| /* |
| * Copyright (c) 2012 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 "webrtc/modules/congestion_controller/include/send_side_congestion_controller.h" |
| |
| #include <algorithm> |
| #include <memory> |
| #include <vector> |
| |
| #include "webrtc/modules/bitrate_controller/include/bitrate_controller.h" |
| #include "webrtc/modules/congestion_controller/acknowledged_bitrate_estimator.h" |
| #include "webrtc/modules/congestion_controller/probe_controller.h" |
| #include "webrtc/modules/pacing/alr_detector.h" |
| #include "webrtc/modules/remote_bitrate_estimator/include/bwe_defines.h" |
| #include "webrtc/rtc_base/checks.h" |
| #include "webrtc/rtc_base/format_macros.h" |
| #include "webrtc/rtc_base/logging.h" |
| #include "webrtc/rtc_base/ptr_util.h" |
| #include "webrtc/rtc_base/rate_limiter.h" |
| #include "webrtc/rtc_base/socket.h" |
| #include "webrtc/rtc_base/timeutils.h" |
| #include "webrtc/system_wrappers/include/field_trial.h" |
| |
| namespace webrtc { |
| namespace { |
| |
| const char kCwndExperiment[] = "WebRTC-CwndExperiment"; |
| const int64_t kDefaultAcceptedQueueMs = 250; |
| |
| 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; |
| } |
| |
| static const int64_t kRetransmitWindowSizeMs = 500; |
| |
| // Makes sure that the bitrate and the min, max values are in valid range. |
| static void ClampBitrates(int* bitrate_bps, |
| int* min_bitrate_bps, |
| int* 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<webrtc::PacketFeedback> ReceivedPacketFeedbackVector( |
| const std::vector<webrtc::PacketFeedback>& input) { |
| std::vector<PacketFeedback> received_packet_feedback_vector; |
| auto is_received = [](const webrtc::PacketFeedback& packet_feedback) { |
| return packet_feedback.arrival_time_ms != |
| webrtc::PacketFeedback::kNotReceived; |
| }; |
| std::copy_if(input.begin(), input.end(), |
| std::back_inserter(received_packet_feedback_vector), |
| is_received); |
| return received_packet_feedback_vector; |
| } |
| |
| void SortPacketFeedbackVector( |
| std::vector<webrtc::PacketFeedback>* const input) { |
| RTC_DCHECK(input); |
| std::sort(input->begin(), input->end(), PacketFeedbackComparator()); |
| } |
| |
| } // namespace |
| |
| SendSideCongestionController::SendSideCongestionController( |
| const Clock* clock, |
| Observer* observer, |
| RtcEventLog* event_log, |
| PacketRouter* packet_router) |
| : clock_(clock), |
| observer_(observer), |
| event_log_(event_log), |
| owned_pacer_( |
| rtc::MakeUnique<PacedSender>(clock, packet_router, event_log)), |
| pacer_(owned_pacer_.get()), |
| bitrate_controller_( |
| BitrateController::CreateBitrateController(clock_, event_log)), |
| acknowledged_bitrate_estimator_( |
| rtc::MakeUnique<AcknowledgedBitrateEstimator>()), |
| probe_controller_(new ProbeController(pacer_, clock_)), |
| retransmission_rate_limiter_( |
| new RateLimiter(clock, kRetransmitWindowSizeMs)), |
| transport_feedback_adapter_(clock_), |
| last_reported_bitrate_bps_(0), |
| last_reported_fraction_loss_(0), |
| last_reported_rtt_(0), |
| network_state_(kNetworkUp), |
| pause_pacer_(false), |
| pacer_paused_(false), |
| min_bitrate_bps_(congestion_controller::GetMinBitrateBps()), |
| delay_based_bwe_(new DelayBasedBwe(event_log_, clock_)), |
| in_cwnd_experiment_(CwndExperimentEnabled()), |
| accepted_queue_ms_(kDefaultAcceptedQueueMs), |
| was_in_alr_(0) { |
| delay_based_bwe_->SetMinBitrate(min_bitrate_bps_); |
| if (in_cwnd_experiment_ && |
| !ReadCwndExperimentParameter(&accepted_queue_ms_)) { |
| LOG(LS_WARNING) << "Failed to parse parameters for CwndExperiment " |
| "from field trial string. Experiment disabled."; |
| in_cwnd_experiment_ = false; |
| } |
| } |
| |
| SendSideCongestionController::SendSideCongestionController( |
| const Clock* clock, |
| Observer* observer, |
| RtcEventLog* event_log, |
| PacedSender* pacer) |
| : clock_(clock), |
| observer_(observer), |
| event_log_(event_log), |
| pacer_(pacer), |
| bitrate_controller_( |
| BitrateController::CreateBitrateController(clock_, event_log)), |
| acknowledged_bitrate_estimator_( |
| rtc::MakeUnique<AcknowledgedBitrateEstimator>()), |
| probe_controller_(new ProbeController(pacer_, clock_)), |
| retransmission_rate_limiter_( |
| new RateLimiter(clock, kRetransmitWindowSizeMs)), |
| transport_feedback_adapter_(clock_), |
| last_reported_bitrate_bps_(0), |
| last_reported_fraction_loss_(0), |
| last_reported_rtt_(0), |
| network_state_(kNetworkUp), |
| pause_pacer_(false), |
| pacer_paused_(false), |
| min_bitrate_bps_(congestion_controller::GetMinBitrateBps()), |
| delay_based_bwe_(new DelayBasedBwe(event_log_, clock_)), |
| in_cwnd_experiment_(CwndExperimentEnabled()), |
| accepted_queue_ms_(kDefaultAcceptedQueueMs), |
| was_in_alr_(0) { |
| delay_based_bwe_->SetMinBitrate(min_bitrate_bps_); |
| if (in_cwnd_experiment_ && |
| !ReadCwndExperimentParameter(&accepted_queue_ms_)) { |
| LOG(LS_WARNING) << "Failed to parse parameters for CwndExperiment " |
| "from field trial string. Experiment disabled."; |
| in_cwnd_experiment_ = false; |
| } |
| } |
| |
| SendSideCongestionController::~SendSideCongestionController() {} |
| |
| void SendSideCongestionController::RegisterPacketFeedbackObserver( |
| PacketFeedbackObserver* observer) { |
| transport_feedback_adapter_.RegisterPacketFeedbackObserver(observer); |
| } |
| |
| void SendSideCongestionController::DeRegisterPacketFeedbackObserver( |
| PacketFeedbackObserver* observer) { |
| transport_feedback_adapter_.DeRegisterPacketFeedbackObserver(observer); |
| } |
| |
| void SendSideCongestionController::RegisterNetworkObserver(Observer* observer) { |
| rtc::CritScope cs(&observer_lock_); |
| RTC_DCHECK(observer_ == nullptr); |
| observer_ = observer; |
| } |
| |
| void SendSideCongestionController::DeRegisterNetworkObserver( |
| Observer* observer) { |
| rtc::CritScope cs(&observer_lock_); |
| RTC_DCHECK_EQ(observer_, observer); |
| observer_ = nullptr; |
| } |
| |
| void SendSideCongestionController::SetBweBitrates(int min_bitrate_bps, |
| int start_bitrate_bps, |
| int max_bitrate_bps) { |
| ClampBitrates(&start_bitrate_bps, &min_bitrate_bps, &max_bitrate_bps); |
| bitrate_controller_->SetBitrates(start_bitrate_bps, min_bitrate_bps, |
| max_bitrate_bps); |
| |
| probe_controller_->SetBitrates(min_bitrate_bps, start_bitrate_bps, |
| max_bitrate_bps); |
| |
| { |
| rtc::CritScope cs(&bwe_lock_); |
| if (start_bitrate_bps > 0) |
| delay_based_bwe_->SetStartBitrate(start_bitrate_bps); |
| min_bitrate_bps_ = min_bitrate_bps; |
| delay_based_bwe_->SetMinBitrate(min_bitrate_bps_); |
| } |
| MaybeTriggerOnNetworkChanged(); |
| } |
| |
| // TODO(holmer): Split this up and use SetBweBitrates in combination with |
| // OnNetworkRouteChanged. |
| void SendSideCongestionController::OnNetworkRouteChanged( |
| const rtc::NetworkRoute& network_route, |
| int bitrate_bps, |
| int min_bitrate_bps, |
| int max_bitrate_bps) { |
| ClampBitrates(&bitrate_bps, &min_bitrate_bps, &max_bitrate_bps); |
| // TODO(honghaiz): Recreate this object once the bitrate controller is |
| // no longer exposed outside SendSideCongestionController. |
| bitrate_controller_->ResetBitrates(bitrate_bps, min_bitrate_bps, |
| max_bitrate_bps); |
| |
| transport_feedback_adapter_.SetNetworkIds(network_route.local_network_id, |
| network_route.remote_network_id); |
| { |
| rtc::CritScope cs(&bwe_lock_); |
| min_bitrate_bps_ = min_bitrate_bps; |
| delay_based_bwe_.reset(new DelayBasedBwe(event_log_, clock_)); |
| acknowledged_bitrate_estimator_.reset(new AcknowledgedBitrateEstimator()); |
| delay_based_bwe_->SetStartBitrate(bitrate_bps); |
| delay_based_bwe_->SetMinBitrate(min_bitrate_bps); |
| } |
| |
| probe_controller_->Reset(); |
| probe_controller_->SetBitrates(min_bitrate_bps, bitrate_bps, max_bitrate_bps); |
| |
| MaybeTriggerOnNetworkChanged(); |
| } |
| |
| BitrateController* SendSideCongestionController::GetBitrateController() const { |
| return bitrate_controller_.get(); |
| } |
| |
| RateLimiter* SendSideCongestionController::GetRetransmissionRateLimiter() { |
| return retransmission_rate_limiter_.get(); |
| } |
| |
| void SendSideCongestionController::EnablePeriodicAlrProbing(bool enable) { |
| probe_controller_->EnablePeriodicAlrProbing(enable); |
| } |
| |
| int64_t SendSideCongestionController::GetPacerQueuingDelayMs() const { |
| return IsNetworkDown() ? 0 : pacer_->QueueInMs(); |
| } |
| |
| int64_t SendSideCongestionController::GetFirstPacketTimeMs() const { |
| return pacer_->FirstSentPacketTimeMs(); |
| } |
| |
| TransportFeedbackObserver* |
| SendSideCongestionController::GetTransportFeedbackObserver() { |
| return this; |
| } |
| |
| void SendSideCongestionController::SignalNetworkState(NetworkState state) { |
| LOG(LS_INFO) << "SignalNetworkState " |
| << (state == kNetworkUp ? "Up" : "Down"); |
| { |
| rtc::CritScope cs(&network_state_lock_); |
| pause_pacer_ = state == kNetworkDown; |
| network_state_ = state; |
| } |
| probe_controller_->OnNetworkStateChanged(state); |
| MaybeTriggerOnNetworkChanged(); |
| } |
| |
| void SendSideCongestionController::SetTransportOverhead( |
| size_t transport_overhead_bytes_per_packet) { |
| transport_feedback_adapter_.SetTransportOverhead( |
| transport_overhead_bytes_per_packet); |
| } |
| |
| void SendSideCongestionController::OnSentPacket( |
| const rtc::SentPacket& sent_packet) { |
| // We're not interested in packets without an id, which may be stun packets, |
| // etc, sent on the same transport. |
| if (sent_packet.packet_id == -1) |
| return; |
| transport_feedback_adapter_.OnSentPacket(sent_packet.packet_id, |
| sent_packet.send_time_ms); |
| if (in_cwnd_experiment_) |
| LimitOutstandingBytes(transport_feedback_adapter_.GetOutstandingBytes()); |
| } |
| |
| void SendSideCongestionController::OnRttUpdate(int64_t avg_rtt_ms, |
| int64_t max_rtt_ms) { |
| rtc::CritScope cs(&bwe_lock_); |
| delay_based_bwe_->OnRttUpdate(avg_rtt_ms, max_rtt_ms); |
| } |
| |
| int64_t SendSideCongestionController::TimeUntilNextProcess() { |
| return bitrate_controller_->TimeUntilNextProcess(); |
| } |
| |
| void SendSideCongestionController::Process() { |
| bool pause_pacer; |
| // TODO(holmer): Once this class is running on a task queue we should |
| // replace this with a task instead. |
| { |
| rtc::CritScope lock(&network_state_lock_); |
| pause_pacer = pause_pacer_; |
| } |
| if (pause_pacer && !pacer_paused_) { |
| pacer_->Pause(); |
| pacer_paused_ = true; |
| } else if (!pause_pacer && pacer_paused_) { |
| pacer_->Resume(); |
| pacer_paused_ = false; |
| } |
| bitrate_controller_->Process(); |
| probe_controller_->Process(); |
| MaybeTriggerOnNetworkChanged(); |
| } |
| |
| void SendSideCongestionController::AddPacket( |
| uint32_t ssrc, |
| uint16_t sequence_number, |
| size_t length, |
| const PacedPacketInfo& pacing_info) { |
| transport_feedback_adapter_.AddPacket(ssrc, sequence_number, length, |
| pacing_info); |
| } |
| |
| void SendSideCongestionController::OnTransportFeedback( |
| const rtcp::TransportFeedback& feedback) { |
| RTC_DCHECK_RUNS_SERIALIZED(&worker_race_); |
| transport_feedback_adapter_.OnTransportFeedback(feedback); |
| std::vector<PacketFeedback> feedback_vector = ReceivedPacketFeedbackVector( |
| transport_feedback_adapter_.GetTransportFeedbackVector()); |
| SortPacketFeedbackVector(&feedback_vector); |
| |
| bool currently_in_alr = |
| pacer_->GetApplicationLimitedRegionStartTime().has_value(); |
| if (was_in_alr_ && !currently_in_alr) { |
| int64_t now_ms = rtc::TimeMillis(); |
| acknowledged_bitrate_estimator_->SetAlrEndedTimeMs(now_ms); |
| probe_controller_->SetAlrEndedTimeMs(now_ms); |
| } |
| was_in_alr_ = currently_in_alr; |
| |
| acknowledged_bitrate_estimator_->IncomingPacketFeedbackVector( |
| feedback_vector); |
| DelayBasedBwe::Result result; |
| { |
| rtc::CritScope cs(&bwe_lock_); |
| result = delay_based_bwe_->IncomingPacketFeedbackVector( |
| feedback_vector, acknowledged_bitrate_estimator_->bitrate_bps()); |
| } |
| if (result.updated) { |
| bitrate_controller_->OnDelayBasedBweResult(result); |
| // Update the estimate in the ProbeController, in case we want to probe. |
| MaybeTriggerOnNetworkChanged(); |
| } |
| if (result.recovered_from_overuse) |
| probe_controller_->RequestProbe(); |
| if (in_cwnd_experiment_) |
| LimitOutstandingBytes(transport_feedback_adapter_.GetOutstandingBytes()); |
| } |
| |
| void SendSideCongestionController::LimitOutstandingBytes( |
| size_t num_outstanding_bytes) { |
| RTC_DCHECK(in_cwnd_experiment_); |
| rtc::CritScope lock(&network_state_lock_); |
| rtc::Optional<int64_t> min_rtt_ms = |
| transport_feedback_adapter_.GetMinFeedbackLoopRtt(); |
| // 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_rtt_ms) |
| return; |
| const size_t kMinCwndBytes = 2 * 1500; |
| size_t max_outstanding_bytes = |
| std::max<size_t>((*min_rtt_ms + accepted_queue_ms_) * |
| last_reported_bitrate_bps_ / 1000 / 8, |
| kMinCwndBytes); |
| LOG(LS_INFO) << clock_->TimeInMilliseconds() |
| << " Outstanding bytes: " << num_outstanding_bytes |
| << " pacer queue: " << pacer_->QueueInMs() |
| << " max outstanding: " << max_outstanding_bytes; |
| LOG(LS_INFO) << "Feedback rtt: " << *min_rtt_ms |
| << " Bitrate: " << last_reported_bitrate_bps_; |
| pause_pacer_ = num_outstanding_bytes > max_outstanding_bytes; |
| } |
| |
| std::vector<PacketFeedback> |
| SendSideCongestionController::GetTransportFeedbackVector() const { |
| RTC_DCHECK_RUNS_SERIALIZED(&worker_race_); |
| return transport_feedback_adapter_.GetTransportFeedbackVector(); |
| } |
| |
| void SendSideCongestionController::MaybeTriggerOnNetworkChanged() { |
| uint32_t bitrate_bps; |
| uint8_t fraction_loss; |
| int64_t rtt; |
| bool estimate_changed = bitrate_controller_->GetNetworkParameters( |
| &bitrate_bps, &fraction_loss, &rtt); |
| if (estimate_changed) { |
| pacer_->SetEstimatedBitrate(bitrate_bps); |
| probe_controller_->SetEstimatedBitrate(bitrate_bps); |
| retransmission_rate_limiter_->SetMaxRate(bitrate_bps); |
| } |
| |
| bitrate_bps = IsNetworkDown() || IsSendQueueFull() ? 0 : bitrate_bps; |
| |
| if (HasNetworkParametersToReportChanged(bitrate_bps, fraction_loss, rtt)) { |
| int64_t probing_interval_ms; |
| { |
| rtc::CritScope cs(&bwe_lock_); |
| probing_interval_ms = delay_based_bwe_->GetExpectedBwePeriodMs(); |
| } |
| { |
| rtc::CritScope cs(&observer_lock_); |
| if (observer_) { |
| observer_->OnNetworkChanged(bitrate_bps, fraction_loss, rtt, |
| probing_interval_ms); |
| } |
| } |
| } |
| } |
| |
| bool SendSideCongestionController::HasNetworkParametersToReportChanged( |
| uint32_t bitrate_bps, |
| uint8_t fraction_loss, |
| int64_t rtt) { |
| rtc::CritScope cs(&network_state_lock_); |
| bool changed = |
| last_reported_bitrate_bps_ != bitrate_bps || |
| (bitrate_bps > 0 && (last_reported_fraction_loss_ != fraction_loss || |
| last_reported_rtt_ != rtt)); |
| if (changed && (last_reported_bitrate_bps_ == 0 || bitrate_bps == 0)) { |
| LOG(LS_INFO) << "Bitrate estimate state changed, BWE: " << bitrate_bps |
| << " bps."; |
| } |
| last_reported_bitrate_bps_ = bitrate_bps; |
| last_reported_fraction_loss_ = fraction_loss; |
| last_reported_rtt_ = rtt; |
| return changed; |
| } |
| |
| bool SendSideCongestionController::IsSendQueueFull() const { |
| return pacer_->ExpectedQueueTimeMs() > PacedSender::kMaxQueueLengthMs; |
| } |
| |
| bool SendSideCongestionController::IsNetworkDown() const { |
| rtc::CritScope cs(&network_state_lock_); |
| return network_state_ == kNetworkDown; |
| } |
| |
| } // namespace webrtc |