1 // Copyright 2014 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_QUIC_QUIC_SUSTAINED_BANDWIDTH_RECORDER_H_ 6 #define NET_QUIC_QUIC_SUSTAINED_BANDWIDTH_RECORDER_H_ 7 8 #include "base/logging.h" 9 #include "net/quic/quic_bandwidth.h" 10 #include "net/quic/quic_time.h" 11 12 namespace net { 13 14 namespace test { 15 class QuicSustainedBandwidthRecorderPeer; 16 } // namespace test 17 18 // This class keeps track of a sustained bandwidth estimate to ultimately send 19 // to the client in a server config update message. A sustained bandwidth 20 // estimate is only marked as valid if the QuicSustainedBandwidthRecorder has 21 // been given uninterrupted reliable estimates over a certain period of time. 22 class NET_EXPORT_PRIVATE QuicSustainedBandwidthRecorder { 23 public: 24 QuicSustainedBandwidthRecorder(); 25 26 // As long as |in_recovery| is consistently false, multiple calls to this 27 // method over a 3 * srtt period results in storage of a valid sustained 28 // bandwidth estimate. 29 // |time_now| is used as a max bandwidth timestamp if needed. 30 void RecordEstimate(bool in_recovery, 31 bool in_slow_start, 32 QuicBandwidth bandwidth, 33 QuicTime estimate_time, 34 QuicWallTime wall_time, 35 QuicTime::Delta srtt); 36 37 bool HasEstimate() const { 38 return has_estimate_; 39 } 40 41 QuicBandwidth BandwidthEstimate() const { 42 DCHECK(has_estimate_); 43 return bandwidth_estimate_; 44 } 45 46 QuicBandwidth MaxBandwidthEstimate() const { 47 DCHECK(has_estimate_); 48 return max_bandwidth_estimate_; 49 } 50 51 int64 MaxBandwidthTimestamp() const { 52 DCHECK(has_estimate_); 53 return max_bandwidth_timestamp_; 54 } 55 56 bool EstimateRecordedDuringSlowStart() const { 57 DCHECK(has_estimate_); 58 return bandwidth_estimate_recorded_during_slow_start_; 59 } 60 61 private: 62 friend class test::QuicSustainedBandwidthRecorderPeer; 63 64 // True if we have been able to calculate sustained bandwidth, over at least 65 // one recording period (3 * rtt). 66 bool has_estimate_; 67 68 // True if the last call to RecordEstimate had a reliable estimate. 69 bool is_recording_; 70 71 // True if the current sustained bandwidth estimate was generated while in 72 // slow start. 73 bool bandwidth_estimate_recorded_during_slow_start_; 74 75 // The latest sustained bandwidth estimate. 76 QuicBandwidth bandwidth_estimate_; 77 78 // The maximum sustained bandwidth seen over the lifetime of the connection. 79 QuicBandwidth max_bandwidth_estimate_; 80 81 // Timestamp indicating when the max_bandwidth_estimate_ was seen. 82 int64 max_bandwidth_timestamp_; 83 84 // Timestamp marking the beginning of the latest recording period. 85 QuicTime start_time_; 86 87 DISALLOW_COPY_AND_ASSIGN(QuicSustainedBandwidthRecorder); 88 }; 89 90 } // namespace net 91 92 #endif // NET_QUIC_QUIC_SUSTAINED_BANDWIDTH_RECORDER_H_ 93