Expose packet loss counts from QUIC to NetworkQualityEstimator

net/base/network_quality_estimator.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/base/network_quality_estimator.h"
 
 #include <float.h>
 #include <algorithm>
 #include <cmath>
 #include <limits>
@@ skipping 101 matching lines @@
       prefix + statistic_name + GetNameForConnectionType(type), kLowerLimit,
       max_limit, kBucketCount, base::HistogramBase::kUmaTargetedHistogramFlag);
 }
 
 }  // namespace
 
 namespace net {
 
 const int32_t NetworkQualityEstimator::kInvalidThroughput = 0;
 
+const float NetworkQualityEstimator::kInvalidPacketLossRate = -1.0f;
+
 NetworkQualityEstimator::NetworkQualityEstimator(
     scoped_ptr<ExternalEstimateProvider> external_estimates_provider,
     const std::map<std::string, std::string>& variation_params)
     : NetworkQualityEstimator(std::move(external_estimates_provider),
                               variation_params,
                               false,
                               false) {}
 
 NetworkQualityEstimator::NetworkQualityEstimator(
     scoped_ptr<ExternalEstimateProvider> external_estimates_provider,
     const std::map<std::string, std::string>& variation_params,
     bool allow_local_host_requests_for_tests,
     bool allow_smaller_responses_for_tests)
     : allow_localhost_requests_(allow_local_host_requests_for_tests),
       allow_small_responses_(allow_smaller_responses_for_tests),
       last_connection_change_(base::TimeTicks::Now()),
       current_network_id_(
           NetworkID(NetworkChangeNotifier::ConnectionType::CONNECTION_UNKNOWN,
                     std::string())),
       downstream_throughput_kbps_observations_(
           GetWeightMultiplierPerSecond(variation_params)),
       rtt_msec_observations_(GetWeightMultiplierPerSecond(variation_params)),
+      packet_loss_rate_observations_(
+          GetWeightMultiplierPerSecond(variation_params)),
       external_estimate_provider_(std::move(external_estimates_provider)) {
   static_assert(kMinRequestDurationMicroseconds > 0,
                 "Minimum request duration must be > 0");
   static_assert(kDefaultHalfLifeSeconds > 0,
                 "Default half life duration must be > 0");
   static_assert(kMaximumNetworkQualityCacheSize > 0,
                 "Size of the network quality cache must be > 0");
   // This limit should not be increased unless the logic for removing the
   // oldest cache entry is rewritten to use a doubly-linked-list LRU queue.
   static_assert(kMaximumNetworkQualityCacheSize <= 10,
@@ skipping 215 matching lines @@
   DCHECK(thread_checker_.CalledOnValidThread());
   throughput_observer_list_.AddObserver(throughput_observer);
 }
 
 void NetworkQualityEstimator::RemoveThroughputObserver(
     ThroughputObserver* throughput_observer) {
   DCHECK(thread_checker_.CalledOnValidThread());
   throughput_observer_list_.RemoveObserver(throughput_observer);
 }
 
+void NetworkQualityEstimator::AddPacketLossObserver(
+    PacketLossObserver* packet_loss_observer) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  packet_loss_observer_list_.AddObserver(packet_loss_observer);
+}
+
+void NetworkQualityEstimator::RemovePacketLossObserver(
+    PacketLossObserver* packet_loss_observer) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  packet_loss_observer_list_.RemoveObserver(packet_loss_observer);
+}
+
 void NetworkQualityEstimator::RecordRTTUMA(int32_t estimated_value_msec,
                                            int32_t actual_value_msec) const {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   // Record the difference between the actual and the estimated value.
   if (estimated_value_msec >= actual_value_msec) {
     base::HistogramBase* difference_rtt =
         GetHistogram("DifferenceRTTEstimatedAndActual.",
                      current_network_id_.type, 10 * 1000);  // 10 seconds
     difference_rtt->Add(estimated_value_msec - actual_value_msec);
@@ skipping 33 matching lines @@
          !request.was_cached() &&
          request.creation_time() >= last_connection_change_;
 }
 
 void NetworkQualityEstimator::RecordExternalEstimateProviderMetrics(
     NQEExternalEstimateProviderStatus status) const {
   UMA_HISTOGRAM_ENUMERATION("NQE.ExternalEstimateProviderStatus", status,
                             EXTERNAL_ESTIMATE_PROVIDER_STATUS_BOUNDARY);
 }
 
+bool NetworkQualityEstimator::GetObservationSourceForProtocol(
+    const Protocol protocol,
+    NetworkQualityEstimator::ObservationSource* observation_source) const {
+  switch (protocol) {
+    case PROTOCOL_TCP:
+      *observation_source = TCP;
+      return true;
+    case PROTOCOL_QUIC:
+      *observation_source = QUIC;
+      return true;
+    default:
+      NOTREACHED();
+      return false;
+  }
+}
+
 void NetworkQualityEstimator::OnConnectionTypeChanged(
     NetworkChangeNotifier::ConnectionType type) {
   DCHECK(thread_checker_.CalledOnValidThread());
+
   if (peak_network_quality_.rtt() != InvalidRTT()) {
-    switch (current_network_id_.type) {
-      case NetworkChangeNotifier::CONNECTION_UNKNOWN:
-        UMA_HISTOGRAM_TIMES("NQE.FastestRTT.Unknown",
-                            peak_network_quality_.rtt());
-        break;
-      case NetworkChangeNotifier::CONNECTION_ETHERNET:
-        UMA_HISTOGRAM_TIMES("NQE.FastestRTT.Ethernet",
-                            peak_network_quality_.rtt());
-        break;
-      case NetworkChangeNotifier::CONNECTION_WIFI:
-        UMA_HISTOGRAM_TIMES("NQE.FastestRTT.Wifi", peak_network_quality_.rtt());
-        break;
-      case NetworkChangeNotifier::CONNECTION_2G:
-        UMA_HISTOGRAM_TIMES("NQE.FastestRTT.2G", peak_network_quality_.rtt());
-        break;
-      case NetworkChangeNotifier::CONNECTION_3G:
-        UMA_HISTOGRAM_TIMES("NQE.FastestRTT.3G", peak_network_quality_.rtt());
-        break;
-      case NetworkChangeNotifier::CONNECTION_4G:
-        UMA_HISTOGRAM_TIMES("NQE.FastestRTT.4G", peak_network_quality_.rtt());
-        break;
-      case NetworkChangeNotifier::CONNECTION_NONE:
-        UMA_HISTOGRAM_TIMES("NQE.FastestRTT.None", peak_network_quality_.rtt());
-        break;
-      case NetworkChangeNotifier::CONNECTION_BLUETOOTH:
-        UMA_HISTOGRAM_TIMES("NQE.FastestRTT.Bluetooth",
-                            peak_network_quality_.rtt());
-        break;
-      default:
-        NOTREACHED() << "Unexpected connection type = "
-                     << current_network_id_.type;
-        break;
-    }
+    // Largest bucket is 10 seconds.
+    base::HistogramBase* fastest_rtt_histogram =
+        GetHistogram("FastestRTT.", current_network_id_.type, 10 * 1000);
+    fastest_rtt_histogram->Add(peak_network_quality_.rtt().InMilliseconds());
   }
 
   if (peak_network_quality_.downstream_throughput_kbps() !=
       kInvalidThroughput) {
-    switch (current_network_id_.type) {
-      case NetworkChangeNotifier::CONNECTION_UNKNOWN:
-        UMA_HISTOGRAM_COUNTS(
-            "NQE.PeakKbps.Unknown",
-            peak_network_quality_.downstream_throughput_kbps());
-        break;
-      case NetworkChangeNotifier::CONNECTION_ETHERNET:
-        UMA_HISTOGRAM_COUNTS(
-            "NQE.PeakKbps.Ethernet",
-            peak_network_quality_.downstream_throughput_kbps());
-        break;
-      case NetworkChangeNotifier::CONNECTION_WIFI:
-        UMA_HISTOGRAM_COUNTS(
-            "NQE.PeakKbps.Wifi",
-            peak_network_quality_.downstream_throughput_kbps());
-        break;
-      case NetworkChangeNotifier::CONNECTION_2G:
-        UMA_HISTOGRAM_COUNTS(
-            "NQE.PeakKbps.2G",
-            peak_network_quality_.downstream_throughput_kbps());
-        break;
-      case NetworkChangeNotifier::CONNECTION_3G:
-        UMA_HISTOGRAM_COUNTS(
-            "NQE.PeakKbps.3G",
-            peak_network_quality_.downstream_throughput_kbps());
-        break;
-      case NetworkChangeNotifier::CONNECTION_4G:
-        UMA_HISTOGRAM_COUNTS(
-            "NQE.PeakKbps.4G",
-            peak_network_quality_.downstream_throughput_kbps());
-        break;
-      case NetworkChangeNotifier::CONNECTION_NONE:
-        UMA_HISTOGRAM_COUNTS(
-            "NQE.PeakKbps.None",
-            peak_network_quality_.downstream_throughput_kbps());
-        break;
-      case NetworkChangeNotifier::CONNECTION_BLUETOOTH:
-        UMA_HISTOGRAM_COUNTS(
-            "NQE.PeakKbps.Bluetooth",
-            peak_network_quality_.downstream_throughput_kbps());
-        break;
-      default:
-        NOTREACHED() << "Unexpected connection type = "
-                     << current_network_id_.type;
-        break;
-    }
+    // Largest bucket is 1000000 Kbps (~1 Gbps).
+    base::HistogramBase* peak_kbps_histogram =
+        GetHistogram("PeakKbps.", current_network_id_.type,
+                     1000000);  // UMA_HISTOGRAM_COUNTS
+    peak_kbps_histogram->Add(
+        peak_network_quality_.downstream_throughput_kbps());
+  }
+
+  float packet_loss_rate = kInvalidPacketLossRate;
+  if (GetPacketLossRateEstimate(&packet_loss_rate)) {
+    DCHECK_NE(kInvalidPacketLossRate, packet_loss_rate);
+
+    // Largest bucket is 101.
+    base::HistogramBase* packet_loss_histogram =
+        GetHistogram("PacketLossRate.", current_network_id_.type, 101);
+    packet_loss_histogram->Add(packet_loss_rate * 100);
   }
 
   base::TimeDelta rtt = GetRTTEstimateInternal(base::TimeTicks(), 50);
   if (rtt != InvalidRTT()) {
     // Add the 50th percentile value.
     base::HistogramBase* rtt_percentile =
         GetHistogram("RTT.Percentile50.", current_network_id_.type,
                      10 * 1000);  // 10 seconds
     rtt_percentile->Add(rtt.InMilliseconds());
 
@@ skipping 10 matching lines @@
   }
 
   // Write the estimates of the previous network to the cache.
   CacheNetworkQualityEstimate();
 
   // Clear the local state.
   last_connection_change_ = base::TimeTicks::Now();
   peak_network_quality_ = NetworkQuality();
   downstream_throughput_kbps_observations_.Clear();
   rtt_msec_observations_.Clear();
+  packet_loss_rate_observations_.Clear();
   current_network_id_ = GetCurrentNetworkID();
 
   QueryExternalEstimateProvider();
 
   // Read any cached estimates for the new network. If cached estimates are
   // unavailable, add the default estimates.
   if (!ReadCachedNetworkQualityEstimate())
     AddDefaultEstimates();
   estimated_median_network_quality_ = NetworkQuality();
 }
@@ skipping 14 matching lines @@
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(kbps);
   if (downstream_throughput_kbps_observations_.Size() == 0) {
     *kbps = kInvalidThroughput;
     return false;
   }
   *kbps = GetDownlinkThroughputKbpsEstimateInternal(base::TimeTicks(), 50);
   return (*kbps != kInvalidThroughput);
 }
 
+bool NetworkQualityEstimator::GetPacketLossRateEstimate(
+    float* packet_loss) const {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  *packet_loss = GetPacketLossRateEstimateInternal(base::TimeTicks());
+  return (*packet_loss != kInvalidPacketLossRate);

[bengr, 2016/02/16 17:02:01]

Is any packet loss rate below 0 valid?

[tbansal1, 2016/02/17 18:35:10]

No.

+}
+
 bool NetworkQualityEstimator::GetRecentMedianRTT(
     const base::TimeTicks& begin_timestamp,
     base::TimeDelta* rtt) const {
   DCHECK(thread_checker_.CalledOnValidThread());
   DCHECK(rtt);
   *rtt = GetRTTEstimateInternal(begin_timestamp, 50);
   return (*rtt != InvalidRTT());
 }
 
 bool NetworkQualityEstimator::GetRecentMedianDownlinkThroughputKbps(
@@ skipping 44 matching lines @@
     return kInvalidThroughput;
 
   // Throughput observations are sorted by kbps from slowest to fastest,
   // thus a higher percentile throughput will be faster than a lower one.
   int32_t kbps = kInvalidThroughput;
   downstream_throughput_kbps_observations_.GetPercentile(begin_timestamp, &kbps,
                                                          100 - percentile);
   return kbps;
 }
 
+float NetworkQualityEstimator::GetPacketLossRateEstimateInternal(
+    const base::TimeTicks& begin_timestamp) const {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  if (packet_loss_rate_observations_.Size() == 0)
+    return kInvalidPacketLossRate;
+
+  float packet_loss_rate = kInvalidPacketLossRate;
+  packet_loss_rate_observations_.GetWeightedAverage(begin_timestamp,
+                                                    &packet_loss_rate);
+  return packet_loss_rate;
+}
+
 template <typename ValueType>
 void NetworkQualityEstimator::ObservationBuffer<ValueType>::
     ComputeWeightedObservations(
         const base::TimeTicks& begin_timestamp,
         std::vector<WeightedObservation<ValueType>>& weighted_observations,
         double* total_weight) const {
   weighted_observations.clear();
   double total_weight_observations = 0.0;
   base::TimeTicks now = base::TimeTicks::Now();
 
@@ skipping 53 matching lines @@
 
   // Computation may reach here due to floating point errors. This may happen
   // if |percentile| was 100 (or close to 100), and |desired_weight| was
   // slightly larger than |total_weight| (due to floating point errors).
   // In this case, we return the highest |value| among all observations.
   // This is same as value of the last observation in the sorted vector.
   *result = weighted_observations.at(weighted_observations.size() - 1).value;
   return true;
 }
 
+template <typename ValueType>
+bool NetworkQualityEstimator::ObservationBuffer<ValueType>::GetWeightedAverage(
+    const base::TimeTicks& begin_timestamp,
+    ValueType* result) const {
+  DCHECK(result);
+
+  // Stores WeightedObservation in increasing order of value, although for the
+  // purpose of computing weighted average, the order does not matter.
+  std::vector<WeightedObservation<ValueType>> weighted_observations;
+
+  // Total weight of all observations in |weighted_observations|.
+  double total_weight = 0.0;
+
+  ComputeWeightedObservations(begin_timestamp, weighted_observations,
+                              &total_weight);
+  if (weighted_observations.empty())
+    return false;
+
+  DCHECK_GT(total_weight, 0.0);
+
+  // |weighted_observations| may have a smaller size than |observations_| since

[bengr, 2016/02/16 17:02:01]

similar size than -> size similar to

[tbansal1, 2016/02/17 18:35:10]

Did you mean "smaller" instead of "similar"?

+  // the former only contains the observations later than |begin_timestamp|.
+  DCHECK_GE(observations_.size(), weighted_observations.size());
+
+  double total_weight_times_value = 0.0;
+  for (const auto& weighted_observation : weighted_observations) {
+    total_weight_times_value +=
+        (weighted_observation.weight * weighted_observation.value);
+  }
+  *result = total_weight_times_value / total_weight;
+  return true;
+}
+
 NetworkQualityEstimator::NetworkID
 NetworkQualityEstimator::GetCurrentNetworkID() const {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   // TODO(tbansal): crbug.com/498068 Add NetworkQualityEstimatorAndroid class
   // that overrides this method on the Android platform.
 
   // It is possible that the connection type changed between when
   // GetConnectionType() was called and when the API to determine the
   // network name was called. Check if that happened and retry until the
@@ skipping 163 matching lines @@
 
   return scoped_ptr<SocketPerformanceWatcher>(
       new SocketPerformanceWatcher(protocol, this));
 }
 
 void NetworkQualityEstimator::OnUpdatedRTTAvailable(
     const Protocol protocol,
     const base::TimeDelta& rtt) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
-  switch (protocol) {
-    case PROTOCOL_TCP:
-      NotifyObserversOfRTT(RttObservation(rtt, base::TimeTicks::Now(), TCP));
-      return;
-    case PROTOCOL_QUIC:
-      NotifyObserversOfRTT(RttObservation(rtt, base::TimeTicks::Now(), QUIC));
-      return;
-    default:
-      NOTREACHED();
+  ObservationSource observation_source;
+  if (!GetObservationSourceForProtocol(protocol, &observation_source))
+    return;
+
+  NotifyObserversOfRTT(
+      RttObservation(rtt, base::TimeTicks::Now(), observation_source));
+}
+
+void NetworkQualityEstimator::OnUpdatedPacketCountAvailable(
+    const Protocol protocol,
+    uint64_t num_packets_lost,
+    uint64_t num_packets_received_in_order,
+    uint64_t num_packets_received_not_in_order) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  const base::TimeTicks now = base::TimeTicks::Now();
+
+  ObservationSource observation_source;
+  if (!GetObservationSourceForProtocol(protocol, &observation_source))
+    return;
+
+  for (size_t i = 0; i < num_packets_lost; ++i) {
+    packet_loss_rate_observations_.AddObservation(
+        PacketLossObservation(1.0, now, observation_source));
   }
+  for (size_t i = 0; i < num_packets_received_in_order; ++i) {
+    packet_loss_rate_observations_.AddObservation(
+        PacketLossObservation(0.0, now, observation_source));
+  }
+  // For packet loss estimation, we neglect the packets that were previously
+  // marked as lost but are later received out-of-order.
+  NotifyObserversOfPacketLoss(num_packets_lost, num_packets_received_in_order,
+                              num_packets_received_not_in_order, now,
+                              observation_source);
 }
 
 void NetworkQualityEstimator::NotifyObserversOfRTT(
     const RttObservation& observation) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK_NE(EXTERNAL_ESTIMATE, observation.source);
+
   FOR_EACH_OBSERVER(
       RTTObserver, rtt_observer_list_,
       OnRTTObservation(observation.value.InMilliseconds(),
                        observation.timestamp, observation.source));
 }
 
 void NetworkQualityEstimator::NotifyObserversOfThroughput(
     const ThroughputObservation& observation) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK_NE(EXTERNAL_ESTIMATE, observation.source);
+
   FOR_EACH_OBSERVER(
       ThroughputObserver, throughput_observer_list_,
       OnThroughputObservation(observation.value, observation.timestamp,
                               observation.source));
 }
 
+void NetworkQualityEstimator::NotifyObserversOfPacketLoss(
+    uint64_t num_packets_lost,
+    uint64_t num_packets_received_in_order,
+    uint64_t num_packets_received_not_in_order,
+    const base::TimeTicks& timestamp,
+    ObservationSource source) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK_NE(EXTERNAL_ESTIMATE, source);
+
+  FOR_EACH_OBSERVER(PacketLossObserver, packet_loss_observer_list_,
+                    OnPacketLossObservation(
+                        num_packets_lost, num_packets_received_in_order,
+                        num_packets_received_not_in_order, timestamp, source));
+}
+
 NetworkQualityEstimator::CachedNetworkQuality::CachedNetworkQuality(
     const NetworkQuality& network_quality)
     : last_update_time_(base::TimeTicks::Now()),
       network_quality_(network_quality) {
 }
 
 NetworkQualityEstimator::CachedNetworkQuality::CachedNetworkQuality(
     const CachedNetworkQuality& other)
     : last_update_time_(other.last_update_time_),
       network_quality_(other.network_quality_) {
@@ skipping 27 matching lines @@
 
 NetworkQualityEstimator::NetworkQuality&
     NetworkQualityEstimator::NetworkQuality::
     operator=(const NetworkQuality& other) {
   rtt_ = other.rtt_;
   downstream_throughput_kbps_ = other.downstream_throughput_kbps_;
   return *this;
 }
 
 }  // namespace net