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/*
* Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef VIDEO_STATS_COUNTER_H_
#define VIDEO_STATS_COUNTER_H_
#include <memory>
#include <string>
namespace webrtc {
class AggregatedCounter;
class Clock;
class Samples;
// `StatsCounterObserver` is called periodically when a metric is updated.
class StatsCounterObserver {
public:
virtual void OnMetricUpdated(int sample) = 0;
virtual ~StatsCounterObserver() {}
};
struct AggregatedStats {
std::string ToString() const;
std::string ToStringWithMultiplier(int multiplier) const;
int64_t num_samples = 0;
int min = -1;
int max = -1;
int average = -1;
// TODO(asapersson): Consider adding median/percentiles.
};
// Classes which periodically computes a metric.
//
// During a period, `kProcessIntervalMs`, different metrics can be computed e.g:
// - `AvgCounter`: average of samples
// - `PercentCounter`: percentage of samples
// - `PermilleCounter`: permille of samples
//
// Each periodic metric can be either:
// - reported to an `observer` each period
// - aggregated during the call (e.g. min, max, average)
//
// periodically computed
// GetMetric() GetMetric() => AggregatedStats
// ^ ^ (e.g. min/max/avg)
// | |
// | * * * * | ** * * * * | ...
// |<- process interval ->|
//
// (*) - samples
//
//
// Example usage:
//
// AvgCounter counter(&clock, nullptr);
// counter.Add(5);
// counter.Add(1);
// counter.Add(6); // process interval passed -> GetMetric() avg:4
// counter.Add(7);
// counter.Add(3); // process interval passed -> GetMetric() avg:5
// counter.Add(10);
// counter.Add(20); // process interval passed -> GetMetric() avg:15
// AggregatedStats stats = counter.GetStats();
// stats: {min:4, max:15, avg:8}
//
// Note: StatsCounter takes ownership of `observer`.
class StatsCounter {
public:
virtual ~StatsCounter();
// Gets metric within an interval. Returns true on success false otherwise.
virtual bool GetMetric(int* metric) const = 0;
// Gets the value to use for an interval without samples.
virtual int GetValueForEmptyInterval() const = 0;
// Gets aggregated stats (i.e. aggregate of periodically computed metrics).
AggregatedStats GetStats();
// Reports metrics for elapsed intervals to AggregatedCounter and GetStats.
AggregatedStats ProcessAndGetStats();
// Reports metrics for elapsed intervals to AggregatedCounter and pauses stats
// (i.e. empty intervals will be discarded until next sample is added).
void ProcessAndPause();
// As above with a minimum pause time. Added samples within this interval will
// not resume the stats (i.e. stop the pause).
void ProcessAndPauseForDuration(int64_t min_pause_time_ms);
// Reports metrics for elapsed intervals to AggregatedCounter and stops pause.
void ProcessAndStopPause();
// Checks if a sample has been added (i.e. Add or Set called).
bool HasSample() const;
protected:
StatsCounter(Clock* clock,
int64_t process_intervals_ms,
bool include_empty_intervals,
StatsCounterObserver* observer);
void Add(int sample);
void Set(int64_t sample, uint32_t stream_id);
void SetLast(int64_t sample, uint32_t stream_id);
const bool include_empty_intervals_;
const int64_t process_intervals_ms_;
const std::unique_ptr<AggregatedCounter> aggregated_counter_;
const std::unique_ptr<Samples> samples_;
private:
bool TimeToProcess(int* num_elapsed_intervals);
void TryProcess();
void ReportMetricToAggregatedCounter(int value, int num_values_to_add) const;
bool IncludeEmptyIntervals() const;
void Resume();
void ResumeIfMinTimePassed();
Clock* const clock_;
const std::unique_ptr<StatsCounterObserver> observer_;
int64_t last_process_time_ms_;
bool paused_;
int64_t pause_time_ms_;
int64_t min_pause_time_ms_;
};
// AvgCounter: average of samples
//
// | * * * | * * | ...
// | Add(5) Add(1) Add(6) | Add(5) Add(5) |
// GetMetric | (5 + 1 + 6) / 3 | (5 + 5) / 2 |
//
// `include_empty_intervals`: If set, intervals without samples will be included
// in the stats. The value for an interval is
// determined by GetValueForEmptyInterval().
//
class AvgCounter : public StatsCounter {
public:
AvgCounter(Clock* clock,
StatsCounterObserver* observer,
bool include_empty_intervals);
~AvgCounter() override {}
AvgCounter(const AvgCounter&) = delete;
AvgCounter& operator=(const AvgCounter&) = delete;
void Add(int sample);
private:
bool GetMetric(int* metric) const override;
// Returns the last computed metric (i.e. from GetMetric).
int GetValueForEmptyInterval() const override;
};
// MaxCounter: maximum of samples
//
// | * * * | * * | ...
// | Add(5) Add(1) Add(6) | Add(5) Add(5) |
// GetMetric | max: (5, 1, 6) | max: (5, 5) |
//
class MaxCounter : public StatsCounter {
public:
MaxCounter(Clock* clock,
StatsCounterObserver* observer,
int64_t process_intervals_ms);
~MaxCounter() override {}
MaxCounter(const MaxCounter&) = delete;
MaxCounter& operator=(const MaxCounter&) = delete;
void Add(int sample);
private:
bool GetMetric(int* metric) const override;
int GetValueForEmptyInterval() const override;
};
// PercentCounter: percentage of samples
//
// | * * * | * * | ...
// | Add(T) Add(F) Add(T) | Add(F) Add(T) |
// GetMetric | 100 * 2 / 3 | 100 * 1 / 2 |
//
class PercentCounter : public StatsCounter {
public:
PercentCounter(Clock* clock, StatsCounterObserver* observer);
~PercentCounter() override {}
PercentCounter(const PercentCounter&) = delete;
PercentCounter& operator=(const PercentCounter&) = delete;
void Add(bool sample);
private:
bool GetMetric(int* metric) const override;
int GetValueForEmptyInterval() const override;
};
// PermilleCounter: permille of samples
//
// | * * * | * * | ...
// | Add(T) Add(F) Add(T) | Add(F) Add(T) |
// GetMetric | 1000 * 2 / 3 | 1000 * 1 / 2 |
//
class PermilleCounter : public StatsCounter {
public:
PermilleCounter(Clock* clock, StatsCounterObserver* observer);
~PermilleCounter() override {}
PermilleCounter(const PermilleCounter&) = delete;
PermilleCounter& operator=(const PermilleCounter&) = delete;
void Add(bool sample);
private:
bool GetMetric(int* metric) const override;
int GetValueForEmptyInterval() const override;
};
// RateCounter: units per second
//
// | * * * | * * | ...
// | Add(5) Add(1) Add(6) | Add(5) Add(5) |
// |<------ 2 sec ------->| |
// GetMetric | (5 + 1 + 6) / 2 | (5 + 5) / 2 |
//
// `include_empty_intervals`: If set, intervals without samples will be included
// in the stats. The value for an interval is
// determined by GetValueForEmptyInterval().
//
class RateCounter : public StatsCounter {
public:
RateCounter(Clock* clock,
StatsCounterObserver* observer,
bool include_empty_intervals);
~RateCounter() override {}
RateCounter(const RateCounter&) = delete;
RateCounter& operator=(const RateCounter&) = delete;
void Add(int sample);
private:
bool GetMetric(int* metric) const override;
int GetValueForEmptyInterval() const override; // Returns zero.
};
// RateAccCounter: units per second (used for counters)
//
// | * * * | * * | ...
// | Set(5) Set(6) Set(8) | Set(11) Set(13) |
// |<------ 2 sec ------->| |
// GetMetric | (8 - 0) / 2 | (13 - 8) / 2 |
//
// `include_empty_intervals`: If set, intervals without samples will be included
// in the stats. The value for an interval is
// determined by GetValueForEmptyInterval().
//
class RateAccCounter : public StatsCounter {
public:
RateAccCounter(Clock* clock,
StatsCounterObserver* observer,
bool include_empty_intervals);
~RateAccCounter() override {}
RateAccCounter(const RateAccCounter&) = delete;
RateAccCounter& operator=(const RateAccCounter&) = delete;
void Set(int64_t sample, uint32_t stream_id);
// Sets the value for previous interval.
// To be used if a value other than zero is initially required.
void SetLast(int64_t sample, uint32_t stream_id);
private:
bool GetMetric(int* metric) const override;
int GetValueForEmptyInterval() const override; // Returns zero.
};
} // namespace webrtc
#endif // VIDEO_STATS_COUNTER_H_