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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_ALR_DETECTOR_H_
#define MODULES_CONGESTION_CONTROLLER_GOOG_CC_ALR_DETECTOR_H_
#include "absl/types/optional.h"
#include "common_types.h" // NOLINT(build/include)
#include "modules/pacing/interval_budget.h"
#include "rtc_base/rate_statistics.h"
namespace webrtc {
class RtcEventLog;
// Application limited region detector is a class that utilizes signals of
// elapsed time and bytes sent to estimate whether network traffic is
// currently limited by the application's ability to generate traffic.
//
// AlrDetector provides a signal that can be utilized to adjust
// estimate bandwidth.
// Note: This class is not thread-safe.
class AlrDetector {
public:
AlrDetector();
explicit AlrDetector(RtcEventLog* event_log);
~AlrDetector();
void OnBytesSent(size_t bytes_sent, int64_t send_time_ms);
// Set current estimated bandwidth.
void SetEstimatedBitrate(int bitrate_bps);
// Returns time in milliseconds when the current application-limited region
// started or empty result if the sender is currently not application-limited.
absl::optional<int64_t> GetApplicationLimitedRegionStartTime() const;
// Sent traffic percentage as a function of network capacity used to determine
// application-limited region. ALR region start when bandwidth usage drops
// below kAlrStartUsagePercent and ends when it raises above
// kAlrEndUsagePercent. NOTE: This is intentionally conservative at the moment
// until BW adjustments of application limited region is fine tuned.
static constexpr int kDefaultAlrBandwidthUsagePercent = 65;
static constexpr int kDefaultAlrStartBudgetLevelPercent = 80;
static constexpr int kDefaultAlrStopBudgetLevelPercent = 50;
void UpdateBudgetWithElapsedTime(int64_t delta_time_ms);
void UpdateBudgetWithBytesSent(size_t bytes_sent);
private:
friend class GoogCcStatePrinter;
int bandwidth_usage_percent_;
int alr_start_budget_level_percent_;
int alr_stop_budget_level_percent_;
absl::optional<int64_t> last_send_time_ms_;
IntervalBudget alr_budget_;
absl::optional<int64_t> alr_started_time_ms_;
RtcEventLog* event_log_;
};
} // namespace webrtc
#endif // MODULES_CONGESTION_CONTROLLER_GOOG_CC_ALR_DETECTOR_H_