license.bot | f003cfe | 2008-08-24 09:55:55 +0900 | [diff] [blame^] | 1 | // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style license that can be |
| 3 | // found in the LICENSE file. |
initial.commit | 3f4a732 | 2008-07-27 06:49:38 +0900 | [diff] [blame] | 4 | |
| 5 | |
| 6 | #ifndef BASE_STATS_COUNTERS_H__ |
| 7 | #define BASE_STATS_COUNTERS_H__ |
| 8 | |
| 9 | #include <string> |
| 10 | #include "base/stats_table.h" |
| 11 | #include "base/time.h" |
| 12 | |
| 13 | // StatsCounters are dynamically created values which can be tracked in |
| 14 | // the StatsTable. They are designed to be lightweight to create and |
| 15 | // easy to use. |
| 16 | // |
| 17 | // Since StatsCounters can be created dynamically by name, there is |
| 18 | // a hash table lookup to find the counter in the table. A StatsCounter |
| 19 | // object can be created once and used across multiple threads safely. |
| 20 | // |
| 21 | // Example usage: |
| 22 | // { |
| 23 | // StatsCounter request_count("RequestCount"); |
| 24 | // request_count.Increment(); |
| 25 | // } |
| 26 | // |
| 27 | // Note that creating counters on the stack does work, however creating |
| 28 | // the counter object requires a hash table lookup. For inner loops, it |
| 29 | // may be better to create the counter either as a member of another object |
| 30 | // (or otherwise outside of the loop) for maximum performance. |
| 31 | // |
| 32 | // Internally, a counter represents a value in a row of a StatsTable. |
| 33 | // The row has a 32bit value for each process/thread in the table and also |
| 34 | // a name (stored in the table metadata). |
| 35 | // |
| 36 | // NOTE: In order to make stats_counters usable in lots of different code, |
| 37 | // avoid any dependencies inside this header file. |
| 38 | // |
| 39 | |
| 40 | //------------------------------------------------------------------------------ |
| 41 | // Define macros for ease of use. They also allow us to change definitions |
| 42 | // as the implementation varies, or depending on compile options. |
| 43 | //------------------------------------------------------------------------------ |
| 44 | // First provide generic macros, which exist in production as well as debug. |
| 45 | #define STATS_COUNTER(name, delta) do { \ |
| 46 | static StatsCounter counter(name); \ |
| 47 | counter.Add(delta); \ |
| 48 | } while (0) |
| 49 | |
| 50 | #define SIMPLE_STATS_COUNTER(name) STATS_COUNTER(name, 1) |
| 51 | |
| 52 | #define RATE_COUNTER(name, duration) do { \ |
| 53 | static StatsRate hit_count(name); \ |
| 54 | hit_count.AddTime(duration); \ |
| 55 | } while (0) |
| 56 | |
| 57 | // Define Debug vs non-debug flavors of macros. |
| 58 | #ifndef NDEBUG |
| 59 | |
| 60 | #define DSTATS_COUNTER(name, delta) STATS_COUNTER(name, delta) |
| 61 | #define DSIMPLE_STATS_COUNTER(name) SIMPLE_STATS_COUNTER(name) |
| 62 | #define DRATE_COUNTER(name, duration) RATE_COUNTER(name, duration) |
| 63 | |
| 64 | #else // NDEBUG |
| 65 | |
| 66 | #define DSTATS_COUNTER(name, delta) do {} while (0) |
| 67 | #define DSIMPLE_STATS_COUNTER(name) do {} while (0) |
| 68 | #define DRATE_COUNTER(name, duration) do {} while (0) |
| 69 | |
| 70 | #endif // NDEBUG |
| 71 | |
| 72 | //------------------------------------------------------------------------------ |
| 73 | // StatsCounter represents a counter in the StatsTable class. |
| 74 | class StatsCounter { |
| 75 | public: |
| 76 | // Create a StatsCounter object. |
| 77 | explicit StatsCounter(const std::wstring& name) |
| 78 | : counter_id_(-1) { |
| 79 | // We prepend the name with 'c:' to indicate that it is a counter. |
| 80 | name_ = L"c:"; |
| 81 | name_.append(name); |
| 82 | }; |
| 83 | |
| 84 | virtual ~StatsCounter() {} |
| 85 | |
| 86 | // Sets the counter to a specific value. |
| 87 | void Set(int value) { |
| 88 | int* loc = GetPtr(); |
| 89 | if (loc) *loc = value; |
| 90 | } |
| 91 | |
| 92 | // Increments the counter. |
| 93 | void Increment() { |
| 94 | Add(1); |
| 95 | } |
| 96 | |
| 97 | // TODO(jar) temporary hack include method till base and chrome use new name. |
| 98 | void Increment(int value) { |
| 99 | Add(value); |
| 100 | } |
| 101 | |
| 102 | virtual void Add(int value) { |
| 103 | int* loc = GetPtr(); |
| 104 | if (loc) |
| 105 | (*loc) += value; |
| 106 | } |
| 107 | |
| 108 | // Decrements the counter. |
| 109 | void Decrement() { |
| 110 | Add(-1); |
| 111 | } |
| 112 | |
| 113 | void Subtract(int value) { |
| 114 | Add(-value); |
| 115 | } |
| 116 | |
| 117 | // TODO(jar) temporary hack includes method till base and chrome use new name. |
| 118 | void Decrement(int value) { |
| 119 | Add(-value); |
| 120 | } |
| 121 | |
| 122 | // Is this counter enabled? |
| 123 | // Returns false if table is full. |
| 124 | bool Enabled() { |
| 125 | return GetPtr() != NULL; |
| 126 | } |
| 127 | |
| 128 | int value() { |
| 129 | int* loc = GetPtr(); |
| 130 | if (loc) return *loc; |
| 131 | return 0; |
| 132 | } |
| 133 | |
| 134 | protected: |
| 135 | StatsCounter() |
| 136 | : counter_id_(-1) { |
| 137 | } |
| 138 | |
| 139 | // Returns the cached address of this counter location. |
| 140 | int* GetPtr() { |
| 141 | StatsTable* table = StatsTable::current(); |
| 142 | if (!table) |
| 143 | return NULL; |
| 144 | |
| 145 | // If counter_id_ is -1, then we haven't looked it up yet. |
| 146 | if (counter_id_ == -1) { |
| 147 | counter_id_ = table->FindCounter(name_); |
| 148 | if (table->GetSlot() == 0) { |
| 149 | if (!table->RegisterThread(L"")) { |
| 150 | // There is no room for this thread. This thread |
| 151 | // cannot use counters. |
| 152 | counter_id_ = 0; |
| 153 | return NULL; |
| 154 | } |
| 155 | } |
| 156 | } |
| 157 | |
| 158 | // If counter_id_ is > 0, then we have a valid counter. |
| 159 | if (counter_id_ > 0) |
| 160 | return table->GetLocation(counter_id_, table->GetSlot()); |
| 161 | |
| 162 | // counter_id_ was zero, which means the table is full. |
| 163 | return NULL; |
| 164 | } |
| 165 | |
| 166 | std::wstring name_; |
| 167 | // The counter id in the table. We initialize to -1 (an invalid value) |
| 168 | // and then cache it once it has been looked up. The counter_id is |
| 169 | // valid across all threads and processes. |
| 170 | int32 counter_id_; |
| 171 | }; |
| 172 | |
| 173 | |
| 174 | // A StatsCounterTimer is a StatsCounter which keeps a timer during |
| 175 | // the scope of the StatsCounterTimer. On destruction, it will record |
| 176 | // its time measurement. |
| 177 | class StatsCounterTimer : protected StatsCounter { |
| 178 | public: |
| 179 | // Constructs and starts the timer. |
| 180 | explicit StatsCounterTimer(const std::wstring& name) { |
| 181 | // we prepend the name with 't:' to indicate that it is a timer. |
| 182 | name_ = L"t:"; |
| 183 | name_.append(name); |
| 184 | } |
| 185 | |
| 186 | // Start the timer. |
| 187 | void Start() { |
| 188 | if (!Enabled()) |
| 189 | return; |
| 190 | start_time_ = TimeTicks::Now(); |
| 191 | stop_time_ = TimeTicks(); |
| 192 | } |
| 193 | |
| 194 | // Stop the timer and record the results. |
| 195 | void Stop() { |
| 196 | if (!Enabled() || !Running()) |
| 197 | return; |
| 198 | stop_time_ = TimeTicks::Now(); |
| 199 | Record(); |
| 200 | } |
| 201 | |
| 202 | // Returns true if the timer is running. |
| 203 | bool Running() { |
| 204 | return Enabled() && !start_time_.is_null() && stop_time_.is_null(); |
| 205 | } |
| 206 | |
| 207 | // Accept a TimeDelta to increment. |
| 208 | virtual void AddTime(TimeDelta time) { |
| 209 | Add(static_cast<int>(time.InMilliseconds())); |
| 210 | } |
| 211 | |
| 212 | // TODO(jar) temporary hack include method till base and chrome use new name. |
| 213 | void IncrementTimer(TimeDelta time) { |
| 214 | AddTime(time); |
| 215 | } |
| 216 | |
| 217 | protected: |
| 218 | // Compute the delta between start and stop, in milliseconds. |
| 219 | void Record() { |
| 220 | AddTime(stop_time_ - start_time_); |
| 221 | } |
| 222 | |
| 223 | TimeTicks start_time_; |
| 224 | TimeTicks stop_time_; |
| 225 | }; |
| 226 | |
| 227 | // A StatsRate is a timer that keeps a count of the number of intervals added so |
| 228 | // that several statistics can be produced: |
| 229 | // min, max, avg, count, total |
| 230 | class StatsRate : public StatsCounterTimer { |
| 231 | public: |
| 232 | // Constructs and starts the timer. |
| 233 | explicit StatsRate(const wchar_t* name) |
| 234 | : StatsCounterTimer(name), |
| 235 | counter_(name), |
| 236 | largest_add_(std::wstring(L" ").append(name).append(L"MAX").c_str()) { |
| 237 | } |
| 238 | |
| 239 | virtual void Add(int value) { |
| 240 | counter_.Increment(); |
| 241 | StatsCounterTimer::Add(value); |
| 242 | if (value > largest_add_.value()) |
| 243 | largest_add_.Set(value); |
| 244 | } |
| 245 | |
| 246 | private: |
| 247 | StatsCounter counter_; |
| 248 | StatsCounter largest_add_; |
| 249 | }; |
| 250 | |
| 251 | |
| 252 | // Helper class for scoping a timer or rate. |
| 253 | template<class T> class StatsScope { |
| 254 | public: |
| 255 | explicit StatsScope<T>(T& timer) |
| 256 | : timer_(timer) { |
| 257 | timer_.Start(); |
| 258 | } |
| 259 | |
| 260 | ~StatsScope() { |
| 261 | timer_.Stop(); |
| 262 | } |
| 263 | |
| 264 | void Stop() { |
| 265 | timer_.Stop(); |
| 266 | } |
| 267 | |
| 268 | private: |
| 269 | T& timer_; |
| 270 | }; |
| 271 | |
| 272 | #endif // BASE_STATS_COUNTERS_H__ |
license.bot | f003cfe | 2008-08-24 09:55:55 +0900 | [diff] [blame^] | 273 | |