Implement AggregatableHistogramTimer and use it to measure how much time

src/counters.h

 // 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.
 
 #ifndef V8_COUNTERS_H_
 #define V8_COUNTERS_H_
 
 #include "include/v8.h"
 #include "src/allocation.h"
 #include "src/base/platform/elapsed-timer.h"
+#include "src/base/platform/time.h"
 #include "src/globals.h"
 #include "src/objects.h"
 
 namespace v8 {
 namespace internal {
 
 // StatsCounters is an interface for plugging into external
 // counters for monitoring.  Counters can be looked up and
 // manipulated by name.
 
@@ skipping 263 matching lines @@
 #endif
   }
 
  private:
   HistogramTimer* timer_;
 #ifdef DEBUG
   bool skipped_timer_start_;
 #endif
 };
 
+
+// A histogram timer that can aggregate events within a larger scope.
+//
+// Intended use of this timer is to have an outer (aggregating) and an inner
+// (to be aggregated) scope, where the inner scope measure the time of events,
+// and all those inner scope measurements will be summed up by the outer scope.
+// An example use might be to aggregate the time spent in lazy compilation
+// while running a script.
+//
+// Helpers:
+// - AggregatingHistogramTimerScope, the "outer" scope within which
+//     times will be summed up.
+// - AggregatedHistogramTimerScope, the "inner" scope which defines the
+//     events to be timed.
+class AggregatableHistogramTimer : public Histogram {
+ public:
+  AggregatableHistogramTimer() {}
+  AggregatableHistogramTimer(const char* name, int min, int max,
+                             int num_buckets, Isolate* isolate)
+      : Histogram(name, min, max, num_buckets, isolate) {}
+
+  // Start/stop the "outer" scope.
+  void Start() { time_ = base::TimeDelta(); }
+  void Stop() { AddSample(time_.InMilliseconds()); }
+
+  // Add a time value ("inner" scope).
+  void Add(base::TimeDelta other) { time_ += other; }
+
+ private:
+  base::TimeDelta time_;
+};
+
+
+// A helper class for use with AggregatableHistogramTimer.
+class AggregatingHistogramTimerScope {
+ public:
+  explicit AggregatingHistogramTimerScope(AggregatableHistogramTimer* histogram)
+      : histogram_(histogram) {
+    histogram_->Start();
+  }
+  ~AggregatingHistogramTimerScope() { histogram_->Stop(); }
+
+ private:
+  AggregatableHistogramTimer* histogram_;
+};
+
+
+// A helper class for use with AggregatableHistogramTimer.
+class AggregatedHistogramTimerScope {
+ public:
+  expliti AggregatedHistogramTimerScope(AggregatableHistogramTimer* histogram)
+      : histogram_(histogram) {
+    timer_.Start();
+  }
+  ~AggregatedHistogramTimerScope() { histogram_->Add(timer_.Elapsed()); }
+
+ private:
+  base::ElapsedTimer timer_;
+  AggregatableHistogramTimer* histogram_;
+};
+
+
 #define HISTOGRAM_RANGE_LIST(HR)                                              \
   /* Generic range histograms */                                              \
   HR(gc_idle_time_allotted_in_ms, V8.GCIdleTimeAllottedInMS, 0, 10000, 101)   \
   HR(gc_idle_time_limit_overshot, V8.GCIdleTimeLimit.Overshot, 0, 10000, 101) \
   HR(gc_idle_time_limit_undershot, V8.GCIdleTimeLimit.Undershot, 0, 10000, 101)
 
 #define HISTOGRAM_TIMER_LIST(HT)                             \
   /* Garbage collection timers. */                           \
   HT(gc_compactor, V8.GCCompactor)                           \
   HT(gc_scavenger, V8.GCScavenger)                           \
   HT(gc_context, V8.GCContext) /* GC context cleanup time */ \
   HT(gc_idle_notification, V8.GCIdleNotification)            \
   HT(gc_incremental_marking, V8.GCIncrementalMarking)        \
   HT(gc_low_memory_notification, V8.GCLowMemoryNotification) \
   /* Parsing timers. */                                      \
   HT(parse, V8.Parse)                                        \
   HT(parse_lazy, V8.ParseLazy)                               \
   HT(pre_parse, V8.PreParse)                                 \
   /* Compilation times. */                                   \
   HT(compile, V8.Compile)                                    \
   HT(compile_eval, V8.CompileEval)                           \
   /* Serialization as part of compilation (code caching) */  \
   HT(compile_serialize, V8.CompileSerialize)                 \
   HT(compile_deserialize, V8.CompileDeserialize)             \
   /* Total compilation time incl. caching/parsing */         \
   HT(compile_script, V8.CompileScript)
 
 
+#define AGGREGATABLE_HISTOGRAM_TIMER_LIST(AHT) \
+  AHT(compile_lazy, V8.CompileLazy)
+
+
 #define HISTOGRAM_PERCENTAGE_LIST(HP)                                 \
   /* Heap fragmentation. */                                           \
   HP(external_fragmentation_total,                                    \
      V8.MemoryExternalFragmentationTotal)                             \
   HP(external_fragmentation_old_pointer_space,                        \
      V8.MemoryExternalFragmentationOldPointerSpace)                   \
   HP(external_fragmentation_old_data_space,                           \
      V8.MemoryExternalFragmentationOldDataSpace)                      \
   HP(external_fragmentation_code_space,                               \
      V8.MemoryExternalFragmentationCodeSpace)                         \
@@ skipping 230 matching lines @@
 #define HR(name, caption, min, max, num_buckets) \
   Histogram* name() { return &name##_; }
   HISTOGRAM_RANGE_LIST(HR)
 #undef HR
 
 #define HT(name, caption) \
   HistogramTimer* name() { return &name##_; }
   HISTOGRAM_TIMER_LIST(HT)
 #undef HT
 
+#define AHT(name, caption) \
+  AggregatableHistogramTimer* name() { return &name##_; }
+  AGGREGATABLE_HISTOGRAM_TIMER_LIST(AHT)
+#undef AHT
+
 #define HP(name, caption) \
   Histogram* name() { return &name##_; }
   HISTOGRAM_PERCENTAGE_LIST(HP)
 #undef HP
 
 #define HM(name, caption) \
   Histogram* name() { return &name##_; }
   HISTOGRAM_MEMORY_LIST(HM)
 #undef HM
 
@@ skipping 30 matching lines @@
     { return &count_of_CODE_AGE_##name##_; } \
   StatsCounter* size_of_CODE_AGE_##name() \
     { return &size_of_CODE_AGE_##name##_; }
   CODE_AGE_LIST_COMPLETE(SC)
 #undef SC
 
   enum Id {
 #define RATE_ID(name, caption) k_##name,
     HISTOGRAM_TIMER_LIST(RATE_ID)
 #undef RATE_ID
+#define AGGREGATABLE_ID(name, caption) k_##name,
+    AGGREGATABLE_HISTOGRAM_TIMER_LIST(AGGREGATABLE_ID)
+#undef AGGREGATABLE_ID
 #define PERCENTAGE_ID(name, caption) k_##name,
     HISTOGRAM_PERCENTAGE_LIST(PERCENTAGE_ID)
 #undef PERCENTAGE_ID
 #define MEMORY_ID(name, caption) k_##name,
     HISTOGRAM_MEMORY_LIST(MEMORY_ID)
 #undef MEMORY_ID
 #define COUNTER_ID(name, caption) k_##name,
     STATS_COUNTER_LIST_1(COUNTER_ID)
     STATS_COUNTER_LIST_2(COUNTER_ID)
 #undef COUNTER_ID
@@ skipping 21 matching lines @@
  private:
 #define HR(name, caption, min, max, num_buckets) Histogram name##_;
   HISTOGRAM_RANGE_LIST(HR)
 #undef HR
 
 #define HT(name, caption) \
   HistogramTimer name##_;
   HISTOGRAM_TIMER_LIST(HT)
 #undef HT
 
+#define AHT(name, caption) \
+  AggregatableHistogramTimer name##_;
+  AGGREGATABLE_HISTOGRAM_TIMER_LIST(AHT)
+#undef AHT
+
 #define HP(name, caption) \
   Histogram name##_;
   HISTOGRAM_PERCENTAGE_LIST(HP)
 #undef HP
 
 #define HM(name, caption) \
   Histogram name##_;
   HISTOGRAM_MEMORY_LIST(HM)
 #undef HM
 
@@ skipping 30 matching lines @@
   friend class Isolate;
 
   explicit Counters(Isolate* isolate);
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(Counters);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_COUNTERS_H_