scavenge");
       break;
     case DO_FINALIZE_SWEEPING:
       mark_compact_collector()->EnsureSweepingCompleted();
       break;
     case DO_NOTHING:
       break;
   }
 
-  actual_time_in_ms = static_cast<int>(timer.Elapsed().InMilliseconds());
-  if (actual_time_in_ms <= idle_time_in_ms) {
+
+  double deadline_difference =
+      deadline - V8::GetCurrentPlatform()->MonotonicallyIncreasingTime();
+  if (deadline_difference >= 0) {
     if (action.type != DONE && action.type != DO_NOTHING) {
       isolate()->counters()->gc_idle_time_limit_undershot()->AddSample(
-          idle_time_in_ms - actual_time_in_ms);
+          static_cast<int>(deadline_difference));
     }
   } else {
     isolate()->counters()->gc_idle_time_limit_overshot()->AddSample(
-        actual_time_in_ms - idle_time_in_ms);
+        static_cast<int>(-deadline_difference));
   }
 
   if (FLAG_trace_idle_notification) {
-    PrintF("Idle notification: requested idle time %d ms, actual time %d ms [",
-           idle_time_in_ms, actual_time_in_ms);
+    PrintF(
+        "Idle notification: requested idle time %.2f ms, deadline difference "
+        "%.2f ms [",
+        idle_time, deadline_difference);
     action.Print();
     PrintF("]");
     if (FLAG_trace_idle_notification_verbose) {
       PrintF("[");
       heap_state.Print();
       PrintF("]");
     }
     PrintF("\n");
   }
 
@@ skipping 1815 matching lines @@
       static_cast<int>(object_sizes_last_time_[index]));
   CODE_AGE_LIST_COMPLETE(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   MemCopy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   MemCopy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
 }
 }  // namespace v8::internal