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1 // Copyright (c) 2015 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2015 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #include "net/quic/congestion_control/tcp_cubic_bytes_sender.h" | 5 #include "net/quic/congestion_control/tcp_cubic_bytes_sender.h" |
6 | 6 |
7 #include <algorithm> | 7 #include <algorithm> |
8 | 8 |
9 #include "net/quic/congestion_control/prr_sender.h" | 9 #include "net/quic/congestion_control/prr_sender.h" |
10 #include "net/quic/congestion_control/rtt_stats.h" | 10 #include "net/quic/congestion_control/rtt_stats.h" |
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70 } | 70 } |
71 if (using_pacing) { | 71 if (using_pacing) { |
72 // Disable the ack train mode in hystart when pacing is enabled, since it | 72 // Disable the ack train mode in hystart when pacing is enabled, since it |
73 // may be falsely triggered. | 73 // may be falsely triggered. |
74 hybrid_slow_start_.set_ack_train_detection(false); | 74 hybrid_slow_start_.set_ack_train_detection(false); |
75 } | 75 } |
76 } | 76 } |
77 } | 77 } |
78 | 78 |
79 bool TcpCubicBytesSender::ResumeConnectionState( | 79 bool TcpCubicBytesSender::ResumeConnectionState( |
80 const CachedNetworkParameters& cached_network_params) { | 80 const CachedNetworkParameters& cached_network_params, |
| 81 bool max_bandwidth_resumption) { |
81 // If the previous bandwidth estimate is less than an hour old, store in | 82 // If the previous bandwidth estimate is less than an hour old, store in |
82 // preparation for doing bandwidth resumption. | 83 // preparation for doing bandwidth resumption. |
83 int64 seconds_since_estimate = | 84 int64 seconds_since_estimate = |
84 clock_->WallNow().ToUNIXSeconds() - cached_network_params.timestamp(); | 85 clock_->WallNow().ToUNIXSeconds() - cached_network_params.timestamp(); |
85 if (seconds_since_estimate > kNumSecondsPerHour) { | 86 if (seconds_since_estimate > kNumSecondsPerHour) { |
86 return false; | 87 return false; |
87 } | 88 } |
88 | 89 |
89 QuicBandwidth bandwidth = QuicBandwidth::FromBytesPerSecond( | 90 QuicBandwidth bandwidth = QuicBandwidth::FromBytesPerSecond( |
90 cached_network_params.bandwidth_estimate_bytes_per_second()); | 91 max_bandwidth_resumption |
| 92 ? cached_network_params.max_bandwidth_estimate_bytes_per_second() |
| 93 : cached_network_params.bandwidth_estimate_bytes_per_second()); |
91 QuicTime::Delta rtt_ms = | 94 QuicTime::Delta rtt_ms = |
92 QuicTime::Delta::FromMilliseconds(cached_network_params.min_rtt_ms()); | 95 QuicTime::Delta::FromMilliseconds(cached_network_params.min_rtt_ms()); |
93 | 96 |
94 // Make sure CWND is in appropriate range (in case of bad data). | 97 // Make sure CWND is in appropriate range (in case of bad data). |
95 QuicByteCount new_congestion_window = bandwidth.ToBytesPerPeriod(rtt_ms); | 98 QuicByteCount new_congestion_window = bandwidth.ToBytesPerPeriod(rtt_ms); |
96 congestion_window_ = | 99 congestion_window_ = |
97 max(min(new_congestion_window, kMaxTcpCongestionWindow * kMaxSegmentSize), | 100 max(min(new_congestion_window, kMaxTcpCongestionWindow * kMaxSegmentSize), |
98 kMinCongestionWindowForBandwidthResumption * kMaxSegmentSize); | 101 kMinCongestionWindowForBandwidthResumption * kMaxSegmentSize); |
99 | 102 |
100 // TODO(rjshade): Set appropriate CWND when previous connection was in slow | 103 // TODO(rjshade): Set appropriate CWND when previous connection was in slow |
101 // start at time of estimate. | 104 // start at time of estimate. |
102 return true; | 105 return true; |
103 } | 106 } |
104 | 107 |
105 void TcpCubicBytesSender::SetNumEmulatedConnections(int num_connections) { | 108 void TcpCubicBytesSender::SetNumEmulatedConnections(int num_connections) { |
106 num_connections_ = max(1, num_connections); | 109 num_connections_ = max(1, num_connections); |
107 cubic_.SetNumConnections(num_connections_); | 110 cubic_.SetNumConnections(num_connections_); |
108 } | 111 } |
109 | 112 |
| 113 void TcpCubicBytesSender::SetMaxCongestionWindow( |
| 114 QuicByteCount max_congestion_window) { |
| 115 max_congestion_window_ = max_congestion_window; |
| 116 } |
| 117 |
110 float TcpCubicBytesSender::RenoBeta() const { | 118 float TcpCubicBytesSender::RenoBeta() const { |
111 // kNConnectionBeta is the backoff factor after loss for our N-connection | 119 // kNConnectionBeta is the backoff factor after loss for our N-connection |
112 // emulation, which emulates the effective backoff of an ensemble of N | 120 // emulation, which emulates the effective backoff of an ensemble of N |
113 // TCP-Reno connections on a single loss event. The effective multiplier is | 121 // TCP-Reno connections on a single loss event. The effective multiplier is |
114 // computed as: | 122 // computed as: |
115 return (num_connections_ - 1 + kRenoBeta) / num_connections_; | 123 return (num_connections_ - 1 + kRenoBeta) / num_connections_; |
116 } | 124 } |
117 | 125 |
118 void TcpCubicBytesSender::OnCongestionEvent( | 126 void TcpCubicBytesSender::OnCongestionEvent( |
119 bool rtt_updated, | 127 bool rtt_updated, |
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190 DVLOG(1) << "Incoming loss; congestion window: " << congestion_window_ | 198 DVLOG(1) << "Incoming loss; congestion window: " << congestion_window_ |
191 << " slowstart threshold: " << slowstart_threshold_; | 199 << " slowstart threshold: " << slowstart_threshold_; |
192 } | 200 } |
193 | 201 |
194 bool TcpCubicBytesSender::OnPacketSent( | 202 bool TcpCubicBytesSender::OnPacketSent( |
195 QuicTime /*sent_time*/, | 203 QuicTime /*sent_time*/, |
196 QuicByteCount /*bytes_in_flight*/, | 204 QuicByteCount /*bytes_in_flight*/, |
197 QuicPacketSequenceNumber sequence_number, | 205 QuicPacketSequenceNumber sequence_number, |
198 QuicByteCount bytes, | 206 QuicByteCount bytes, |
199 HasRetransmittableData is_retransmittable) { | 207 HasRetransmittableData is_retransmittable) { |
| 208 if (InSlowStart()) { |
| 209 ++(stats_->slowstart_packets_sent); |
| 210 } |
| 211 |
200 // Only update bytes_in_flight_ for data packets. | 212 // Only update bytes_in_flight_ for data packets. |
201 if (is_retransmittable != HAS_RETRANSMITTABLE_DATA) { | 213 if (is_retransmittable != HAS_RETRANSMITTABLE_DATA) { |
202 return false; | 214 return false; |
203 } | 215 } |
204 if (InRecovery()) { | 216 if (InRecovery()) { |
205 // PRR is used when in recovery. | 217 // PRR is used when in recovery. |
206 prr_.OnPacketSent(bytes); | 218 prr_.OnPacketSent(bytes); |
207 } | 219 } |
208 DCHECK_LT(largest_sent_sequence_number_, sequence_number); | 220 DCHECK_LT(largest_sent_sequence_number_, sequence_number); |
209 largest_sent_sequence_number_ = sequence_number; | 221 largest_sent_sequence_number_ = sequence_number; |
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347 hybrid_slow_start_.Restart(); | 359 hybrid_slow_start_.Restart(); |
348 slowstart_threshold_ = congestion_window_ / 2; | 360 slowstart_threshold_ = congestion_window_ / 2; |
349 congestion_window_ = min_congestion_window_; | 361 congestion_window_ = min_congestion_window_; |
350 } | 362 } |
351 | 363 |
352 CongestionControlType TcpCubicBytesSender::GetCongestionControlType() const { | 364 CongestionControlType TcpCubicBytesSender::GetCongestionControlType() const { |
353 return reno_ ? kRenoBytes : kCubicBytes; | 365 return reno_ ? kRenoBytes : kCubicBytes; |
354 } | 366 } |
355 | 367 |
356 } // namespace net | 368 } // namespace net |
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