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 | // Histogram is an object that aggregates statistics, and can summarize them in |
| 6 | // various forms, including ASCII graphical, HTML, and numerically (as a |
| 7 | // vector of numbers corresponding to each of the aggregating buckets). |
| 8 | // See header file for details and examples. |
| 9 | |
| 10 | #include "base/histogram.h" |
| 11 | |
| 12 | #include <math.h> |
| 13 | #include <string> |
| 14 | |
| 15 | #include "base/logging.h" |
| 16 | #include "base/scoped_ptr.h" |
| 17 | #include "base/string_util.h" |
| 18 | |
| 19 | typedef Histogram::Count Count; |
| 20 | |
darin@google.com | 12d40bb | 2008-08-20 03:36:23 +0900 | [diff] [blame] | 21 | // static |
| 22 | const int Histogram::kHexRangePrintingFlag = 0x8000; |
| 23 | |
initial.commit | 3f4a732 | 2008-07-27 06:49:38 +0900 | [diff] [blame] | 24 | Histogram::Histogram(const wchar_t* name, Sample minimum, |
| 25 | Sample maximum, size_t bucket_count) |
| 26 | : StatsRate(name), |
| 27 | histogram_name_(WideToASCII(name)), |
| 28 | declared_min_(minimum), |
| 29 | declared_max_(maximum), |
| 30 | bucket_count_(bucket_count), |
| 31 | flags_(0), |
| 32 | ranges_(bucket_count + 1, 0), |
| 33 | sample_(), |
| 34 | registered_(false) { |
| 35 | Initialize(); |
| 36 | } |
| 37 | |
| 38 | Histogram::Histogram(const wchar_t* name, TimeDelta minimum, |
| 39 | TimeDelta maximum, size_t bucket_count) |
| 40 | : StatsRate(name), |
| 41 | histogram_name_(WideToASCII(name)), |
| 42 | declared_min_(static_cast<int> (minimum.InMilliseconds())), |
| 43 | declared_max_(static_cast<int> (maximum.InMilliseconds())), |
| 44 | bucket_count_(bucket_count), |
| 45 | flags_(0), |
| 46 | ranges_(bucket_count + 1, 0), |
| 47 | sample_(), |
| 48 | registered_(false) { |
| 49 | Initialize(); |
| 50 | } |
| 51 | |
| 52 | Histogram::~Histogram() { |
| 53 | if (registered_) |
| 54 | StatisticsRecorder::UnRegister(*this); |
| 55 | // Just to make sure most derived class did this properly... |
| 56 | DCHECK(ValidateBucketRanges()); |
| 57 | } |
| 58 | |
| 59 | |
| 60 | // Hooks to override stats counter methods. This ensures that we gather all |
| 61 | // input the stats counter sees. |
| 62 | void Histogram::Add(int value) { |
| 63 | if (!registered_) |
| 64 | registered_ = StatisticsRecorder::Register(*this); |
| 65 | if (value >= kSampleType_MAX) |
| 66 | value = kSampleType_MAX - 1; |
| 67 | StatsRate::Add(value); |
| 68 | if (value < 0) |
| 69 | value = 0; |
| 70 | size_t index = BucketIndex(value); |
| 71 | DCHECK(value >= ranges(index)); |
| 72 | DCHECK(value < ranges(index + 1)); |
| 73 | Accumulate(value, 1, index); |
| 74 | } |
| 75 | |
| 76 | // The following methods provide a graphical histogram display. |
| 77 | void Histogram::WriteHTMLGraph(std::string* output) const { |
| 78 | // TBD(jar) Write a nice HTML bar chart, with divs an mouse-overs etc. |
| 79 | output->append("<PRE>"); |
| 80 | WriteAscii(true, "<br>", output); |
| 81 | output->append("</PRE>"); |
| 82 | } |
| 83 | |
| 84 | void Histogram::WriteAscii(bool graph_it, const std::string& newline, |
| 85 | std::string* output) const { |
| 86 | // Get local (stack) copies of all effectively volatile class data so that we |
| 87 | // are consistent across our output activities. |
| 88 | SampleSet snapshot; |
| 89 | SnapshotSample(&snapshot); |
| 90 | Count sample_count = snapshot.TotalCount(); |
| 91 | |
| 92 | WriteAsciiHeader(snapshot, sample_count, output); |
| 93 | output->append(newline); |
| 94 | |
| 95 | // Prepare to normalize graphical rendering of bucket contents. |
| 96 | double max_size = 0; |
| 97 | if (graph_it) |
| 98 | max_size = GetPeakBucketSize(snapshot); |
| 99 | |
| 100 | // Calculate space needed to print bucket range numbers. Leave room to print |
| 101 | // nearly the largest bucket range without sliding over the histogram. |
| 102 | size_t largest_non_empty_bucket = bucket_count_ - 1; |
| 103 | while (0 == sample_.counts(largest_non_empty_bucket)) { |
| 104 | if (0 == largest_non_empty_bucket) |
| 105 | break; // All buckets are empty. |
| 106 | largest_non_empty_bucket--; |
| 107 | } |
| 108 | |
| 109 | // Calculate largest print width needed for any of our bucket range displays. |
| 110 | size_t print_width = 1; |
| 111 | for (size_t i = 0; i < bucket_count_; ++i) { |
| 112 | if (snapshot.counts(i)) { |
| 113 | size_t width = GetAsciiBucketRange(i).size() + 1; |
| 114 | if (width > print_width) |
| 115 | print_width = width; |
| 116 | } |
| 117 | } |
| 118 | |
| 119 | int64 remaining = sample_count; |
| 120 | int64 past = 0; |
| 121 | // Output the actual histogram graph. |
| 122 | for (size_t i = 0; i < bucket_count_; i++) { |
| 123 | Count current = snapshot.counts(i); |
| 124 | if (!current && !PrintEmptyBucket(i)) |
| 125 | continue; |
| 126 | remaining -= current; |
| 127 | StringAppendF(output, "%#*s ", print_width, GetAsciiBucketRange(i).c_str()); |
| 128 | if (0 == current && i < bucket_count_ - 1 && 0 == snapshot.counts(i + 1)) { |
| 129 | while (i < bucket_count_ - 1 && 0 == snapshot.counts(i + 1)) |
| 130 | i++; |
| 131 | output->append("... "); |
| 132 | output->append(newline); |
| 133 | continue; // No reason to plot emptiness. |
| 134 | } |
| 135 | double current_size = GetBucketSize(current, i); |
| 136 | if (graph_it) |
| 137 | WriteAsciiBucketGraph(current_size, max_size, output); |
| 138 | WriteAsciiBucketContext(past, current, remaining, i, output); |
| 139 | output->append(newline); |
| 140 | past += current; |
| 141 | } |
| 142 | DCHECK(past == sample_count); |
| 143 | } |
| 144 | |
| 145 | bool Histogram::ValidateBucketRanges() const { |
| 146 | // Standard assertions that all bucket ranges should satisfy. |
| 147 | DCHECK(ranges_.size() == bucket_count_ + 1); |
| 148 | DCHECK(0 == ranges_[0]); |
| 149 | DCHECK(declared_min() == ranges_[1]); |
| 150 | DCHECK(declared_max() == ranges_[bucket_count_ - 1]); |
| 151 | DCHECK(kSampleType_MAX == ranges_[bucket_count_]); |
| 152 | return true; |
| 153 | } |
| 154 | |
| 155 | void Histogram::Initialize() { |
| 156 | sample_.Resize(*this); |
| 157 | if (declared_min_ <= 0) |
| 158 | declared_min_ = 1; |
| 159 | if (declared_max_ >= kSampleType_MAX) |
| 160 | declared_max_ = kSampleType_MAX - 1; |
| 161 | DCHECK(declared_min_ > 0); // We provide underflow bucket. |
| 162 | DCHECK(declared_min_ < declared_max_); |
| 163 | DCHECK(1 < bucket_count_); |
| 164 | size_t maximal_bucket_count = declared_max_ - declared_min_ + 2; |
| 165 | DCHECK(bucket_count_ <= maximal_bucket_count); |
| 166 | DCHECK(0 == ranges_[0]); |
| 167 | ranges_[bucket_count_] = kSampleType_MAX; |
| 168 | InitializeBucketRange(); |
| 169 | DCHECK(ValidateBucketRanges()); |
| 170 | registered_ = StatisticsRecorder::Register(*this); |
| 171 | } |
| 172 | |
| 173 | // Calculate what range of values are held in each bucket. |
| 174 | // We have to be careful that we don't pick a ratio between starting points in |
| 175 | // consecutive buckets that is sooo small, that the integer bounds are the same |
| 176 | // (effectively making one bucket get no values). We need to avoid: |
| 177 | // (ranges_[i] == ranges_[i + 1] |
| 178 | // To avoid that, we just do a fine-grained bucket width as far as we need to |
| 179 | // until we get a ratio that moves us along at least 2 units at a time. From |
| 180 | // that bucket onward we do use the exponential growth of buckets. |
| 181 | void Histogram::InitializeBucketRange() { |
| 182 | double log_max = log(static_cast<double>(declared_max())); |
| 183 | double log_ratio; |
| 184 | double log_next; |
| 185 | size_t bucket_index = 1; |
| 186 | Sample current = declared_min(); |
| 187 | SetBucketRange(bucket_index, current); |
| 188 | while (bucket_count() > ++bucket_index) { |
| 189 | double log_current; |
| 190 | log_current = log(static_cast<double>(current)); |
| 191 | // Calculate the count'th root of the range. |
| 192 | log_ratio = (log_max - log_current) / (bucket_count() - bucket_index); |
| 193 | // See where the next bucket would start. |
| 194 | log_next = log_current + log_ratio; |
| 195 | int next; |
| 196 | next = static_cast<int>(floor(exp(log_next) + 0.5)); |
| 197 | if (next > current) |
| 198 | current = next; |
| 199 | else |
| 200 | current++; // Just do a narrow bucket, and keep trying. |
| 201 | SetBucketRange(bucket_index, current); |
| 202 | } |
| 203 | |
| 204 | DCHECK(bucket_count() == bucket_index); |
| 205 | } |
| 206 | |
| 207 | size_t Histogram::BucketIndex(Sample value) const { |
| 208 | // Use simple binary search. This is very general, but there are better |
| 209 | // approaches if we knew that the buckets were linearly distributed. |
| 210 | DCHECK(ranges(0) <= value); |
| 211 | DCHECK(ranges(bucket_count()) > value); |
| 212 | size_t under = 0; |
| 213 | size_t over = bucket_count(); |
| 214 | size_t mid; |
| 215 | |
| 216 | do { |
| 217 | DCHECK(over >= under); |
| 218 | mid = (over + under)/2; |
| 219 | if (mid == under) |
| 220 | break; |
| 221 | if (ranges(mid) <= value) |
| 222 | under = mid; |
| 223 | else |
| 224 | over = mid; |
| 225 | } while (true); |
| 226 | |
| 227 | DCHECK(ranges(mid) <= value && ranges(mid+1) > value); |
| 228 | return mid; |
| 229 | } |
| 230 | |
| 231 | // Use the actual bucket widths (like a linear histogram) until the widths get |
| 232 | // over some transition value, and then use that transition width. Exponentials |
| 233 | // get so big so fast (and we don't expect to see a lot of entries in the large |
| 234 | // buckets), so we need this to make it possible to see what is going on and |
| 235 | // not have 0-graphical-height buckets. |
| 236 | double Histogram::GetBucketSize(Count current, size_t i) const { |
| 237 | DCHECK(ranges(i + 1) > ranges(i)); |
| 238 | static const double kTransitionWidth = 5; |
| 239 | double denominator = ranges(i + 1) - ranges(i); |
| 240 | if (denominator > kTransitionWidth) |
| 241 | denominator = kTransitionWidth; // Stop trying to normalize. |
| 242 | return current/denominator; |
| 243 | } |
| 244 | |
| 245 | //------------------------------------------------------------------------------ |
| 246 | // The following two methods can be overridden to provide a thread safe |
| 247 | // version of this class. The cost of locking is low... but an error in each |
| 248 | // of these methods has minimal impact. For now, I'll leave this unlocked, |
| 249 | // and I don't believe I can loose more than a count or two. |
| 250 | // The vectors are NOT reallocated, so there is no risk of them moving around. |
| 251 | |
| 252 | // Update histogram data with new sample. |
| 253 | void Histogram::Accumulate(Sample value, Count count, size_t index) { |
| 254 | // Note locking not done in this version!!! |
| 255 | sample_.Accumulate(value, count, index); |
| 256 | } |
| 257 | |
| 258 | // Do a safe atomic snapshot of sample data. |
| 259 | // This implementation assumes we are on a safe single thread. |
| 260 | void Histogram::SnapshotSample(SampleSet* sample) const { |
| 261 | // Note locking not done in this version!!! |
| 262 | *sample = sample_; |
| 263 | } |
| 264 | |
| 265 | //------------------------------------------------------------------------------ |
| 266 | // Accessor methods |
| 267 | |
| 268 | void Histogram::SetBucketRange(size_t i, Sample value) { |
| 269 | DCHECK(bucket_count_ > i); |
| 270 | ranges_[i] = value; |
| 271 | } |
| 272 | |
| 273 | //------------------------------------------------------------------------------ |
| 274 | // Private methods |
| 275 | |
| 276 | double Histogram::GetPeakBucketSize(const SampleSet& snapshot) const { |
| 277 | double max = 0; |
| 278 | for (size_t i = 0; i < bucket_count_ ; i++) { |
| 279 | double current_size = GetBucketSize(snapshot.counts(i), i); |
| 280 | if (current_size > max) |
| 281 | max = current_size; |
| 282 | } |
| 283 | return max; |
| 284 | } |
| 285 | |
| 286 | void Histogram::WriteAsciiHeader(const SampleSet& snapshot, |
| 287 | Count sample_count, |
| 288 | std::string* output) const { |
| 289 | StringAppendF(output, |
| 290 | "Histogram: %s recorded %ld samples", |
| 291 | histogram_name().c_str(), |
| 292 | sample_count); |
| 293 | if (0 == sample_count) { |
| 294 | DCHECK(0 == snapshot.sum()); |
| 295 | } else { |
| 296 | double average = static_cast<float>(snapshot.sum()) / sample_count; |
| 297 | double variance = static_cast<float>(snapshot.square_sum())/sample_count |
| 298 | - average * average; |
| 299 | double standard_deviation = sqrt(variance); |
| 300 | |
| 301 | StringAppendF(output, |
| 302 | ", average = %.1f, standard deviation = %.1f", |
| 303 | average, standard_deviation); |
| 304 | } |
| 305 | if (flags_ & ~kHexRangePrintingFlag ) |
| 306 | StringAppendF(output, " (flags = 0x%x)", flags_ & ~kHexRangePrintingFlag); |
| 307 | } |
| 308 | |
| 309 | void Histogram::WriteAsciiBucketContext(const int64 past, |
| 310 | const Count current, |
| 311 | const int64 remaining, |
| 312 | const size_t i, |
| 313 | std::string* output) const { |
| 314 | double scaled_sum = (past + current + remaining) / 100.0; |
| 315 | WriteAsciiBucketValue(current, scaled_sum, output); |
| 316 | if (0 < i) { |
| 317 | double percentage = past / scaled_sum; |
| 318 | StringAppendF(output, " {%3.1f%%}", percentage); |
| 319 | } |
| 320 | } |
| 321 | |
| 322 | const std::string Histogram::GetAsciiBucketRange(size_t i) const { |
| 323 | std::string result; |
| 324 | if (kHexRangePrintingFlag & flags_) |
| 325 | StringAppendF(&result, "%#x", ranges_[i]); |
| 326 | else |
| 327 | StringAppendF(&result, "%d", ranges_[i]); |
| 328 | return result; |
| 329 | } |
| 330 | |
| 331 | void Histogram::WriteAsciiBucketValue(Count current, double scaled_sum, |
| 332 | std::string* output) const { |
| 333 | StringAppendF(output, " (%d = %3.1f%%)", current, current/scaled_sum); |
| 334 | } |
| 335 | |
| 336 | void Histogram::WriteAsciiBucketGraph(double current_size, double max_size, |
| 337 | std::string* output) const { |
| 338 | const int k_line_length = 72; // Maximal horizontal width of graph. |
| 339 | int x_count = static_cast<int>(k_line_length * (current_size / max_size) |
| 340 | + 0.5); |
| 341 | int x_remainder = k_line_length - x_count; |
| 342 | |
| 343 | while (0 < x_count--) |
| 344 | output->append("-"); |
| 345 | output->append("O"); |
| 346 | while (0 < x_remainder--) |
| 347 | output->append(" "); |
| 348 | } |
| 349 | |
| 350 | //------------------------------------------------------------------------------ |
| 351 | // Methods for the Histogram::SampleSet class |
| 352 | //------------------------------------------------------------------------------ |
| 353 | |
| 354 | Histogram::SampleSet::SampleSet() |
| 355 | : counts_(), |
| 356 | sum_(0), |
| 357 | square_sum_(0) { |
| 358 | } |
| 359 | |
| 360 | void Histogram::SampleSet::Resize(const Histogram& histogram) { |
| 361 | counts_.resize(histogram.bucket_count(), 0); |
| 362 | } |
| 363 | |
| 364 | void Histogram::SampleSet::CheckSize(const Histogram& histogram) const { |
| 365 | DCHECK(counts_.size() == histogram.bucket_count()); |
| 366 | } |
| 367 | |
| 368 | |
| 369 | void Histogram::SampleSet::Accumulate(Sample value, Count count, |
| 370 | size_t index) { |
| 371 | DCHECK(count == 1 || count == -1); |
| 372 | counts_[index] += count; |
| 373 | sum_ += count * value; |
| 374 | square_sum_ += (count * value) * static_cast<int64>(value); |
| 375 | DCHECK(counts_[index] >= 0); |
| 376 | DCHECK(sum_ >= 0); |
| 377 | DCHECK(square_sum_ >= 0); |
| 378 | } |
| 379 | |
| 380 | Count Histogram::SampleSet::TotalCount() const { |
| 381 | Count total = 0; |
| 382 | for (Counts::const_iterator it = counts_.begin(); |
| 383 | it != counts_.end(); |
| 384 | it++) { |
| 385 | total += *it; |
| 386 | } |
| 387 | return total; |
| 388 | } |
| 389 | |
| 390 | void Histogram::SampleSet::Add(const SampleSet& other) { |
| 391 | DCHECK(counts_.size() == other.counts_.size()); |
| 392 | sum_ += other.sum_; |
| 393 | square_sum_ += other.square_sum_; |
| 394 | for (size_t index = 0; index < counts_.size(); index++) |
| 395 | counts_[index] += other.counts_[index]; |
| 396 | } |
| 397 | |
| 398 | void Histogram::SampleSet::Subtract(const SampleSet& other) { |
| 399 | DCHECK(counts_.size() == other.counts_.size()); |
| 400 | // Note: Race conditions in snapshotting a sum or square_sum may lead to |
| 401 | // (temporary) negative values when snapshots are later combined (and deltas |
| 402 | // calculated). As a result, we don't currently CHCEK() for positive values. |
| 403 | sum_ -= other.sum_; |
| 404 | square_sum_ -= other.square_sum_; |
| 405 | for (size_t index = 0; index < counts_.size(); index++) { |
| 406 | counts_[index] -= other.counts_[index]; |
| 407 | DCHECK(counts_[index] >= 0); |
| 408 | } |
| 409 | } |
| 410 | |
| 411 | //------------------------------------------------------------------------------ |
| 412 | // LinearHistogram: This histogram uses a traditional set of evenly spaced |
| 413 | // buckets. |
| 414 | //------------------------------------------------------------------------------ |
| 415 | |
| 416 | LinearHistogram::LinearHistogram(const wchar_t* name, |
| 417 | Sample minimum, Sample maximum, size_t bucket_count) |
| 418 | : Histogram(name, minimum >= 1 ? minimum : 1, maximum, bucket_count) { |
| 419 | InitializeBucketRange(); |
| 420 | DCHECK(ValidateBucketRanges()); |
| 421 | } |
| 422 | |
| 423 | LinearHistogram::LinearHistogram(const wchar_t* name, |
| 424 | TimeDelta minimum, TimeDelta maximum, size_t bucket_count) |
| 425 | : Histogram(name, minimum >= TimeDelta::FromMilliseconds(1) ? |
| 426 | minimum : TimeDelta::FromMilliseconds(1), |
| 427 | maximum, bucket_count) { |
| 428 | // Do a "better" (different) job at init than a base classes did... |
| 429 | InitializeBucketRange(); |
| 430 | DCHECK(ValidateBucketRanges()); |
| 431 | } |
| 432 | |
| 433 | void LinearHistogram::SetRangeDescriptions(const DescriptionPair descriptions[]) { |
| 434 | for (int i =0; descriptions[i].description; ++i) { |
| 435 | bucket_description_[descriptions[i].sample] = descriptions[i].description; |
| 436 | } |
| 437 | } |
| 438 | |
| 439 | const std::string LinearHistogram::GetAsciiBucketRange(size_t i) const { |
| 440 | int range = ranges(i); |
| 441 | BucketDescriptionMap::const_iterator it = bucket_description_.find(range); |
| 442 | if (it == bucket_description_.end()) |
| 443 | return Histogram::GetAsciiBucketRange(i); |
| 444 | return it->second; |
| 445 | } |
| 446 | |
| 447 | bool LinearHistogram::PrintEmptyBucket(size_t index) const { |
| 448 | return bucket_description_.find(ranges(index)) == bucket_description_.end(); |
| 449 | } |
| 450 | |
| 451 | |
| 452 | void LinearHistogram::InitializeBucketRange() { |
| 453 | DCHECK(0 < declared_min()); // 0 is the underflow bucket here. |
| 454 | double min = declared_min(); |
| 455 | double max = declared_max(); |
| 456 | size_t i; |
| 457 | for (i = 1; i < bucket_count(); i++) { |
| 458 | double linear_range = (min * (bucket_count() -1 - i) + max * (i - 1)) / |
| 459 | (bucket_count() - 2); |
| 460 | SetBucketRange(i, static_cast<int> (linear_range + 0.5)); |
| 461 | } |
| 462 | } |
| 463 | |
| 464 | // Find bucket to increment for sample value. |
| 465 | size_t LinearHistogram::BucketIndex(Sample value) const { |
| 466 | if (value < declared_min()) return 0; |
| 467 | if (value >= declared_max()) return bucket_count() - 1; |
| 468 | size_t index; |
| 469 | index = static_cast<size_t>(((value - declared_min()) * (bucket_count() - 2)) |
| 470 | / (declared_max() - declared_min()) + 1); |
| 471 | DCHECK(1 <= index && bucket_count() > index); |
| 472 | return index; |
| 473 | } |
| 474 | |
| 475 | double LinearHistogram::GetBucketSize(Count current, size_t i) const { |
| 476 | DCHECK(ranges(i + 1) > ranges(i)); |
| 477 | // Adjacent buckets with different widths would have "surprisingly" many (few) |
| 478 | // samples in a histogram if we didn't normalize this way. |
| 479 | double denominator = ranges(i + 1) - ranges(i); |
| 480 | return current/denominator; |
| 481 | } |
| 482 | |
| 483 | //------------------------------------------------------------------------------ |
| 484 | // This section provides implementation for ThreadSafeHistogram. |
| 485 | //------------------------------------------------------------------------------ |
| 486 | |
| 487 | ThreadSafeHistogram::ThreadSafeHistogram(const wchar_t* name, Sample minimum, |
| 488 | Sample maximum, size_t bucket_count) |
| 489 | : Histogram(name, minimum, maximum, bucket_count), |
| 490 | lock_() { |
| 491 | } |
| 492 | |
| 493 | void ThreadSafeHistogram::Remove(int value) { |
| 494 | if (value >= kSampleType_MAX) |
| 495 | value = kSampleType_MAX - 1; |
| 496 | StatsRate::Add(-value); |
| 497 | size_t index = BucketIndex(value); |
| 498 | Accumulate(value, -1, index); |
| 499 | } |
| 500 | |
| 501 | void ThreadSafeHistogram::Accumulate(Sample value, Count count, size_t index) { |
| 502 | AutoLock lock(lock_); |
| 503 | Histogram::Accumulate(value, count, index); |
| 504 | } |
| 505 | |
| 506 | void ThreadSafeHistogram::SnapshotSample(SampleSet* sample) { |
| 507 | AutoLock lock(lock_); |
| 508 | Histogram::SnapshotSample(sample); |
| 509 | }; |
| 510 | |
| 511 | |
| 512 | //------------------------------------------------------------------------------ |
| 513 | // The next section handles global (central) support for all histograms, as well |
| 514 | // as startup/teardown of this service. |
| 515 | //------------------------------------------------------------------------------ |
| 516 | |
| 517 | // This singleton instance should be started during the single threaded portion |
| 518 | // of main(), and hence it is not thread safe. It initializes globals to |
| 519 | // provide support for all future calls. |
| 520 | StatisticsRecorder::StatisticsRecorder() { |
| 521 | DCHECK(!histograms_); |
| 522 | lock_ = new Lock; |
| 523 | histograms_ = new HistogramMap; |
| 524 | } |
| 525 | |
| 526 | StatisticsRecorder::~StatisticsRecorder() { |
| 527 | DCHECK(histograms_); |
| 528 | |
| 529 | if (dump_on_exit_) { |
| 530 | std::string output; |
| 531 | WriteGraph("", &output); |
| 532 | LOG(INFO) << output; |
| 533 | } |
| 534 | |
| 535 | // Clean up. |
| 536 | delete histograms_; |
| 537 | histograms_ = NULL; |
| 538 | delete lock_; |
| 539 | lock_ = NULL; |
| 540 | } |
| 541 | |
| 542 | // static |
| 543 | bool StatisticsRecorder::WasStarted() { |
| 544 | return NULL != histograms_; |
| 545 | } |
| 546 | |
| 547 | // static |
| 548 | bool StatisticsRecorder::Register(const Histogram& histogram) { |
| 549 | if (!histograms_) |
| 550 | return false; |
| 551 | const std::string name = histogram.histogram_name(); |
| 552 | AutoLock auto_lock(*lock_); |
| 553 | DCHECK(histograms_->end() == histograms_->find(name)); // Only register once. |
| 554 | (*histograms_)[name] = &histogram; |
| 555 | return true; |
| 556 | } |
| 557 | |
| 558 | // static |
| 559 | void StatisticsRecorder::UnRegister(const Histogram& histogram) { |
| 560 | if (!histograms_) |
| 561 | return; |
| 562 | const std::string name = histogram.histogram_name(); |
| 563 | AutoLock auto_lock(*lock_); |
| 564 | DCHECK(histograms_->end() != histograms_->find(name)); |
| 565 | histograms_->erase(name); |
| 566 | if (dump_on_exit_) { |
| 567 | std::string output; |
| 568 | histogram.WriteAscii(true, "\n", &output); |
| 569 | LOG(INFO) << output; |
| 570 | } |
| 571 | } |
| 572 | |
| 573 | // static |
| 574 | void StatisticsRecorder::WriteHTMLGraph(const std::string& query, |
| 575 | std::string* output) { |
| 576 | if (!histograms_) |
| 577 | return; |
| 578 | output->append("<html><head><title>About Histograms"); |
| 579 | if (!query.empty()) |
| 580 | output->append(" - " + query); |
| 581 | output->append("</title>" |
| 582 | // We'd like the following no-cache... but it doesn't work. |
| 583 | // "<META HTTP-EQUIV=\"Pragma\" CONTENT=\"no-cache\">" |
| 584 | "</head><body>"); |
| 585 | |
| 586 | Histograms snapshot; |
| 587 | GetSnapshot(query, &snapshot); |
| 588 | for (Histograms::iterator it = snapshot.begin(); |
| 589 | it != snapshot.end(); |
| 590 | it++) { |
| 591 | (*it)->WriteHTMLGraph(output); |
| 592 | output->append("<br><hr><br>"); |
| 593 | } |
| 594 | output->append("</body></html>"); |
| 595 | } |
| 596 | |
| 597 | // static |
| 598 | void StatisticsRecorder::WriteGraph(const std::string& query, |
| 599 | std::string* output) { |
| 600 | if (!histograms_) |
| 601 | return; |
| 602 | if (query.length()) |
| 603 | StringAppendF(output, "Collections of histograms for %s\n", query.c_str()); |
| 604 | else |
| 605 | output->append("Collections of all histograms\n"); |
| 606 | |
| 607 | Histograms snapshot; |
| 608 | GetSnapshot(query, &snapshot); |
| 609 | for (Histograms::iterator it = snapshot.begin(); |
| 610 | it != snapshot.end(); |
| 611 | it++) { |
| 612 | (*it)->WriteAscii(true, "\n", output); |
| 613 | output->append("\n"); |
| 614 | } |
| 615 | } |
| 616 | |
| 617 | // static |
| 618 | void StatisticsRecorder::GetHistograms(Histograms* output) { |
| 619 | if (!histograms_) |
| 620 | return; |
| 621 | AutoLock auto_lock(*lock_); |
| 622 | for (HistogramMap::iterator it = histograms_->begin(); |
| 623 | histograms_->end() != it; |
| 624 | it++) { |
| 625 | output->push_back(it->second); |
| 626 | } |
| 627 | } |
| 628 | |
| 629 | // private static |
| 630 | void StatisticsRecorder::GetSnapshot(const std::string& query, |
| 631 | Histograms* snapshot) { |
| 632 | AutoLock auto_lock(*lock_); |
| 633 | for (HistogramMap::iterator it = histograms_->begin(); |
| 634 | histograms_->end() != it; |
| 635 | it++) { |
| 636 | if (it->first.find(query) != std::string::npos) |
| 637 | snapshot->push_back(it->second); |
| 638 | } |
| 639 | } |
| 640 | |
| 641 | // static |
| 642 | StatisticsRecorder::HistogramMap* StatisticsRecorder::histograms_ = NULL; |
| 643 | // static |
| 644 | Lock* StatisticsRecorder::lock_ = NULL; |
| 645 | // static |
| 646 | bool StatisticsRecorder::dump_on_exit_ = false; |
license.bot | f003cfe | 2008-08-24 09:55:55 +0900 | [diff] [blame^] | 647 | |