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111 lines
3.5 KiB
C++
111 lines
3.5 KiB
C++
/*
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* Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef MODULES_CONGESTION_CONTROLLER_GOOG_CC_TRENDLINE_ESTIMATOR_H_
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#define MODULES_CONGESTION_CONTROLLER_GOOG_CC_TRENDLINE_ESTIMATOR_H_
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#include <stddef.h>
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#include <stdint.h>
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#include <deque>
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#include <memory>
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#include "api/transport/bandwidth_usage.h"
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#include "delay_increase_detector_interface.h"
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namespace webrtc {
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struct TrendlineEstimatorSettings {
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static constexpr char kKey[] = "WebRTC-Bwe-TrendlineEstimatorSettings";
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static constexpr unsigned kDefaultTrendlineWindowSize = 20;
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TrendlineEstimatorSettings();
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// Sort the packets in the window. Should be redundant,
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// but then almost no cost.
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bool enable_sort = false;
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// Cap the trendline slope based on the minimum delay seen
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// in the beginning_packets and end_packets respectively.
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bool enable_cap = false;
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unsigned beginning_packets = 7;
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unsigned end_packets = 7;
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double cap_uncertainty = 0.0;
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// Size (in packets) of the window.
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unsigned window_size = kDefaultTrendlineWindowSize;
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};
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class TrendlineEstimator : public DelayIncreaseDetectorInterface {
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public:
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TrendlineEstimator();
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~TrendlineEstimator();
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TrendlineEstimator(const TrendlineEstimator&) = delete;
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TrendlineEstimator& operator=(const TrendlineEstimator&) = delete;
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// Update the estimator with a new sample. The deltas should represent deltas
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// between timestamp groups as defined by the InterArrival class.
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void Update(double recv_delta_ms, double send_delta_ms, int64_t send_time_ms,
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int64_t arrival_time_ms, size_t packet_size,
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bool calculated_deltas);
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void UpdateTrendline(double recv_delta_ms, double send_delta_ms,
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int64_t send_time_ms, int64_t arrival_time_ms,
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size_t packet_size);
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BandwidthUsage State() const;
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struct PacketTiming {
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PacketTiming(double arrival_time_ms, double smoothed_delay_ms,
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double raw_delay_ms)
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: arrival_time_ms(arrival_time_ms),
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smoothed_delay_ms(smoothed_delay_ms),
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raw_delay_ms(raw_delay_ms) {}
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double arrival_time_ms;
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double smoothed_delay_ms;
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double raw_delay_ms;
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};
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private:
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friend class GoogCcStatePrinter;
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void Detect(double trend, double ts_delta, int64_t now_ms);
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void UpdateThreshold(double modified_trend, int64_t now_ms);
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// Parameters.
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TrendlineEstimatorSettings settings_;
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const double smoothing_coef_;
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const double threshold_gain_;
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// Used by the existing threshold.
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int num_of_deltas_;
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// Keep the arrival times small by using the change from the first packet.
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int64_t first_arrival_time_ms_;
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// Exponential backoff filtering.
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double accumulated_delay_;
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double smoothed_delay_;
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// Linear least squares regression.
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std::deque<PacketTiming> delay_hist_;
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const double k_up_;
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const double k_down_;
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double overusing_time_threshold_;
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double threshold_;
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double prev_modified_trend_;
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int64_t last_update_ms_;
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double prev_trend_;
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double time_over_using_;
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int overuse_counter_;
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BandwidthUsage hypothesis_;
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BandwidthUsage hypothesis_predicted_;
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};
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} // namespace webrtc
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#endif // MODULES_CONGESTION_CONTROLLER_GOOG_CC_TRENDLINE_ESTIMATOR_H_
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