f5759c5149
[ Merge of http://go/wvgerrit/137811 ] Renamed TimerMetric to Timer. Timer is used to generate durations included in metrics, but is not a metric itself. The method of getting the current time did not require creating an instance of std::steady_clock. Updated Distribution and Timer to use default initializers instead of constructor initialization list. Bug: 204946540 Test: Metric unit tests Change-Id: I7ed291b586347dd0b7ab305960883bec04637315
53 lines
1.7 KiB
C++
53 lines
1.7 KiB
C++
// Copyright 2017 Google LLC. All Rights Reserved. This file and proprietary
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// source code may only be used and distributed under the Widevine License
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// Agreement.
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//
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// This file contains the definition of a Distribution class which computes
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// the distribution values of a series of samples.
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#ifndef WVCDM_METRICS_DISTRIBUTION_H_
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#define WVCDM_METRICS_DISTRIBUTION_H_
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#include <stdint.h>
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#include <limits>
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namespace wvcdm {
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namespace metrics {
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// The Distribution class holds statistics about a series of values that the
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// client provides via the Record method. A caller will call Record once for
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// each of the values in a series. The Distribution instance will calculate the
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// mean, count, min, max and variance of the distribution.
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//
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// Example usage:
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// Distribution dist;
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// dist.Record(1);
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// dist.Record(2);
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// dist.Mean(); // Returns 1.5.
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// dist.Count(); // Returns 2.
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class Distribution {
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public:
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Distribution() {}
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// Uses the provided sample value to update the computed statistics.
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void Record(float value);
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// Return the value for each of the stats computed about the series of
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// values (min, max, count, etc.).
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float Min() const { return min_; }
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float Max() const { return max_; }
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float Mean() const { return mean_; }
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uint64_t Count() const { return count_; }
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double Variance() const {
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return count_ == 0 ? 0.0 : sum_squared_deviation_ / count_;
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}
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private:
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uint64_t count_ = 0;
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float min_ = std::numeric_limits<float>::max();
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float max_ = std::numeric_limits<float>::lowest();
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float mean_ = 0.0f;
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double sum_squared_deviation_ = 0.0;
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};
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} // namespace metrics
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} // namespace wvcdm
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#endif // WVCDM_METRICS_DISTRIBUTION_H_
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