Probing: Add support for exponential startup probing

webrtc/modules/congestion_controller/congestion_controller.cc

 /*
  *  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 "webrtc/modules/congestion_controller/include/congestion_controller.h"
 
 #include <algorithm>
 #include <memory>
 #include <vector>
 
 #include "webrtc/base/checks.h"
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/base/logging.h"
 #include "webrtc/base/rate_limiter.h"
 #include "webrtc/base/socket.h"
 #include "webrtc/base/thread_annotations.h"
 #include "webrtc/modules/bitrate_controller/include/bitrate_controller.h"
 #include "webrtc/modules/congestion_controller/delay_based_bwe.h"
+#include "webrtc/modules/congestion_controller/probe_controller.h"
 #include "webrtc/modules/remote_bitrate_estimator/include/send_time_history.h"
 #include "webrtc/modules/remote_bitrate_estimator/remote_bitrate_estimator_abs_send_time.h"
 #include "webrtc/modules/remote_bitrate_estimator/remote_bitrate_estimator_single_stream.h"
 #include "webrtc/modules/utility/include/process_thread.h"
 #include "webrtc/system_wrappers/include/critical_section_wrapper.h"
 #include "webrtc/video/payload_router.h"
 
 namespace webrtc {
 namespace {
 
@@ skipping 124 matching lines @@
     RemoteBitrateObserver* remote_bitrate_observer,
     RtcEventLog* event_log)
     : clock_(clock),
       observer_(observer),
       packet_router_(new PacketRouter()),
       pacer_(new PacedSender(clock_, packet_router_.get())),
       remote_bitrate_estimator_(
           new WrappingBitrateEstimator(remote_bitrate_observer, clock_)),
       bitrate_controller_(
           BitrateController::CreateBitrateController(clock_, event_log)),
+      probe_controller_(new ProbeController(pacer_.get(), clock_)),
       retransmission_rate_limiter_(
           new RateLimiter(clock, kRetransmitWindowSizeMs)),
       remote_estimator_proxy_(clock_, packet_router_.get()),
-      transport_feedback_adapter_(bitrate_controller_.get(), clock_),
+      transport_feedback_adapter_(clock_),
       min_bitrate_bps_(RemoteBitrateEstimator::kDefaultMinBitrateBps),
       max_bitrate_bps_(0),
-      initial_probing_triggered_(false),
       last_reported_bitrate_bps_(0),
       last_reported_fraction_loss_(0),
       last_reported_rtt_(0),
       network_state_(kNetworkUp) {
   Init();
 }
 
 CongestionController::CongestionController(
     Clock* clock,
     Observer* observer,
     RemoteBitrateObserver* remote_bitrate_observer,
     RtcEventLog* event_log,
     std::unique_ptr<PacketRouter> packet_router,
     std::unique_ptr<PacedSender> pacer)
     : clock_(clock),
       observer_(observer),
       packet_router_(std::move(packet_router)),
       pacer_(std::move(pacer)),
       remote_bitrate_estimator_(
           new WrappingBitrateEstimator(remote_bitrate_observer, clock_)),
       // Constructed last as this object calls the provided callback on
       // construction.
       bitrate_controller_(
           BitrateController::CreateBitrateController(clock_, event_log)),
+      probe_controller_(new ProbeController(pacer_.get(), clock_)),
       retransmission_rate_limiter_(
           new RateLimiter(clock, kRetransmitWindowSizeMs)),
       remote_estimator_proxy_(clock_, packet_router_.get()),
-      transport_feedback_adapter_(bitrate_controller_.get(), clock_),
+      transport_feedback_adapter_(clock_),
       min_bitrate_bps_(RemoteBitrateEstimator::kDefaultMinBitrateBps),
       max_bitrate_bps_(0),
-      initial_probing_triggered_(false),
       last_reported_bitrate_bps_(0),
       last_reported_fraction_loss_(0),
       last_reported_rtt_(0),
       network_state_(kNetworkUp) {
   Init();
 }
 
 CongestionController::~CongestionController() {}
 
 void CongestionController::Init() {
   transport_feedback_adapter_.SetBitrateEstimator(
-      new DelayBasedBwe(&transport_feedback_adapter_, clock_));
+      new DelayBasedBwe(bitrate_controller_.get(), clock_));
   transport_feedback_adapter_.GetBitrateEstimator()->SetMinBitrate(
       min_bitrate_bps_);
 }
 
 void CongestionController::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(&critsect_);
-    if (!initial_probing_triggered_) {
-      pacer_->CreateProbeCluster(start_bitrate_bps * 3, 6);
-      pacer_->CreateProbeCluster(start_bitrate_bps * 6, 5);
-      initial_probing_triggered_ = true;
-    }
-
-    // Only do probing if:
-    //   - we are mid-call, which we consider to be if
-    //     |last_reported_bitrate_bps_| != 0, and
-    //   - the current bitrate is lower than the new |max_bitrate_bps|, and
-    //   - we actually want to increase the |max_bitrate_bps_|.
-    if (last_reported_bitrate_bps_ != 0 &&
-        last_reported_bitrate_bps_ < static_cast<uint32_t>(max_bitrate_bps) &&
-        max_bitrate_bps > max_bitrate_bps_) {
-      pacer_->CreateProbeCluster(max_bitrate_bps, 5);
-    }
-  }
+  probe_controller_->SetBitrates(min_bitrate_bps, start_bitrate_bps,
+                                 max_bitrate_bps);
   max_bitrate_bps_ = max_bitrate_bps;
 
   if (remote_bitrate_estimator_)
     remote_bitrate_estimator_->SetMinBitrate(min_bitrate_bps);
   min_bitrate_bps_ = min_bitrate_bps;
   transport_feedback_adapter_.GetBitrateEstimator()->SetMinBitrate(
       min_bitrate_bps_);
   MaybeTriggerOnNetworkChanged();
 }
 
 void CongestionController::ResetBweAndBitrates(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 CongestionController.
   bitrate_controller_->ResetBitrates(bitrate_bps, min_bitrate_bps,
                                      max_bitrate_bps);
   min_bitrate_bps_ = min_bitrate_bps;
   max_bitrate_bps_ = max_bitrate_bps;
   // TODO(honghaiz): Recreate this object once the remote bitrate estimator is
   // no longer exposed outside CongestionController.
   if (remote_bitrate_estimator_)
     remote_bitrate_estimator_->SetMinBitrate(min_bitrate_bps);
 
-  RemoteBitrateEstimator* rbe = new DelayBasedBwe(
-      &transport_feedback_adapter_, clock_);
+  RemoteBitrateEstimator* rbe =
+      new DelayBasedBwe(bitrate_controller_.get(), clock_);
   transport_feedback_adapter_.SetBitrateEstimator(rbe);
   rbe->SetMinBitrate(min_bitrate_bps);
   // TODO(holmer): Trigger a new probe once mid-call probing is implemented.
   MaybeTriggerOnNetworkChanged();
 }
 
 BitrateController* CongestionController::GetBitrateController() const {
   return bitrate_controller_.get();
 }
 
@@ skipping 67 matching lines @@
   if (!observer_)
     return;
 
   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);
+    probe_controller_->SetEstimatedBitrate(bitrate_bps);
     retransmission_rate_limiter_->SetMaxRate(bitrate_bps);
   }
 
   bitrate_bps = IsNetworkDown() || IsSendQueueFull() ? 0 : bitrate_bps;
 
   if (HasNetworkParametersToReportChanged(bitrate_bps, fraction_loss, rtt)) {
     observer_->OnNetworkChanged(bitrate_bps, fraction_loss, rtt);
   }
 }
 
@@ skipping 19 matching lines @@
 bool CongestionController::IsSendQueueFull() const {
   return pacer_->ExpectedQueueTimeMs() > PacedSender::kMaxQueueLengthMs;
 }
 
 bool CongestionController::IsNetworkDown() const {
   rtc::CritScope cs(&critsect_);
   return network_state_ == kNetworkDown;
 }
 
 }  // namespace webrtc