webrtc_m130/call/rtp_transport_controller_send.h
Erik Språng 6673437775 Move ownership of congestion window state to rtp sender controller.
When congestion window is used, two different mechanisms can currently
update the outstanding data state in the pacer:
* OnPacketSent() withing the pacer itself, when a packet is sent
* UpdateOutstandingData(), when RtpTransportControllerSend either:
  a. Receives an OnPacketSent() callback (increase outstanding data)
  b. Receives transport feedback (decrease outstanding data)

This creates a lot of calls to UpdateOutstandingData(), more than one
per sent packet. Each requires locking and/or thread jumps. To avoid
that, this CL moves the congestion window state to
RtpTransportController send - and we only post a congested flag down
the the pacer when the state is changed.

The only benefit I can see is of the old way is we prevent sending
new packets immedately when the window is full, rather than in some
edge cases queue extra packets on the network task queue before the
congestion signal is received. That should be rare and benign.
I think this simplified logic, which is easier to read and more
performant, is a better tradeoff.

Bug: webrtc:13417
Change-Id: I326dd88db86dc0d6dc685c61920654ac024e57ef
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/255600
Auto-Submit: Erik Språng <sprang@webrtc.org>
Reviewed-by: Henrik Boström <hbos@webrtc.org>
Commit-Queue: Henrik Boström <hbos@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#36220}
2022-03-16 15:30:03 +00:00

232 lines
9.4 KiB
C++

/*
* Copyright (c) 2017 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 CALL_RTP_TRANSPORT_CONTROLLER_SEND_H_
#define CALL_RTP_TRANSPORT_CONTROLLER_SEND_H_
#include <atomic>
#include <map>
#include <memory>
#include <string>
#include <vector>
#include "api/network_state_predictor.h"
#include "api/sequence_checker.h"
#include "api/transport/network_control.h"
#include "api/units/data_rate.h"
#include "call/rtp_bitrate_configurator.h"
#include "call/rtp_transport_controller_send_interface.h"
#include "call/rtp_video_sender.h"
#include "modules/congestion_controller/rtp/control_handler.h"
#include "modules/congestion_controller/rtp/transport_feedback_adapter.h"
#include "modules/congestion_controller/rtp/transport_feedback_demuxer.h"
#include "modules/pacing/paced_sender.h"
#include "modules/pacing/packet_router.h"
#include "modules/pacing/rtp_packet_pacer.h"
#include "modules/pacing/task_queue_paced_sender.h"
#include "modules/utility/include/process_thread.h"
#include "rtc_base/network_route.h"
#include "rtc_base/race_checker.h"
#include "rtc_base/task_queue.h"
#include "rtc_base/task_utils/repeating_task.h"
namespace webrtc {
class Clock;
class FrameEncryptorInterface;
class RtcEventLog;
// TODO(nisse): When we get the underlying transports here, we should
// have one object implementing RtpTransportControllerSendInterface
// per transport, sharing the same congestion controller.
class RtpTransportControllerSend final
: public RtpTransportControllerSendInterface,
public RtcpBandwidthObserver,
public TransportFeedbackObserver,
public NetworkStateEstimateObserver {
public:
RtpTransportControllerSend(
Clock* clock,
RtcEventLog* event_log,
NetworkStatePredictorFactoryInterface* predictor_factory,
NetworkControllerFactoryInterface* controller_factory,
const BitrateConstraints& bitrate_config,
std::unique_ptr<ProcessThread> process_thread,
TaskQueueFactory* task_queue_factory,
const WebRtcKeyValueConfig& trials);
~RtpTransportControllerSend() override;
RtpTransportControllerSend(const RtpTransportControllerSend&) = delete;
RtpTransportControllerSend& operator=(const RtpTransportControllerSend&) =
delete;
// TODO(tommi): Change to std::unique_ptr<>.
RtpVideoSenderInterface* CreateRtpVideoSender(
const std::map<uint32_t, RtpState>& suspended_ssrcs,
const std::map<uint32_t, RtpPayloadState>&
states, // move states into RtpTransportControllerSend
const RtpConfig& rtp_config,
int rtcp_report_interval_ms,
Transport* send_transport,
const RtpSenderObservers& observers,
RtcEventLog* event_log,
std::unique_ptr<FecController> fec_controller,
const RtpSenderFrameEncryptionConfig& frame_encryption_config,
rtc::scoped_refptr<FrameTransformerInterface> frame_transformer) override;
void DestroyRtpVideoSender(
RtpVideoSenderInterface* rtp_video_sender) override;
// Implements RtpTransportControllerSendInterface
rtc::TaskQueue* GetWorkerQueue() override;
PacketRouter* packet_router() override;
NetworkStateEstimateObserver* network_state_estimate_observer() override;
TransportFeedbackObserver* transport_feedback_observer() override;
RtpPacketSender* packet_sender() override;
void SetAllocatedSendBitrateLimits(BitrateAllocationLimits limits) override;
void SetPacingFactor(float pacing_factor) override;
void SetQueueTimeLimit(int limit_ms) override;
StreamFeedbackProvider* GetStreamFeedbackProvider() override;
void RegisterTargetTransferRateObserver(
TargetTransferRateObserver* observer) override;
void OnNetworkRouteChanged(const std::string& transport_name,
const rtc::NetworkRoute& network_route) override;
void OnNetworkAvailability(bool network_available) override;
RtcpBandwidthObserver* GetBandwidthObserver() override;
int64_t GetPacerQueuingDelayMs() const override;
absl::optional<Timestamp> GetFirstPacketTime() const override;
void EnablePeriodicAlrProbing(bool enable) override;
void OnSentPacket(const rtc::SentPacket& sent_packet) override;
void OnReceivedPacket(const ReceivedPacket& packet_msg) override;
void SetSdpBitrateParameters(const BitrateConstraints& constraints) override;
void SetClientBitratePreferences(const BitrateSettings& preferences) override;
void OnTransportOverheadChanged(
size_t transport_overhead_bytes_per_packet) override;
void AccountForAudioPacketsInPacedSender(bool account_for_audio) override;
void IncludeOverheadInPacedSender() override;
void EnsureStarted() override;
// Implements RtcpBandwidthObserver interface
void OnReceivedEstimatedBitrate(uint32_t bitrate) override;
void OnReceivedRtcpReceiverReport(const ReportBlockList& report_blocks,
int64_t rtt,
int64_t now_ms) override;
// Implements TransportFeedbackObserver interface
void OnAddPacket(const RtpPacketSendInfo& packet_info) override;
void OnTransportFeedback(const rtcp::TransportFeedback& feedback) override;
// Implements NetworkStateEstimateObserver interface
void OnRemoteNetworkEstimate(NetworkStateEstimate estimate) override;
private:
struct PacerSettings {
explicit PacerSettings(const WebRtcKeyValueConfig& trials);
bool use_task_queue_pacer() const { return !tq_disabled.Get(); }
FieldTrialFlag tq_disabled; // Kill-switch not normally used.
FieldTrialParameter<TimeDelta> holdback_window;
FieldTrialParameter<int> holdback_packets;
};
void MaybeCreateControllers() RTC_RUN_ON(task_queue_);
void UpdateInitialConstraints(TargetRateConstraints new_contraints)
RTC_RUN_ON(task_queue_);
void StartProcessPeriodicTasks() RTC_RUN_ON(task_queue_);
void UpdateControllerWithTimeInterval() RTC_RUN_ON(task_queue_);
absl::optional<BitrateConstraints> ApplyOrLiftRelayCap(bool is_relayed);
bool IsRelevantRouteChange(const rtc::NetworkRoute& old_route,
const rtc::NetworkRoute& new_route) const;
void UpdateBitrateConstraints(const BitrateConstraints& updated);
void UpdateStreamsConfig() RTC_RUN_ON(task_queue_);
void OnReceivedRtcpReceiverReportBlocks(const ReportBlockList& report_blocks,
int64_t now_ms)
RTC_RUN_ON(task_queue_);
void PostUpdates(NetworkControlUpdate update) RTC_RUN_ON(task_queue_);
void UpdateControlState() RTC_RUN_ON(task_queue_);
void UpdateCongestedState() RTC_RUN_ON(task_queue_);
RtpPacketPacer* pacer();
const RtpPacketPacer* pacer() const;
Clock* const clock_;
RtcEventLog* const event_log_;
SequenceChecker main_thread_;
PacketRouter packet_router_;
std::vector<std::unique_ptr<RtpVideoSenderInterface>> video_rtp_senders_
RTC_GUARDED_BY(&main_thread_);
RtpBitrateConfigurator bitrate_configurator_;
std::map<std::string, rtc::NetworkRoute> network_routes_;
bool pacer_started_;
const std::unique_ptr<ProcessThread> process_thread_;
const PacerSettings pacer_settings_;
std::unique_ptr<PacedSender> process_thread_pacer_;
std::unique_ptr<TaskQueuePacedSender> task_queue_pacer_;
TargetTransferRateObserver* observer_ RTC_GUARDED_BY(task_queue_);
TransportFeedbackDemuxer feedback_demuxer_;
TransportFeedbackAdapter transport_feedback_adapter_
RTC_GUARDED_BY(task_queue_);
NetworkControllerFactoryInterface* const controller_factory_override_
RTC_PT_GUARDED_BY(task_queue_);
const std::unique_ptr<NetworkControllerFactoryInterface>
controller_factory_fallback_ RTC_PT_GUARDED_BY(task_queue_);
std::unique_ptr<CongestionControlHandler> control_handler_
RTC_GUARDED_BY(task_queue_) RTC_PT_GUARDED_BY(task_queue_);
std::unique_ptr<NetworkControllerInterface> controller_
RTC_GUARDED_BY(task_queue_) RTC_PT_GUARDED_BY(task_queue_);
TimeDelta process_interval_ RTC_GUARDED_BY(task_queue_);
std::map<uint32_t, RTCPReportBlock> last_report_blocks_
RTC_GUARDED_BY(task_queue_);
Timestamp last_report_block_time_ RTC_GUARDED_BY(task_queue_);
NetworkControllerConfig initial_config_ RTC_GUARDED_BY(task_queue_);
StreamsConfig streams_config_ RTC_GUARDED_BY(task_queue_);
const bool reset_feedback_on_route_change_;
const bool send_side_bwe_with_overhead_;
const bool add_pacing_to_cwin_;
FieldTrialParameter<DataRate> relay_bandwidth_cap_;
size_t transport_overhead_bytes_per_packet_ RTC_GUARDED_BY(task_queue_);
bool network_available_ RTC_GUARDED_BY(task_queue_);
RepeatingTaskHandle pacer_queue_update_task_ RTC_GUARDED_BY(task_queue_);
RepeatingTaskHandle controller_task_ RTC_GUARDED_BY(task_queue_);
DataSize congestion_window_size_ RTC_GUARDED_BY(task_queue_);
bool is_congested_ RTC_GUARDED_BY(task_queue_);
// Protected by internal locks.
RateLimiter retransmission_rate_limiter_;
// TODO(perkj): `task_queue_` is supposed to replace `process_thread_`.
// `task_queue_` is defined last to ensure all pending tasks are cancelled
// and deleted before any other members.
rtc::TaskQueue task_queue_;
const WebRtcKeyValueConfig& field_trials_;
};
} // namespace webrtc
#endif // CALL_RTP_TRANSPORT_CONTROLLER_SEND_H_