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/*
* Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "modules/congestion_controller/include/send_side_congestion_controller.h"
#include <inttypes.h>
#include <algorithm>
#include <cstdio>
#include <iterator>
#include <memory>
#include <string>
#include <vector>
#include "absl/memory/memory.h"
#include "absl/types/optional.h"
#include "api/units/data_rate.h"
#include "api/units/timestamp.h"
#include "modules/bitrate_controller/include/bitrate_controller.h"
#include "modules/congestion_controller/goog_cc/acknowledged_bitrate_estimator.h"
#include "modules/congestion_controller/goog_cc/congestion_window_pushback_controller.h"
#include "modules/congestion_controller/goog_cc/probe_controller.h"
#include "modules/remote_bitrate_estimator/include/bwe_defines.h"
#include "rtc_base/checks.h"
#include "rtc_base/experiments/rate_control_settings.h"
#include "rtc_base/logging.h"
#include "rtc_base/network/sent_packet.h"
#include "rtc_base/rate_limiter.h"
#include "rtc_base/time_utils.h"
namespace webrtc {
namespace {
static const int64_t kRetransmitWindowSizeMs = 500;
// Makes sure that the bitrate and the min, max values are in valid range.
static void ClampBitrates(int* bitrate_bps,
int* min_bitrate_bps,
int* max_bitrate_bps) {
// TODO(holmer): We should make sure the default bitrates are set to 10 kbps,
// and that we don't try to set the min bitrate to 0 from any applications.
// The congestion controller should allow a min bitrate of 0.
if (*min_bitrate_bps < congestion_controller::GetMinBitrateBps())
*min_bitrate_bps = congestion_controller::GetMinBitrateBps();
if (*max_bitrate_bps > 0)
*max_bitrate_bps = std::max(*min_bitrate_bps, *max_bitrate_bps);
if (*bitrate_bps > 0)
*bitrate_bps = std::max(*min_bitrate_bps, *bitrate_bps);
}
std::vector<webrtc::PacketFeedback> ReceivedPacketFeedbackVector(
const std::vector<webrtc::PacketFeedback>& input) {
std::vector<PacketFeedback> received_packet_feedback_vector;
auto is_received = [](const webrtc::PacketFeedback& packet_feedback) {
return packet_feedback.arrival_time_ms !=
webrtc::PacketFeedback::kNotReceived;
};
std::copy_if(input.begin(), input.end(),
std::back_inserter(received_packet_feedback_vector),
is_received);
return received_packet_feedback_vector;
}
void SortPacketFeedbackVector(
std::vector<webrtc::PacketFeedback>* const input) {
RTC_DCHECK(input);
std::sort(input->begin(), input->end(), PacketFeedbackComparator());
}
} // namespace
DEPRECATED_SendSideCongestionController::
DEPRECATED_SendSideCongestionController(
Clock* clock,
Observer* observer,
RtcEventLog* event_log,
PacedSender* pacer,
const WebRtcKeyValueConfig* key_value_config)
: key_value_config_(key_value_config ? key_value_config
: &field_trial_config_),
clock_(clock),
observer_(observer),
event_log_(event_log),
pacer_(pacer),
bitrate_controller_(
BitrateController::CreateBitrateController(clock_, event_log)),
acknowledged_bitrate_estimator_(
absl::make_unique<AcknowledgedBitrateEstimator>(key_value_config_)),
probe_controller_(new ProbeController(key_value_config_, event_log)),
retransmission_rate_limiter_(
new RateLimiter(clock, kRetransmitWindowSizeMs)),
transport_feedback_adapter_(clock_),
last_reported_bitrate_bps_(0),
last_reported_fraction_loss_(0),
last_reported_rtt_(0),
network_state_(kNetworkUp),
pause_pacer_(false),
pacer_paused_(false),
min_bitrate_bps_(congestion_controller::GetMinBitrateBps()),
probe_bitrate_estimator_(new ProbeBitrateEstimator(event_log_)),
delay_based_bwe_(
new DelayBasedBwe(key_value_config_, event_log_, nullptr)),
was_in_alr_(false),
send_side_bwe_with_overhead_(
key_value_config_->Lookup("WebRTC-SendSideBwe-WithOverhead")
.find("Enabled") == 0),
transport_overhead_bytes_per_packet_(0) {
RateControlSettings experiment_params =
RateControlSettings::ParseFromKeyValueConfig(key_value_config);
if (experiment_params.UseCongestionWindow()) {
cwnd_experiment_parameter_ =
experiment_params.GetCongestionWindowAdditionalTimeMs();
}
if (experiment_params.UseCongestionWindowPushback()) {
congestion_window_pushback_controller_ =
absl::make_unique<CongestionWindowPushbackController>(
key_value_config_);
}
delay_based_bwe_->SetMinBitrate(DataRate::bps(min_bitrate_bps_));
}
DEPRECATED_SendSideCongestionController::
~DEPRECATED_SendSideCongestionController() {}
void DEPRECATED_SendSideCongestionController::EnableCongestionWindowPushback(
int64_t accepted_queue_ms,
uint32_t min_pushback_target_bitrate_bps) {
RTC_DCHECK(!congestion_window_pushback_controller_)
<< "The congestion pushback is already enabled.";
RTC_CHECK_GE(accepted_queue_ms, 0)
<< "Accepted must be greater than or equal to 0.";
RTC_CHECK_GE(min_pushback_target_bitrate_bps, 0)
<< "Min pushback target bitrate must be greater than or equal to 0.";
cwnd_experiment_parameter_ = accepted_queue_ms;
congestion_window_pushback_controller_ =
absl::make_unique<CongestionWindowPushbackController>(
key_value_config_, min_pushback_target_bitrate_bps);
}
void DEPRECATED_SendSideCongestionController::SetAlrLimitedBackoffExperiment(
bool enable) {
rtc::CritScope cs(&bwe_lock_);
delay_based_bwe_->SetAlrLimitedBackoffExperiment(enable);
}
void DEPRECATED_SendSideCongestionController::SetMaxProbingBitrate(
int64_t max_probing_bitrate_bps) {
rtc::CritScope cs(&probe_lock_);
probe_controller_->SetMaxBitrate(max_probing_bitrate_bps);
}
void DEPRECATED_SendSideCongestionController::RegisterPacketFeedbackObserver(
PacketFeedbackObserver* observer) {
transport_feedback_adapter_.RegisterPacketFeedbackObserver(observer);
}
void DEPRECATED_SendSideCongestionController::DeRegisterPacketFeedbackObserver(
PacketFeedbackObserver* observer) {
transport_feedback_adapter_.DeRegisterPacketFeedbackObserver(observer);
}
void DEPRECATED_SendSideCongestionController::RegisterNetworkObserver(
Observer* observer) {
rtc::CritScope cs(&observer_lock_);
RTC_DCHECK(observer_ == nullptr);
observer_ = observer;
}
void DEPRECATED_SendSideCongestionController::DeRegisterNetworkObserver(
Observer* observer) {
rtc::CritScope cs(&observer_lock_);
RTC_DCHECK_EQ(observer_, observer);
observer_ = nullptr;
}
void DEPRECATED_SendSideCongestionController::SetBweBitrates(
int min_bitrate_bps,
int start_bitrate_bps,
int max_bitrate_bps) {
ClampBitrates(&start_bitrate_bps, &min_bitrate_bps, &max_bitrate_bps);
bitrate_controller_->SetBitrates(start_bitrate_bps, min_bitrate_bps,
max_bitrate_bps);
{
rtc::CritScope cs(&probe_lock_);
SendProbes(probe_controller_->SetBitrates(
min_bitrate_bps, start_bitrate_bps, max_bitrate_bps,
clock_->TimeInMilliseconds()));
}
{
rtc::CritScope cs(&bwe_lock_);
if (start_bitrate_bps > 0)
delay_based_bwe_->SetStartBitrate(DataRate::bps(start_bitrate_bps));
min_bitrate_bps_ = min_bitrate_bps;
delay_based_bwe_->SetMinBitrate(DataRate::bps(min_bitrate_bps_));
}
MaybeTriggerOnNetworkChanged();
}
void DEPRECATED_SendSideCongestionController::SetAllocatedSendBitrateLimits(
int64_t min_send_bitrate_bps,
int64_t max_padding_bitrate_bps,
int64_t max_total_bitrate_bps) {
pacer_->SetSendBitrateLimits(min_send_bitrate_bps, max_padding_bitrate_bps);
rtc::CritScope cs(&probe_lock_);
SendProbes(probe_controller_->OnMaxTotalAllocatedBitrate(
max_total_bitrate_bps, clock_->TimeInMilliseconds()));
}
// TODO(holmer): Split this up and use SetBweBitrates in combination with
// OnNetworkRouteChanged.
void DEPRECATED_SendSideCongestionController::OnNetworkRouteChanged(
const rtc::NetworkRoute& network_route,
int bitrate_bps,
int min_bitrate_bps,
int max_bitrate_bps) {
ClampBitrates(&bitrate_bps, &min_bitrate_bps, &max_bitrate_bps);
// TODO(honghaiz): Recreate this object once the bitrate controller is
// no longer exposed outside SendSideCongestionController.
bitrate_controller_->ResetBitrates(bitrate_bps, min_bitrate_bps,
max_bitrate_bps);
transport_feedback_adapter_.SetNetworkIds(network_route.local_network_id,
network_route.remote_network_id);
{
rtc::CritScope cs(&bwe_lock_);
transport_overhead_bytes_per_packet_ = network_route.packet_overhead;
min_bitrate_bps_ = min_bitrate_bps;
probe_bitrate_estimator_.reset(new ProbeBitrateEstimator(event_log_));
delay_based_bwe_.reset(
new DelayBasedBwe(key_value_config_, event_log_, nullptr));
acknowledged_bitrate_estimator_.reset(
new AcknowledgedBitrateEstimator(key_value_config_));
if (bitrate_bps > 0) {
delay_based_bwe_->SetStartBitrate(DataRate::bps(bitrate_bps));
}
delay_based_bwe_->SetMinBitrate(DataRate::bps(min_bitrate_bps));
}
{
rtc::CritScope cs(&probe_lock_);
probe_controller_->Reset(clock_->TimeInMilliseconds());
SendProbes(probe_controller_->SetBitrates(min_bitrate_bps, bitrate_bps,
max_bitrate_bps,
clock_->TimeInMilliseconds()));
}
MaybeTriggerOnNetworkChanged();
}
bool DEPRECATED_SendSideCongestionController::AvailableBandwidth(
uint32_t* bandwidth) const {
return bitrate_controller_->AvailableBandwidth(bandwidth);
}
RtcpBandwidthObserver*
DEPRECATED_SendSideCongestionController::GetBandwidthObserver() {
return bitrate_controller_.get();
}
void DEPRECATED_SendSideCongestionController::SetPerPacketFeedbackAvailable(
bool available) {}
void DEPRECATED_SendSideCongestionController::EnablePeriodicAlrProbing(
bool enable) {
rtc::CritScope cs(&probe_lock_);
probe_controller_->EnablePeriodicAlrProbing(enable);
}
int64_t DEPRECATED_SendSideCongestionController::GetPacerQueuingDelayMs()
const {
return IsNetworkDown() ? 0 : pacer_->QueueInMs();
}
int64_t DEPRECATED_SendSideCongestionController::GetFirstPacketTimeMs() const {
return pacer_->FirstSentPacketTimeMs();
}
TransportFeedbackObserver*
DEPRECATED_SendSideCongestionController::GetTransportFeedbackObserver() {
return this;
}
void DEPRECATED_SendSideCongestionController::SignalNetworkState(
NetworkState state) {
RTC_LOG(LS_INFO) << "SignalNetworkState "
<< (state == kNetworkUp ? "Up" : "Down");
{
rtc::CritScope cs(&network_state_lock_);
pause_pacer_ = state == kNetworkDown;
network_state_ = state;
}
{
rtc::CritScope cs(&probe_lock_);
NetworkAvailability msg;
msg.at_time = Timestamp::ms(clock_->TimeInMilliseconds());
msg.network_available = state == kNetworkUp;
SendProbes(probe_controller_->OnNetworkAvailability(msg));
}
MaybeTriggerOnNetworkChanged();
}
void DEPRECATED_SendSideCongestionController::OnSentPacket(
const rtc::SentPacket& sent_packet) {
// We're not interested in packets without an id, which may be stun packets,
// etc, sent on the same transport.
if (sent_packet.packet_id == -1)
return;
transport_feedback_adapter_.OnSentPacket(sent_packet.packet_id,
sent_packet.send_time_ms);
if (cwnd_experiment_parameter_)
LimitOutstandingBytes(transport_feedback_adapter_.GetOutstandingBytes());
}
void DEPRECATED_SendSideCongestionController::OnRttUpdate(int64_t avg_rtt_ms,
int64_t max_rtt_ms) {
rtc::CritScope cs(&bwe_lock_);
delay_based_bwe_->OnRttUpdate(TimeDelta::ms(avg_rtt_ms));
}
int64_t DEPRECATED_SendSideCongestionController::TimeUntilNextProcess() {
return bitrate_controller_->TimeUntilNextProcess();
}
void DEPRECATED_SendSideCongestionController::SendProbes(
std::vector<ProbeClusterConfig> probe_configs) {
for (auto probe_config : probe_configs) {
pacer_->CreateProbeCluster(probe_config.target_data_rate.bps(),
probe_config.id);
}
}
void DEPRECATED_SendSideCongestionController::Process() {
bool pause_pacer;
// TODO(holmer): Once this class is running on a task queue we should
// replace this with a task instead.
{
rtc::CritScope lock(&network_state_lock_);
pause_pacer = pause_pacer_;
}
if (pause_pacer && !pacer_paused_) {
pacer_->Pause();
pacer_paused_ = true;
} else if (!pause_pacer && pacer_paused_) {
pacer_->Resume();
pacer_paused_ = false;
}
bitrate_controller_->Process();
{
rtc::CritScope cs(&probe_lock_);
probe_controller_->SetAlrStartTimeMs(
pacer_->GetApplicationLimitedRegionStartTime());
SendProbes(probe_controller_->Process(clock_->TimeInMilliseconds()));
}
MaybeTriggerOnNetworkChanged();
}
void DEPRECATED_SendSideCongestionController::OnAddPacket(
const RtpPacketSendInfo& packet_info) {
size_t overhead_bytes = 0;
if (send_side_bwe_with_overhead_) {
rtc::CritScope cs(&bwe_lock_);
overhead_bytes = transport_overhead_bytes_per_packet_;
}
transport_feedback_adapter_.AddPacket(
packet_info.ssrc, packet_info.transport_sequence_number,
packet_info.length + overhead_bytes, packet_info.pacing_info);
}
void DEPRECATED_SendSideCongestionController::OnTransportFeedback(
const rtcp::TransportFeedback& feedback) {
RTC_DCHECK_RUNS_SERIALIZED(&worker_race_);
transport_feedback_adapter_.OnTransportFeedback(feedback);
std::vector<PacketFeedback> feedback_vector = ReceivedPacketFeedbackVector(
transport_feedback_adapter_.GetTransportFeedbackVector());
SortPacketFeedbackVector(&feedback_vector);
bool currently_in_alr =
pacer_->GetApplicationLimitedRegionStartTime().has_value();
if (was_in_alr_ && !currently_in_alr) {
int64_t now_ms = rtc::TimeMillis();
acknowledged_bitrate_estimator_->SetAlrEndedTimeMs(now_ms);
rtc::CritScope cs(&probe_lock_);
probe_controller_->SetAlrEndedTimeMs(now_ms);
}
was_in_alr_ = currently_in_alr;
acknowledged_bitrate_estimator_->IncomingPacketFeedbackVector(
feedback_vector);
DelayBasedBwe::Result result;
{
rtc::CritScope cs(&bwe_lock_);
for (const auto& packet : feedback_vector) {
if (packet.send_time_ms != PacketFeedback::kNoSendTime &&
packet.pacing_info.probe_cluster_id != PacedPacketInfo::kNotAProbe) {
probe_bitrate_estimator_->HandleProbeAndEstimateBitrate(packet);
}
}
result = delay_based_bwe_->IncomingPacketFeedbackVector(
feedback_vector, acknowledged_bitrate_estimator_->bitrate(),
probe_bitrate_estimator_->FetchAndResetLastEstimatedBitrate(),
absl::nullopt, currently_in_alr,
Timestamp::ms(clock_->TimeInMilliseconds()));
}
if (result.updated) {
bitrate_controller_->OnDelayBasedBweResult(result);
// Update the estimate in the ProbeController, in case we want to probe.
MaybeTriggerOnNetworkChanged();
}
if (result.recovered_from_overuse) {
rtc::CritScope cs(&probe_lock_);
probe_controller_->SetAlrStartTimeMs(
pacer_->GetApplicationLimitedRegionStartTime());
SendProbes(probe_controller_->RequestProbe(clock_->TimeInMilliseconds()));
} else if (result.backoff_in_alr) {
rtc::CritScope cs(&probe_lock_);
SendProbes(probe_controller_->RequestProbe(clock_->TimeInMilliseconds()));
}
if (cwnd_experiment_parameter_) {
LimitOutstandingBytes(transport_feedback_adapter_.GetOutstandingBytes());
}
}
void DEPRECATED_SendSideCongestionController::LimitOutstandingBytes(
size_t num_outstanding_bytes) {
RTC_DCHECK(cwnd_experiment_parameter_);
rtc::CritScope lock(&network_state_lock_);
absl::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)
return;
const size_t kMinCwndBytes = 2 * 1500;
size_t max_outstanding_bytes =
std::max<size_t>((*min_rtt_ms + *cwnd_experiment_parameter_) *
last_reported_bitrate_bps_ / 1000 / 8,
kMinCwndBytes);
if (congestion_window_pushback_controller_) {
congestion_window_pushback_controller_->UpdateOutstandingData(
num_outstanding_bytes);
congestion_window_pushback_controller_->UpdateMaxOutstandingData(
max_outstanding_bytes);
} else {
pause_pacer_ = num_outstanding_bytes > max_outstanding_bytes;
}
}
std::vector<PacketFeedback>
DEPRECATED_SendSideCongestionController::GetTransportFeedbackVector() const {
RTC_DCHECK_RUNS_SERIALIZED(&worker_race_);
return transport_feedback_adapter_.GetTransportFeedbackVector();
}
void DEPRECATED_SendSideCongestionController::SetPacingFactor(
float pacing_factor) {
pacer_->SetPacingFactor(pacing_factor);
}
void DEPRECATED_SendSideCongestionController::
SetAllocatedBitrateWithoutFeedback(uint32_t bitrate_bps) {
}
void DEPRECATED_SendSideCongestionController::MaybeTriggerOnNetworkChanged() {
uint32_t bitrate_bps;
uint8_t fraction_loss;
int64_t rtt;
bool estimate_changed = bitrate_controller_->GetNetworkParameters(
&bitrate_bps, &fraction_loss, &rtt);
if (estimate_changed) {
pacer_->SetEstimatedBitrate(bitrate_bps);
{
rtc::CritScope cs(&probe_lock_);
SendProbes(probe_controller_->SetEstimatedBitrate(
bitrate_bps, clock_->TimeInMilliseconds()));
}
retransmission_rate_limiter_->SetMaxRate(bitrate_bps);
}
if (IsNetworkDown()) {
bitrate_bps = 0;
} else if (congestion_window_pushback_controller_) {
rtc::CritScope lock(&network_state_lock_);
bitrate_bps = congestion_window_pushback_controller_->UpdateTargetBitrate(
bitrate_bps);
} else {
bitrate_bps = IsSendQueueFull() ? 0 : bitrate_bps;
}
if (HasNetworkParametersToReportChanged(bitrate_bps, fraction_loss, rtt)) {
int64_t probing_interval_ms;
{
rtc::CritScope cs(&bwe_lock_);
probing_interval_ms = delay_based_bwe_->GetExpectedBwePeriod().ms();
}
{
rtc::CritScope cs(&observer_lock_);
if (observer_) {
observer_->OnNetworkChanged(bitrate_bps, fraction_loss, rtt,
probing_interval_ms);
}
}
}
}
bool DEPRECATED_SendSideCongestionController::
HasNetworkParametersToReportChanged(uint32_t bitrate_bps,
uint8_t fraction_loss,
int64_t rtt) {
rtc::CritScope cs(&network_state_lock_);
bool changed =
last_reported_bitrate_bps_ != bitrate_bps ||
(bitrate_bps > 0 && (last_reported_fraction_loss_ != fraction_loss ||
last_reported_rtt_ != rtt));
if (changed && (last_reported_bitrate_bps_ == 0 || bitrate_bps == 0)) {
RTC_LOG(LS_INFO) << "Bitrate estimate state changed, BWE: " << bitrate_bps
<< " bps.";
}
last_reported_bitrate_bps_ = bitrate_bps;
last_reported_fraction_loss_ = fraction_loss;
last_reported_rtt_ = rtt;
return changed;
}
bool DEPRECATED_SendSideCongestionController::IsSendQueueFull() const {
return pacer_->ExpectedQueueTimeMs() > PacedSender::kMaxQueueLengthMs;
}
bool DEPRECATED_SendSideCongestionController::IsNetworkDown() const {
rtc::CritScope cs(&network_state_lock_);
return network_state_ == kNetworkDown;
}
} // namespace webrtc