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| 1 // Copyright 2015 The Chromium Authors. All rights reserved. | |
| 2 // Use of this source code is governed by a BSD-style license that can be | |
| 3 // found in the LICENSE file. | |
| 4 | |
| 5 #ifndef NET_BASE_NETWORK_QUALITY_ESTIMATOR_H_ | |
| 6 #define NET_BASE_NETWORK_QUALITY_ESTIMATOR_H_ | |
| 7 | |
| 8 #include <stddef.h> | |
| 9 #include <stdint.h> | |
| 10 | |
| 11 #include <deque> | |
| 12 #include <map> | |
| 13 #include <memory> | |
| 14 #include <string> | |
| 15 #include <tuple> | |
| 16 | |
| 17 #include "base/compiler_specific.h" | |
| 18 #include "base/gtest_prod_util.h" | |
| 19 #include "base/macros.h" | |
| 20 #include "base/memory/ref_counted.h" | |
| 21 #include "base/memory/weak_ptr.h" | |
| 22 #include "base/observer_list.h" | |
| 23 #include "base/threading/thread_checker.h" | |
| 24 #include "base/time/time.h" | |
| 25 #include "net/base/external_estimate_provider.h" | |
| 26 #include "net/base/net_export.h" | |
| 27 #include "net/base/network_change_notifier.h" | |
| 28 #include "net/base/socket_performance_watcher_factory.h" | |
| 29 | |
| 30 namespace base { | |
| 31 class SingleThreadTaskRunner; | |
| 32 } // namespace base | |
| 33 | |
| 34 namespace net { | |
| 35 | |
| 36 class URLRequest; | |
| 37 | |
| 38 // NetworkQualityEstimator provides network quality estimates (quality of the | |
| 39 // full paths to all origins that have been connected to). | |
| 40 // The estimates are based on the observed organic traffic. | |
| 41 // A NetworkQualityEstimator instance is attached to URLRequestContexts and | |
| 42 // observes the traffic of URLRequests spawned from the URLRequestContexts. | |
| 43 // A single instance of NQE can be attached to multiple URLRequestContexts, | |
| 44 // thereby increasing the single NQE instance's accuracy by providing more | |
| 45 // observed traffic characteristics. | |
| 46 class NET_EXPORT_PRIVATE NetworkQualityEstimator | |
| 47 : public NetworkChangeNotifier::ConnectionTypeObserver, | |
| 48 public ExternalEstimateProvider::UpdatedEstimateDelegate { | |
| 49 public: | |
| 50 // EffectiveConnectionType is the connection type whose typical performance is | |
| 51 // most similar to the measured performance of the network in use. In many | |
| 52 // cases, the "effective" connection type and the actual type of connection in | |
| 53 // use are the same, but often a network connection performs significantly | |
| 54 // different, usually worse, from its expected capabilities. | |
| 55 // EffectiveConnectionType of a network is independent of if the current | |
| 56 // connection is metered or not. For example, an unmetered slow connection may | |
| 57 // have EFFECTIVE_CONNECTION_TYPE_SLOW_2G as its effective connection type. | |
| 58 enum EffectiveConnectionType { | |
| 59 // The connection types should be in increasing order of quality. | |
| 60 EFFECTIVE_CONNECTION_TYPE_UNKNOWN = 0, | |
| 61 EFFECTIVE_CONNECTION_TYPE_OFFLINE, | |
| 62 EFFECTIVE_CONNECTION_TYPE_SLOW_2G, | |
| 63 EFFECTIVE_CONNECTION_TYPE_2G, | |
| 64 EFFECTIVE_CONNECTION_TYPE_3G, | |
| 65 EFFECTIVE_CONNECTION_TYPE_4G, | |
| 66 EFFECTIVE_CONNECTION_TYPE_BROADBAND, | |
| 67 EFFECTIVE_CONNECTION_TYPE_LAST, | |
| 68 }; | |
| 69 | |
| 70 // On Android, a Java counterpart will be generated for this enum. | |
| 71 // GENERATED_JAVA_ENUM_PACKAGE: org.chromium.net | |
| 72 // GENERATED_JAVA_CLASS_NAME_OVERRIDE: NetworkQualityObservationSource | |
| 73 // GENERATED_JAVA_PREFIX_TO_STRIP: | |
| 74 enum ObservationSource { | |
| 75 // The observation was taken at the request layer, e.g., a round trip time | |
| 76 // is recorded as the time between the request being sent and the first byte | |
| 77 // being received. | |
| 78 URL_REQUEST, | |
| 79 // The observation is taken from TCP statistics maintained by the kernel. | |
| 80 TCP, | |
| 81 // The observation is taken at the QUIC layer. | |
| 82 QUIC, | |
| 83 // The observation is a previously cached estimate of the metric. | |
| 84 CACHED_ESTIMATE, | |
| 85 // The observation is derived from network connection information provided | |
| 86 // by the platform. For example, typical RTT and throughput values are used | |
| 87 // for a given type of network connection. | |
| 88 DEFAULT_FROM_PLATFORM, | |
| 89 // The observation came from a Chromium-external source. | |
| 90 EXTERNAL_ESTIMATE | |
| 91 }; | |
| 92 | |
| 93 // Observes measurements of round trip time. | |
| 94 class NET_EXPORT_PRIVATE RTTObserver { | |
| 95 public: | |
| 96 // Will be called when a new RTT observation is available. The round trip | |
| 97 // time is specified in milliseconds. The time when the observation was | |
| 98 // taken and the source of the observation are provided. | |
| 99 virtual void OnRTTObservation(int32_t rtt_ms, | |
| 100 const base::TimeTicks& timestamp, | |
| 101 ObservationSource source) = 0; | |
| 102 | |
| 103 protected: | |
| 104 RTTObserver() {} | |
| 105 virtual ~RTTObserver() {} | |
| 106 | |
| 107 private: | |
| 108 DISALLOW_COPY_AND_ASSIGN(RTTObserver); | |
| 109 }; | |
| 110 | |
| 111 // Observes measurements of throughput. | |
| 112 class NET_EXPORT_PRIVATE ThroughputObserver { | |
| 113 public: | |
| 114 // Will be called when a new throughput observation is available. | |
| 115 // Throughput is specified in kilobits per second. | |
| 116 virtual void OnThroughputObservation(int32_t throughput_kbps, | |
| 117 const base::TimeTicks& timestamp, | |
| 118 ObservationSource source) = 0; | |
| 119 | |
| 120 protected: | |
| 121 ThroughputObserver() {} | |
| 122 virtual ~ThroughputObserver() {} | |
| 123 | |
| 124 private: | |
| 125 DISALLOW_COPY_AND_ASSIGN(ThroughputObserver); | |
| 126 }; | |
| 127 | |
| 128 // Creates a new NetworkQualityEstimator. | |
| 129 // |variation_params| is the map containing all field trial parameters | |
| 130 // related to NetworkQualityEstimator field trial. | |
| 131 // |external_estimates_provider| may be NULL. | |
| 132 NetworkQualityEstimator( | |
| 133 std::unique_ptr<ExternalEstimateProvider> external_estimates_provider, | |
| 134 const std::map<std::string, std::string>& variation_params); | |
| 135 | |
| 136 // Construct a NetworkQualityEstimator instance allowing for test | |
| 137 // configuration. Registers for network type change notifications so estimates | |
| 138 // can be kept network specific. | |
| 139 // |external_estimates_provider| may be NULL. | |
| 140 // |variation_params| is the map containing all field trial parameters for the | |
| 141 // network quality estimator field trial. | |
| 142 // |allow_local_host_requests_for_tests| should only be true when testing | |
| 143 // against local HTTP server and allows the requests to local host to be | |
| 144 // used for network quality estimation. | |
| 145 // |allow_smaller_responses_for_tests| should only be true when testing. | |
| 146 // Allows the responses smaller than |kMinTransferSizeInBytes| or shorter than | |
| 147 // |kMinRequestDurationMicroseconds| to be used for network quality | |
| 148 // estimation. | |
| 149 NetworkQualityEstimator( | |
| 150 std::unique_ptr<ExternalEstimateProvider> external_estimates_provider, | |
| 151 const std::map<std::string, std::string>& variation_params, | |
| 152 bool allow_local_host_requests_for_tests, | |
| 153 bool allow_smaller_responses_for_tests); | |
| 154 | |
| 155 ~NetworkQualityEstimator() override; | |
| 156 | |
| 157 // Returns the effective type of the current connection. | |
| 158 EffectiveConnectionType GetEffectiveConnectionType() const; | |
| 159 | |
| 160 // Returns true if RTT is available and sets |rtt| to estimated RTT at the | |
| 161 // HTTP layer. Virtualized for testing. |rtt| should not be null. The RTT at | |
| 162 // the HTTP layer measures the time from when the request was sent (this | |
| 163 // happens after the connection is established) to the time when the response | |
| 164 // headers were received. | |
| 165 virtual bool GetURLRequestRTTEstimate(base::TimeDelta* rtt) const | |
| 166 WARN_UNUSED_RESULT; | |
| 167 | |
| 168 // Returns true if downlink throughput is available and sets |kbps| to | |
| 169 // estimated downlink throughput (in kilobits per second). | |
| 170 // Virtualized for testing. |kbps| should not be null. | |
| 171 virtual bool GetDownlinkThroughputKbpsEstimate(int32_t* kbps) const; | |
| 172 | |
| 173 // Notifies NetworkQualityEstimator that the response header of |request| has | |
| 174 // been received. | |
| 175 void NotifyHeadersReceived(const URLRequest& request); | |
| 176 | |
| 177 // Notifies NetworkQualityEstimator that the response body of |request| has | |
| 178 // been received. | |
| 179 void NotifyRequestCompleted(const URLRequest& request); | |
| 180 | |
| 181 // Returns true if median RTT at the HTTP layer is available and sets |rtt| | |
| 182 // to the median of RTT observations since |begin_timestamp|. | |
| 183 // Virtualized for testing. |rtt| should not be null. The RTT at the HTTP | |
| 184 // layer measures the time from when the request was sent (this happens after | |
| 185 // the connection is established) to the time when the response headers were | |
| 186 // received. | |
| 187 virtual bool GetRecentURLRequestRTTMedian( | |
| 188 const base::TimeTicks& begin_timestamp, | |
| 189 base::TimeDelta* rtt) const WARN_UNUSED_RESULT; | |
| 190 | |
| 191 // Returns true if median downstream throughput is available and sets |kbps| | |
| 192 // to the median of downstream throughput (in kilobits per second) | |
| 193 // observations since |begin_timestamp|. Virtualized for testing. |kbps| | |
| 194 // should not be null. | |
| 195 virtual bool GetRecentMedianDownlinkThroughputKbps( | |
| 196 const base::TimeTicks& begin_timestamp, | |
| 197 int32_t* kbps) const WARN_UNUSED_RESULT; | |
| 198 | |
| 199 // Adds |rtt_observer| to the list of round trip time observers. Must be | |
| 200 // called on the IO thread. | |
| 201 void AddRTTObserver(RTTObserver* rtt_observer); | |
| 202 | |
| 203 // Removes |rtt_observer| from the list of round trip time observers if it | |
| 204 // is on the list of observers. Must be called on the IO thread. | |
| 205 void RemoveRTTObserver(RTTObserver* rtt_observer); | |
| 206 | |
| 207 // Adds |throughput_observer| to the list of throughput observers. Must be | |
| 208 // called on the IO thread. | |
| 209 void AddThroughputObserver(ThroughputObserver* throughput_observer); | |
| 210 | |
| 211 // Removes |throughput_observer| from the list of throughput observers if it | |
| 212 // is on the list of observers. Must be called on the IO thread. | |
| 213 void RemoveThroughputObserver(ThroughputObserver* throughput_observer); | |
| 214 | |
| 215 SocketPerformanceWatcherFactory* GetSocketPerformanceWatcherFactory(); | |
| 216 | |
| 217 protected: | |
| 218 // NetworkID is used to uniquely identify a network. | |
| 219 // For the purpose of network quality estimation and caching, a network is | |
| 220 // uniquely identified by a combination of |type| and | |
| 221 // |id|. This approach is unable to distinguish networks with | |
| 222 // same name (e.g., different Wi-Fi networks with same SSID). | |
| 223 // This is a protected member to expose it to tests. | |
| 224 struct NET_EXPORT_PRIVATE NetworkID { | |
| 225 NetworkID(NetworkChangeNotifier::ConnectionType type, const std::string& id) | |
| 226 : type(type), id(id) {} | |
| 227 NetworkID(const NetworkID& other) : type(other.type), id(other.id) {} | |
| 228 ~NetworkID() {} | |
| 229 | |
| 230 NetworkID& operator=(const NetworkID& other) { | |
| 231 type = other.type; | |
| 232 id = other.id; | |
| 233 return *this; | |
| 234 } | |
| 235 | |
| 236 // Overloaded because NetworkID is used as key in a map. | |
| 237 bool operator<(const NetworkID& other) const { | |
| 238 return std::tie(type, id) < std::tie(other.type, other.id); | |
| 239 } | |
| 240 | |
| 241 // Connection type of the network. | |
| 242 NetworkChangeNotifier::ConnectionType type; | |
| 243 | |
| 244 // Name of this network. This is set to: | |
| 245 // - Wi-Fi SSID if the device is connected to a Wi-Fi access point and the | |
| 246 // SSID name is available, or | |
| 247 // - MCC/MNC code of the cellular carrier if the device is connected to a | |
| 248 // cellular network, or | |
| 249 // - "Ethernet" in case the device is connected to ethernet. | |
| 250 // - An empty string in all other cases or if the network name is not | |
| 251 // exposed by platform APIs. | |
| 252 std::string id; | |
| 253 }; | |
| 254 | |
| 255 // Returns true if the cached network quality estimate was successfully read. | |
| 256 bool ReadCachedNetworkQualityEstimate(); | |
| 257 | |
| 258 // NetworkChangeNotifier::ConnectionTypeObserver implementation: | |
| 259 void OnConnectionTypeChanged( | |
| 260 NetworkChangeNotifier::ConnectionType type) override; | |
| 261 | |
| 262 // ExternalEstimateProvider::UpdatedEstimateObserver implementation. | |
| 263 void OnUpdatedEstimateAvailable() override; | |
| 264 | |
| 265 // Return a string equivalent to |type|. | |
| 266 const char* GetNameForEffectiveConnectionType( | |
| 267 EffectiveConnectionType type) const; | |
| 268 | |
| 269 private: | |
| 270 FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, StoreObservations); | |
| 271 FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, TestAddObservation); | |
| 272 FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, ObtainOperatingParams); | |
| 273 FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, HalfLifeParam); | |
| 274 FRIEND_TEST_ALL_PREFIXES(URLRequestTestHTTP, NetworkQualityEstimator); | |
| 275 FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, | |
| 276 PercentileSameTimestamps); | |
| 277 FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, | |
| 278 PercentileDifferentTimestamps); | |
| 279 FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, ComputedPercentiles); | |
| 280 FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, TestCaching); | |
| 281 FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, | |
| 282 TestLRUCacheMaximumSize); | |
| 283 FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, TestGetMedianRTTSince); | |
| 284 FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, | |
| 285 TestExternalEstimateProviderMergeEstimates); | |
| 286 | |
| 287 class SocketWatcher; | |
| 288 class SocketWatcherFactory; | |
| 289 | |
| 290 // NetworkQuality is used to cache the quality of a network connection. | |
| 291 class NET_EXPORT_PRIVATE NetworkQuality { | |
| 292 public: | |
| 293 NetworkQuality(); | |
| 294 // |rtt| is the estimate of the round trip time. | |
| 295 // |downstream_throughput_kbps| is the estimate of the downstream | |
| 296 // throughput in kilobits per second. | |
| 297 NetworkQuality(const base::TimeDelta& rtt, | |
| 298 int32_t downstream_throughput_kbps); | |
| 299 NetworkQuality(const NetworkQuality& other); | |
| 300 ~NetworkQuality(); | |
| 301 | |
| 302 NetworkQuality& operator=(const NetworkQuality& other); | |
| 303 | |
| 304 // Returns the estimate of the round trip time. | |
| 305 const base::TimeDelta& rtt() const { return rtt_; } | |
| 306 | |
| 307 // Returns the estimate of the downstream throughput in Kbps (Kilobits per | |
| 308 // second). | |
| 309 int32_t downstream_throughput_kbps() const { | |
| 310 return downstream_throughput_kbps_; | |
| 311 } | |
| 312 | |
| 313 private: | |
| 314 // Estimated round trip time. | |
| 315 base::TimeDelta rtt_; | |
| 316 | |
| 317 // Estimated downstream throughput in kilobits per second. | |
| 318 int32_t downstream_throughput_kbps_; | |
| 319 }; | |
| 320 | |
| 321 // CachedNetworkQuality stores the quality of a previously seen network. | |
| 322 class NET_EXPORT_PRIVATE CachedNetworkQuality { | |
| 323 public: | |
| 324 explicit CachedNetworkQuality(const NetworkQuality& network_quality); | |
| 325 CachedNetworkQuality(const CachedNetworkQuality& other); | |
| 326 ~CachedNetworkQuality(); | |
| 327 | |
| 328 // Returns the network quality associated with this cached entry. | |
| 329 const NetworkQuality& network_quality() const { return network_quality_; } | |
| 330 | |
| 331 // Returns true if this cache entry was updated before | |
| 332 // |cached_network_quality|. | |
| 333 bool OlderThan(const CachedNetworkQuality& cached_network_quality) const; | |
| 334 | |
| 335 // Time when this cache entry was last updated. | |
| 336 const base::TimeTicks last_update_time_; | |
| 337 | |
| 338 // Quality of this cached network. | |
| 339 const NetworkQuality network_quality_; | |
| 340 | |
| 341 private: | |
| 342 DISALLOW_ASSIGN(CachedNetworkQuality); | |
| 343 }; | |
| 344 | |
| 345 // Records observations of network quality metrics (such as round trip time | |
| 346 // or throughput), along with the time the observation was made. Observations | |
| 347 // can be made at several places in the network stack, thus the observation | |
| 348 // source is provided as well. ValueType must be numerical so that statistics | |
| 349 // such as median, average can be computed. | |
| 350 template <typename ValueType> | |
| 351 struct NET_EXPORT_PRIVATE Observation { | |
| 352 Observation(const ValueType& value, | |
| 353 base::TimeTicks timestamp, | |
| 354 ObservationSource source) | |
| 355 : value(value), timestamp(timestamp), source(source) { | |
| 356 DCHECK(!timestamp.is_null()); | |
| 357 } | |
| 358 ~Observation() {} | |
| 359 | |
| 360 // Value of the observation. | |
| 361 const ValueType value; | |
| 362 | |
| 363 // Time when the observation was taken. | |
| 364 const base::TimeTicks timestamp; | |
| 365 | |
| 366 // The source of the observation. | |
| 367 const ObservationSource source; | |
| 368 }; | |
| 369 | |
| 370 // Holds an observation and its weight. | |
| 371 template <typename ValueType> | |
| 372 struct NET_EXPORT_PRIVATE WeightedObservation { | |
| 373 WeightedObservation(ValueType value, double weight) | |
| 374 : value(value), weight(weight) {} | |
| 375 WeightedObservation(const WeightedObservation& other) | |
| 376 : WeightedObservation(other.value, other.weight) {} | |
| 377 | |
| 378 WeightedObservation& operator=(const WeightedObservation& other) { | |
| 379 value = other.value; | |
| 380 weight = other.weight; | |
| 381 return *this; | |
| 382 } | |
| 383 | |
| 384 // Required for sorting the samples in the ascending order of values. | |
| 385 bool operator<(const WeightedObservation& other) const { | |
| 386 return (value < other.value); | |
| 387 } | |
| 388 | |
| 389 // Value of the sample. | |
| 390 ValueType value; | |
| 391 | |
| 392 // Weight of the sample. This is computed based on how much time has passed | |
| 393 // since the sample was taken. | |
| 394 double weight; | |
| 395 }; | |
| 396 | |
| 397 // Stores observations sorted by time. | |
| 398 template <typename ValueType> | |
| 399 class NET_EXPORT_PRIVATE ObservationBuffer { | |
| 400 public: | |
| 401 explicit ObservationBuffer(double weight_multiplier_per_second); | |
| 402 ~ObservationBuffer(); | |
| 403 | |
| 404 // Adds |observation| to the buffer. The oldest observation in the buffer | |
| 405 // will be evicted to make room if the buffer is already full. | |
| 406 void AddObservation(const Observation<ValueType>& observation) { | |
| 407 DCHECK_LE(observations_.size(), | |
| 408 static_cast<size_t>(kMaximumObservationsBufferSize)); | |
| 409 // Evict the oldest element if the buffer is already full. | |
| 410 if (observations_.size() == kMaximumObservationsBufferSize) | |
| 411 observations_.pop_front(); | |
| 412 | |
| 413 observations_.push_back(observation); | |
| 414 DCHECK_LE(observations_.size(), | |
| 415 static_cast<size_t>(kMaximumObservationsBufferSize)); | |
| 416 } | |
| 417 | |
| 418 // Clears the observations stored in this buffer. | |
| 419 void Clear() { observations_.clear(); } | |
| 420 | |
| 421 // Returns true iff the |percentile| value of the observations in this | |
| 422 // buffer is available. Sets |result| to the computed |percentile| | |
| 423 // value among all observations since |begin_timestamp|. If the value is | |
| 424 // unavailable, false is returned and |result| is not modified. Percentile | |
| 425 // value is unavailable if all the values in observation buffer are older | |
| 426 // than |begin_timestamp|. |result| must not be null. | |
| 427 // |disallowed_observation_sources| is the list of observation sources that | |
| 428 // should be excluded when computing the percentile. | |
| 429 bool GetPercentile( | |
| 430 const base::TimeTicks& begin_timestamp, | |
| 431 ValueType* result, | |
| 432 int percentile, | |
| 433 const std::vector<ObservationSource>& disallowed_observation_sources) | |
| 434 const WARN_UNUSED_RESULT; | |
| 435 | |
| 436 private: | |
| 437 FRIEND_TEST_ALL_PREFIXES(NetworkQualityEstimatorTest, HalfLifeParam); | |
| 438 | |
| 439 // Computes the weighted observations and stores them in | |
| 440 // |weighted_observations| sorted by ascending |WeightedObservation.value|. | |
| 441 // Only the observations with timestamp later than |begin_timestamp| are | |
| 442 // considered. Also, sets |total_weight| to the total weight of all | |
| 443 // observations. Should be called only when there is at least one | |
| 444 // observation in the buffer. |disallowed_observation_sources| is the list | |
| 445 // of observation sources that should be excluded when computing the | |
| 446 // weighted observations. | |
| 447 void ComputeWeightedObservations( | |
| 448 const base::TimeTicks& begin_timestamp, | |
| 449 std::vector<WeightedObservation<ValueType>>& weighted_observations, | |
| 450 double* total_weight, | |
| 451 const std::vector<ObservationSource>& disallowed_observation_sources) | |
| 452 const; | |
| 453 | |
| 454 // Holds observations sorted by time, with the oldest observation at the | |
| 455 // front of the queue. | |
| 456 std::deque<Observation<ValueType>> observations_; | |
| 457 | |
| 458 // The factor by which the weight of an observation reduces every second. | |
| 459 // For example, if an observation is 6 seconds old, its weight would be: | |
| 460 // weight_multiplier_per_second_ ^ 6 | |
| 461 // Calculated from |kHalfLifeSeconds| by solving the following equation: | |
| 462 // weight_multiplier_per_second_ ^ kHalfLifeSeconds = 0.5 | |
| 463 const double weight_multiplier_per_second_; | |
| 464 | |
| 465 DISALLOW_COPY_AND_ASSIGN(ObservationBuffer); | |
| 466 }; | |
| 467 | |
| 468 // Value of round trip time observations is in base::TimeDelta. | |
| 469 typedef net::NetworkQualityEstimator::Observation<base::TimeDelta> | |
| 470 RttObservation; | |
| 471 typedef net::NetworkQualityEstimator::ObservationBuffer<base::TimeDelta> | |
| 472 RttObservationBuffer; | |
| 473 | |
| 474 // Value of throughput observations is in kilobits per second. | |
| 475 typedef net::NetworkQualityEstimator::Observation<int32_t> | |
| 476 ThroughputObservation; | |
| 477 typedef net::NetworkQualityEstimator::ObservationBuffer<int32_t> | |
| 478 ThroughputObservationBuffer; | |
| 479 | |
| 480 // This does not use a unordered_map or hash_map for code simplicity (key just | |
| 481 // implements operator<, rather than hash and equality) and because the map is | |
| 482 // tiny. | |
| 483 typedef std::map<NetworkID, CachedNetworkQuality> CachedNetworkQualities; | |
| 484 | |
| 485 // Throughput is set to |kInvalidThroughput| if a valid value is | |
| 486 // unavailable. Readers should discard throughput value if it is set to | |
| 487 // |kInvalidThroughput|. | |
| 488 static const int32_t kInvalidThroughput; | |
| 489 | |
| 490 // Tiny transfer sizes may give inaccurate throughput results. | |
| 491 // Minimum size of the transfer over which the throughput is computed. | |
| 492 static const int kMinTransferSizeInBytes = 10000; | |
| 493 | |
| 494 // Minimum duration (in microseconds) of the transfer over which the | |
| 495 // throughput is computed. | |
| 496 static const int kMinRequestDurationMicroseconds = 1000; | |
| 497 | |
| 498 // Minimum valid value of the variation parameter that holds RTT (in | |
| 499 // milliseconds) values. | |
| 500 static const int kMinimumRTTVariationParameterMsec = 1; | |
| 501 | |
| 502 // Minimum valid value of the variation parameter that holds throughput (in | |
| 503 // kilobits per second) values. | |
| 504 static const int kMinimumThroughputVariationParameterKbps = 1; | |
| 505 | |
| 506 // Maximum size of the cache that holds network quality estimates. | |
| 507 // Smaller size may reduce the cache hit rate due to frequent evictions. | |
| 508 // Larger size may affect performance. | |
| 509 static const size_t kMaximumNetworkQualityCacheSize = 10; | |
| 510 | |
| 511 // Maximum number of observations that can be held in the ObservationBuffer. | |
| 512 static const size_t kMaximumObservationsBufferSize = 300; | |
| 513 | |
| 514 // Time duration (in milliseconds) after which the estimate provided by | |
| 515 // external estimate provider is considered stale. | |
| 516 static const int kExternalEstimateProviderFreshnessDurationMsec = | |
| 517 5 * 60 * 1000; | |
| 518 | |
| 519 // Returns the RTT value to be used when the valid RTT is unavailable. Readers | |
| 520 // should discard RTT if it is set to the value returned by |InvalidRTT()|. | |
| 521 static const base::TimeDelta InvalidRTT(); | |
| 522 | |
| 523 // Notifies |this| of a new transport layer RTT. | |
| 524 void OnUpdatedRTTAvailable(SocketPerformanceWatcherFactory::Protocol protocol, | |
| 525 const base::TimeDelta& rtt); | |
| 526 | |
| 527 // Queries the external estimate provider for the latest network quality | |
| 528 // estimates, and adds those estimates to the current observation buffer. | |
| 529 void QueryExternalEstimateProvider(); | |
| 530 | |
| 531 // Obtains operating parameters from the field trial parameters. | |
| 532 void ObtainOperatingParams( | |
| 533 const std::map<std::string, std::string>& variation_params); | |
| 534 | |
| 535 // Obtains the model parameters for different effective connection types from | |
| 536 // the field trial parameters. For each effective connection type, a model | |
| 537 // (currently composed of a RTT threshold and a downlink throughput threshold) | |
| 538 // is provided by the field trial. | |
| 539 void ObtainEffectiveConnectionTypeModelParams( | |
| 540 const std::map<std::string, std::string>& variation_params); | |
| 541 | |
| 542 // Adds the default median RTT and downstream throughput estimate for the | |
| 543 // current connection type to the observation buffer. | |
| 544 void AddDefaultEstimates(); | |
| 545 | |
| 546 // Returns an estimate of network quality at the specified |percentile|. | |
| 547 // |disallowed_observation_sources| is the list of observation sources that | |
| 548 // should be excluded when computing the percentile. | |
| 549 // Only the observations later than |begin_timestamp| are taken into account. | |
| 550 // |percentile| must be between 0 and 100 (both inclusive) with higher | |
| 551 // percentiles indicating less performant networks. For example, if | |
| 552 // |percentile| is 90, then the network is expected to be faster than the | |
| 553 // returned estimate with 0.9 probability. Similarly, network is expected to | |
| 554 // be slower than the returned estimate with 0.1 probability. | |
| 555 base::TimeDelta GetRTTEstimateInternal( | |
| 556 const std::vector<ObservationSource>& disallowed_observation_sources, | |
| 557 const base::TimeTicks& begin_timestamp, | |
| 558 int percentile) const; | |
| 559 int32_t GetDownlinkThroughputKbpsEstimateInternal( | |
| 560 const base::TimeTicks& begin_timestamp, | |
| 561 int percentile) const; | |
| 562 | |
| 563 // Returns the current network ID checking by calling the platform APIs. | |
| 564 // Virtualized for testing. | |
| 565 virtual NetworkID GetCurrentNetworkID() const; | |
| 566 | |
| 567 // Writes the estimated quality of the current network to the cache. | |
| 568 void CacheNetworkQualityEstimate(); | |
| 569 | |
| 570 void NotifyObserversOfRTT(const RttObservation& observation); | |
| 571 | |
| 572 void NotifyObserversOfThroughput(const ThroughputObservation& observation); | |
| 573 | |
| 574 // Records the UMA related to RTT. | |
| 575 void RecordRTTUMA(int32_t estimated_value_msec, | |
| 576 int32_t actual_value_msec) const; | |
| 577 | |
| 578 // Returns true only if |request| can be used for network quality estimation. | |
| 579 // Only the requests that go over network are considered to provide useful | |
| 580 // observations. | |
| 581 bool RequestProvidesUsefulObservations(const URLRequest& request) const; | |
| 582 | |
| 583 // Values of external estimate provider status. This enum must remain | |
| 584 // synchronized with the enum of the same name in | |
| 585 // metrics/histograms/histograms.xml. | |
| 586 enum NQEExternalEstimateProviderStatus { | |
| 587 EXTERNAL_ESTIMATE_PROVIDER_STATUS_NOT_AVAILABLE, | |
| 588 EXTERNAL_ESTIMATE_PROVIDER_STATUS_AVAILABLE, | |
| 589 EXTERNAL_ESTIMATE_PROVIDER_STATUS_QUERIED, | |
| 590 EXTERNAL_ESTIMATE_PROVIDER_STATUS_QUERY_SUCCESSFUL, | |
| 591 EXTERNAL_ESTIMATE_PROVIDER_STATUS_CALLBACK, | |
| 592 EXTERNAL_ESTIMATE_PROVIDER_STATUS_RTT_AVAILABLE, | |
| 593 EXTERNAL_ESTIMATE_PROVIDER_STATUS_DOWNLINK_BANDWIDTH_AVAILABLE, | |
| 594 EXTERNAL_ESTIMATE_PROVIDER_STATUS_BOUNDARY | |
| 595 }; | |
| 596 | |
| 597 // Records the metrics related to external estimate provider. | |
| 598 void RecordExternalEstimateProviderMetrics( | |
| 599 NQEExternalEstimateProviderStatus status) const; | |
| 600 | |
| 601 // Determines if the requests to local host can be used in estimating the | |
| 602 // network quality. Set to true only for tests. | |
| 603 const bool allow_localhost_requests_; | |
| 604 | |
| 605 // Determines if the responses smaller than |kMinTransferSizeInBytes| | |
| 606 // or shorter than |kMinTransferSizeInBytes| can be used in estimating the | |
| 607 // network quality. Set to true only for tests. | |
| 608 const bool allow_small_responses_; | |
| 609 | |
| 610 // The factor by which the weight of an observation reduces every second. | |
| 611 const double weight_multiplier_per_second_; | |
| 612 | |
| 613 // Time when last connection change was observed. | |
| 614 base::TimeTicks last_connection_change_; | |
| 615 | |
| 616 // ID of the current network. | |
| 617 NetworkID current_network_id_; | |
| 618 | |
| 619 // Peak network quality (fastest round-trip-time (RTT) and highest | |
| 620 // downstream throughput) measured since last connectivity change. RTT is | |
| 621 // measured from time the request is sent until the first byte received. | |
| 622 // The accuracy is decreased by ignoring these factors: | |
| 623 // 1) Multiple URLRequests can occur concurrently. | |
| 624 // 2) Includes server processing time. | |
| 625 NetworkQuality peak_network_quality_; | |
| 626 | |
| 627 // Cache that stores quality of previously seen networks. | |
| 628 CachedNetworkQualities cached_network_qualities_; | |
| 629 | |
| 630 // Buffer that holds throughput observations (in kilobits per second) sorted | |
| 631 // by timestamp. | |
| 632 ThroughputObservationBuffer downstream_throughput_kbps_observations_; | |
| 633 | |
| 634 // Buffer that holds RTT observations sorted by timestamp. | |
| 635 RttObservationBuffer rtt_observations_; | |
| 636 | |
| 637 // Default network quality observations obtained from the network quality | |
| 638 // estimator field trial parameters. The observations are indexed by | |
| 639 // ConnectionType. | |
| 640 NetworkQuality | |
| 641 default_observations_[NetworkChangeNotifier::CONNECTION_LAST + 1]; | |
| 642 | |
| 643 // Thresholds for different effective connection types obtained from field | |
| 644 // trial variation params. These thresholds encode how different connection | |
| 645 // types behave in general. In future, complex encodings (e.g., curve | |
| 646 // fitting) may be used. | |
| 647 NetworkQuality connection_thresholds_[EFFECTIVE_CONNECTION_TYPE_LAST]; | |
| 648 | |
| 649 // Estimated network quality. Updated on mainframe requests. | |
| 650 NetworkQuality estimated_median_network_quality_; | |
| 651 | |
| 652 // ExternalEstimateProvider that provides network quality using operating | |
| 653 // system APIs. May be NULL. | |
| 654 const std::unique_ptr<ExternalEstimateProvider> external_estimate_provider_; | |
| 655 | |
| 656 // Observer lists for round trip times and throughput measurements. | |
| 657 base::ObserverList<RTTObserver> rtt_observer_list_; | |
| 658 base::ObserverList<ThroughputObserver> throughput_observer_list_; | |
| 659 | |
| 660 std::unique_ptr<SocketPerformanceWatcherFactory> watcher_factory_; | |
| 661 | |
| 662 base::ThreadChecker thread_checker_; | |
| 663 | |
| 664 base::WeakPtrFactory<NetworkQualityEstimator> weak_ptr_factory_; | |
| 665 | |
| 666 DISALLOW_COPY_AND_ASSIGN(NetworkQualityEstimator); | |
| 667 }; | |
| 668 | |
| 669 } // namespace net | |
| 670 | |
| 671 #endif // NET_BASE_NETWORK_QUALITY_ESTIMATOR_H_ | |
| OLD | NEW |
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Chromium Code Reviews
Issue 1898603002:
Move Network Quality Estimator files to //net/nqe (Closed)
Base URL: https://chromium.googlesource.com/chromium/src.git@master