blob: 9ff40779a19d511285aecfca643debf5714676db [file] [log] [blame]
/*
* 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.
*/
#include "modules/congestion_controller/goog_cc/alr_detector.h"
#include <cstdint>
#include <cstdio>
#include "absl/memory/memory.h"
#include "logging/rtc_event_log/events/rtc_event.h"
#include "logging/rtc_event_log/events/rtc_event_alr_state.h"
#include "logging/rtc_event_log/rtc_event_log.h"
#include "rtc_base/checks.h"
#include "rtc_base/experiments/alr_experiment.h"
#include "rtc_base/numerics/safe_conversions.h"
namespace webrtc {
AlrDetector::AlrDetector() : AlrDetector(nullptr) {}
AlrDetector::AlrDetector(RtcEventLog* event_log)
: bandwidth_usage_percent_(kDefaultAlrBandwidthUsagePercent),
alr_start_budget_level_percent_(kDefaultAlrStartBudgetLevelPercent),
alr_stop_budget_level_percent_(kDefaultAlrStopBudgetLevelPercent),
alr_budget_(0, true),
event_log_(event_log) {
RTC_CHECK(AlrExperimentSettings::MaxOneFieldTrialEnabled());
absl::optional<AlrExperimentSettings> experiment_settings =
AlrExperimentSettings::CreateFromFieldTrial(
AlrExperimentSettings::kScreenshareProbingBweExperimentName);
if (!experiment_settings) {
experiment_settings = AlrExperimentSettings::CreateFromFieldTrial(
AlrExperimentSettings::kStrictPacingAndProbingExperimentName);
}
if (experiment_settings) {
alr_stop_budget_level_percent_ =
experiment_settings->alr_stop_budget_level_percent;
alr_start_budget_level_percent_ =
experiment_settings->alr_start_budget_level_percent;
bandwidth_usage_percent_ = experiment_settings->alr_bandwidth_usage_percent;
}
}
AlrDetector::~AlrDetector() {}
void AlrDetector::OnBytesSent(size_t bytes_sent, int64_t send_time_ms) {
if (!last_send_time_ms_.has_value()) {
last_send_time_ms_ = send_time_ms;
// Since the duration for sending the bytes is unknwon, return without
// updating alr state.
return;
}
int64_t delta_time_ms = send_time_ms - *last_send_time_ms_;
last_send_time_ms_ = send_time_ms;
alr_budget_.UseBudget(bytes_sent);
alr_budget_.IncreaseBudget(delta_time_ms);
bool state_changed = false;
if (alr_budget_.budget_level_percent() > alr_start_budget_level_percent_ &&
!alr_started_time_ms_) {
alr_started_time_ms_.emplace(send_time_ms);
state_changed = true;
} else if (alr_budget_.budget_level_percent() <
alr_stop_budget_level_percent_ &&
alr_started_time_ms_) {
state_changed = true;
alr_started_time_ms_.reset();
}
if (event_log_ && state_changed) {
event_log_->Log(
absl::make_unique<RtcEventAlrState>(alr_started_time_ms_.has_value()));
}
}
void AlrDetector::SetEstimatedBitrate(int bitrate_bps) {
RTC_DCHECK(bitrate_bps);
const auto target_rate_kbps = static_cast<int64_t>(bitrate_bps) *
bandwidth_usage_percent_ / (1000 * 100);
alr_budget_.set_target_rate_kbps(rtc::dchecked_cast<int>(target_rate_kbps));
}
absl::optional<int64_t> AlrDetector::GetApplicationLimitedRegionStartTime()
const {
return alr_started_time_ms_;
}
} // namespace webrtc