Provide default thresholds for effective connection types

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 126 matching lines @@
   DCHECK_GT(max_limit, kLowerLimit);
   const size_t kBucketCount = 50;
 
   // Prefix of network quality estimator histograms.
   const char prefix[] = "NQE.";
   return base::Histogram::FactoryGet(
       prefix + statistic_name + GetNameForConnectionType(type), kLowerLimit,
       max_limit, kBucketCount, base::HistogramBase::kUmaTargetedHistogramFlag);
 }
 
-bool GetValueForVariationParam(
+// Sets |variations_value| to the value of |parameter_name| read from
+// |variation_params|. If the value is unavailable from |variation_params|, then
+// |variations_value| is set to |default_value|.
+void GetValueForVariationParam(
     const std::map<std::string, std::string>& variation_params,
     const std::string& parameter_name,
-    int32_t* variations_value) {
+    int64_t default_value,
+    int64_t* variations_value) {
   const auto it = variation_params.find(parameter_name);
-  return it != variation_params.end() &&
-         base::StringToInt(it->second, variations_value);
+  if (it != variation_params.end() &&
+      base::StringToInt64(it->second, variations_value)) {
+    return;
+  }
+  *variations_value = default_value;
 }
 
 // Returns the variation value for |parameter_name|. If the value is
 // unavailable, |default_value| is returned.
 double GetDoubleValueForVariationParamWithDefaultValue(
     const std::map<std::string, std::string>& variation_params,
     const std::string& parameter_name,
     double default_value) {
   const auto it = variation_params.find(parameter_name);
   if (it == variation_params.end())
@@ skipping 249 matching lines @@
           default_observations_[i].http_rtt(),
           default_observations_[i].transport_rtt(), variations_value);
     }
   }
 }
 
 void NetworkQualityEstimator::ObtainEffectiveConnectionTypeModelParams(
     const std::map<std::string, std::string>& variation_params) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
+  default_effective_connection_type_thresholds_
+      [EFFECTIVE_CONNECTION_TYPE_SLOW_2G] = nqe::internal::NetworkQuality(
+          // Set to 2010 milliseconds which corresponds to the 33rd percentile

[bengr, 2016/07/26 23:14:51]

nit: milliseconds, which

everywhere.

[tbansal1, 2016/07/26 23:42:24]

Done.

+          // of 2G HTTP RTT observations on Android.
+          base::TimeDelta::FromMilliseconds(2010),
+          // Set to 1870 milliseconds which corresponds to the 33rd percentile
+          // of 2G transport RTT observations on Android.
+          base::TimeDelta::FromMilliseconds(1870),
+          nqe::internal::kInvalidThroughput);
+
+  default_effective_connection_type_thresholds_[EFFECTIVE_CONNECTION_TYPE_2G] =
+      nqe::internal::NetworkQuality(
+          // Set to 1420 milliseconds which corresponds to 50th percentile of 2G
+          // HTTP RTT observations on Android.
+          base::TimeDelta::FromMilliseconds(1420),
+          // Set to 1280 milliseconds which corresponds to 50th percentile of 2G
+          // transport RTT observations on Android.
+          base::TimeDelta::FromMilliseconds(1280),
+          nqe::internal::kInvalidThroughput);
+
   for (size_t i = 0; i < EFFECTIVE_CONNECTION_TYPE_LAST; ++i) {
     EffectiveConnectionType effective_connection_type =
         static_cast<EffectiveConnectionType>(i);
     DCHECK_EQ(nqe::internal::InvalidRTT(),
               connection_thresholds_[i].http_rtt());
     DCHECK_EQ(nqe::internal::InvalidRTT(),
               connection_thresholds_[i].transport_rtt());
     DCHECK_EQ(nqe::internal::kInvalidThroughput,
               connection_thresholds_[i].downstream_throughput_kbps());
     if (effective_connection_type == EFFECTIVE_CONNECTION_TYPE_UNKNOWN)
       continue;
 
     std::string connection_type_name = std::string(
         GetNameForEffectiveConnectionType(effective_connection_type));
 
-    int32_t variations_value = kMinimumRTTVariationParameterMsec - 1;
-    if (GetValueForVariationParam(
-            variation_params, connection_type_name + kThresholdURLRTTMsecSuffix,
-            &variations_value) &&
-        variations_value >= kMinimumRTTVariationParameterMsec) {
-      connection_thresholds_[i].set_http_rtt(
-          base::TimeDelta(base::TimeDelta::FromMilliseconds(variations_value)));
+    int64_t variations_value;
+    GetValueForVariationParam(variation_params,
+                              connection_type_name + kThresholdURLRTTMsecSuffix,
+                              default_effective_connection_type_thresholds_[i]
+                                  .http_rtt()
+                                  .InMilliseconds(),
+                              &variations_value);
+    connection_thresholds_[i].set_http_rtt(
+        base::TimeDelta::FromMilliseconds(variations_value));
+    // Verify that the RTT values are in decreasing order as the network
+    // quality improves.
+    DCHECK(i == 0 ||
+           connection_thresholds_[i].http_rtt() ==

[bengr, 2016/07/26 23:14:51]

It might be clearer and reduce redundancy if you had a helper method for these
comparisons. I'm ok with it as is, but your methods tend to get uncomfortably
long.

[tbansal1, 2016/07/26 23:42:23]

Done.

+               nqe::internal::InvalidRTT() ||
+           connection_thresholds_[i - 1].http_rtt() ==
+               nqe::internal::InvalidRTT() ||
+           connection_thresholds_[i].http_rtt() <=
+               connection_thresholds_[i - 1].http_rtt());
 
-      // Verify that the RTT values are in decreasing order as the network
-      // quality improves.
-      DCHECK(i == 0 ||
-             connection_thresholds_[i - 1].http_rtt() ==
-                 nqe::internal::InvalidRTT() ||
-             connection_thresholds_[i].http_rtt() <=
-                 connection_thresholds_[i - 1].http_rtt());
-    }
+    GetValueForVariationParam(
+        variation_params,
+        connection_type_name + kThresholdTransportRTTMsecSuffix,
+        default_effective_connection_type_thresholds_[i]
+            .transport_rtt()
+            .InMilliseconds(),
+        &variations_value);
+    connection_thresholds_[i].set_transport_rtt(
+        base::TimeDelta::FromMilliseconds(variations_value));
+    // Verify that the transport RTT values are in decreasing order as the
+    // network quality improves.
+    DCHECK(i == 0 ||
+           connection_thresholds_[i].transport_rtt() ==
+               nqe::internal::InvalidRTT() ||
+           connection_thresholds_[i - 1].transport_rtt() ==
+               nqe::internal::InvalidRTT() ||
+           connection_thresholds_[i].transport_rtt() <=
+               connection_thresholds_[i - 1].transport_rtt());
 
-    variations_value = kMinimumRTTVariationParameterMsec - 1;
-    if (GetValueForVariationParam(
-            variation_params,
-            connection_type_name + kThresholdTransportRTTMsecSuffix,
-            &variations_value) &&
-        variations_value >= kMinimumRTTVariationParameterMsec) {
-      connection_thresholds_[i].set_transport_rtt(
-          base::TimeDelta(base::TimeDelta::FromMilliseconds(variations_value)));
-
-      // Verify that the transport RTT values are in decreasing order as the
-      // network quality improves.
-      DCHECK(i == 0 ||
-             connection_thresholds_[i - 1].transport_rtt() ==
-                 nqe::internal::InvalidRTT() ||
-             connection_thresholds_[i].transport_rtt() <=
-                 connection_thresholds_[i - 1].transport_rtt());
-    }
-
-    variations_value = kMinimumThroughputVariationParameterKbps - 1;
-    if (GetValueForVariationParam(variation_params,
-                                  connection_type_name + kThresholdKbpsSuffix,
-                                  &variations_value) &&
-        variations_value >= kMinimumThroughputVariationParameterKbps) {
-      connection_thresholds_[i].set_downstream_throughput_kbps(
-          variations_value);
-
-      // Verify that the throughput values are in increasing order as the
-      // network quality improves.
-      DCHECK(i == 0 ||
-             connection_thresholds_[i - 1].downstream_throughput_kbps() ==
-                 kMinimumThroughputVariationParameterKbps ||
-             connection_thresholds_[i].downstream_throughput_kbps() >=
-                 connection_thresholds_[i - 1].downstream_throughput_kbps());
-    }
+    GetValueForVariationParam(variation_params,
+                              connection_type_name + kThresholdKbpsSuffix,
+                              default_effective_connection_type_thresholds_[i]
+                                  .downstream_throughput_kbps(),
+                              &variations_value);
+    connection_thresholds_[i].set_downstream_throughput_kbps(variations_value);
+    // Verify that the throughput values are in increasing order as the
+    // network quality improves.
+    DCHECK(i == 0 ||
+           connection_thresholds_[i].downstream_throughput_kbps() ==
+               kMinimumThroughputVariationParameterKbps ||
+           connection_thresholds_[i - 1].downstream_throughput_kbps() ==
+               kMinimumThroughputVariationParameterKbps ||
+           connection_thresholds_[i].downstream_throughput_kbps() >=
+               connection_thresholds_[i - 1].downstream_throughput_kbps());
   }
 }
 
 void NetworkQualityEstimator::AddDefaultEstimates() {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   if (default_observations_[current_network_id_.type].http_rtt() !=
       nqe::internal::InvalidRTT()) {
     RttObservation rtt_observation(
         default_observations_[current_network_id_.type].http_rtt(),
@@ skipping 1113 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