| /* |
| * Copyright (c) 2018 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_network_control.h" |
| |
| #include <algorithm> |
| #include <functional> |
| #include <limits> |
| #include <memory> |
| #include <string> |
| #include <utility> |
| #include <vector> |
| |
| #include "modules/congestion_controller/acknowledged_bitrate_estimator.h" |
| #include "modules/congestion_controller/alr_detector.h" |
| #include "modules/congestion_controller/include/goog_cc_factory.h" |
| #include "modules/congestion_controller/probe_controller.h" |
| #include "modules/remote_bitrate_estimator/include/bwe_defines.h" |
| #include "modules/remote_bitrate_estimator/test/bwe_test_logging.h" |
| #include "rtc_base/checks.h" |
| #include "rtc_base/format_macros.h" |
| #include "rtc_base/logging.h" |
| #include "rtc_base/ptr_util.h" |
| #include "rtc_base/timeutils.h" |
| #include "system_wrappers/include/field_trial.h" |
| |
| namespace webrtc { |
| namespace { |
| |
| const char kCwndExperiment[] = "WebRTC-CwndExperiment"; |
| const int64_t kDefaultAcceptedQueueMs = 250; |
| |
| // Pacing-rate relative to our target send rate. |
| // Multiplicative factor that is applied to the target bitrate to calculate |
| // the number of bytes that can be transmitted per interval. |
| // Increasing this factor will result in lower delays in cases of bitrate |
| // overshoots from the encoder. |
| const float kDefaultPaceMultiplier = 2.5f; |
| |
| bool CwndExperimentEnabled() { |
| std::string experiment_string = |
| webrtc::field_trial::FindFullName(kCwndExperiment); |
| // The experiment is enabled iff the field trial string begins with "Enabled". |
| return experiment_string.find("Enabled") == 0; |
| } |
| |
| bool ReadCwndExperimentParameter(int64_t* accepted_queue_ms) { |
| RTC_DCHECK(accepted_queue_ms); |
| std::string experiment_string = |
| webrtc::field_trial::FindFullName(kCwndExperiment); |
| int parsed_values = |
| sscanf(experiment_string.c_str(), "Enabled-%" PRId64, accepted_queue_ms); |
| if (parsed_values == 1) { |
| RTC_CHECK_GE(*accepted_queue_ms, 0) |
| << "Accepted must be greater than or equal to 0."; |
| return true; |
| } |
| return false; |
| } |
| |
| // Makes sure that the bitrate and the min, max values are in valid range. |
| static void ClampBitrates(int64_t* bitrate_bps, |
| int64_t* min_bitrate_bps, |
| int64_t* max_bitrate_bps) { |
| // TODO(holmer): We should make sure the default bitrates are set to 10 kbps, |
| // and that we don't try to set the min bitrate to 0 from any applications. |
| // The congestion controller should allow a min bitrate of 0. |
| if (*min_bitrate_bps < congestion_controller::GetMinBitrateBps()) |
| *min_bitrate_bps = congestion_controller::GetMinBitrateBps(); |
| if (*max_bitrate_bps > 0) |
| *max_bitrate_bps = std::max(*min_bitrate_bps, *max_bitrate_bps); |
| if (*bitrate_bps > 0) |
| *bitrate_bps = std::max(*min_bitrate_bps, *bitrate_bps); |
| } |
| |
| std::vector<PacketFeedback> ReceivedPacketsFeedbackAsRtp( |
| const TransportPacketsFeedback report) { |
| std::vector<PacketFeedback> packet_feedback_vector; |
| for (auto& fb : report.PacketsWithFeedback()) { |
| if (fb.receive_time.IsFinite()) { |
| PacketFeedback pf(fb.receive_time.ms(), 0); |
| pf.creation_time_ms = report.feedback_time.ms(); |
| if (fb.sent_packet.has_value()) { |
| pf.payload_size = fb.sent_packet->size.bytes(); |
| pf.pacing_info = fb.sent_packet->pacing_info; |
| pf.send_time_ms = fb.sent_packet->send_time.ms(); |
| } else { |
| pf.send_time_ms = PacketFeedback::kNoSendTime; |
| } |
| packet_feedback_vector.push_back(pf); |
| } |
| } |
| return packet_feedback_vector; |
| } |
| |
| } // namespace |
| |
| GoogCcNetworkControllerFactory::GoogCcNetworkControllerFactory( |
| RtcEventLog* event_log) |
| : event_log_(event_log) {} |
| |
| NetworkControllerInterface::uptr GoogCcNetworkControllerFactory::Create( |
| NetworkControllerObserver* observer) { |
| return rtc::MakeUnique<GoogCcNetworkController>(event_log_, observer); |
| } |
| |
| TimeDelta GoogCcNetworkControllerFactory::GetProcessInterval() const { |
| const int64_t kUpdateIntervalMs = 25; |
| return TimeDelta::ms(kUpdateIntervalMs); |
| } |
| |
| GoogCcNetworkController::GoogCcNetworkController( |
| RtcEventLog* event_log, |
| NetworkControllerObserver* observer) |
| : event_log_(event_log), |
| observer_(observer), |
| probe_controller_(new ProbeController(observer_)), |
| bandwidth_estimation_( |
| rtc::MakeUnique<SendSideBandwidthEstimation>(event_log_)), |
| alr_detector_(rtc::MakeUnique<AlrDetector>()), |
| delay_based_bwe_(new DelayBasedBwe(event_log_)), |
| acknowledged_bitrate_estimator_( |
| rtc::MakeUnique<AcknowledgedBitrateEstimator>()), |
| pacing_factor_(kDefaultPaceMultiplier), |
| min_pacing_rate_(DataRate::Zero()), |
| max_padding_rate_(DataRate::Zero()), |
| in_cwnd_experiment_(CwndExperimentEnabled()), |
| accepted_queue_ms_(kDefaultAcceptedQueueMs) { |
| delay_based_bwe_->SetMinBitrate(congestion_controller::GetMinBitrateBps()); |
| if (in_cwnd_experiment_ && |
| !ReadCwndExperimentParameter(&accepted_queue_ms_)) { |
| RTC_LOG(LS_WARNING) << "Failed to parse parameters for CwndExperiment " |
| "from field trial string. Experiment disabled."; |
| in_cwnd_experiment_ = false; |
| } |
| } |
| |
| GoogCcNetworkController::~GoogCcNetworkController() {} |
| |
| void GoogCcNetworkController::OnNetworkAvailability(NetworkAvailability msg) { |
| probe_controller_->OnNetworkAvailability(msg); |
| } |
| |
| void GoogCcNetworkController::OnNetworkRouteChange(NetworkRouteChange msg) { |
| int64_t min_bitrate_bps = msg.constraints.min_data_rate.bps(); |
| int64_t max_bitrate_bps = -1; |
| int64_t start_bitrate_bps = -1; |
| |
| if (msg.constraints.max_data_rate.IsFinite()) |
| max_bitrate_bps = msg.constraints.max_data_rate.bps(); |
| if (msg.constraints.starting_rate.IsFinite()) |
| start_bitrate_bps = msg.constraints.starting_rate.bps(); |
| |
| ClampBitrates(&start_bitrate_bps, &min_bitrate_bps, &max_bitrate_bps); |
| |
| bandwidth_estimation_ = |
| rtc::MakeUnique<SendSideBandwidthEstimation>(event_log_); |
| bandwidth_estimation_->SetBitrates(start_bitrate_bps, min_bitrate_bps, |
| max_bitrate_bps); |
| delay_based_bwe_.reset(new DelayBasedBwe(event_log_)); |
| acknowledged_bitrate_estimator_.reset(new AcknowledgedBitrateEstimator()); |
| delay_based_bwe_->SetStartBitrate(start_bitrate_bps); |
| delay_based_bwe_->SetMinBitrate(min_bitrate_bps); |
| |
| probe_controller_->Reset(msg.at_time.ms()); |
| probe_controller_->SetBitrates(min_bitrate_bps, start_bitrate_bps, |
| max_bitrate_bps, msg.at_time.ms()); |
| |
| MaybeTriggerOnNetworkChanged(msg.at_time); |
| } |
| |
| void GoogCcNetworkController::OnProcessInterval(ProcessInterval msg) { |
| bandwidth_estimation_->UpdateEstimate(msg.at_time.ms()); |
| rtc::Optional<int64_t> start_time_ms = |
| alr_detector_->GetApplicationLimitedRegionStartTime(); |
| probe_controller_->SetAlrStartTimeMs(start_time_ms); |
| probe_controller_->Process(msg.at_time.ms()); |
| MaybeTriggerOnNetworkChanged(msg.at_time); |
| } |
| |
| void GoogCcNetworkController::OnRemoteBitrateReport(RemoteBitrateReport msg) { |
| bandwidth_estimation_->UpdateReceiverEstimate(msg.receive_time.ms(), |
| msg.bandwidth.bps()); |
| BWE_TEST_LOGGING_PLOT(1, "REMB_kbps", msg.receive_time.ms(), |
| msg.bandwidth.bps() / 1000); |
| } |
| |
| void GoogCcNetworkController::OnRoundTripTimeUpdate(RoundTripTimeUpdate msg) { |
| if (msg.smoothed) { |
| delay_based_bwe_->OnRttUpdate(msg.round_trip_time.ms()); |
| } else { |
| bandwidth_estimation_->UpdateRtt(msg.round_trip_time.ms(), |
| msg.receive_time.ms()); |
| } |
| } |
| |
| void GoogCcNetworkController::OnSentPacket(SentPacket sent_packet) { |
| alr_detector_->OnBytesSent(sent_packet.size.bytes(), |
| sent_packet.send_time.ms()); |
| } |
| |
| void GoogCcNetworkController::OnStreamsConfig(StreamsConfig msg) { |
| probe_controller_->EnablePeriodicAlrProbing(msg.requests_alr_probing); |
| |
| bool pacing_changed = false; |
| if (msg.pacing_factor && *msg.pacing_factor != pacing_factor_) { |
| pacing_factor_ = *msg.pacing_factor; |
| pacing_changed = true; |
| } |
| if (msg.min_pacing_rate && *msg.min_pacing_rate != min_pacing_rate_) { |
| min_pacing_rate_ = *msg.min_pacing_rate; |
| pacing_changed = true; |
| } |
| if (msg.max_padding_rate && *msg.max_padding_rate != max_padding_rate_) { |
| max_padding_rate_ = *msg.max_padding_rate; |
| pacing_changed = true; |
| } |
| if (pacing_changed) |
| UpdatePacingRates(msg.at_time); |
| } |
| |
| void GoogCcNetworkController::OnTargetRateConstraints( |
| TargetRateConstraints constraints) { |
| int64_t min_bitrate_bps = constraints.min_data_rate.bps(); |
| int64_t max_bitrate_bps = -1; |
| int64_t start_bitrate_bps = -1; |
| |
| if (constraints.max_data_rate.IsFinite()) |
| max_bitrate_bps = constraints.max_data_rate.bps(); |
| if (constraints.starting_rate.IsFinite()) |
| start_bitrate_bps = constraints.starting_rate.bps(); |
| |
| ClampBitrates(&start_bitrate_bps, &min_bitrate_bps, &max_bitrate_bps); |
| |
| probe_controller_->SetBitrates(min_bitrate_bps, start_bitrate_bps, |
| max_bitrate_bps, constraints.at_time.ms()); |
| |
| bandwidth_estimation_->SetBitrates(start_bitrate_bps, min_bitrate_bps, |
| max_bitrate_bps); |
| if (start_bitrate_bps > 0) |
| delay_based_bwe_->SetStartBitrate(start_bitrate_bps); |
| delay_based_bwe_->SetMinBitrate(min_bitrate_bps); |
| |
| MaybeTriggerOnNetworkChanged(constraints.at_time); |
| } |
| |
| void GoogCcNetworkController::OnTransportLossReport(TransportLossReport msg) { |
| int64_t total_packets_delta = |
| msg.packets_received_delta + msg.packets_lost_delta; |
| bandwidth_estimation_->UpdatePacketsLost( |
| msg.packets_lost_delta, total_packets_delta, msg.receive_time.ms()); |
| } |
| |
| void GoogCcNetworkController::OnTransportPacketsFeedback( |
| TransportPacketsFeedback report) { |
| int64_t feedback_rtt = -1; |
| for (const auto& packet_feedback : report.PacketsWithFeedback()) { |
| if (packet_feedback.sent_packet.has_value() && |
| packet_feedback.receive_time.IsFinite()) { |
| int64_t rtt = report.feedback_time.ms() - |
| packet_feedback.sent_packet->send_time.ms(); |
| // max() is used to account for feedback being delayed by the |
| // receiver. |
| feedback_rtt = std::max(rtt, feedback_rtt); |
| } |
| } |
| if (feedback_rtt > -1) { |
| feedback_rtts_.push_back(feedback_rtt); |
| const size_t kFeedbackRttWindow = 32; |
| if (feedback_rtts_.size() > kFeedbackRttWindow) |
| feedback_rtts_.pop_front(); |
| min_feedback_rtt_ms_.emplace( |
| *std::min_element(feedback_rtts_.begin(), feedback_rtts_.end())); |
| } |
| |
| std::vector<PacketFeedback> received_feedback_vector = |
| ReceivedPacketsFeedbackAsRtp(report); |
| |
| rtc::Optional<int64_t> alr_start_time = |
| alr_detector_->GetApplicationLimitedRegionStartTime(); |
| |
| if (previously_in_alr && !alr_start_time.has_value()) { |
| int64_t now_ms = report.feedback_time.ms(); |
| acknowledged_bitrate_estimator_->SetAlrEndedTimeMs(now_ms); |
| probe_controller_->SetAlrEndedTimeMs(now_ms); |
| } |
| previously_in_alr = alr_start_time.has_value(); |
| acknowledged_bitrate_estimator_->IncomingPacketFeedbackVector( |
| received_feedback_vector); |
| DelayBasedBwe::Result result; |
| result = delay_based_bwe_->IncomingPacketFeedbackVector( |
| received_feedback_vector, acknowledged_bitrate_estimator_->bitrate_bps(), |
| report.feedback_time.ms()); |
| if (result.updated) { |
| if (result.probe) { |
| bandwidth_estimation_->SetSendBitrate(result.target_bitrate_bps); |
| } |
| // Since SetSendBitrate now resets the delay-based estimate, we have to call |
| // UpdateDelayBasedEstimate after SetSendBitrate. |
| bandwidth_estimation_->UpdateDelayBasedEstimate(report.feedback_time.ms(), |
| result.target_bitrate_bps); |
| // Update the estimate in the ProbeController, in case we want to probe. |
| MaybeTriggerOnNetworkChanged(report.feedback_time); |
| } |
| if (result.recovered_from_overuse) { |
| probe_controller_->SetAlrStartTimeMs(alr_start_time); |
| probe_controller_->RequestProbe(report.feedback_time.ms()); |
| } |
| MaybeUpdateCongestionWindow(); |
| } |
| |
| void GoogCcNetworkController::MaybeUpdateCongestionWindow() { |
| if (!in_cwnd_experiment_) |
| return; |
| // No valid RTT. Could be because send-side BWE isn't used, in which case |
| // we don't try to limit the outstanding packets. |
| if (!min_feedback_rtt_ms_) |
| return; |
| if (!last_estimate_.has_value()) |
| return; |
| const DataSize kMinCwnd = DataSize::bytes(2 * 1500); |
| TimeDelta time_window = |
| TimeDelta::ms(*min_feedback_rtt_ms_ + accepted_queue_ms_); |
| DataSize data_window = last_estimate_->bandwidth * time_window; |
| CongestionWindow msg; |
| msg.enabled = true; |
| msg.data_window = std::max(kMinCwnd, data_window); |
| observer_->OnCongestionWindow(msg); |
| RTC_LOG(LS_INFO) << "Feedback rtt: " << *min_feedback_rtt_ms_ |
| << " Bitrate: " << last_estimate_->bandwidth.bps(); |
| } |
| |
| void GoogCcNetworkController::MaybeTriggerOnNetworkChanged(Timestamp at_time) { |
| int32_t estimated_bitrate_bps; |
| uint8_t fraction_loss; |
| int64_t rtt_ms; |
| |
| bool estimate_changed = GetNetworkParameters( |
| &estimated_bitrate_bps, &fraction_loss, &rtt_ms, at_time); |
| if (estimate_changed) { |
| TimeDelta bwe_period = |
| TimeDelta::ms(delay_based_bwe_->GetExpectedBwePeriodMs()); |
| |
| NetworkEstimate new_estimate; |
| new_estimate.at_time = at_time; |
| new_estimate.round_trip_time = TimeDelta::ms(rtt_ms); |
| new_estimate.bandwidth = DataRate::bps(estimated_bitrate_bps); |
| new_estimate.loss_rate_ratio = fraction_loss / 255.0f; |
| new_estimate.bwe_period = bwe_period; |
| new_estimate.changed = true; |
| last_estimate_ = new_estimate; |
| OnNetworkEstimate(new_estimate); |
| } |
| } |
| |
| bool GoogCcNetworkController::GetNetworkParameters( |
| int32_t* estimated_bitrate_bps, |
| uint8_t* fraction_loss, |
| int64_t* rtt_ms, |
| Timestamp at_time) { |
| bandwidth_estimation_->CurrentEstimate(estimated_bitrate_bps, fraction_loss, |
| rtt_ms); |
| *estimated_bitrate_bps = std::max<int32_t>( |
| *estimated_bitrate_bps, bandwidth_estimation_->GetMinBitrate()); |
| |
| bool estimate_changed = false; |
| if ((*estimated_bitrate_bps != last_estimated_bitrate_bps_) || |
| (*fraction_loss != last_estimated_fraction_loss_) || |
| (*rtt_ms != last_estimated_rtt_ms_)) { |
| last_estimated_bitrate_bps_ = *estimated_bitrate_bps; |
| last_estimated_fraction_loss_ = *fraction_loss; |
| last_estimated_rtt_ms_ = *rtt_ms; |
| estimate_changed = true; |
| } |
| |
| BWE_TEST_LOGGING_PLOT(1, "fraction_loss_%", at_time.ms(), |
| (*fraction_loss * 100) / 256); |
| BWE_TEST_LOGGING_PLOT(1, "rtt_ms", at_time.ms(), *rtt_ms); |
| BWE_TEST_LOGGING_PLOT(1, "Target_bitrate_kbps", at_time.ms(), |
| *estimated_bitrate_bps / 1000); |
| |
| return estimate_changed; |
| } |
| |
| void GoogCcNetworkController::OnNetworkEstimate(NetworkEstimate estimate) { |
| if (!estimate.changed) |
| return; |
| |
| UpdatePacingRates(estimate.at_time); |
| alr_detector_->SetEstimatedBitrate(estimate.bandwidth.bps()); |
| probe_controller_->SetEstimatedBitrate(estimate.bandwidth.bps(), |
| estimate.at_time.ms()); |
| |
| TargetTransferRate target_rate; |
| target_rate.at_time = estimate.at_time; |
| // Set the target rate to the full estimated bandwidth since the estimation |
| // for legacy reasons includes target rate constraints. |
| target_rate.target_rate = estimate.bandwidth; |
| target_rate.network_estimate = estimate; |
| observer_->OnTargetTransferRate(target_rate); |
| } |
| |
| void GoogCcNetworkController::UpdatePacingRates(Timestamp at_time) { |
| if (!last_estimate_) |
| return; |
| DataRate pacing_rate = |
| std::max(min_pacing_rate_, last_estimate_->bandwidth) * pacing_factor_; |
| DataRate padding_rate = |
| std::min(max_padding_rate_, last_estimate_->bandwidth); |
| PacerConfig msg; |
| msg.at_time = at_time; |
| msg.time_window = TimeDelta::s(1); |
| msg.data_window = pacing_rate * msg.time_window; |
| msg.pad_window = padding_rate * msg.time_window; |
| observer_->OnPacerConfig(msg); |
| } |
| |
| } // namespace webrtc |