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Field trial for pacing relative lower link capacity

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This adds a field trial to change the pacing rate to pace
at a rate relative to max(bwe ,lower link capacity)





Bug: none
Change-Id: Ibe9ef3e08eb422e9abff6488780e82188958eeeb
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/248865
Reviewed-by: Björn Terelius <terelius@webrtc.org>
Commit-Queue: Per Kjellander <perkj@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35795}
This commit is contained in:
Per Kjellander 2022-01-25 11:21:41 +01:00 committed by WebRTC LUCI CQ
parent 7f761573b3
commit 5f133dbc29
3 changed files with 68 additions and 3 deletions
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18
modules/congestion_controller/goog_cc/goog_cc_network_control.cc
View File

@ -22,6 +22,7 @@
#include <vector>
#include "absl/strings/match.h"
#include "api/units/data_rate.h"
#include "api/units/time_delta.h"
#include "logging/rtc_event_log/events/rtc_event_remote_estimate.h"
#include "modules/congestion_controller/goog_cc/alr_detector.h"
@ -88,6 +89,9 @@ GoogCcNetworkController::GoogCcNetworkController(NetworkControllerConfig config,
RateControlSettings::ParseFromKeyValueConfig(key_value_config_)),
loss_based_stable_rate_(
IsEnabled(key_value_config_, "WebRTC-Bwe-LossBasedStableRate")),
pace_at_max_of_bwe_and_lower_link_capacity_(
IsEnabled(key_value_config_,
"WebRTC-Bwe-PaceAtMaxOfBweAndLowerLinkCapacity")),
probe_controller_(
new ProbeController(key_value_config_, config.event_log)),
congestion_window_pushback_controller_(
@ -694,9 +698,17 @@ void GoogCcNetworkController::MaybeTriggerOnNetworkChanged(
PacerConfig GoogCcNetworkController::GetPacingRates(Timestamp at_time) const {
// Pacing rate is based on target rate before congestion window pushback,
// because we don't want to build queues in the pacer when pushback occurs.
DataRate pacing_rate =
std::max(min_total_allocated_bitrate_, last_loss_based_target_rate_) *
pacing_factor_;
DataRate pacing_rate = DataRate::Zero();
if (pace_at_max_of_bwe_and_lower_link_capacity_ && estimate_) {
pacing_rate =
std::max({min_total_allocated_bitrate_, estimate_->link_capacity_lower,
last_loss_based_target_rate_}) *
pacing_factor_;
} else {
pacing_rate =
std::max(min_total_allocated_bitrate_, last_loss_based_target_rate_) *
pacing_factor_;
}
DataRate padding_rate =
std::min(max_padding_rate_, last_pushback_target_rate_);
PacerConfig msg;

1
modules/congestion_controller/goog_cc/goog_cc_network_control.h
View File

@ -94,6 +94,7 @@ class GoogCcNetworkController : public NetworkControllerInterface {
const bool limit_probes_lower_than_throughput_estimate_;
const RateControlSettings rate_control_settings_;
const bool loss_based_stable_rate_;
const bool pace_at_max_of_bwe_and_lower_link_capacity_;
const std::unique_ptr<ProbeController> probe_controller_;
const std::unique_ptr<CongestionWindowPushbackController>

52
modules/congestion_controller/goog_cc/goog_cc_network_control_unittest.cc
View File

@ -13,6 +13,7 @@
#include "api/test/network_emulation/create_cross_traffic.h"
#include "api/test/network_emulation/cross_traffic.h"
#include "api/transport/goog_cc_factory.h"
#include "api/transport/network_types.h"
#include "api/units/data_rate.h"
#include "logging/rtc_event_log/mock/mock_rtc_event_log.h"
#include "test/field_trial.h"
@ -359,6 +360,57 @@ TEST(GoogCcNetworkControllerTest, UpdatesDelayBasedEstimate) {
EXPECT_LT(*target_bitrate_after_delay, *target_bitrate_before_delay);
}
TEST(GoogCcNetworkControllerTest, PaceAtMaxOfLowerLinkCapacityAndBwe) {
ScopedFieldTrials trial(
"WebRTC-Bwe-PaceAtMaxOfBweAndLowerLinkCapacity/Enabled/");
NetworkControllerTestFixture fixture;
std::unique_ptr<NetworkControllerInterface> controller =
fixture.CreateController();
Timestamp current_time = Timestamp::Millis(123);
NetworkControlUpdate update =
controller->OnProcessInterval({.at_time = current_time});
current_time += TimeDelta::Millis(100);
NetworkStateEstimate network_estimate = {.link_capacity_lower =
10 * kInitialBitrate};
update = controller->OnNetworkStateEstimate(network_estimate);
// OnNetworkStateEstimate does not trigger processing a new estimate. So add a
// dummy loss report to trigger a BWE update in the next process interval.
TransportLossReport loss_report;
loss_report.start_time = current_time;
loss_report.end_time = current_time;
loss_report.receive_time = current_time;
loss_report.packets_received_delta = 50;
loss_report.packets_lost_delta = 1;
update = controller->OnTransportLossReport(loss_report);
update = controller->OnProcessInterval({.at_time = current_time});
ASSERT_TRUE(update.pacer_config);
ASSERT_TRUE(update.target_rate);
ASSERT_LT(update.target_rate->target_rate,
network_estimate.link_capacity_lower);
EXPECT_EQ(update.pacer_config->data_rate().kbps(),
network_estimate.link_capacity_lower.kbps() * kDefaultPacingRate);
current_time += TimeDelta::Millis(100);
// Set a low link capacity estimate and verify that pacing rate is set
// relative to loss based/delay based estimate.
network_estimate = {.link_capacity_lower = 0.5 * kInitialBitrate};
update = controller->OnNetworkStateEstimate(network_estimate);
// Again, we need to inject a dummy loss report to trigger an update of the
// BWE in the next process interval.
loss_report.start_time = current_time;
loss_report.end_time = current_time;
loss_report.receive_time = current_time;
loss_report.packets_received_delta = 50;
loss_report.packets_lost_delta = 0;
update = controller->OnTransportLossReport(loss_report);
update = controller->OnProcessInterval({.at_time = current_time});
ASSERT_TRUE(update.target_rate);
ASSERT_GT(update.target_rate->target_rate,
network_estimate.link_capacity_lower);
EXPECT_EQ(update.pacer_config->data_rate().kbps(),
update.target_rate->target_rate.kbps() * kDefaultPacingRate);
}
// Test congestion window pushback on network delay happens.
TEST(GoogCcScenario, CongestionWindowPushbackOnNetworkDelay) {
auto factory = CreateFeedbackOnlyFactory();