Now calculates RTT in SendSideCongestionController.
Moved calculation of round trip time from transport feedback adapter to send side congestion
controller. This reduces the role of the transport specific transport feedback adapter and
gives more power to the congestion controller to decide how the feedback rtt should be
calculated and used.
Bug: webrtc:8415
Change-Id: I7878d9fb32c3f4ed11993a6f39e6d9c69fab190a
Reviewed-on: https://webrtc-review.googlesource.com/27980
Reviewed-by: Stefan Holmer <stefan@webrtc.org>
Commit-Queue: Sebastian Jansson <srte@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20973}diff --git a/modules/congestion_controller/include/send_side_congestion_controller.h b/modules/congestion_controller/include/send_side_congestion_controller.h
index b33fad0..ac70d60 100644
--- a/modules/congestion_controller/include/send_side_congestion_controller.h
+++ b/modules/congestion_controller/include/send_side_congestion_controller.h
@@ -11,6 +11,7 @@
#ifndef MODULES_CONGESTION_CONTROLLER_INCLUDE_SEND_SIDE_CONGESTION_CONTROLLER_H_
#define MODULES_CONGESTION_CONTROLLER_INCLUDE_SEND_SIDE_CONGESTION_CONTROLLER_H_
+#include <deque>
#include <memory>
#include <vector>
@@ -136,7 +137,11 @@
const std::unique_ptr<ProbeController> probe_controller_;
const std::unique_ptr<RateLimiter> retransmission_rate_limiter_;
TransportFeedbackAdapter transport_feedback_adapter_;
+
rtc::CriticalSection network_state_lock_;
+ std::deque<int64_t> feedback_rtts_ RTC_GUARDED_BY(network_state_lock_);
+ rtc::Optional<int64_t> min_feedback_rtt_ms_
+ RTC_GUARDED_BY(network_state_lock_);
uint32_t last_reported_bitrate_bps_ RTC_GUARDED_BY(network_state_lock_);
uint8_t last_reported_fraction_loss_ RTC_GUARDED_BY(network_state_lock_);
int64_t last_reported_rtt_ RTC_GUARDED_BY(network_state_lock_);
diff --git a/modules/congestion_controller/send_side_congestion_controller.cc b/modules/congestion_controller/send_side_congestion_controller.cc
index ccca692..5bee61f 100644
--- a/modules/congestion_controller/send_side_congestion_controller.cc
+++ b/modules/congestion_controller/send_side_congestion_controller.cc
@@ -315,11 +315,36 @@
void SendSideCongestionController::OnTransportFeedback(
const rtcp::TransportFeedback& feedback) {
RTC_DCHECK_RUNS_SERIALIZED(&worker_race_);
+ int64_t feedback_time_ms = clock_->TimeInMilliseconds();
+
transport_feedback_adapter_.OnTransportFeedback(feedback);
- std::vector<PacketFeedback> feedback_vector = ReceivedPacketFeedbackVector(
- transport_feedback_adapter_.GetTransportFeedbackVector());
+ std::vector<PacketFeedback> feedback_vector =
+ transport_feedback_adapter_.GetTransportFeedbackVector();
SortPacketFeedbackVector(&feedback_vector);
+ int64_t feedback_rtt = -1;
+ for (const auto& packet_feedback : feedback_vector) {
+ if (packet_feedback.send_time_ms != PacketFeedback::kNoSendTime &&
+ packet_feedback.arrival_time_ms != PacketFeedback::kNotReceived) {
+ int64_t rtt = feedback_time_ms - packet_feedback.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) {
+ rtc::CritScope cs(&network_state_lock_);
+ 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 =
+ ReceivedPacketFeedbackVector(feedback_vector);
+
bool currently_in_alr =
pacer_->GetApplicationLimitedRegionStartTime().has_value();
if (was_in_alr_ && !currently_in_alr) {
@@ -352,22 +377,20 @@
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)
+ if (!min_feedback_rtt_ms_)
return;
const size_t kMinCwndBytes = 2 * 1500;
size_t max_outstanding_bytes =
- std::max<size_t>((*min_rtt_ms + accepted_queue_ms_) *
+ std::max<size_t>((*min_feedback_rtt_ms_ + accepted_queue_ms_) *
last_reported_bitrate_bps_ / 1000 / 8,
kMinCwndBytes);
RTC_LOG(LS_INFO) << clock_->TimeInMilliseconds()
<< " Outstanding bytes: " << num_outstanding_bytes
<< " pacer queue: " << pacer_->QueueInMs()
<< " max outstanding: " << max_outstanding_bytes;
- RTC_LOG(LS_INFO) << "Feedback rtt: " << *min_rtt_ms
+ RTC_LOG(LS_INFO) << "Feedback rtt: " << *min_feedback_rtt_ms_
<< " Bitrate: " << last_reported_bitrate_bps_;
pause_pacer_ = num_outstanding_bytes > max_outstanding_bytes;
}
diff --git a/modules/congestion_controller/transport_feedback_adapter.cc b/modules/congestion_controller/transport_feedback_adapter.cc
index 0989875..89ddce0 100644
--- a/modules/congestion_controller/transport_feedback_adapter.cc
+++ b/modules/congestion_controller/transport_feedback_adapter.cc
@@ -131,7 +131,6 @@
return packet_feedback_vector;
}
packet_feedback_vector.reserve(feedback.GetPacketStatusCount());
- int64_t feedback_rtt = -1;
{
rtc::CritScope cs(&lock_);
size_t failed_lookups = 0;
@@ -161,12 +160,6 @@
++failed_lookups;
if (packet_feedback.local_net_id == local_net_id_ &&
packet_feedback.remote_net_id == remote_net_id_) {
- if (packet_feedback.send_time_ms >= 0) {
- int64_t rtt = now_ms - packet_feedback.send_time_ms;
- // max() is used to account for feedback being delayed by the
- // receiver.
- feedback_rtt = std::max(rtt, feedback_rtt);
- }
packet_feedback_vector.push_back(packet_feedback);
}
@@ -178,14 +171,6 @@
<< " packet" << (failed_lookups > 1 ? "s" : "")
<< ". Send time history too small?";
}
- 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_.emplace(
- *std::min_element(feedback_rtts_.begin(), feedback_rtts_.end()));
- }
}
return packet_feedback_vector;
}
@@ -206,11 +191,6 @@
return last_packet_feedback_vector_;
}
-rtc::Optional<int64_t> TransportFeedbackAdapter::GetMinFeedbackLoopRtt() const {
- rtc::CritScope cs(&lock_);
- return min_feedback_rtt_;
-}
-
size_t TransportFeedbackAdapter::GetOutstandingBytes() const {
rtc::CritScope cs(&lock_);
return send_time_history_.GetOutstandingBytes(local_net_id_, remote_net_id_);
diff --git a/modules/congestion_controller/transport_feedback_adapter.h b/modules/congestion_controller/transport_feedback_adapter.h
index 008bab8..bb3a1f7 100644
--- a/modules/congestion_controller/transport_feedback_adapter.h
+++ b/modules/congestion_controller/transport_feedback_adapter.h
@@ -11,7 +11,6 @@
#ifndef MODULES_CONGESTION_CONTROLLER_TRANSPORT_FEEDBACK_ADAPTER_H_
#define MODULES_CONGESTION_CONTROLLER_TRANSPORT_FEEDBACK_ADAPTER_H_
-#include <deque>
#include <vector>
#include "modules/remote_bitrate_estimator/include/send_time_history.h"
@@ -47,7 +46,6 @@
// to the CongestionController interface.
void OnTransportFeedback(const rtcp::TransportFeedback& feedback);
std::vector<PacketFeedback> GetTransportFeedbackVector() const;
- rtc::Optional<int64_t> GetMinFeedbackLoopRtt() const;
void SetTransportOverhead(int transport_overhead_bytes_per_packet);
@@ -69,8 +67,6 @@
std::vector<PacketFeedback> last_packet_feedback_vector_;
uint16_t local_net_id_ RTC_GUARDED_BY(&lock_);
uint16_t remote_net_id_ RTC_GUARDED_BY(&lock_);
- std::deque<int64_t> feedback_rtts_ RTC_GUARDED_BY(&lock_);
- rtc::Optional<int64_t> min_feedback_rtt_ RTC_GUARDED_BY(&lock_);
rtc::CriticalSection observers_lock_;
std::vector<PacketFeedbackObserver*> observers_
