1 // Copyright 2007-2008 the V8 project authors. All rights reserved.
2 // Redistribution and use in source and binary forms, with or without
3 // modification, are permitted provided that the following conditions are
6 // * Redistributions of source code must retain the above copyright
7 // notice, this list of conditions and the following disclaimer.
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9 // copyright notice, this list of conditions and the following
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11 // with the distribution.
12 // * Neither the name of Google Inc. nor the names of its
13 // contributors may be used to endorse or promote products derived
14 // from this software without specific prior written permission.
16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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28 #ifndef V8_COUNTERS_H_
29 #define V8_COUNTERS_H_
31 #include "../include/v8.h"
32 #include "allocation.h"
37 // StatsCounters is an interface for plugging into external
38 // counters for monitoring. Counters can be looked up and
39 // manipulated by name.
43 // Register an application-defined function where
44 // counters can be looked up.
45 void SetCounterFunction(CounterLookupCallback f) {
49 // Register an application-defined function to create
50 // a histogram for passing to the AddHistogramSample function
51 void SetCreateHistogramFunction(CreateHistogramCallback f) {
52 create_histogram_function_ = f;
55 // Register an application-defined function to add a sample
56 // to a histogram created with CreateHistogram function
57 void SetAddHistogramSampleFunction(AddHistogramSampleCallback f) {
58 add_histogram_sample_function_ = f;
61 bool HasCounterFunction() const {
62 return lookup_function_ != NULL;
65 // Lookup the location of a counter by name. If the lookup
66 // is successful, returns a non-NULL pointer for writing the
67 // value of the counter. Each thread calling this function
68 // may receive a different location to store it's counter.
69 // The return value must not be cached and re-used across
70 // threads, although a single thread is free to cache it.
71 int* FindLocation(const char* name) {
72 if (!lookup_function_) return NULL;
73 return lookup_function_(name);
76 // Create a histogram by name. If the create is successful,
77 // returns a non-NULL pointer for use with AddHistogramSample
78 // function. min and max define the expected minimum and maximum
79 // sample values. buckets is the maximum number of buckets
80 // that the samples will be grouped into.
81 void* CreateHistogram(const char* name,
85 if (!create_histogram_function_) return NULL;
86 return create_histogram_function_(name, min, max, buckets);
89 // Add a sample to a histogram created with the CreateHistogram
91 void AddHistogramSample(void* histogram, int sample) {
92 if (!add_histogram_sample_function_) return;
93 return add_histogram_sample_function_(histogram, sample);
99 CounterLookupCallback lookup_function_;
100 CreateHistogramCallback create_histogram_function_;
101 AddHistogramSampleCallback add_histogram_sample_function_;
103 friend class Isolate;
105 DISALLOW_COPY_AND_ASSIGN(StatsTable);
108 // StatsCounters are dynamically created values which can be tracked in
109 // the StatsTable. They are designed to be lightweight to create and
112 // Internally, a counter represents a value in a row of a StatsTable.
113 // The row has a 32bit value for each process/thread in the table and also
114 // a name (stored in the table metadata). Since the storage location can be
115 // thread-specific, this class cannot be shared across threads.
117 // This class is designed to be POD initialized. It will be registered with
118 // the counter system on first use. For example:
119 // StatsCounter c = { "c:myctr", NULL, false };
120 struct StatsCounter {
125 // Sets the counter to a specific value.
126 void Set(int value) {
128 if (loc) *loc = value;
131 // Increments the counter.
137 void Increment(int value) {
143 // Decrements the counter.
149 void Decrement(int value) {
151 if (loc) (*loc) -= value;
154 // Is this counter enabled?
155 // Returns false if table is full.
157 return GetPtr() != NULL;
160 // Get the internal pointer to the counter. This is used
161 // by the code generator to emit code that manipulates a
162 // given counter without calling the runtime system.
163 int* GetInternalPointer() {
170 // Returns the cached address of this counter location.
175 ptr_ = FindLocationInStatsTable();
180 int* FindLocationInStatsTable() const;
183 // StatsCounterTimer t = { { L"t:foo", NULL, false }, 0, 0 };
184 struct StatsCounterTimer {
185 StatsCounter counter_;
193 // Stop the timer and record the results.
196 // Returns true if the timer is running.
198 return counter_.Enabled() && start_time_ != 0 && stop_time_ == 0;
202 // A HistogramTimer allows distributions of results to be created
203 // HistogramTimer t = { L"foo", NULL, false, 0, 0 };
204 struct HistogramTimer {
215 // Stop the timer and record the results.
218 // Returns true if the timer is running.
220 return (histogram_ != NULL) && (start_time_ != 0) && (stop_time_ == 0);
224 // Returns the handle to the histogram.
225 void* GetHistogram() {
228 histogram_ = CreateHistogram();
234 void* CreateHistogram() const;
237 // Helper class for scoping a HistogramTimer.
238 class HistogramTimerScope BASE_EMBEDDED {
240 explicit HistogramTimerScope(HistogramTimer* timer) :
244 ~HistogramTimerScope() {
248 HistogramTimer* timer_;
252 } } // namespace v8::internal
254 #endif // V8_COUNTERS_H_