Add the rate of js invocations from the api as a signal of idleness

test/cctest/test-heap.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 17 matching lines @@
 #include <stdlib.h>
 #include <utility>
 
 #include "src/compilation-cache.h"
 #include "src/context-measure.h"
 #include "src/deoptimizer.h"
 #include "src/execution.h"
 #include "src/factory.h"
 #include "src/global-handles.h"
 #include "src/heap/gc-tracer.h"
+#include "src/heap/memory-reducer.h"
 #include "src/ic/ic.h"
 #include "src/macro-assembler.h"
 #include "src/snapshot/snapshot.h"
 #include "test/cctest/cctest.h"
 #include "test/cctest/heap-tester.h"
 #include "test/cctest/test-feedback-vector.h"
 
 using v8::Just;
 
 namespace v8 {
@@ skipping 6219 matching lines @@
     isolate->SetReferenceFromGroup(id, child);
   }
   // The CollectGarbage call above starts sweeper threads.
   // The crash will happen if the following two functions
   // are called before sweeping finishes.
   heap->StartIncrementalMarking();
   heap->FinalizeIncrementalMarkingIfComplete("test");
 }
 
 
+// Checks equality for doubles.
+void CheckEquals(double expected, double actual) {

[Hannes Payer (out of office), 2015/10/28 14:58:08]

Let's move this one to cctest.h since it is a utility function.

[ulan, 2015/10/29 12:39:25]

Done.

+  const double kEpsilon = 1e-10;
+  CHECK_LE(expected, actual + kEpsilon);
+  CHECK_GE(expected, actual - kEpsilon);
+}
+
+
+HEAP_TEST(TestMemoryReducerSampleJsCalls) {
+  CcTest::InitializeVM();
+  v8::HandleScope scope(CcTest::isolate());
+  Heap* heap = CcTest::heap();
+  Isolate* isolate = CcTest::i_isolate();
+  MemoryReducer* memory_reducer = heap->memory_reducer_;
+  memory_reducer->SampleAndGetJsCallsPerMs(0);
+  isolate->IncrementJsCallsFromApiCounter();
+  isolate->IncrementJsCallsFromApiCounter();
+  isolate->IncrementJsCallsFromApiCounter();
+  double calls_per_ms = memory_reducer->SampleAndGetJsCallsPerMs(1);
+  CheckEquals(3, calls_per_ms);
+
+  calls_per_ms = memory_reducer->SampleAndGetJsCallsPerMs(2);
+  CheckEquals(0, calls_per_ms);
+
+  isolate->IncrementJsCallsFromApiCounter();
+  isolate->IncrementJsCallsFromApiCounter();
+  isolate->IncrementJsCallsFromApiCounter();
+  isolate->IncrementJsCallsFromApiCounter();
+  calls_per_ms = memory_reducer->SampleAndGetJsCallsPerMs(4);
+  CheckEquals(2, calls_per_ms);
+}
+
+
 }  // namespace internal
 }  // namespace v8