From 36d22d82aa202bb199967e9512281e9a53db42c9 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 21:33:14 +0200 Subject: Adding upstream version 115.7.0esr. Signed-off-by: Daniel Baumann --- ipc/chromium/src/base/histogram.h | 432 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 432 insertions(+) create mode 100644 ipc/chromium/src/base/histogram.h (limited to 'ipc/chromium/src/base/histogram.h') diff --git a/ipc/chromium/src/base/histogram.h b/ipc/chromium/src/base/histogram.h new file mode 100644 index 0000000000..f9ea21c8df --- /dev/null +++ b/ipc/chromium/src/base/histogram.h @@ -0,0 +1,432 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +// Copyright (c) 2011 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). + +// It supports calls to accumulate either time intervals (which are processed +// as integral number of milliseconds), or arbitrary integral units. + +// The default layout of buckets is exponential. For example, buckets might +// contain (sequentially) the count of values in the following intervals: +// [0,1), [1,2), [2,4), [4,8), [8,16), [16,32), [32,64), [64,infinity) +// That bucket allocation would actually result from construction of a histogram +// for values between 1 and 64, with 8 buckets, such as: +// Histogram count(L"some name", 1, 64, 8); +// Note that the underflow bucket [0,1) and the overflow bucket [64,infinity) +// are not counted by the constructor in the user supplied "bucket_count" +// argument. +// The above example has an exponential ratio of 2 (doubling the bucket width +// in each consecutive bucket. The Histogram class automatically calculates +// the smallest ratio that it can use to construct the number of buckets +// selected in the constructor. An another example, if you had 50 buckets, +// and millisecond time values from 1 to 10000, then the ratio between +// consecutive bucket widths will be approximately somewhere around the 50th +// root of 10000. This approach provides very fine grain (narrow) buckets +// at the low end of the histogram scale, but allows the histogram to cover a +// gigantic range with the addition of very few buckets. + +// Histograms use a pattern involving a function static variable, that is a +// pointer to a histogram. This static is explicitly initialized on any thread +// that detects a uninitialized (NULL) pointer. The potentially racy +// initialization is not a problem as it is always set to point to the same +// value (i.e., the FactoryGet always returns the same value). FactoryGet +// is also completely thread safe, which results in a completely thread safe, +// and relatively fast, set of counters. To avoid races at shutdown, the static +// pointer is NOT deleted, and we leak the histograms at process termination. + +#ifndef BASE_METRICS_HISTOGRAM_H_ +#define BASE_METRICS_HISTOGRAM_H_ +#pragma once + +#include "mozilla/Atomics.h" +#include "mozilla/MemoryReporting.h" + +#include +#include + +#include "base/time.h" + +#include "nsTArray.h" + +namespace base { + +//------------------------------------------------------------------------------ + +class BooleanHistogram; +class CustomHistogram; +class Histogram; +class LinearHistogram; + +class Histogram { + public: + typedef int Sample; // Used for samples (and ranges of samples). + typedef int Count; // Used to count samples in a bucket. + static const Sample kSampleType_MAX = INT_MAX; + // Initialize maximum number of buckets in histograms as 16,384. + static const size_t kBucketCount_MAX; + + typedef nsTArray Counts; + typedef const Sample* Ranges; + + // These enums are used to facilitate deserialization of renderer histograms + // into the browser. + enum ClassType { + HISTOGRAM, + LINEAR_HISTOGRAM, + BOOLEAN_HISTOGRAM, + FLAG_HISTOGRAM, + COUNT_HISTOGRAM, + CUSTOM_HISTOGRAM, + NOT_VALID_IN_RENDERER + }; + + enum BucketLayout { EXPONENTIAL, LINEAR, CUSTOM }; + + enum Flags { + kNoFlags = 0, + kUmaTargetedHistogramFlag = 0x1, // Histogram should be UMA uploaded. + + kHexRangePrintingFlag = 0x8000 // Fancy bucket-naming supported. + }; + + enum Inconsistencies { + NO_INCONSISTENCIES = 0x0, + RANGE_CHECKSUM_ERROR = 0x1, + BUCKET_ORDER_ERROR = 0x2, + COUNT_HIGH_ERROR = 0x4, + COUNT_LOW_ERROR = 0x8, + + NEVER_EXCEEDED_VALUE = 0x10 + }; + + struct DescriptionPair { + Sample sample; + const char* description; // Null means end of a list of pairs. + }; + + size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf); + + bool is_empty() const { + return this->sample_.counts(0) == 0 && this->sample_.sum() == 0; + } + + //---------------------------------------------------------------------------- + // Statistic values, developed over the life of the histogram. + + class SampleSet { + public: + explicit SampleSet(); + ~SampleSet(); + SampleSet(SampleSet&&) = default; + + // None of the methods in this class are thread-safe. Callers + // must deal with locking themselves. + + // Adjust size of counts_ for use with given histogram. + void Resize(const Histogram& histogram); + + // Accessor for histogram to make routine additions. + void Accumulate(Sample value, Count count, size_t index); + + // Arithmetic manipulation of corresponding elements of the set. + void Add(const SampleSet& other); + + size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf); + + Count counts(size_t i) const { return counts_[i]; } + Count TotalCount() const; + int64_t sum() const { return sum_; } + int64_t redundant_count() const { return redundant_count_; } + size_t size() const { return counts_.Length(); } + SampleSet Clone() const { + SampleSet result; + result.counts_ = counts_.Clone(); + result.sum_ = sum_; + result.redundant_count_ = redundant_count_; + return result; + } + void Clear() { + sum_ = 0; + redundant_count_ = 0; + for (int& i : counts_) { + i = 0; + } + } + + protected: + // Actual histogram data is stored in buckets, showing the count of values + // that fit into each bucket. + Counts counts_; + + // Save simple stats locally. Note that this MIGHT get done in base class + // without shared memory at some point. + int64_t sum_; // sum of samples. + + // To help identify memory corruption, we reduntantly save the number of + // samples we've accumulated into all of our buckets. We can compare this + // count to the sum of the counts in all buckets, and detect problems. Note + // that due to races in histogram accumulation (if a histogram is indeed + // updated on several threads simultaneously), the tallies might mismatch, + // and also the snapshotting code may asynchronously get a mismatch (though + // generally either race based mismatch cause is VERY rare). + int64_t redundant_count_; + }; + + //---------------------------------------------------------------------------- + // minimum should start from 1. 0 is invalid as a minimum. 0 is an implicit + // default underflow bucket. + static Histogram* FactoryGet(Sample minimum, Sample maximum, + size_t bucket_count, Flags flags, + const int* buckets); + + virtual ~Histogram(); + + void Add(int value); + void Subtract(int value); + + // This method is an interface, used only by BooleanHistogram. + virtual void AddBoolean(bool value); + + // Accept a TimeDelta to increment. + void AddTime(TimeDelta time) { Add(static_cast(time.InMilliseconds())); } + + virtual void AddSampleSet(const SampleSet& sample); + + virtual void Clear(); + + // This method is an interface, used only by LinearHistogram. + virtual void SetRangeDescriptions(const DescriptionPair descriptions[]); + + // Support generic flagging of Histograms. + // 0x1 Currently used to mark this histogram to be recorded by UMA.. + // 0x8000 means print ranges in hex. + void SetFlags(Flags flags) { flags_ = static_cast(flags_ | flags); } + void ClearFlags(Flags flags) { flags_ = static_cast(flags_ & ~flags); } + int flags() const { return flags_; } + + // Check to see if bucket ranges, counts and tallies in the snapshot are + // consistent with the bucket ranges and checksums in our histogram. This can + // produce a false-alarm if a race occurred in the reading of the data during + // a SnapShot process, but should otherwise be false at all times (unless we + // have memory over-writes, or DRAM failures). + virtual Inconsistencies FindCorruption(const SampleSet& snapshot) const; + + //---------------------------------------------------------------------------- + // Accessors for factory constuction, serialization and testing. + //---------------------------------------------------------------------------- + virtual ClassType histogram_type() const; + Sample declared_min() const { return declared_min_; } + Sample declared_max() const { return declared_max_; } + virtual Sample ranges(size_t i) const; + uint32_t range_checksum() const { return range_checksum_; } + virtual size_t bucket_count() const; + + virtual SampleSet SnapshotSample() const; + + virtual bool HasConstructorArguments(Sample minimum, Sample maximum, + size_t bucket_count); + + virtual bool HasConstructorTimeDeltaArguments(TimeDelta minimum, + TimeDelta maximum, + size_t bucket_count); + // Return true iff the range_checksum_ matches current ranges_ vector. + bool HasValidRangeChecksum() const; + + protected: + Histogram(Sample minimum, Sample maximum, size_t bucket_count); + Histogram(TimeDelta minimum, TimeDelta maximum, size_t bucket_count); + + // Initialize ranges_ mapping from raw data. + void InitializeBucketRangeFromData(const int* buckets); + + // Method to override to skip the display of the i'th bucket if it's empty. + virtual bool PrintEmptyBucket(size_t index) const; + + //---------------------------------------------------------------------------- + // Methods to override to create histogram with different bucket widths. + //---------------------------------------------------------------------------- + // Find bucket to increment for sample value. + virtual size_t BucketIndex(Sample value) const; + // Get normalized size, relative to the ranges_[i]. + virtual double GetBucketSize(Count current, size_t i) const; + + // Recalculate range_checksum_. + void ResetRangeChecksum(); + + // Return a string description of what goes in a given bucket. + // Most commonly this is the numeric value, but in derived classes it may + // be a name (or string description) given to the bucket. + virtual const std::string GetAsciiBucketRange(size_t it) const; + + //---------------------------------------------------------------------------- + // Methods to override to create thread safe histogram. + //---------------------------------------------------------------------------- + // Update all our internal data, including histogram + virtual void Accumulate(Sample value, Count count, size_t index); + + // Validate that ranges_ was created sensibly (top and bottom range + // values relate properly to the declared_min_ and declared_max_).. + bool ValidateBucketRanges() const; + + virtual uint32_t CalculateRangeChecksum() const; + + // Finally, provide the state that changes with the addition of each new + // sample. + SampleSet sample_; + + private: + // Post constructor initialization. + void Initialize(); + + // Checksum function for accumulating range values into a checksum. + static uint32_t Crc32(uint32_t sum, Sample range); + + //---------------------------------------------------------------------------- + // Helpers for emitting Ascii graphic. Each method appends data to output. + + // Find out how large the (graphically) the largest bucket will appear to be. + double GetPeakBucketSize(const SampleSet& snapshot) const; + + //---------------------------------------------------------------------------- + // Table for generating Crc32 values. + static const uint32_t kCrcTable[256]; + //---------------------------------------------------------------------------- + // Invariant values set at/near construction time + + Sample declared_min_; // Less than this goes into counts_[0] + Sample declared_max_; // Over this goes into counts_[bucket_count_ - 1]. + size_t bucket_count_; // Dimension of counts_[]. + + // Flag the histogram for recording by UMA via metric_services.h. + Flags flags_; + + // For each index, show the least value that can be stored in the + // corresponding bucket. We also append one extra element in this array, + // containing kSampleType_MAX, to make calculations easy. + // The dimension of ranges_ is bucket_count + 1. + Ranges ranges_; + + // For redundancy, we store a checksum of all the sample ranges when ranges + // are generated. If ever there is ever a difference, then the histogram must + // have been corrupted. + uint32_t range_checksum_; + + DISALLOW_COPY_AND_ASSIGN(Histogram); +}; + +//------------------------------------------------------------------------------ + +// LinearHistogram is a more traditional histogram, with evenly spaced +// buckets. +class LinearHistogram : public Histogram { + public: + virtual ~LinearHistogram(); + + /* minimum should start from 1. 0 is as minimum is invalid. 0 is an implicit + default underflow bucket. */ + static Histogram* FactoryGet(Sample minimum, Sample maximum, + size_t bucket_count, Flags flags, + const int* buckets); + + // Overridden from Histogram: + virtual ClassType histogram_type() const override; + + virtual void Accumulate(Sample value, Count count, size_t index) override; + + // Store a list of number/text values for use in rendering the histogram. + // The last element in the array has a null in its "description" slot. + virtual void SetRangeDescriptions( + const DescriptionPair descriptions[]) override; + + protected: + LinearHistogram(Sample minimum, Sample maximum, size_t bucket_count); + + LinearHistogram(TimeDelta minimum, TimeDelta maximum, size_t bucket_count); + + virtual double GetBucketSize(Count current, size_t i) const override; + + // If we have a description for a bucket, then return that. Otherwise + // let parent class provide a (numeric) description. + virtual const std::string GetAsciiBucketRange(size_t i) const override; + + // Skip printing of name for numeric range if we have a name (and if this is + // an empty bucket). + virtual bool PrintEmptyBucket(size_t index) const override; + + private: + // For some ranges, we store a printable description of a bucket range. + // If there is no desciption, then GetAsciiBucketRange() uses parent class + // to provide a description. + typedef std::map BucketDescriptionMap; + BucketDescriptionMap bucket_description_; + + DISALLOW_COPY_AND_ASSIGN(LinearHistogram); +}; + +//------------------------------------------------------------------------------ + +// BooleanHistogram is a histogram for booleans. +class BooleanHistogram : public LinearHistogram { + public: + static Histogram* FactoryGet(Flags flags, const int* buckets); + + virtual ClassType histogram_type() const override; + + virtual void AddBoolean(bool value) override; + + virtual void Accumulate(Sample value, Count count, size_t index) override; + + protected: + explicit BooleanHistogram(); + + DISALLOW_COPY_AND_ASSIGN(BooleanHistogram); +}; + +//------------------------------------------------------------------------------ + +// FlagHistogram is like boolean histogram, but only allows a single off/on +// value. +class FlagHistogram : public BooleanHistogram { + public: + static Histogram* FactoryGet(Flags flags, const int* buckets); + + virtual ClassType histogram_type() const override; + + virtual void Accumulate(Sample value, Count count, size_t index) override; + + virtual void AddSampleSet(const SampleSet& sample) override; + + virtual void Clear() override; + + private: + explicit FlagHistogram(); + bool mSwitched; + + DISALLOW_COPY_AND_ASSIGN(FlagHistogram); +}; + +// CountHistogram only allows a single monotic counter value. +class CountHistogram : public LinearHistogram { + public: + static Histogram* FactoryGet(Flags flags, const int* buckets); + + virtual ClassType histogram_type() const override; + + virtual void Accumulate(Sample value, Count count, size_t index) override; + + virtual void AddSampleSet(const SampleSet& sample) override; + + private: + explicit CountHistogram(); + + DISALLOW_COPY_AND_ASSIGN(CountHistogram); +}; + +} // namespace base + +#endif // BASE_METRICS_HISTOGRAM_H_ -- cgit v1.2.3