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Adds improved estimate bounded backoff to AimdRateControl.

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Bug: webrtc:10498
Change-Id: I4e006e437dfa667b738beb009a599bacc6778da5
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/146215
Reviewed-by: Jonas Olsson <jonasolsson@webrtc.org>
Commit-Queue: Sebastian Jansson <srte@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28632}
This commit is contained in:
Sebastian Jansson 2019-07-19 17:13:11 +02:00 committed by Commit Bot
parent c36c8e114d
commit 7ea6b290d0
2 changed files with 24 additions and 31 deletions
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46
modules/remote_bitrate_estimator/aimd_rate_control.cc
View File

@ -89,10 +89,13 @@ AimdRateControl::AimdRateControl(const WebRtcKeyValueConfig* key_value_config,
"WebRTC-DontIncreaseDelayBasedBweInAlr")),
smoothing_experiment_(
IsEnabled(*key_value_config, "WebRTC-Audio-BandwidthSmoothing")),
estimate_bounded_backoff_(
IsEnabled(*key_value_config, "WebRTC-Bwe-EstimateBoundedBackoff")),
estimate_bounded_increase_(
IsEnabled(*key_value_config, "WebRTC-Bwe-EstimateBoundedIncrease")),
initial_backoff_interval_("initial_backoff_interval"),
low_throughput_threshold_("low_throughput", DataRate::Zero()),
capacity_deviation_ratio_threshold_("cap_thr", 0.2),
cross_traffic_factor_("cross", 1.0),
capacity_limit_deviation_factor_("cap_lim", 1) {
// E.g
// WebRTC-BweAimdRateControlConfig/initial_backoff_interval:100ms,
@ -105,8 +108,7 @@ AimdRateControl::AimdRateControl(const WebRtcKeyValueConfig* key_value_config,
}
RTC_LOG(LS_INFO) << "Using aimd rate control with back off factor " << beta_;
ParseFieldTrial(
{&capacity_deviation_ratio_threshold_, &cross_traffic_factor_,
&capacity_limit_deviation_factor_},
{&capacity_deviation_ratio_threshold_, &capacity_limit_deviation_factor_},
key_value_config->Lookup("WebRTC-Bwe-AimdRateControl-NetworkState"));
}
@ -304,26 +306,11 @@ DataRate AimdRateControl::ChangeBitrate(DataRate new_bitrate,
break;
case kRcDecrease:
if (network_estimate_ && capacity_deviation_ratio_threshold_) {
DataRate lower_bound = network_estimate_->link_capacity_lower;
// TODO(srte): Remove this when link_capacity_lower is available.
if (lower_bound.IsInfinite()) {
// If we have a low variance network estimate, we use it over the
// acknowledged rate to avoid dropping the bitrate too far. This
// avoids overcompensating when the send rate is lower than the
// capacity.
double deviation_ratio = network_estimate_->link_capacity_std_dev /
network_estimate_->link_capacity;
if (deviation_ratio < *capacity_deviation_ratio_threshold_) {
double available_ratio =
std::max(0.0, 1.0 - network_estimate_->cross_traffic_ratio *
cross_traffic_factor_);
lower_bound = network_estimate_->link_capacity * available_ratio;
}
}
if (lower_bound > DataRate::Zero()) {
estimated_throughput = std::max(lower_bound, estimated_throughput);
}
// TODO(srte): Remove when |estimate_bounded_backoff_| has been validated.
if (network_estimate_ && capacity_deviation_ratio_threshold_ &&
!estimate_bounded_backoff_) {
estimated_throughput = std::max(estimated_throughput,
network_estimate_->link_capacity_lower);
}
if (estimated_throughput > low_throughput_threshold_) {
// Set bit rate to something slightly lower than the measured throughput
@ -335,6 +322,10 @@ DataRate AimdRateControl::ChangeBitrate(DataRate new_bitrate,
new_bitrate = beta_ * link_capacity_.estimate();
}
}
if (estimate_bounded_backoff_ && network_estimate_) {
new_bitrate = std::max(
new_bitrate, network_estimate_->link_capacity_lower * beta_);
}
} else {
new_bitrate = estimated_throughput;
if (link_capacity_.has_estimate()) {
@ -393,14 +384,9 @@ DataRate AimdRateControl::ClampBitrate(DataRate new_bitrate,
}
}
if (network_estimate_ && capacity_limit_deviation_factor_) {
if (network_estimate_ &&
(estimate_bounded_increase_ || capacity_limit_deviation_factor_)) {
DataRate upper_bound = network_estimate_->link_capacity_upper;
// TODO(srte): Remove this when link_capacity_lower is available.
if (upper_bound.IsMinusInfinity()) {
upper_bound = network_estimate_->link_capacity +
network_estimate_->link_capacity_std_dev *
capacity_limit_deviation_factor_.Value();
}
new_bitrate = std::min(new_bitrate, upper_bound);
}
new_bitrate = std::max(new_bitrate, min_configured_bitrate_);

9
modules/remote_bitrate_estimator/aimd_rate_control.h
View File

@ -108,11 +108,18 @@ class AimdRateControl {
// limited region (alr) is not detected.
const bool no_bitrate_increase_in_alr_;
const bool smoothing_experiment_;
// Use estimated link capacity lower bound if it is higher than the
// acknowledged rate when backing off due to overuse.
const bool estimate_bounded_backoff_;
// Use estimated link capacity upper bound as upper limit for increasing
// bitrate over the acknowledged rate.
const bool estimate_bounded_increase_;
absl::optional<DataRate> last_decrease_;
FieldTrialOptional<TimeDelta> initial_backoff_interval_;
FieldTrialParameter<DataRate> low_throughput_threshold_;
// Deprecated, enable |estimate_bounded_backoff_| instead.
FieldTrialOptional<double> capacity_deviation_ratio_threshold_;
FieldTrialParameter<double> cross_traffic_factor_;
// Deprecated, enable |estimate_bounded_increase_| instead.
FieldTrialOptional<double> capacity_limit_deviation_factor_;
};
} // namespace webrtc