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- // Copyright 2016 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.
- #ifndef NET_NQE_THROUGHPUT_ANALYZER_H_
- #define NET_NQE_THROUGHPUT_ANALYZER_H_
- #include <stdint.h>
- #include <unordered_map>
- #include <unordered_set>
- #include "base/callback.h"
- #include "base/memory/raw_ptr.h"
- #include "base/memory/ref_counted.h"
- #include "base/sequence_checker.h"
- #include "base/time/time.h"
- #include "net/base/net_export.h"
- #include "net/log/net_log_with_source.h"
- namespace {
- typedef base::RepeatingCallback<void(int32_t)> ThroughputObservationCallback;
- }
- namespace base {
- class SingleThreadTaskRunner;
- class TickClock;
- }
- namespace net {
- class NetworkQualityEstimatorParams;
- class NetworkQualityEstimator;
- class URLRequest;
- namespace nqe::internal {
- // Makes throughput observations. Polls NetworkActivityMonitor
- // (TrafficStats on Android) to count number of bits received over throughput
- // observation windows in accordance with the following rules:
- // (1) A new window of observation begins any time a URL request header is
- // about to be sent, or a request completes or is destroyed.
- // (2) A request is "active" if its headers are sent, but it hasn't completed,
- // and "local" if destined to local host. If at any time during a
- // throughput observation window there is an active, local request, the
- // window is discarded.
- // (3) If less than 32KB is received over the network during a window of
- // observation, that window is discarded.
- class NET_EXPORT_PRIVATE ThroughputAnalyzer {
- public:
- // |throughput_observation_callback| is called on the |task_runner| when
- // |this| has a new throughput observation.
- // |use_local_host_requests_for_tests| should only be true when testing
- // against local HTTP server and allows the requests to local host to be
- // used for network quality estimation. |use_smaller_responses_for_tests|
- // should only be true when testing, and allows the responses smaller than
- // |kMinTransferSizeInBits| or shorter than
- // |kMinRequestDurationMicroseconds| to be used for network quality
- // estimation.
- // Virtualized for testing.
- ThroughputAnalyzer(
- const NetworkQualityEstimator* network_quality_estimator,
- const NetworkQualityEstimatorParams* params,
- scoped_refptr<base::SingleThreadTaskRunner> task_runner,
- ThroughputObservationCallback throughput_observation_callback,
- const base::TickClock* tick_clock,
- const NetLogWithSource& net_log);
- ThroughputAnalyzer(const ThroughputAnalyzer&) = delete;
- ThroughputAnalyzer& operator=(const ThroughputAnalyzer&) = delete;
- virtual ~ThroughputAnalyzer();
- // Notifies |this| that the headers of |request| are about to be sent.
- void NotifyStartTransaction(const URLRequest& request);
- // Notifies |this| that unfiltered bytes have been read for |request|.
- void NotifyBytesRead(const URLRequest& request);
- // Notifies |this| that |request| has completed.
- void NotifyRequestCompleted(const URLRequest& request);
- // Notifies |this| that |request| has an expected response body size in octets
- // (8-bit bytes). |expected_content_size| is an estimate of total body length
- // based on the Content-Length header field when available or a general size
- // estimate when the Content-Length is not provided.
- void NotifyExpectedResponseContentSize(const URLRequest& request,
- int64_t expected_content_size);
- // Notifies |this| of a change in connection type.
- void OnConnectionTypeChanged();
- // |use_localhost_requests| should only be true when testing against local
- // HTTP server and allows the requests to local host to be used for network
- // quality estimation.
- void SetUseLocalHostRequestsForTesting(bool use_localhost_requests);
- // Returns true if throughput is currently tracked by a throughput
- // observation window.
- bool IsCurrentlyTrackingThroughput() const;
- // Overrides the tick clock used by |this| for testing.
- void SetTickClockForTesting(const base::TickClock* tick_clock);
- // Returns the number of bits received by Chromium so far. The count may not
- // start from zero, so the caller should only look at difference from a prior
- // call. The count is obtained by polling TrafficStats on Android, and
- // net::NetworkActivityMonitor on all other platforms. Virtualized for
- // testing.
- virtual int64_t GetBitsReceived() const;
- // Returns the number of in-flight requests that can be used for computing
- // throughput.
- size_t CountActiveInFlightRequests() const;
- // Returns the total number of in-flight requests. This also includes hanging
- // requests.
- size_t CountTotalInFlightRequests() const;
- // Returns the sum of expected response content size in bytes for all inflight
- // requests. Request with an unknown response content size have the default
- // response content size.
- int64_t CountTotalContentSizeBytes() const;
- protected:
- // Exposed for testing.
- bool disable_throughput_measurements_for_testing() const {
- return disable_throughput_measurements_;
- }
- // Removes hanging requests from |requests_|. If any hanging requests are
- // detected to be in-flight, the observation window is ended. Protected for
- // testing.
- void EraseHangingRequests(const URLRequest& request);
- // Returns true if the current throughput observation window is heuristically
- // determined to contain hanging requests.
- bool IsHangingWindow(int64_t bits_received,
- base::TimeDelta duration,
- double downstream_kbps_double) const;
- private:
- friend class TestThroughputAnalyzer;
- // Mapping from URL request to the expected content size of the response body
- // for that request. The map tracks all inflight requests. If the expected
- // content size is not available, the value is set to the default value.
- typedef std::unordered_map<const URLRequest*, int64_t> ResponseContentSizes;
- // Mapping from URL request to the last time data was received for that
- // request.
- typedef std::unordered_map<const URLRequest*, base::TimeTicks> Requests;
- // Set of URL requests to hold the requests that reduce the accuracy of
- // throughput computation. These requests are not used in throughput
- // computation.
- typedef std::unordered_set<const URLRequest*> AccuracyDegradingRequests;
- // Updates the response content size map for |request|. Also keeps the total
- // response content size counter updated. Adds an new entry if there is no
- // matching record in the map.
- void UpdateResponseContentSize(const URLRequest* request,
- int64_t response_size);
- // Returns true if downstream throughput can be recorded. In that case,
- // |downstream_kbps| is set to the computed downstream throughput (in
- // kilobits per second). If a downstream throughput observation is taken,
- // then the throughput observation window is reset so as to continue
- // tracking throughput. A throughput observation can be taken only if the
- // time-window is currently active, and enough bytes have accumulated in
- // that window. |downstream_kbps| should not be null.
- bool MaybeGetThroughputObservation(int32_t* downstream_kbps);
- // Starts the throughput observation window that keeps track of network
- // bytes if the following conditions are true:
- // (i) All active requests are non-local;
- // (ii) There is at least one active, non-local request; and,
- // (iii) The throughput observation window is not already tracking
- // throughput. The window is started by setting the |start_| and
- // |bits_received_|.
- void MaybeStartThroughputObservationWindow();
- // EndThroughputObservationWindow ends the throughput observation window.
- void EndThroughputObservationWindow();
- // Returns true if the |request| degrades the accuracy of the throughput
- // observation window. A local request or a request that spans a connection
- // change degrades the accuracy of the throughput computation.
- bool DegradesAccuracy(const URLRequest& request) const;
- // Bounds |accuracy_degrading_requests_| and |requests_| to ensure their sizes
- // do not exceed their capacities.
- void BoundRequestsSize();
- // Guaranteed to be non-null during the duration of |this|.
- const raw_ptr<const NetworkQualityEstimator> network_quality_estimator_;
- // Guaranteed to be non-null during the duration of |this|.
- const raw_ptr<const NetworkQualityEstimatorParams> params_;
- scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
- // Called every time a new throughput observation is available.
- ThroughputObservationCallback throughput_observation_callback_;
- // Guaranteed to be non-null during the lifetime of |this|.
- // This isn't a const pointer since SetTickClockForTesting() modifies it.
- raw_ptr<const base::TickClock> tick_clock_;
- // Time when last connection change was observed.
- base::TimeTicks last_connection_change_;
- // Start time of the current throughput observation window. Set to null if
- // the window is not currently active.
- base::TimeTicks window_start_time_;
- // Number of bits received prior to |start_| as reported by
- // NetworkActivityMonitor.
- int64_t bits_received_at_window_start_ = 0;
- // Container that holds active requests that reduce the accuracy of
- // throughput computation. These requests are not used in throughput
- // computation.
- AccuracyDegradingRequests accuracy_degrading_requests_;
- // Container that holds active requests that do not reduce the accuracy of
- // throughput computation. These requests are used in throughput computation.
- Requests requests_;
- // Container that holds inflight request sizes. These requests are used in
- // computing the total of response content size for all inflight requests.
- ResponseContentSizes response_content_sizes_;
- // The running total of response content size for all inflight requests.
- int64_t total_response_content_size_ = 0;
- // Last time when the check for hanging requests was run.
- base::TimeTicks last_hanging_request_check_;
- // If true, then |this| throughput analyzer stops tracking the throughput
- // observations until Chromium is restarted. This may happen if the throughput
- // analyzer has lost track of the requests that degrade throughput computation
- // accuracy.
- bool disable_throughput_measurements_ = false;
- // Determines if the requests to local host can be used in estimating the
- // network quality. Set to true only for tests.
- bool use_localhost_requests_for_tests_ = false;
- SEQUENCE_CHECKER(sequence_checker_);
- NetLogWithSource net_log_;
- };
- } // namespace nqe::internal
- } // namespace net
- #endif // NET_NQE_THROUGHPUT_ANALYZER_H_
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