| // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // Histogram is an object that aggregates statistics, and can summarize them in |
| // various forms, including ASCII graphical, HTML, and numerically (as a |
| // vector of numbers corresponding to each of the aggregating buckets). |
| // See header file for details and examples. |
| |
| #include "base/metrics/histogram.h" |
| |
| #include <math.h> |
| |
| #include <algorithm> |
| #include <string> |
| |
| #include "base/logging.h" |
| #include "base/metrics/statistics_recorder.h" |
| #include "base/pickle.h" |
| #include "base/stringprintf.h" |
| #include "base/synchronization/lock.h" |
| |
| namespace base { |
| |
| // Static table of checksums for all possible 8 bit bytes. |
| const uint32 Histogram::kCrcTable[256] = {0x0, 0x77073096L, 0xee0e612cL, |
| 0x990951baL, 0x76dc419L, 0x706af48fL, 0xe963a535L, 0x9e6495a3L, 0xedb8832L, |
| 0x79dcb8a4L, 0xe0d5e91eL, 0x97d2d988L, 0x9b64c2bL, 0x7eb17cbdL, 0xe7b82d07L, |
| 0x90bf1d91L, 0x1db71064L, 0x6ab020f2L, 0xf3b97148L, 0x84be41deL, 0x1adad47dL, |
| 0x6ddde4ebL, 0xf4d4b551L, 0x83d385c7L, 0x136c9856L, 0x646ba8c0L, 0xfd62f97aL, |
| 0x8a65c9ecL, 0x14015c4fL, 0x63066cd9L, 0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L, |
| 0x4c69105eL, 0xd56041e4L, 0xa2677172L, 0x3c03e4d1L, 0x4b04d447L, 0xd20d85fdL, |
| 0xa50ab56bL, 0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L, 0xacbcf940L, 0x32d86ce3L, |
| 0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L, 0x26d930acL, 0x51de003aL, 0xc8d75180L, |
| 0xbfd06116L, 0x21b4f4b5L, 0x56b3c423L, 0xcfba9599L, 0xb8bda50fL, 0x2802b89eL, |
| 0x5f058808L, 0xc60cd9b2L, 0xb10be924L, 0x2f6f7c87L, 0x58684c11L, 0xc1611dabL, |
| 0xb6662d3dL, 0x76dc4190L, 0x1db7106L, 0x98d220bcL, 0xefd5102aL, 0x71b18589L, |
| 0x6b6b51fL, 0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L, 0xf00f934L, 0x9609a88eL, |
| 0xe10e9818L, 0x7f6a0dbbL, 0x86d3d2dL, 0x91646c97L, 0xe6635c01L, 0x6b6b51f4L, |
| 0x1c6c6162L, 0x856530d8L, 0xf262004eL, 0x6c0695edL, 0x1b01a57bL, 0x8208f4c1L, |
| 0xf50fc457L, 0x65b0d9c6L, 0x12b7e950L, 0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL, |
| 0x15da2d49L, 0x8cd37cf3L, 0xfbd44c65L, 0x4db26158L, 0x3ab551ceL, 0xa3bc0074L, |
| 0xd4bb30e2L, 0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL, 0xd3d6f4fbL, 0x4369e96aL, |
| 0x346ed9fcL, 0xad678846L, 0xda60b8d0L, 0x44042d73L, 0x33031de5L, 0xaa0a4c5fL, |
| 0xdd0d7cc9L, 0x5005713cL, 0x270241aaL, 0xbe0b1010L, 0xc90c2086L, 0x5768b525L, |
| 0x206f85b3L, 0xb966d409L, 0xce61e49fL, 0x5edef90eL, 0x29d9c998L, 0xb0d09822L, |
| 0xc7d7a8b4L, 0x59b33d17L, 0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL, 0xedb88320L, |
| 0x9abfb3b6L, 0x3b6e20cL, 0x74b1d29aL, 0xead54739L, 0x9dd277afL, 0x4db2615L, |
| 0x73dc1683L, 0xe3630b12L, 0x94643b84L, 0xd6d6a3eL, 0x7a6a5aa8L, 0xe40ecf0bL, |
| 0x9309ff9dL, 0xa00ae27L, 0x7d079eb1L, 0xf00f9344L, 0x8708a3d2L, 0x1e01f268L, |
| 0x6906c2feL, 0xf762575dL, 0x806567cbL, 0x196c3671L, 0x6e6b06e7L, 0xfed41b76L, |
| 0x89d32be0L, 0x10da7a5aL, 0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L, 0x17b7be43L, |
| 0x60b08ed5L, 0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L, 0x4fdff252L, 0xd1bb67f1L, |
| 0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL, 0xd80d2bdaL, 0xaf0a1b4cL, 0x36034af6L, |
| 0x41047a60L, 0xdf60efc3L, 0xa867df55L, 0x316e8eefL, 0x4669be79L, 0xcb61b38cL, |
| 0xbc66831aL, 0x256fd2a0L, 0x5268e236L, 0xcc0c7795L, 0xbb0b4703L, 0x220216b9L, |
| 0x5505262fL, 0xc5ba3bbeL, 0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L, 0xc2d7ffa7L, |
| 0xb5d0cf31L, 0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L, 0xec63f226L, 0x756aa39cL, |
| 0x26d930aL, 0x9c0906a9L, 0xeb0e363fL, 0x72076785L, 0x5005713L, 0x95bf4a82L, |
| 0xe2b87a14L, 0x7bb12baeL, 0xcb61b38L, 0x92d28e9bL, 0xe5d5be0dL, 0x7cdcefb7L, |
| 0xbdbdf21L, 0x86d3d2d4L, 0xf1d4e242L, 0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL, |
| 0xf6b9265bL, 0x6fb077e1L, 0x18b74777L, 0x88085ae6L, 0xff0f6a70L, 0x66063bcaL, |
| 0x11010b5cL, 0x8f659effL, 0xf862ae69L, 0x616bffd3L, 0x166ccf45L, 0xa00ae278L, |
| 0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L, 0xa7672661L, 0xd06016f7L, 0x4969474dL, |
| 0x3e6e77dbL, 0xaed16a4aL, 0xd9d65adcL, 0x40df0b66L, 0x37d83bf0L, 0xa9bcae53L, |
| 0xdebb9ec5L, 0x47b2cf7fL, 0x30b5ffe9L, 0xbdbdf21cL, 0xcabac28aL, 0x53b39330L, |
| 0x24b4a3a6L, 0xbad03605L, 0xcdd70693L, 0x54de5729L, 0x23d967bfL, 0xb3667a2eL, |
| 0xc4614ab8L, 0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL, |
| 0x2d02ef8dL, |
| }; |
| |
| typedef Histogram::Count Count; |
| |
| // static |
| const size_t Histogram::kBucketCount_MAX = 16384u; |
| |
| Histogram* Histogram::FactoryGet(const std::string& name, |
| Sample minimum, |
| Sample maximum, |
| size_t bucket_count, |
| Flags flags) { |
| // Defensive code. |
| if (minimum < 1) |
| minimum = 1; |
| if (maximum > kSampleType_MAX - 1) |
| maximum = kSampleType_MAX - 1; |
| |
| DCHECK_GT(maximum, minimum); |
| DCHECK_GT((Sample) bucket_count, 2); |
| DCHECK_LE((Sample) bucket_count, maximum - minimum + 2); |
| |
| Histogram* histogram = StatisticsRecorder::FindHistogram(name); |
| if (!histogram) { |
| // Extra variable is not needed... but this keeps this section basically |
| // identical to other derived classes in this file (and compiler will |
| // optimize away the extra variable. |
| // To avoid racy destruction at shutdown, the following will be leaked. |
| Histogram* tentative_histogram = |
| new Histogram(name, minimum, maximum, bucket_count); |
| tentative_histogram->InitializeBucketRange(); |
| tentative_histogram->SetFlags(flags); |
| histogram = |
| StatisticsRecorder::RegisterOrDeleteDuplicate(tentative_histogram); |
| } |
| |
| DCHECK_EQ(HISTOGRAM, histogram->histogram_type()); |
| DCHECK(histogram->HasConstructorArguments(minimum, maximum, bucket_count)); |
| return histogram; |
| } |
| |
| Histogram* Histogram::FactoryTimeGet(const std::string& name, |
| TimeDelta minimum, |
| TimeDelta maximum, |
| size_t bucket_count, |
| Flags flags) { |
| return FactoryGet(name, minimum.InMilliseconds(), maximum.InMilliseconds(), |
| bucket_count, flags); |
| } |
| |
| TimeTicks Histogram::DebugNow() { |
| #ifndef NDEBUG |
| return TimeTicks::Now(); |
| #else |
| return TimeTicks(); |
| #endif |
| } |
| |
| void Histogram::Add(int value) { |
| if (value > kSampleType_MAX - 1) |
| value = kSampleType_MAX - 1; |
| if (value < 0) |
| value = 0; |
| size_t index = BucketIndex(value); |
| DCHECK_GE(value, ranges(index)); |
| DCHECK_LT(value, ranges(index + 1)); |
| Accumulate(value, 1, index); |
| } |
| |
| void Histogram::AddBoolean(bool value) { |
| DCHECK(false); |
| } |
| |
| void Histogram::AddSampleSet(const SampleSet& sample) { |
| sample_.Add(sample); |
| } |
| |
| void Histogram::SetRangeDescriptions(const DescriptionPair descriptions[]) { |
| DCHECK(false); |
| } |
| |
| // The following methods provide a graphical histogram display. |
| void Histogram::WriteHTMLGraph(std::string* output) const { |
| // TBD(jar) Write a nice HTML bar chart, with divs an mouse-overs etc. |
| output->append("<PRE>"); |
| WriteAsciiImpl(true, "<br>", output); |
| output->append("</PRE>"); |
| } |
| |
| void Histogram::WriteAscii(std::string* output) const { |
| WriteAsciiImpl(true, "\n", output); |
| } |
| |
| void Histogram::WriteAsciiImpl(bool graph_it, |
| const std::string& newline, |
| std::string* output) const { |
| // Get local (stack) copies of all effectively volatile class data so that we |
| // are consistent across our output activities. |
| SampleSet snapshot; |
| SnapshotSample(&snapshot); |
| Count sample_count = snapshot.TotalCount(); |
| |
| WriteAsciiHeader(snapshot, sample_count, output); |
| output->append(newline); |
| |
| // Prepare to normalize graphical rendering of bucket contents. |
| double max_size = 0; |
| if (graph_it) |
| max_size = GetPeakBucketSize(snapshot); |
| |
| // Calculate space needed to print bucket range numbers. Leave room to print |
| // nearly the largest bucket range without sliding over the histogram. |
| size_t largest_non_empty_bucket = bucket_count() - 1; |
| while (0 == snapshot.counts(largest_non_empty_bucket)) { |
| if (0 == largest_non_empty_bucket) |
| break; // All buckets are empty. |
| --largest_non_empty_bucket; |
| } |
| |
| // Calculate largest print width needed for any of our bucket range displays. |
| size_t print_width = 1; |
| for (size_t i = 0; i < bucket_count(); ++i) { |
| if (snapshot.counts(i)) { |
| size_t width = GetAsciiBucketRange(i).size() + 1; |
| if (width > print_width) |
| print_width = width; |
| } |
| } |
| |
| int64 remaining = sample_count; |
| int64 past = 0; |
| // Output the actual histogram graph. |
| for (size_t i = 0; i < bucket_count(); ++i) { |
| Count current = snapshot.counts(i); |
| if (!current && !PrintEmptyBucket(i)) |
| continue; |
| remaining -= current; |
| std::string range = GetAsciiBucketRange(i); |
| output->append(range); |
| for (size_t j = 0; range.size() + j < print_width + 1; ++j) |
| output->push_back(' '); |
| if (0 == current && i < bucket_count() - 1 && 0 == snapshot.counts(i + 1)) { |
| while (i < bucket_count() - 1 && 0 == snapshot.counts(i + 1)) |
| ++i; |
| output->append("... "); |
| output->append(newline); |
| continue; // No reason to plot emptiness. |
| } |
| double current_size = GetBucketSize(current, i); |
| if (graph_it) |
| WriteAsciiBucketGraph(current_size, max_size, output); |
| WriteAsciiBucketContext(past, current, remaining, i, output); |
| output->append(newline); |
| past += current; |
| } |
| DCHECK_EQ(sample_count, past); |
| } |
| |
| // static |
| std::string Histogram::SerializeHistogramInfo(const Histogram& histogram, |
| const SampleSet& snapshot) { |
| DCHECK_NE(NOT_VALID_IN_RENDERER, histogram.histogram_type()); |
| |
| Pickle pickle; |
| pickle.WriteString(histogram.histogram_name()); |
| pickle.WriteInt(histogram.declared_min()); |
| pickle.WriteInt(histogram.declared_max()); |
| pickle.WriteUInt64(histogram.bucket_count()); |
| pickle.WriteUInt32(histogram.range_checksum()); |
| pickle.WriteInt(histogram.histogram_type()); |
| pickle.WriteInt(histogram.flags()); |
| |
| snapshot.Serialize(&pickle); |
| |
| histogram.SerializeRanges(&pickle); |
| |
| return std::string(static_cast<const char*>(pickle.data()), pickle.size()); |
| } |
| |
| // static |
| bool Histogram::DeserializeHistogramInfo(const std::string& histogram_info) { |
| if (histogram_info.empty()) { |
| return false; |
| } |
| |
| Pickle pickle(histogram_info.data(), |
| static_cast<int>(histogram_info.size())); |
| std::string histogram_name; |
| int declared_min; |
| int declared_max; |
| uint64 bucket_count; |
| uint32 range_checksum; |
| int histogram_type; |
| int pickle_flags; |
| SampleSet sample; |
| |
| PickleIterator iter(pickle); |
| if (!iter.ReadString(&histogram_name) || |
| !iter.ReadInt(&declared_min) || |
| !iter.ReadInt(&declared_max) || |
| !iter.ReadUInt64(&bucket_count) || |
| !iter.ReadUInt32(&range_checksum) || |
| !iter.ReadInt(&histogram_type) || |
| !iter.ReadInt(&pickle_flags) || |
| !sample.Histogram::SampleSet::Deserialize(&iter)) { |
| DLOG(ERROR) << "Pickle error decoding Histogram: " << histogram_name; |
| return false; |
| } |
| |
| DCHECK(pickle_flags & kIPCSerializationSourceFlag); |
| // Since these fields may have come from an untrusted renderer, do additional |
| // checks above and beyond those in Histogram::Initialize() |
| if (declared_max <= 0 || declared_min <= 0 || declared_max < declared_min || |
| INT_MAX / sizeof(Count) <= bucket_count || bucket_count < 2) { |
| DLOG(ERROR) << "Values error decoding Histogram: " << histogram_name; |
| return false; |
| } |
| |
| Flags flags = static_cast<Flags>(pickle_flags & ~kIPCSerializationSourceFlag); |
| |
| DCHECK_NE(NOT_VALID_IN_RENDERER, histogram_type); |
| |
| Histogram* render_histogram(NULL); |
| |
| if (histogram_type == HISTOGRAM) { |
| render_histogram = Histogram::FactoryGet( |
| histogram_name, declared_min, declared_max, bucket_count, flags); |
| } else if (histogram_type == LINEAR_HISTOGRAM) { |
| render_histogram = LinearHistogram::FactoryGet( |
| histogram_name, declared_min, declared_max, bucket_count, flags); |
| } else if (histogram_type == BOOLEAN_HISTOGRAM) { |
| render_histogram = BooleanHistogram::FactoryGet(histogram_name, flags); |
| } else if (histogram_type == CUSTOM_HISTOGRAM) { |
| std::vector<Histogram::Sample> sample_ranges(bucket_count); |
| if (!CustomHistogram::DeserializeRanges(&iter, &sample_ranges)) { |
| DLOG(ERROR) << "Pickle error decoding ranges: " << histogram_name; |
| return false; |
| } |
| render_histogram = |
| CustomHistogram::FactoryGet(histogram_name, sample_ranges, flags); |
| } else { |
| DLOG(ERROR) << "Error Deserializing Histogram Unknown histogram_type: " |
| << histogram_type; |
| return false; |
| } |
| |
| DCHECK_EQ(render_histogram->declared_min(), declared_min); |
| DCHECK_EQ(render_histogram->declared_max(), declared_max); |
| DCHECK_EQ(render_histogram->bucket_count(), bucket_count); |
| DCHECK_EQ(render_histogram->range_checksum(), range_checksum); |
| DCHECK_EQ(render_histogram->histogram_type(), histogram_type); |
| |
| if (render_histogram->flags() & kIPCSerializationSourceFlag) { |
| DVLOG(1) << "Single process mode, histogram observed and not copied: " |
| << histogram_name; |
| } else { |
| DCHECK_EQ(flags & render_histogram->flags(), flags); |
| render_histogram->AddSampleSet(sample); |
| } |
| |
| return true; |
| } |
| |
| //------------------------------------------------------------------------------ |
| // Methods for the validating a sample and a related histogram. |
| //------------------------------------------------------------------------------ |
| |
| Histogram::Inconsistencies Histogram::FindCorruption( |
| const SampleSet& snapshot) const { |
| int inconsistencies = NO_INCONSISTENCIES; |
| Sample previous_range = -1; // Bottom range is always 0. |
| int64 count = 0; |
| for (size_t index = 0; index < bucket_count(); ++index) { |
| count += snapshot.counts(index); |
| int new_range = ranges(index); |
| if (previous_range >= new_range) |
| inconsistencies |= BUCKET_ORDER_ERROR; |
| previous_range = new_range; |
| } |
| |
| if (!HasValidRangeChecksum()) |
| inconsistencies |= RANGE_CHECKSUM_ERROR; |
| |
| int64 delta64 = snapshot.redundant_count() - count; |
| if (delta64 != 0) { |
| int delta = static_cast<int>(delta64); |
| if (delta != delta64) |
| delta = INT_MAX; // Flag all giant errors as INT_MAX. |
| // Since snapshots of histograms are taken asynchronously relative to |
| // sampling (and snapped from different threads), it is pretty likely that |
| // we'll catch a redundant count that doesn't match the sample count. We |
| // allow for a certain amount of slop before flagging this as an |
| // inconsistency. Even with an inconsistency, we'll snapshot it again (for |
| // UMA in about a half hour, so we'll eventually get the data, if it was |
| // not the result of a corruption. If histograms show that 1 is "too tight" |
| // then we may try to use 2 or 3 for this slop value. |
| const int kCommonRaceBasedCountMismatch = 1; |
| if (delta > 0) { |
| UMA_HISTOGRAM_COUNTS("Histogram.InconsistentCountHigh", delta); |
| if (delta > kCommonRaceBasedCountMismatch) |
| inconsistencies |= COUNT_HIGH_ERROR; |
| } else { |
| DCHECK_GT(0, delta); |
| UMA_HISTOGRAM_COUNTS("Histogram.InconsistentCountLow", -delta); |
| if (-delta > kCommonRaceBasedCountMismatch) |
| inconsistencies |= COUNT_LOW_ERROR; |
| } |
| } |
| return static_cast<Inconsistencies>(inconsistencies); |
| } |
| |
| Histogram::ClassType Histogram::histogram_type() const { |
| return HISTOGRAM; |
| } |
| |
| Histogram::Sample Histogram::ranges(size_t i) const { |
| return bucket_ranges_->range(i); |
| } |
| |
| size_t Histogram::bucket_count() const { |
| return bucket_count_; |
| } |
| |
| // Do a safe atomic snapshot of sample data. |
| // This implementation assumes we are on a safe single thread. |
| void Histogram::SnapshotSample(SampleSet* sample) const { |
| // Note locking not done in this version!!! |
| *sample = sample_; |
| } |
| |
| bool Histogram::HasConstructorArguments(Sample minimum, |
| Sample maximum, |
| size_t bucket_count) { |
| return ((minimum == declared_min_) && (maximum == declared_max_) && |
| (bucket_count == bucket_count_)); |
| } |
| |
| bool Histogram::HasConstructorTimeDeltaArguments(TimeDelta minimum, |
| TimeDelta maximum, |
| size_t bucket_count) { |
| return ((minimum.InMilliseconds() == declared_min_) && |
| (maximum.InMilliseconds() == declared_max_) && |
| (bucket_count == bucket_count_)); |
| } |
| |
| bool Histogram::HasValidRangeChecksum() const { |
| return CalculateRangeChecksum() == range_checksum_; |
| } |
| |
| Histogram::Histogram(const std::string& name, Sample minimum, |
| Sample maximum, size_t bucket_count) |
| : HistogramBase(name), |
| declared_min_(minimum), |
| declared_max_(maximum), |
| bucket_count_(bucket_count), |
| flags_(kNoFlags), |
| bucket_ranges_(new BucketRanges(bucket_count + 1)), |
| range_checksum_(0), |
| sample_() { |
| Initialize(); |
| } |
| |
| Histogram::Histogram(const std::string& name, TimeDelta minimum, |
| TimeDelta maximum, size_t bucket_count) |
| : HistogramBase(name), |
| declared_min_(static_cast<int> (minimum.InMilliseconds())), |
| declared_max_(static_cast<int> (maximum.InMilliseconds())), |
| bucket_count_(bucket_count), |
| flags_(kNoFlags), |
| bucket_ranges_(new BucketRanges(bucket_count + 1)), |
| range_checksum_(0), |
| sample_() { |
| Initialize(); |
| } |
| |
| Histogram::~Histogram() { |
| if (StatisticsRecorder::dump_on_exit()) { |
| std::string output; |
| WriteAsciiImpl(true, "\n", &output); |
| DLOG(INFO) << output; |
| } |
| |
| // Just to make sure most derived class did this properly... |
| DCHECK(ValidateBucketRanges()); |
| } |
| |
| bool Histogram::SerializeRanges(Pickle* pickle) const { |
| return true; |
| } |
| |
| // Calculate what range of values are held in each bucket. |
| // We have to be careful that we don't pick a ratio between starting points in |
| // consecutive buckets that is sooo small, that the integer bounds are the same |
| // (effectively making one bucket get no values). We need to avoid: |
| // ranges(i) == ranges(i + 1) |
| // To avoid that, we just do a fine-grained bucket width as far as we need to |
| // until we get a ratio that moves us along at least 2 units at a time. From |
| // that bucket onward we do use the exponential growth of buckets. |
| void Histogram::InitializeBucketRange() { |
| double log_max = log(static_cast<double>(declared_max())); |
| double log_ratio; |
| double log_next; |
| size_t bucket_index = 1; |
| Sample current = declared_min(); |
| SetBucketRange(bucket_index, current); |
| while (bucket_count() > ++bucket_index) { |
| double log_current; |
| log_current = log(static_cast<double>(current)); |
| // Calculate the count'th root of the range. |
| log_ratio = (log_max - log_current) / (bucket_count() - bucket_index); |
| // See where the next bucket would start. |
| log_next = log_current + log_ratio; |
| int next; |
| next = static_cast<int>(floor(exp(log_next) + 0.5)); |
| if (next > current) |
| current = next; |
| else |
| ++current; // Just do a narrow bucket, and keep trying. |
| SetBucketRange(bucket_index, current); |
| } |
| ResetRangeChecksum(); |
| |
| DCHECK_EQ(bucket_count(), bucket_index); |
| } |
| |
| bool Histogram::PrintEmptyBucket(size_t index) const { |
| return true; |
| } |
| |
| size_t Histogram::BucketIndex(Sample value) const { |
| // Use simple binary search. This is very general, but there are better |
| // approaches if we knew that the buckets were linearly distributed. |
| DCHECK_LE(ranges(0), value); |
| DCHECK_GT(ranges(bucket_count()), value); |
| size_t under = 0; |
| size_t over = bucket_count(); |
| size_t mid; |
| |
| do { |
| DCHECK_GE(over, under); |
| mid = under + (over - under)/2; |
| if (mid == under) |
| break; |
| if (ranges(mid) <= value) |
| under = mid; |
| else |
| over = mid; |
| } while (true); |
| |
| DCHECK_LE(ranges(mid), value); |
| CHECK_GT(ranges(mid+1), value); |
| return mid; |
| } |
| |
| // Use the actual bucket widths (like a linear histogram) until the widths get |
| // over some transition value, and then use that transition width. Exponentials |
| // get so big so fast (and we don't expect to see a lot of entries in the large |
| // buckets), so we need this to make it possible to see what is going on and |
| // not have 0-graphical-height buckets. |
| double Histogram::GetBucketSize(Count current, size_t i) const { |
| DCHECK_GT(ranges(i + 1), ranges(i)); |
| static const double kTransitionWidth = 5; |
| double denominator = ranges(i + 1) - ranges(i); |
| if (denominator > kTransitionWidth) |
| denominator = kTransitionWidth; // Stop trying to normalize. |
| return current/denominator; |
| } |
| |
| void Histogram::ResetRangeChecksum() { |
| range_checksum_ = CalculateRangeChecksum(); |
| } |
| |
| const std::string Histogram::GetAsciiBucketRange(size_t i) const { |
| std::string result; |
| if (kHexRangePrintingFlag & flags_) |
| StringAppendF(&result, "%#x", ranges(i)); |
| else |
| StringAppendF(&result, "%d", ranges(i)); |
| return result; |
| } |
| |
| // Update histogram data with new sample. |
| void Histogram::Accumulate(Sample value, Count count, size_t index) { |
| // Note locking not done in this version!!! |
| sample_.Accumulate(value, count, index); |
| } |
| |
| void Histogram::SetBucketRange(size_t i, Sample value) { |
| DCHECK_GT(bucket_count_, i); |
| DCHECK_GE(value, 0); |
| bucket_ranges_->set_range(i, value); |
| } |
| |
| bool Histogram::ValidateBucketRanges() const { |
| // Standard assertions that all bucket ranges should satisfy. |
| DCHECK_EQ(bucket_count_ + 1, bucket_ranges_->size()); |
| DCHECK_EQ(0, ranges(0)); |
| DCHECK_EQ(declared_min(), ranges(1)); |
| DCHECK_EQ(declared_max(), ranges(bucket_count_ - 1)); |
| DCHECK_EQ(kSampleType_MAX, ranges(bucket_count_)); |
| return true; |
| } |
| |
| uint32 Histogram::CalculateRangeChecksum() const { |
| DCHECK_EQ(bucket_ranges_->size(), bucket_count() + 1); |
| // Seed checksum. |
| uint32 checksum = static_cast<uint32>(bucket_ranges_->size()); |
| for (size_t index = 0; index < bucket_count(); ++index) |
| checksum = Crc32(checksum, ranges(index)); |
| return checksum; |
| } |
| |
| void Histogram::Initialize() { |
| sample_.Resize(*this); |
| if (declared_min_ < 1) |
| declared_min_ = 1; |
| if (declared_max_ > kSampleType_MAX - 1) |
| declared_max_ = kSampleType_MAX - 1; |
| DCHECK_LE(declared_min_, declared_max_); |
| DCHECK_GT(bucket_count_, 1u); |
| CHECK_LT(bucket_count_, kBucketCount_MAX); |
| size_t maximal_bucket_count = declared_max_ - declared_min_ + 2; |
| DCHECK_LE(bucket_count_, maximal_bucket_count); |
| DCHECK_EQ(0, ranges(0)); |
| bucket_ranges_->set_range(bucket_count_, kSampleType_MAX); |
| } |
| |
| // We generate the CRC-32 using the low order bits to select whether to XOR in |
| // the reversed polynomial 0xedb88320L. This is nice and simple, and allows us |
| // to keep the quotient in a uint32. Since we're not concerned about the nature |
| // of corruptions (i.e., we don't care about bit sequencing, since we are |
| // handling memory changes, which are more grotesque) so we don't bother to |
| // get the CRC correct for big-endian vs little-ending calculations. All we |
| // need is a nice hash, that tends to depend on all the bits of the sample, with |
| // very little chance of changes in one place impacting changes in another |
| // place. |
| uint32 Histogram::Crc32(uint32 sum, Histogram::Sample range) { |
| const bool kUseRealCrc = true; // TODO(jar): Switch to false and watch stats. |
| if (kUseRealCrc) { |
| union { |
| Histogram::Sample range; |
| unsigned char bytes[sizeof(Histogram::Sample)]; |
| } converter; |
| converter.range = range; |
| for (size_t i = 0; i < sizeof(converter); ++i) |
| sum = kCrcTable[(sum & 0xff) ^ converter.bytes[i]] ^ (sum >> 8); |
| } else { |
| // Use hash techniques provided in ReallyFastHash, except we don't care |
| // about "avalanching" (which would worsten the hash, and add collisions), |
| // and we don't care about edge cases since we have an even number of bytes. |
| union { |
| Histogram::Sample range; |
| uint16 ints[sizeof(Histogram::Sample) / 2]; |
| } converter; |
| DCHECK_EQ(sizeof(Histogram::Sample), sizeof(converter)); |
| converter.range = range; |
| sum += converter.ints[0]; |
| sum = (sum << 16) ^ sum ^ (static_cast<uint32>(converter.ints[1]) << 11); |
| sum += sum >> 11; |
| } |
| return sum; |
| } |
| |
| //------------------------------------------------------------------------------ |
| // Private methods |
| |
| double Histogram::GetPeakBucketSize(const SampleSet& snapshot) const { |
| double max = 0; |
| for (size_t i = 0; i < bucket_count() ; ++i) { |
| double current_size = GetBucketSize(snapshot.counts(i), i); |
| if (current_size > max) |
| max = current_size; |
| } |
| return max; |
| } |
| |
| void Histogram::WriteAsciiHeader(const SampleSet& snapshot, |
| Count sample_count, |
| std::string* output) const { |
| StringAppendF(output, |
| "Histogram: %s recorded %d samples", |
| histogram_name().c_str(), |
| sample_count); |
| if (0 == sample_count) { |
| DCHECK_EQ(snapshot.sum(), 0); |
| } else { |
| double average = static_cast<float>(snapshot.sum()) / sample_count; |
| |
| StringAppendF(output, ", average = %.1f", average); |
| } |
| if (flags_ & ~kHexRangePrintingFlag) |
| StringAppendF(output, " (flags = 0x%x)", flags_ & ~kHexRangePrintingFlag); |
| } |
| |
| void Histogram::WriteAsciiBucketContext(const int64 past, |
| const Count current, |
| const int64 remaining, |
| const size_t i, |
| std::string* output) const { |
| double scaled_sum = (past + current + remaining) / 100.0; |
| WriteAsciiBucketValue(current, scaled_sum, output); |
| if (0 < i) { |
| double percentage = past / scaled_sum; |
| StringAppendF(output, " {%3.1f%%}", percentage); |
| } |
| } |
| |
| void Histogram::WriteAsciiBucketValue(Count current, double scaled_sum, |
| std::string* output) const { |
| StringAppendF(output, " (%d = %3.1f%%)", current, current/scaled_sum); |
| } |
| |
| void Histogram::WriteAsciiBucketGraph(double current_size, double max_size, |
| std::string* output) const { |
| const int k_line_length = 72; // Maximal horizontal width of graph. |
| int x_count = static_cast<int>(k_line_length * (current_size / max_size) |
| + 0.5); |
| int x_remainder = k_line_length - x_count; |
| |
| while (0 < x_count--) |
| output->append("-"); |
| output->append("O"); |
| while (0 < x_remainder--) |
| output->append(" "); |
| } |
| |
| //------------------------------------------------------------------------------ |
| // Methods for the Histogram::SampleSet class |
| //------------------------------------------------------------------------------ |
| |
| Histogram::SampleSet::SampleSet() |
| : counts_(), |
| sum_(0), |
| redundant_count_(0) { |
| } |
| |
| Histogram::SampleSet::~SampleSet() { |
| } |
| |
| void Histogram::SampleSet::Resize(const Histogram& histogram) { |
| counts_.resize(histogram.bucket_count(), 0); |
| } |
| |
| void Histogram::SampleSet::CheckSize(const Histogram& histogram) const { |
| DCHECK_EQ(histogram.bucket_count(), counts_.size()); |
| } |
| |
| |
| void Histogram::SampleSet::Accumulate(Sample value, Count count, |
| size_t index) { |
| DCHECK(count == 1 || count == -1); |
| counts_[index] += count; |
| sum_ += count * value; |
| redundant_count_ += count; |
| DCHECK_GE(counts_[index], 0); |
| DCHECK_GE(sum_, 0); |
| DCHECK_GE(redundant_count_, 0); |
| } |
| |
| Count Histogram::SampleSet::TotalCount() const { |
| Count total = 0; |
| for (Counts::const_iterator it = counts_.begin(); |
| it != counts_.end(); |
| ++it) { |
| total += *it; |
| } |
| return total; |
| } |
| |
| void Histogram::SampleSet::Add(const SampleSet& other) { |
| DCHECK_EQ(counts_.size(), other.counts_.size()); |
| sum_ += other.sum_; |
| redundant_count_ += other.redundant_count_; |
| for (size_t index = 0; index < counts_.size(); ++index) |
| counts_[index] += other.counts_[index]; |
| } |
| |
| void Histogram::SampleSet::Subtract(const SampleSet& other) { |
| DCHECK_EQ(counts_.size(), other.counts_.size()); |
| // Note: Race conditions in snapshotting a sum may lead to (temporary) |
| // negative values when snapshots are later combined (and deltas calculated). |
| // As a result, we don't currently CHCEK() for positive values. |
| sum_ -= other.sum_; |
| redundant_count_ -= other.redundant_count_; |
| for (size_t index = 0; index < counts_.size(); ++index) { |
| counts_[index] -= other.counts_[index]; |
| DCHECK_GE(counts_[index], 0); |
| } |
| } |
| |
| bool Histogram::SampleSet::Serialize(Pickle* pickle) const { |
| pickle->WriteInt64(sum_); |
| pickle->WriteInt64(redundant_count_); |
| pickle->WriteUInt64(counts_.size()); |
| |
| for (size_t index = 0; index < counts_.size(); ++index) { |
| pickle->WriteInt(counts_[index]); |
| } |
| |
| return true; |
| } |
| |
| bool Histogram::SampleSet::Deserialize(PickleIterator* iter) { |
| DCHECK_EQ(counts_.size(), 0u); |
| DCHECK_EQ(sum_, 0); |
| DCHECK_EQ(redundant_count_, 0); |
| |
| uint64 counts_size; |
| |
| if (!iter->ReadInt64(&sum_) || |
| !iter->ReadInt64(&redundant_count_) || |
| !iter->ReadUInt64(&counts_size)) { |
| return false; |
| } |
| |
| if (counts_size == 0) |
| return false; |
| |
| int count = 0; |
| for (uint64 index = 0; index < counts_size; ++index) { |
| int i; |
| if (!iter->ReadInt(&i)) |
| return false; |
| counts_.push_back(i); |
| count += i; |
| } |
| DCHECK_EQ(count, redundant_count_); |
| return count == redundant_count_; |
| } |
| |
| //------------------------------------------------------------------------------ |
| // LinearHistogram: This histogram uses a traditional set of evenly spaced |
| // buckets. |
| //------------------------------------------------------------------------------ |
| |
| LinearHistogram::~LinearHistogram() { |
| } |
| |
| Histogram* LinearHistogram::FactoryGet(const std::string& name, |
| Sample minimum, |
| Sample maximum, |
| size_t bucket_count, |
| Flags flags) { |
| if (minimum < 1) |
| minimum = 1; |
| if (maximum > kSampleType_MAX - 1) |
| maximum = kSampleType_MAX - 1; |
| |
| DCHECK_GT(maximum, minimum); |
| DCHECK_GT((Sample) bucket_count, 2); |
| DCHECK_LE((Sample) bucket_count, maximum - minimum + 2); |
| |
| Histogram* histogram = StatisticsRecorder::FindHistogram(name); |
| if (!histogram) { |
| // To avoid racy destruction at shutdown, the following will be leaked. |
| LinearHistogram* tentative_histogram = |
| new LinearHistogram(name, minimum, maximum, bucket_count); |
| tentative_histogram->InitializeBucketRange(); |
| tentative_histogram->SetFlags(flags); |
| histogram = |
| StatisticsRecorder::RegisterOrDeleteDuplicate(tentative_histogram); |
| } |
| |
| DCHECK_EQ(LINEAR_HISTOGRAM, histogram->histogram_type()); |
| DCHECK(histogram->HasConstructorArguments(minimum, maximum, bucket_count)); |
| return histogram; |
| } |
| |
| Histogram* LinearHistogram::FactoryTimeGet(const std::string& name, |
| TimeDelta minimum, |
| TimeDelta maximum, |
| size_t bucket_count, |
| Flags flags) { |
| return FactoryGet(name, minimum.InMilliseconds(), maximum.InMilliseconds(), |
| bucket_count, flags); |
| } |
| |
| Histogram::ClassType LinearHistogram::histogram_type() const { |
| return LINEAR_HISTOGRAM; |
| } |
| |
| void LinearHistogram::SetRangeDescriptions( |
| const DescriptionPair descriptions[]) { |
| for (int i =0; descriptions[i].description; ++i) { |
| bucket_description_[descriptions[i].sample] = descriptions[i].description; |
| } |
| } |
| |
| LinearHistogram::LinearHistogram(const std::string& name, |
| Sample minimum, |
| Sample maximum, |
| size_t bucket_count) |
| : Histogram(name, minimum >= 1 ? minimum : 1, maximum, bucket_count) { |
| } |
| |
| LinearHistogram::LinearHistogram(const std::string& name, |
| TimeDelta minimum, |
| TimeDelta maximum, |
| size_t bucket_count) |
| : Histogram(name, minimum >= TimeDelta::FromMilliseconds(1) ? |
| minimum : TimeDelta::FromMilliseconds(1), |
| maximum, bucket_count) { |
| } |
| |
| void LinearHistogram::InitializeBucketRange() { |
| DCHECK_GT(declared_min(), 0); // 0 is the underflow bucket here. |
| double min = declared_min(); |
| double max = declared_max(); |
| size_t i; |
| for (i = 1; i < bucket_count(); ++i) { |
| double linear_range = (min * (bucket_count() -1 - i) + max * (i - 1)) / |
| (bucket_count() - 2); |
| SetBucketRange(i, static_cast<int> (linear_range + 0.5)); |
| } |
| ResetRangeChecksum(); |
| } |
| |
| double LinearHistogram::GetBucketSize(Count current, size_t i) const { |
| DCHECK_GT(ranges(i + 1), ranges(i)); |
| // Adjacent buckets with different widths would have "surprisingly" many (few) |
| // samples in a histogram if we didn't normalize this way. |
| double denominator = ranges(i + 1) - ranges(i); |
| return current/denominator; |
| } |
| |
| const std::string LinearHistogram::GetAsciiBucketRange(size_t i) const { |
| int range = ranges(i); |
| BucketDescriptionMap::const_iterator it = bucket_description_.find(range); |
| if (it == bucket_description_.end()) |
| return Histogram::GetAsciiBucketRange(i); |
| return it->second; |
| } |
| |
| bool LinearHistogram::PrintEmptyBucket(size_t index) const { |
| return bucket_description_.find(ranges(index)) == bucket_description_.end(); |
| } |
| |
| |
| //------------------------------------------------------------------------------ |
| // This section provides implementation for BooleanHistogram. |
| //------------------------------------------------------------------------------ |
| |
| Histogram* BooleanHistogram::FactoryGet(const std::string& name, Flags flags) { |
| Histogram* histogram = StatisticsRecorder::FindHistogram(name); |
| if (!histogram) { |
| // To avoid racy destruction at shutdown, the following will be leaked. |
| BooleanHistogram* tentative_histogram = new BooleanHistogram(name); |
| tentative_histogram->InitializeBucketRange(); |
| tentative_histogram->SetFlags(flags); |
| histogram = |
| StatisticsRecorder::RegisterOrDeleteDuplicate(tentative_histogram); |
| } |
| |
| DCHECK_EQ(BOOLEAN_HISTOGRAM, histogram->histogram_type()); |
| return histogram; |
| } |
| |
| Histogram::ClassType BooleanHistogram::histogram_type() const { |
| return BOOLEAN_HISTOGRAM; |
| } |
| |
| void BooleanHistogram::AddBoolean(bool value) { |
| Add(value ? 1 : 0); |
| } |
| |
| BooleanHistogram::BooleanHistogram(const std::string& name) |
| : LinearHistogram(name, 1, 2, 3) { |
| } |
| |
| //------------------------------------------------------------------------------ |
| // CustomHistogram: |
| //------------------------------------------------------------------------------ |
| |
| Histogram* CustomHistogram::FactoryGet(const std::string& name, |
| const std::vector<Sample>& custom_ranges, |
| Flags flags) { |
| // Remove the duplicates in the custom ranges array. |
| std::vector<int> ranges = custom_ranges; |
| ranges.push_back(0); // Ensure we have a zero value. |
| std::sort(ranges.begin(), ranges.end()); |
| ranges.erase(std::unique(ranges.begin(), ranges.end()), ranges.end()); |
| if (ranges.size() <= 1) { |
| DCHECK(false); |
| // Note that we pushed a 0 in above, so for defensive code.... |
| ranges.push_back(1); // Put in some data so we can index to [1]. |
| } |
| |
| DCHECK_LT(ranges.back(), kSampleType_MAX); |
| |
| Histogram* histogram = StatisticsRecorder::FindHistogram(name); |
| if (!histogram) { |
| // To avoid racy destruction at shutdown, the following will be leaked. |
| CustomHistogram* tentative_histogram = new CustomHistogram(name, ranges); |
| tentative_histogram->InitializedCustomBucketRange(ranges); |
| tentative_histogram->SetFlags(flags); |
| histogram = |
| StatisticsRecorder::RegisterOrDeleteDuplicate(tentative_histogram); |
| } |
| |
| DCHECK_EQ(histogram->histogram_type(), CUSTOM_HISTOGRAM); |
| DCHECK(histogram->HasConstructorArguments(ranges[1], ranges.back(), |
| ranges.size())); |
| return histogram; |
| } |
| |
| Histogram::ClassType CustomHistogram::histogram_type() const { |
| return CUSTOM_HISTOGRAM; |
| } |
| |
| // static |
| std::vector<Histogram::Sample> CustomHistogram::ArrayToCustomRanges( |
| const Sample* values, size_t num_values) { |
| std::vector<Sample> all_values; |
| for (size_t i = 0; i < num_values; ++i) { |
| Sample value = values[i]; |
| all_values.push_back(value); |
| |
| // Ensure that a guard bucket is added. If we end up with duplicate |
| // values, FactoryGet will take care of removing them. |
| all_values.push_back(value + 1); |
| } |
| return all_values; |
| } |
| |
| CustomHistogram::CustomHistogram(const std::string& name, |
| const std::vector<Sample>& custom_ranges) |
| : Histogram(name, custom_ranges[1], custom_ranges.back(), |
| custom_ranges.size()) { |
| DCHECK_GT(custom_ranges.size(), 1u); |
| DCHECK_EQ(custom_ranges[0], 0); |
| } |
| |
| bool CustomHistogram::SerializeRanges(Pickle* pickle) const { |
| for (size_t i = 0; i < bucket_ranges()->size(); ++i) { |
| if (!pickle->WriteInt(bucket_ranges()->range(i))) |
| return false; |
| } |
| return true; |
| } |
| |
| // static |
| bool CustomHistogram::DeserializeRanges( |
| PickleIterator* iter, std::vector<Histogram::Sample>* ranges) { |
| for (size_t i = 0; i < ranges->size(); ++i) { |
| if (!iter->ReadInt(&(*ranges)[i])) |
| return false; |
| } |
| return true; |
| } |
| |
| void CustomHistogram::InitializedCustomBucketRange( |
| const std::vector<Sample>& custom_ranges) { |
| DCHECK_GT(custom_ranges.size(), 1u); |
| DCHECK_EQ(custom_ranges[0], 0); |
| DCHECK_LE(custom_ranges.size(), bucket_count()); |
| for (size_t index = 0; index < custom_ranges.size(); ++index) |
| SetBucketRange(index, custom_ranges[index]); |
| ResetRangeChecksum(); |
| } |
| |
| double CustomHistogram::GetBucketSize(Count current, size_t i) const { |
| return 1; |
| } |
| |
| } // namespace base |