NQE: Allow algorithm to be set using variation params

net/nqe/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/nqe/network_quality_estimator.h"
 
 #include <algorithm>
 #include <cmath>
 #include <limits>
 #include <utility>
@@ skipping 116 matching lines @@
   const char prefix[] = "NQE.";
   return base::Histogram::FactoryGet(
       prefix + statistic_name + GetNameForConnectionType(type), kLowerLimit,
       max_limit, kBucketCount, base::HistogramBase::kUmaTargetedHistogramFlag);
 }
 
 bool GetValueForVariationParam(
     const std::map<std::string, std::string>& variation_params,
     const std::string& parameter_name,
     int32_t* variations_value) {
-  auto it = variation_params.find(parameter_name);
+  const auto it = variation_params.find(parameter_name);
   return it != variation_params.end() &&
          base::StringToInt(it->second, variations_value);
 }
 
+// Returns the algorithm that should be used for computing effective connection
+// type based on field trial params. Returns an empty string if a valid
+// algorithm paramter is not present in the field trial params.
+std::string GetEffectiveConnectionTypeAlgorithm(
+    const std::map<std::string, std::string>& variation_params) {
+  const auto it = variation_params.find("effective_connection_type_algorithm");
+  if (it == variation_params.end())
+    return std::string();
+  return it->second;
+}
+
 net::NetworkQualityObservationSource ProtocolSourceToObservationSource(
     net::SocketPerformanceWatcherFactory::Protocol protocol) {
   switch (protocol) {
     case net::SocketPerformanceWatcherFactory::PROTOCOL_TCP:
       return net::NETWORK_QUALITY_OBSERVATION_SOURCE_TCP;
     case net::SocketPerformanceWatcherFactory::PROTOCOL_QUIC:
       return net::NETWORK_QUALITY_OBSERVATION_SOURCE_QUIC;
   }
   NOTREACHED();
   return net::NETWORK_QUALITY_OBSERVATION_SOURCE_TCP;
@@ skipping 33 matching lines @@
     : NetworkQualityEstimator(std::move(external_estimates_provider),
                               variation_params,
                               false,
                               false) {}
 
 NetworkQualityEstimator::NetworkQualityEstimator(
     std::unique_ptr<ExternalEstimateProvider> external_estimates_provider,
     const std::map<std::string, std::string>& variation_params,
     bool use_local_host_requests_for_tests,
     bool use_smaller_responses_for_tests)
-    : use_localhost_requests_(use_local_host_requests_for_tests),
+    : algorithm_name_to_enum_({{"HttpRTTAndDownstreamThroughput",
+                                EffectiveConnectionTypeAlgorithm::
+                                    HTTP_RTT_AND_DOWNSTREAM_THROUGHOUT}}),
+      use_localhost_requests_(use_local_host_requests_for_tests),
       use_small_responses_(use_smaller_responses_for_tests),
       weight_multiplier_per_second_(
           GetWeightMultiplierPerSecond(variation_params)),
+      effective_connection_type_algorithm_(
+          algorithm_name_to_enum_.find(GetEffectiveConnectionTypeAlgorithm(
+              variation_params)) == algorithm_name_to_enum_.end()
+              ? kDefaultEffectiveConnectionTypeAlgorithm
+              : algorithm_name_to_enum_
+                    .find(GetEffectiveConnectionTypeAlgorithm(variation_params))
+                    ->second),
       tick_clock_(new base::DefaultTickClock()),
       effective_connection_type_recomputation_interval_(
           base::TimeDelta::FromSeconds(15)),
       last_connection_change_(tick_clock_->NowTicks()),
       current_network_id_(
           NetworkID(NetworkChangeNotifier::ConnectionType::CONNECTION_UNKNOWN,
                     std::string())),
       downstream_throughput_kbps_observations_(weight_multiplier_per_second_),
       rtt_observations_(weight_multiplier_per_second_),
       external_estimate_provider_(std::move(external_estimates_provider)),
       effective_connection_type_(EFFECTIVE_CONNECTION_TYPE_UNKNOWN),
       weak_ptr_factory_(this) {
   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,
                 "Size of the network quality cache must <= 10");
+  // None of the algorithms can have an empty name.
+  DCHECK(algorithm_name_to_enum_.end() ==
+         algorithm_name_to_enum_.find(std::string()));
+
+  DCHECK_EQ(algorithm_name_to_enum_.size(),
+            static_cast<size_t>(EffectiveConnectionTypeAlgorithm::
+                                    EFFECTIVE_CONNECTION_TYPE_ALGORITHM_LAST));
+  DCHECK_NE(EffectiveConnectionTypeAlgorithm::
+                EFFECTIVE_CONNECTION_TYPE_ALGORITHM_LAST,
+            effective_connection_type_algorithm_);
 
   ObtainOperatingParams(variation_params);
   ObtainEffectiveConnectionTypeModelParams(variation_params);
   NetworkChangeNotifier::AddConnectionTypeObserver(this);
   if (external_estimate_provider_) {
     RecordExternalEstimateProviderMetrics(
         EXTERNAL_ESTIMATE_PROVIDER_STATUS_AVAILABLE);
     external_estimate_provider_->SetUpdatedEstimateDelegate(this);
   } else {
     RecordExternalEstimateProviderMetrics(
@@ skipping 520 matching lines @@
 NetworkQualityEstimator::GetEffectiveConnectionType() const {
   DCHECK(thread_checker_.CalledOnValidThread());
   return GetRecentEffectiveConnectionType(base::TimeTicks());
 }
 
 NetworkQualityEstimator::EffectiveConnectionType
 NetworkQualityEstimator::GetRecentEffectiveConnectionType(
     const base::TimeTicks& start_time) const {
   DCHECK(thread_checker_.CalledOnValidThread());
 
+  if (effective_connection_type_algorithm_ ==
+      EffectiveConnectionTypeAlgorithm::HTTP_RTT_AND_DOWNSTREAM_THROUGHOUT) {
+    return GetRecentEffectiveConnectionTypeHttpRTTAndDownstreamThroughput(
+        start_time);
+  }
+  // Add additional algorithms here.
+  NOTREACHED();
+  return EFFECTIVE_CONNECTION_TYPE_UNKNOWN;
+}
+
+NetworkQualityEstimator::EffectiveConnectionType NetworkQualityEstimator::
+    GetRecentEffectiveConnectionTypeHttpRTTAndDownstreamThroughput(
+        const base::TimeTicks& start_time) const {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
   // If the device is currently offline, then return
   // EFFECTIVE_CONNECTION_TYPE_OFFLINE.
   if (GetCurrentNetworkID().type == NetworkChangeNotifier::CONNECTION_NONE)
     return EFFECTIVE_CONNECTION_TYPE_OFFLINE;
 
   base::TimeDelta http_rtt = nqe::internal::InvalidRTT();
   if (!GetRecentHttpRTTMedian(start_time, &http_rtt))
     http_rtt = nqe::internal::InvalidRTT();
 
   int32_t kbps = nqe::internal::kInvalidThroughput;
   if (!GetRecentMedianDownlinkThroughputKbps(start_time, &kbps))
     kbps = nqe::internal::kInvalidThroughput;
 
-  if (http_rtt == nqe::internal::InvalidRTT() &&
+  if (http_rtt == nqe::internal::InvalidRTT() ||
       kbps == nqe::internal::kInvalidThroughput) {
     // Quality of the current network is unknown.
     return EFFECTIVE_CONNECTION_TYPE_UNKNOWN;
   }
 
   // Search from the slowest connection type to the fastest to find the
   // EffectiveConnectionType that best matches the current connection's
   // performance. The match is done by comparing RTT and throughput.
   for (size_t i = 0; i < EFFECTIVE_CONNECTION_TYPE_LAST; ++i) {
     EffectiveConnectionType type = static_cast<EffectiveConnectionType>(i);
@@ skipping 408 matching lines @@
     NotifyObserversOfEffectiveConnectionTypeChanged() {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   // TODO(tbansal): Add hysteresis in the notification.
   FOR_EACH_OBSERVER(
       EffectiveConnectionTypeObserver, effective_connection_type_observer_list_,
       OnEffectiveConnectionTypeChanged(effective_connection_type_));
 }
 
 }  // namespace net