1 // Copyright 2012 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 4 // met: 5 // 6 // * Redistributions of source code must retain the above copyright 7 // notice, this list of conditions and the following disclaimer. 8 // * Redistributions in binary form must reproduce the above 9 // copyright notice, this list of conditions and the following 10 // disclaimer in the documentation and/or other materials provided 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. 15 // 16 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 28 #ifndef V8_COUNTERS_H_ 29 #define V8_COUNTERS_H_ 30 31 #include "../include/v8.h" 32 #include "allocation.h" 33 34 namespace v8 { 35 namespace internal { 36 37 // StatsCounters is an interface for plugging into external 38 // counters for monitoring. Counters can be looked up and 39 // manipulated by name. 40 41 class StatsTable { 42 public: 43 // Register an application-defined function where 44 // counters can be looked up. 45 void SetCounterFunction(CounterLookupCallback f) { 46 lookup_function_ = f; 47 } 48 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; 53 } 54 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; 59 } 60 61 bool HasCounterFunction() const { 62 return lookup_function_ != NULL; 63 } 64 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); 74 } 75 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, 82 int min, 83 int max, 84 size_t buckets) { 85 if (!create_histogram_function_) return NULL; 86 return create_histogram_function_(name, min, max, buckets); 87 } 88 89 // Add a sample to a histogram created with the CreateHistogram 90 // function. 91 void AddHistogramSample(void* histogram, int sample) { 92 if (!add_histogram_sample_function_) return; 93 return add_histogram_sample_function_(histogram, sample); 94 } 95 96 private: 97 StatsTable(); 98 99 CounterLookupCallback lookup_function_; 100 CreateHistogramCallback create_histogram_function_; 101 AddHistogramSampleCallback add_histogram_sample_function_; 102 103 friend class Isolate; 104 105 DISALLOW_COPY_AND_ASSIGN(StatsTable); 106 }; 107 108 // StatsCounters are dynamically created values which can be tracked in 109 // the StatsTable. They are designed to be lightweight to create and 110 // easy to use. 111 // 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. 116 class StatsCounter { 117 public: 118 StatsCounter() { } 119 explicit StatsCounter(const char* name) 120 : name_(name), ptr_(NULL), lookup_done_(false) { } 121 122 // Sets the counter to a specific value. 123 void Set(int value) { 124 int* loc = GetPtr(); 125 if (loc) *loc = value; 126 } 127 128 // Increments the counter. 129 void Increment() { 130 int* loc = GetPtr(); 131 if (loc) (*loc)++; 132 } 133 134 void Increment(int value) { 135 int* loc = GetPtr(); 136 if (loc) 137 (*loc) += value; 138 } 139 140 // Decrements the counter. 141 void Decrement() { 142 int* loc = GetPtr(); 143 if (loc) (*loc)--; 144 } 145 146 void Decrement(int value) { 147 int* loc = GetPtr(); 148 if (loc) (*loc) -= value; 149 } 150 151 // Is this counter enabled? 152 // Returns false if table is full. 153 bool Enabled() { 154 return GetPtr() != NULL; 155 } 156 157 // Get the internal pointer to the counter. This is used 158 // by the code generator to emit code that manipulates a 159 // given counter without calling the runtime system. 160 int* GetInternalPointer() { 161 int* loc = GetPtr(); 162 ASSERT(loc != NULL); 163 return loc; 164 } 165 166 protected: 167 // Returns the cached address of this counter location. 168 int* GetPtr() { 169 if (lookup_done_) return ptr_; 170 lookup_done_ = true; 171 ptr_ = FindLocationInStatsTable(); 172 return ptr_; 173 } 174 175 private: 176 int* FindLocationInStatsTable() const; 177 178 const char* name_; 179 int* ptr_; 180 bool lookup_done_; 181 }; 182 183 // A Histogram represents a dynamically created histogram in the StatsTable. 184 // It will be registered with the histogram system on first use. 185 class Histogram { 186 public: 187 Histogram() { } 188 Histogram(const char* name, 189 int min, 190 int max, 191 int num_buckets, 192 Isolate* isolate) 193 : name_(name), 194 min_(min), 195 max_(max), 196 num_buckets_(num_buckets), 197 histogram_(NULL), 198 lookup_done_(false), 199 isolate_(isolate) { } 200 201 // Add a single sample to this histogram. 202 void AddSample(int sample); 203 204 // Returns true if this histogram is enabled. 205 bool Enabled() { 206 return GetHistogram() != NULL; 207 } 208 209 // Reset the cached internal pointer. 210 void Reset() { 211 lookup_done_ = false; 212 } 213 214 protected: 215 // Returns the handle to the histogram. 216 void* GetHistogram() { 217 if (!lookup_done_) { 218 lookup_done_ = true; 219 histogram_ = CreateHistogram(); 220 } 221 return histogram_; 222 } 223 224 const char* name() { return name_; } 225 Isolate* isolate() const { return isolate_; } 226 227 private: 228 void* CreateHistogram() const; 229 230 const char* name_; 231 int min_; 232 int max_; 233 int num_buckets_; 234 void* histogram_; 235 bool lookup_done_; 236 Isolate* isolate_; 237 }; 238 239 // A HistogramTimer allows distributions of results to be created. 240 class HistogramTimer : public Histogram { 241 public: 242 HistogramTimer() { } 243 HistogramTimer(const char* name, 244 int min, 245 int max, 246 int num_buckets, 247 Isolate* isolate) 248 : Histogram(name, min, max, num_buckets, isolate), 249 start_time_(0), 250 stop_time_(0) { } 251 252 // Start the timer. 253 void Start(); 254 255 // Stop the timer and record the results. 256 void Stop(); 257 258 // Returns true if the timer is running. 259 bool Running() { 260 return Enabled() && (start_time_ != 0) && (stop_time_ == 0); 261 } 262 263 private: 264 int64_t start_time_; 265 int64_t stop_time_; 266 }; 267 268 // Helper class for scoping a HistogramTimer. 269 class HistogramTimerScope BASE_EMBEDDED { 270 public: 271 explicit HistogramTimerScope(HistogramTimer* timer) : 272 timer_(timer) { 273 timer_->Start(); 274 } 275 ~HistogramTimerScope() { 276 timer_->Stop(); 277 } 278 private: 279 HistogramTimer* timer_; 280 }; 281 282 283 } } // namespace v8::internal 284 285 #endif // V8_COUNTERS_H_ 286