Include downlink delay into congestion window size.

Change-Id: I33db0c8134b6b3181a7b3abcf32a622a89ff3ab4

Bug: webrtc:10688
Change-Id: I33db0c8134b6b3181a7b3abcf32a622a89ff3ab4
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/138275
Commit-Queue: Ying Wang <yinwa@webrtc.org>
Reviewed-by: Sebastian Jansson <srte@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28079}

api/transport/network_control.h

@@ -72,6 +72,8 @@ class NetworkControllerInterface {
   virtual NetworkControlUpdate OnRoundTripTimeUpdate(RoundTripTimeUpdate) = 0;
   // Called when a packet is sent on the network.
   virtual NetworkControlUpdate OnSentPacket(SentPacket) = 0;
+  // Called when a packet is received from the remote client.
+  virtual NetworkControlUpdate OnReceivedPacket(ReceivedPacket) = 0;
   // Called when the stream specific configuration has been updated.
   virtual NetworkControlUpdate OnStreamsConfig(StreamsConfig) = 0;
   // Called when target transfer rate constraints has been changed.

api/transport/network_types.h

@@ -101,6 +101,11 @@ struct SentPacket {
   DataSize data_in_flight = DataSize::Zero();
 };
 
+struct ReceivedPacket {
+  Timestamp receive_time = Timestamp::PlusInfinity();
+  DataSize size = DataSize::Zero();
+};
+
 // Transport level feedback
 
 struct RemoteBitrateReport {

call/call.cc

@@ -1498,6 +1498,8 @@ void Call::NotifyBweOfReceivedPacket(const RtpPacketReceived& packet,
   RTPHeader header;
   packet.GetHeader(&header);
 
+  transport_send_ptr_->OnReceivedPacket(packet);
+
   if (!use_send_side_bwe && header.extension.hasTransportSequenceNumber) {
     // Inconsistent configuration of send side BWE. Do nothing.
     // TODO(nisse): Without this check, we may produce RTCP feedback

call/rtp_transport_controller_send.cc

@@ -326,6 +326,18 @@ void RtpTransportControllerSend::OnSentPacket(
       transport_feedback_adapter_.GetOutstandingData().bytes());
 }
 
+void RtpTransportControllerSend::OnReceivedPacket(
+    const RtpPacketReceived& received_packet) {
+  ReceivedPacket packet_msg;
+  packet_msg.size = DataSize::bytes(received_packet.payload_size());
+  packet_msg.receive_time = Timestamp::ms(received_packet.arrival_time_ms());
+  task_queue_.PostTask([this, packet_msg]() {
+    RTC_DCHECK_RUN_ON(&task_queue_);
+    if (controller_)
+      PostUpdates(controller_->OnReceivedPacket(packet_msg));
+  });
+}
+
 void RtpTransportControllerSend::SetSdpBitrateParameters(
     const BitrateConstraints& constraints) {
   absl::optional<BitrateConstraints> updated =

call/rtp_transport_controller_send.h

@@ -96,6 +96,7 @@ class RtpTransportControllerSend final
   int64_t GetFirstPacketTimeMs() const override;
   void EnablePeriodicAlrProbing(bool enable) override;
   void OnSentPacket(const rtc::SentPacket& sent_packet) override;
+  void OnReceivedPacket(const RtpPacketReceived& received_packet) override;
 
   void SetSdpBitrateParameters(const BitrateConstraints& constraints) override;
   void SetClientBitratePreferences(const BitrateSettings& preferences) override;

call/rtp_transport_controller_send_interface.h

@@ -28,6 +28,7 @@
 #include "modules/rtp_rtcp/include/report_block_data.h"
 #include "modules/rtp_rtcp/include/rtcp_statistics.h"
 #include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
+#include "modules/rtp_rtcp/source/rtp_packet_received.h"
 
 namespace rtc {
 struct SentPacket;
@@ -149,6 +150,7 @@ class RtpTransportControllerSendInterface {
   virtual int64_t GetFirstPacketTimeMs() const = 0;
   virtual void EnablePeriodicAlrProbing(bool enable) = 0;
   virtual void OnSentPacket(const rtc::SentPacket& sent_packet) = 0;
+  virtual void OnReceivedPacket(const RtpPacketReceived& received_packet) = 0;
 
   virtual void SetSdpBitrateParameters(
       const BitrateConstraints& constraints) = 0;

call/test/mock_rtp_transport_controller_send.h

@@ -66,6 +66,7 @@ class MockRtpTransportControllerSend
   MOCK_METHOD1(SetSdpBitrateParameters, void(const BitrateConstraints&));
   MOCK_METHOD1(SetClientBitratePreferences, void(const BitrateSettings&));
   MOCK_METHOD1(OnTransportOverheadChanged, void(size_t));
+  MOCK_METHOD1(OnReceivedPacket, void(const RtpPacketReceived&));
 };
 }  // namespace webrtc
 #endif  // CALL_TEST_MOCK_RTP_TRANSPORT_CONTROLLER_SEND_H_

modules/congestion_controller/bbr/bbr_network_controller.cc

@@ -498,6 +498,11 @@ NetworkControlUpdate BbrNetworkController::OnTransportLossReport(
   return NetworkControlUpdate();
 }
 
+NetworkControlUpdate BbrNetworkController::OnReceivedPacket(
+    ReceivedPacket msg) {
+  return NetworkControlUpdate();
+}
+
 TimeDelta BbrNetworkController::GetMinRtt() const {
   return !min_rtt_.IsZero() ? min_rtt_
                             : TimeDelta::us(rtt_stats_.initial_rtt_us());

modules/congestion_controller/bbr/bbr_network_controller.h

@@ -164,6 +164,7 @@ class BbrNetworkController : public NetworkControllerInterface {
   NetworkControlUpdate OnRemoteBitrateReport(RemoteBitrateReport msg) override;
   NetworkControlUpdate OnRoundTripTimeUpdate(RoundTripTimeUpdate msg) override;
   NetworkControlUpdate OnTransportLossReport(TransportLossReport msg) override;
+  NetworkControlUpdate OnReceivedPacket(ReceivedPacket msg) override;
 
   NetworkControlUpdate CreateRateUpdate(Timestamp at_time) const;
 

modules/congestion_controller/goog_cc/goog_cc_network_control.cc

@@ -88,6 +88,9 @@ GoogCcNetworkController::GoogCcNetworkController(NetworkControllerConfig config,
       safe_reset_acknowledged_rate_("ack"),
       use_stable_bandwidth_estimate_(
           IsEnabled(key_value_config_, "WebRTC-Bwe-StableBandwidthEstimate")),
+      use_downlink_delay_for_congestion_window_(
+          IsEnabled(key_value_config_,
+                    "WebRTC-Bwe-CongestionWindowDownlinkDelay")),
       fall_back_to_probe_rate_(
           IsEnabled(key_value_config_, "WebRTC-Bwe-ProbeRateFallback")),
       use_min_allocatable_as_lower_bound_(
@@ -221,6 +224,15 @@ NetworkControlUpdate GoogCcNetworkController::OnProcessInterval(
   update.probe_cluster_configs.insert(update.probe_cluster_configs.end(),
                                       probes.begin(), probes.end());
 
+  time_since_last_received_packet_ =
+      !last_packet_received_time_.IsMinusInfinity() &&
+              use_downlink_delay_for_congestion_window_
+          ? msg.at_time - last_packet_received_time_
+          : TimeDelta::Zero();
+  if (rate_control_settings_.UseCongestionWindow() &&
+      (time_since_last_received_packet_ > TimeDelta::Zero())) {
+    UpdateCongestionWindowSize();
+  }
   MaybeTriggerOnNetworkChanged(&update, msg.at_time);
   return update;
 }
@@ -287,6 +299,12 @@ NetworkControlUpdate GoogCcNetworkController::OnSentPacket(
   }
 }
 
+NetworkControlUpdate GoogCcNetworkController::OnReceivedPacket(
+    ReceivedPacket received_packet) {
+  last_packet_received_time_ = received_packet.receive_time;
+  return NetworkControlUpdate();
+}
+
 NetworkControlUpdate GoogCcNetworkController::OnStreamsConfig(
     StreamsConfig msg) {
   NetworkControlUpdate update;
@@ -387,6 +405,28 @@ NetworkControlUpdate GoogCcNetworkController::OnTransportLossReport(
   return NetworkControlUpdate();
 }
 
+void GoogCcNetworkController::UpdateCongestionWindowSize() {
+  if (feedback_max_rtts_.empty())
+    return;
+  int64_t min_feedback_max_rtt_ms =
+      *std::min_element(feedback_max_rtts_.begin(), feedback_max_rtts_.end());
+
+  const DataSize kMinCwnd = DataSize::bytes(2 * 1500);
+  TimeDelta time_window =
+      TimeDelta::ms(
+          min_feedback_max_rtt_ms +
+          rate_control_settings_.GetCongestionWindowAdditionalTimeMs()) +
+      time_since_last_received_packet_;
+  DataSize data_window = last_raw_target_rate_ * time_window;
+  if (current_data_window_) {
+    data_window =
+        std::max(kMinCwnd, (data_window + current_data_window_.value()) / 2);
+  } else {
+    data_window = std::max(kMinCwnd, data_window);
+  }
+  current_data_window_ = data_window;
+}
+
 NetworkControlUpdate GoogCcNetworkController::OnTransportPacketsFeedback(
     TransportPacketsFeedback report) {
   if (report.packet_feedbacks.empty()) {
@@ -537,21 +577,7 @@ NetworkControlUpdate GoogCcNetworkController::OnTransportPacketsFeedback(
   // we don't try to limit the outstanding packets.
   if (rate_control_settings_.UseCongestionWindow() &&
       max_feedback_rtt.IsFinite()) {
-    int64_t min_feedback_max_rtt_ms =
+    UpdateCongestionWindowSize();
-        *std::min_element(feedback_max_rtts_.begin(), feedback_max_rtts_.end());
-
-    const DataSize kMinCwnd = DataSize::bytes(2 * 1500);
-    TimeDelta time_window = TimeDelta::ms(
-        min_feedback_max_rtt_ms +
-        rate_control_settings_.GetCongestionWindowAdditionalTimeMs());
-    DataSize data_window = last_raw_target_rate_ * time_window;
-    if (current_data_window_) {
-      data_window =
-          std::max(kMinCwnd, (data_window + current_data_window_.value()) / 2);
-    } else {
-      data_window = std::max(kMinCwnd, data_window);
-    }
-    current_data_window_ = data_window;
   }
   if (congestion_window_pushback_controller_ && current_data_window_) {
     congestion_window_pushback_controller_->SetDataWindow(

modules/congestion_controller/goog_cc/goog_cc_network_control.h

@@ -57,6 +57,7 @@ class GoogCcNetworkController : public NetworkControllerInterface {
   NetworkControlUpdate OnRemoteBitrateReport(RemoteBitrateReport msg) override;
   NetworkControlUpdate OnRoundTripTimeUpdate(RoundTripTimeUpdate msg) override;
   NetworkControlUpdate OnSentPacket(SentPacket msg) override;
+  NetworkControlUpdate OnReceivedPacket(ReceivedPacket msg) override;
   NetworkControlUpdate OnStreamsConfig(StreamsConfig msg) override;
   NetworkControlUpdate OnTargetRateConstraints(
       TargetRateConstraints msg) override;
@@ -73,6 +74,7 @@ class GoogCcNetworkController : public NetworkControllerInterface {
   void ClampConstraints();
   void MaybeTriggerOnNetworkChanged(NetworkControlUpdate* update,
                                     Timestamp at_time);
+  void UpdateCongestionWindowSize();
   PacerConfig GetPacingRates(Timestamp at_time) const;
   const FieldTrialBasedConfig trial_based_config_;
 
@@ -82,6 +84,7 @@ class GoogCcNetworkController : public NetworkControllerInterface {
   FieldTrialFlag safe_reset_on_route_change_;
   FieldTrialFlag safe_reset_acknowledged_rate_;
   const bool use_stable_bandwidth_estimate_;
+  const bool use_downlink_delay_for_congestion_window_;
   const bool fall_back_to_probe_rate_;
   const bool use_min_allocatable_as_lower_bound_;
   const RateControlSettings rate_control_settings_;
@@ -119,6 +122,8 @@ class GoogCcNetworkController : public NetworkControllerInterface {
   int32_t last_estimated_bitrate_bps_ = 0;
   uint8_t last_estimated_fraction_loss_ = 0;
   int64_t last_estimated_rtt_ms_ = 0;
+  Timestamp last_packet_received_time_ = Timestamp::MinusInfinity();
+  TimeDelta time_since_last_received_packet_ = TimeDelta::Zero();
 
   double pacing_factor_;
   DataRate min_total_allocated_bitrate_;

modules/congestion_controller/pcc/pcc_network_controller.cc

@@ -376,5 +376,10 @@ NetworkControlUpdate PccNetworkController::OnStreamsConfig(StreamsConfig msg) {
   return NetworkControlUpdate();
 }
 
+NetworkControlUpdate PccNetworkController::OnReceivedPacket(
+    ReceivedPacket msg) {
+  return NetworkControlUpdate();
+}
+
 }  // namespace pcc
 }  // namespace webrtc

modules/congestion_controller/pcc/pcc_network_controller.h

@@ -77,6 +77,7 @@ class PccNetworkController : public NetworkControllerInterface {
   NetworkControlUpdate OnRemoteBitrateReport(RemoteBitrateReport msg) override;
   NetworkControlUpdate OnRoundTripTimeUpdate(RoundTripTimeUpdate msg) override;
   NetworkControlUpdate OnTransportLossReport(TransportLossReport msg) override;
+  NetworkControlUpdate OnReceivedPacket(ReceivedPacket msg) override;
 
  private:
   void UpdateSendingRateAndMode();