Don't reset RTT Backoff timeout on route change.
Bug: webrtc:9718
Change-Id: I536733b33c40838cdfc473988581147bec6a358a
Reviewed-on: https://webrtc-review.googlesource.com/c/109927
Commit-Queue: Sebastian Jansson <srte@webrtc.org>
Reviewed-by: Björn Terelius <terelius@webrtc.org>
Reviewed-by: Christoffer Rodbro <crodbro@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25638}diff --git a/modules/bitrate_controller/send_side_bandwidth_estimation.cc b/modules/bitrate_controller/send_side_bandwidth_estimation.cc
index ce7c510..7dfee62 100644
--- a/modules/bitrate_controller/send_side_bandwidth_estimation.cc
+++ b/modules/bitrate_controller/send_side_bandwidth_estimation.cc
@@ -104,21 +104,43 @@
}
} // namespace
-RttBasedBackoffConfig::RttBasedBackoffConfig()
- : rtt_limit("limit", TimeDelta::PlusInfinity()),
- drop_fraction("fraction", 0.5),
- drop_interval("interval", TimeDelta::ms(300)) {
- std::string trial_string =
- field_trial::FindFullName("WebRTC-Bwe-MaxRttLimit");
- ParseFieldTrial({&rtt_limit, &drop_fraction, &drop_interval}, trial_string);
+RttBasedBackoff::RttBasedBackoff()
+ : rtt_limit_("limit", TimeDelta::PlusInfinity()),
+ drop_fraction_("fraction", 0.5),
+ drop_interval_("interval", TimeDelta::ms(300)),
+ persist_on_route_change_("persist"),
+ // By initializing this to plus infinity, we make sure that we never
+ // trigger rtt backoff unless packet feedback is enabled.
+ last_propagation_rtt_update_(Timestamp::PlusInfinity()),
+ last_propagation_rtt_(TimeDelta::Zero()) {
+ ParseFieldTrial({&rtt_limit_, &drop_fraction_, &drop_interval_,
+ &persist_on_route_change_},
+ field_trial::FindFullName("WebRTC-Bwe-MaxRttLimit"));
}
-RttBasedBackoffConfig::RttBasedBackoffConfig(const RttBasedBackoffConfig&) =
- default;
-RttBasedBackoffConfig::~RttBasedBackoffConfig() = default;
+
+void RttBasedBackoff::OnRouteChange() {
+ if (!persist_on_route_change_) {
+ last_propagation_rtt_update_ = Timestamp::PlusInfinity();
+ last_propagation_rtt_ = TimeDelta::Zero();
+ }
+}
+
+void RttBasedBackoff::UpdatePropagationRtt(Timestamp at_time,
+ TimeDelta propagation_rtt) {
+ last_propagation_rtt_update_ = at_time;
+ last_propagation_rtt_ = propagation_rtt;
+}
+
+TimeDelta RttBasedBackoff::RttLowerBound(Timestamp at_time) const {
+ // TODO(srte): Use time since last unacknowledged packet for this.
+ TimeDelta time_since_rtt = at_time - last_propagation_rtt_update_;
+ return time_since_rtt + last_propagation_rtt_;
+}
+
+RttBasedBackoff::~RttBasedBackoff() = default;
SendSideBandwidthEstimation::SendSideBandwidthEstimation(RtcEventLog* event_log)
- : rtt_backoff_config_(RttBasedBackoffConfig()),
- lost_packets_since_last_loss_update_(0),
+ : lost_packets_since_last_loss_update_(0),
expected_packets_since_last_loss_update_(0),
current_bitrate_(DataRate::Zero()),
min_bitrate_configured_(
@@ -132,10 +154,6 @@
last_fraction_loss_(0),
last_logged_fraction_loss_(0),
last_round_trip_time_(TimeDelta::Zero()),
- // By initializing this to plus infinity, we make sure that we never
- // trigger rtt backoff unless packet feedback is enabled.
- last_propagation_rtt_update_(Timestamp::PlusInfinity()),
- last_propagation_rtt_(TimeDelta::Zero()),
bwe_incoming_(DataRate::Zero()),
delay_based_bitrate_(DataRate::Zero()),
time_last_decrease_(Timestamp::MinusInfinity()),
@@ -168,6 +186,34 @@
SendSideBandwidthEstimation::~SendSideBandwidthEstimation() {}
+void SendSideBandwidthEstimation::OnRouteChange() {
+ lost_packets_since_last_loss_update_ = 0;
+ expected_packets_since_last_loss_update_ = 0;
+ current_bitrate_ = DataRate::Zero();
+ min_bitrate_configured_ =
+ DataRate::bps(congestion_controller::GetMinBitrateBps());
+ max_bitrate_configured_ = kDefaultMaxBitrate;
+ last_low_bitrate_log_ = Timestamp::MinusInfinity();
+ has_decreased_since_last_fraction_loss_ = false;
+ last_loss_feedback_ = Timestamp::MinusInfinity();
+ last_loss_packet_report_ = Timestamp::MinusInfinity();
+ last_timeout_ = Timestamp::MinusInfinity();
+ last_fraction_loss_ = 0;
+ last_logged_fraction_loss_ = 0;
+ last_round_trip_time_ = TimeDelta::Zero();
+ bwe_incoming_ = DataRate::Zero();
+ delay_based_bitrate_ = DataRate::Zero();
+ time_last_decrease_ = Timestamp::MinusInfinity();
+ first_report_time_ = Timestamp::MinusInfinity();
+ initially_lost_packets_ = 0;
+ bitrate_at_2_seconds_ = DataRate::Zero();
+ uma_update_state_ = kNoUpdate;
+ uma_rtt_state_ = kNoUpdate;
+ last_rtc_event_log_ = Timestamp::MinusInfinity();
+
+ rtt_backoff_.OnRouteChange();
+}
+
void SendSideBandwidthEstimation::SetBitrates(
absl::optional<DataRate> send_bitrate,
DataRate min_bitrate,
@@ -312,11 +358,10 @@
void SendSideBandwidthEstimation::UpdateEstimate(Timestamp at_time) {
DataRate new_bitrate = current_bitrate_;
- TimeDelta time_since_rtt = at_time - last_propagation_rtt_update_;
- if (time_since_rtt + last_propagation_rtt_ > rtt_backoff_config_.rtt_limit) {
- if (at_time - time_last_decrease_ >= rtt_backoff_config_.drop_interval) {
+ if (rtt_backoff_.RttLowerBound(at_time) > rtt_backoff_.rtt_limit_) {
+ if (at_time - time_last_decrease_ >= rtt_backoff_.drop_interval_) {
time_last_decrease_ = at_time;
- new_bitrate = current_bitrate_ * rtt_backoff_config_.drop_fraction;
+ new_bitrate = current_bitrate_ * rtt_backoff_.drop_fraction_;
}
CapBitrateToThresholds(at_time, new_bitrate);
return;
@@ -412,8 +457,7 @@
void SendSideBandwidthEstimation::UpdatePropagationRtt(
Timestamp at_time,
TimeDelta propagation_rtt) {
- last_propagation_rtt_update_ = at_time;
- last_propagation_rtt_ = propagation_rtt;
+ rtt_backoff_.UpdatePropagationRtt(at_time, propagation_rtt);
}
bool SendSideBandwidthEstimation::IsInStartPhase(Timestamp at_time) const {
diff --git a/modules/bitrate_controller/send_side_bandwidth_estimation.h b/modules/bitrate_controller/send_side_bandwidth_estimation.h
index 9ee43bb..83efe92 100644
--- a/modules/bitrate_controller/send_side_bandwidth_estimation.h
+++ b/modules/bitrate_controller/send_side_bandwidth_estimation.h
@@ -29,14 +29,22 @@
class RtcEventLog;
-struct RttBasedBackoffConfig {
- RttBasedBackoffConfig();
- RttBasedBackoffConfig(const RttBasedBackoffConfig&);
- RttBasedBackoffConfig& operator=(const RttBasedBackoffConfig&) = default;
- ~RttBasedBackoffConfig();
- FieldTrialParameter<TimeDelta> rtt_limit;
- FieldTrialParameter<double> drop_fraction;
- FieldTrialParameter<TimeDelta> drop_interval;
+class RttBasedBackoff {
+ public:
+ RttBasedBackoff();
+ ~RttBasedBackoff();
+ void OnRouteChange();
+ void UpdatePropagationRtt(Timestamp at_time, TimeDelta propagation_rtt);
+ TimeDelta RttLowerBound(Timestamp at_time) const;
+
+ FieldTrialParameter<TimeDelta> rtt_limit_;
+ FieldTrialParameter<double> drop_fraction_;
+ FieldTrialParameter<TimeDelta> drop_interval_;
+ FieldTrialFlag persist_on_route_change_;
+
+ public:
+ Timestamp last_propagation_rtt_update_;
+ TimeDelta last_propagation_rtt_;
};
class SendSideBandwidthEstimation {
@@ -45,12 +53,13 @@
explicit SendSideBandwidthEstimation(RtcEventLog* event_log);
~SendSideBandwidthEstimation();
+ void OnRouteChange();
void CurrentEstimate(int* bitrate, uint8_t* loss, int64_t* rtt) const;
// Call periodically to update estimate.
void UpdateEstimate(Timestamp at_time);
void OnSentPacket(SentPacket sent_packet);
- void UpdatePropagationRtt(Timestamp at_time, TimeDelta feedback_rtt);
+ void UpdatePropagationRtt(Timestamp at_time, TimeDelta propagation_rtt);
// Call when we receive a RTCP message with TMMBR or REMB.
void UpdateReceiverEstimate(Timestamp at_time, DataRate bandwidth);
@@ -96,7 +105,7 @@
// set |current_bitrate_| to the capped value and updates the event log.
void CapBitrateToThresholds(Timestamp at_time, DataRate bitrate);
- RttBasedBackoffConfig rtt_backoff_config_;
+ RttBasedBackoff rtt_backoff_;
std::deque<std::pair<Timestamp, DataRate> > min_bitrate_history_;
@@ -117,9 +126,6 @@
uint8_t last_logged_fraction_loss_;
TimeDelta last_round_trip_time_;
- Timestamp last_propagation_rtt_update_;
- TimeDelta last_propagation_rtt_;
-
DataRate bwe_incoming_;
DataRate delay_based_bitrate_;
Timestamp time_last_decrease_;
diff --git a/modules/congestion_controller/goog_cc/goog_cc_network_control.cc b/modules/congestion_controller/goog_cc/goog_cc_network_control.cc
index 0088018..3b06ed6 100644
--- a/modules/congestion_controller/goog_cc/goog_cc_network_control.cc
+++ b/modules/congestion_controller/goog_cc/goog_cc_network_control.cc
@@ -213,8 +213,7 @@
delay_based_bwe_.reset(new DelayBasedBwe(event_log_));
delay_based_bwe_->SetStartBitrate(start_bitrate_bps);
delay_based_bwe_->SetMinBitrate(min_bitrate_bps);
- bandwidth_estimation_ =
- absl::make_unique<SendSideBandwidthEstimation>(event_log_);
+ bandwidth_estimation_->OnRouteChange();
bandwidth_estimation_->SetBitrates(
msg.constraints.starting_rate, DataRate::bps(min_bitrate_bps),
msg.constraints.max_data_rate.value_or(DataRate::Infinity()),
@@ -428,6 +427,7 @@
const size_t kMaxFeedbackRttWindow = 32;
if (feedback_max_rtts_.size() > kMaxFeedbackRttWindow)
feedback_max_rtts_.pop_front();
+ // TODO(srte): Use time since last unacknowledged packet.
bandwidth_estimation_->UpdatePropagationRtt(report.feedback_time,
min_propagation_rtt);
}
