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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 MODULES_CONGESTION_CONTROLLER_GOOG_CC_TRENDLINE_ESTIMATOR_H_
#define MODULES_CONGESTION_CONTROLLER_GOOG_CC_TRENDLINE_ESTIMATOR_H_
#include <stddef.h>
#include <stdint.h>
#include <deque>
#include <memory>
#include "api/field_trials_view.h"
#include "api/network_state_predictor.h"
#include "modules/congestion_controller/goog_cc/delay_increase_detector_interface.h"
#include "rtc_base/experiments/struct_parameters_parser.h"
namespace webrtc {
struct TrendlineEstimatorSettings {
static constexpr char kKey[] = "WebRTC-Bwe-TrendlineEstimatorSettings";
static constexpr unsigned kDefaultTrendlineWindowSize = 20;
TrendlineEstimatorSettings() = delete;
explicit TrendlineEstimatorSettings(const FieldTrialsView* key_value_config);
// Sort the packets in the window. Should be redundant,
// but then almost no cost.
bool enable_sort = false;
// Cap the trendline slope based on the minimum delay seen
// in the beginning_packets and end_packets respectively.
bool enable_cap = false;
unsigned beginning_packets = 7;
unsigned end_packets = 7;
double cap_uncertainty = 0.0;
// Size (in packets) of the window.
unsigned window_size = kDefaultTrendlineWindowSize;
std::unique_ptr<StructParametersParser> Parser();
};
class TrendlineEstimator : public DelayIncreaseDetectorInterface {
public:
TrendlineEstimator(const FieldTrialsView* key_value_config,
NetworkStatePredictor* network_state_predictor);
~TrendlineEstimator() override;
TrendlineEstimator(const TrendlineEstimator&) = delete;
TrendlineEstimator& operator=(const TrendlineEstimator&) = delete;
// Update the estimator with a new sample. The deltas should represent deltas
// between timestamp groups as defined by the InterArrival class.
void Update(double recv_delta_ms,
double send_delta_ms,
int64_t send_time_ms,
int64_t arrival_time_ms,
size_t packet_size,
bool calculated_deltas) override;
void UpdateTrendline(double recv_delta_ms,
double send_delta_ms,
int64_t send_time_ms,
int64_t arrival_time_ms,
size_t packet_size);
BandwidthUsage State() const override;
struct PacketTiming {
PacketTiming(double arrival_time_ms,
double smoothed_delay_ms,
double raw_delay_ms)
: arrival_time_ms(arrival_time_ms),
smoothed_delay_ms(smoothed_delay_ms),
raw_delay_ms(raw_delay_ms) {}
double arrival_time_ms;
double smoothed_delay_ms;
double raw_delay_ms;
};
private:
friend class GoogCcStatePrinter;
void Detect(double trend, double ts_delta, int64_t now_ms);
void UpdateThreshold(double modified_offset, int64_t now_ms);
// Parameters.
TrendlineEstimatorSettings settings_;
const double smoothing_coef_;
const double threshold_gain_;
// Used by the existing threshold.
int num_of_deltas_;
// Keep the arrival times small by using the change from the first packet.
int64_t first_arrival_time_ms_;
// Exponential backoff filtering.
double accumulated_delay_;
double smoothed_delay_;
// Linear least squares regression.
std::deque<PacketTiming> delay_hist_;
const double k_up_;
const double k_down_;
double overusing_time_threshold_;
double threshold_;
double prev_modified_trend_;
int64_t last_update_ms_;
double prev_trend_;
double time_over_using_;
int overuse_counter_;
BandwidthUsage hypothesis_;
BandwidthUsage hypothesis_predicted_;
NetworkStatePredictor* network_state_predictor_;
};
} // namespace webrtc
#endif // MODULES_CONGESTION_CONTROLLER_GOOG_CC_TRENDLINE_ESTIMATOR_H_
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