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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.
*/
#include "modules/congestion_controller/goog_cc/alr_detector.h"
#include <cstdint>
#include <cstdio>
#include <memory>
#include <optional>
#include "api/field_trials_view.h"
#include "api/rtc_event_log/rtc_event_log.h"
#include "logging/rtc_event_log/events/rtc_event_alr_state.h"
#include "rtc_base/checks.h"
#include "rtc_base/experiments/alr_experiment.h"
#include "rtc_base/experiments/struct_parameters_parser.h"
#include "rtc_base/time_utils.h"
namespace webrtc {
namespace {
AlrDetectorConfig GetConfigFromTrials(const FieldTrialsView* key_value_config) {
RTC_CHECK(AlrExperimentSettings::MaxOneFieldTrialEnabled(*key_value_config));
std::optional<AlrExperimentSettings> experiment_settings =
AlrExperimentSettings::CreateFromFieldTrial(
*key_value_config,
AlrExperimentSettings::kScreenshareProbingBweExperimentName);
if (!experiment_settings) {
experiment_settings = AlrExperimentSettings::CreateFromFieldTrial(
*key_value_config,
AlrExperimentSettings::kStrictPacingAndProbingExperimentName);
}
AlrDetectorConfig conf;
if (experiment_settings) {
conf.bandwidth_usage_ratio =
experiment_settings->alr_bandwidth_usage_percent / 100.0;
conf.start_budget_level_ratio =
experiment_settings->alr_start_budget_level_percent / 100.0;
conf.stop_budget_level_ratio =
experiment_settings->alr_stop_budget_level_percent / 100.0;
}
conf.Parser()->Parse(
key_value_config->Lookup("WebRTC-AlrDetectorParameters"));
return conf;
}
} // namespace
std::unique_ptr<StructParametersParser> AlrDetectorConfig::Parser() {
return StructParametersParser::Create( //
"bw_usage", &bandwidth_usage_ratio, //
"start", &start_budget_level_ratio, //
"stop", &stop_budget_level_ratio);
}
AlrDetector::AlrDetector(AlrDetectorConfig config, RtcEventLog* event_log)
: conf_(config), alr_budget_(0, true), event_log_(event_log) {}
AlrDetector::AlrDetector(const FieldTrialsView* key_value_config)
: AlrDetector(GetConfigFromTrials(key_value_config), nullptr) {}
AlrDetector::AlrDetector(const FieldTrialsView* key_value_config,
RtcEventLog* event_log)
: AlrDetector(GetConfigFromTrials(key_value_config), event_log) {}
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_ratio() > conf_.start_budget_level_ratio &&
!alr_started_time_ms_) {
alr_started_time_ms_.emplace(TimeMillis());
state_changed = true;
} else if (alr_budget_.budget_ratio() < conf_.stop_budget_level_ratio &&
alr_started_time_ms_) {
state_changed = true;
alr_started_time_ms_.reset();
}
if (event_log_ && state_changed) {
event_log_->Log(
std::make_unique<RtcEventAlrState>(alr_started_time_ms_.has_value()));
}
}
void AlrDetector::SetEstimatedBitrate(int bitrate_bps) {
RTC_DCHECK(bitrate_bps);
int target_rate_kbps =
static_cast<double>(bitrate_bps) * conf_.bandwidth_usage_ratio / 1000;
alr_budget_.set_target_rate_kbps(target_rate_kbps);
}
std::optional<int64_t> AlrDetector::GetApplicationLimitedRegionStartTime()
const {
return alr_started_time_ms_;
}
} // namespace webrtc
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