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| 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 #include "net/quic/congestion_control/time_loss_algorithm.h" | |
| 6 | |
| 7 #include "net/quic/congestion_control/rtt_stats.h" | |
| 8 #include "net/quic/quic_bug_tracker.h" | |
| 9 #include "net/quic/quic_protocol.h" | |
| 10 | |
| 11 namespace net { | |
| 12 namespace { | |
| 13 | |
| 14 // The minimum delay before a packet will be considered lost, | |
| 15 // regardless of SRTT. Half of the minimum TLP, since the loss algorithm only | |
| 16 // triggers when a nack has been receieved for the packet. | |
| 17 static const size_t kMinLossDelayMs = 5; | |
| 18 | |
| 19 // How many RTTs the algorithm waits before determining a packet is lost. | |
| 20 static const double kLossDelayMultiplier = 1.25; | |
| 21 | |
| 22 } // namespace | |
| 23 | |
| 24 TimeLossAlgorithm::TimeLossAlgorithm() | |
| 25 : loss_detection_timeout_(QuicTime::Zero()) {} | |
| 26 | |
| 27 LossDetectionType TimeLossAlgorithm::GetLossDetectionType() const { | |
| 28 return kTime; | |
| 29 } | |
| 30 | |
| 31 PacketNumberSet TimeLossAlgorithm::DetectLostPackets( | |
| 32 const QuicUnackedPacketMap& unacked_packets, | |
| 33 const QuicTime& time, | |
| 34 QuicPacketNumber largest_observed, | |
| 35 const RttStats& rtt_stats) { | |
| 36 PacketNumberSet lost_packets; | |
| 37 loss_detection_timeout_ = QuicTime::Zero(); | |
| 38 QuicTime::Delta loss_delay = QuicTime::Delta::Max( | |
| 39 QuicTime::Delta::FromMilliseconds(kMinLossDelayMs), | |
| 40 QuicTime::Delta::Max(rtt_stats.smoothed_rtt(), rtt_stats.latest_rtt()) | |
| 41 .Multiply(kLossDelayMultiplier)); | |
| 42 | |
| 43 QuicPacketNumber packet_number = unacked_packets.GetLeastUnacked(); | |
| 44 for (QuicUnackedPacketMap::const_iterator it = unacked_packets.begin(); | |
| 45 it != unacked_packets.end() && packet_number <= largest_observed; | |
| 46 ++it, ++packet_number) { | |
| 47 if (!it->in_flight) { | |
| 48 continue; | |
| 49 } | |
| 50 QUIC_BUG_IF(it->nack_count == 0 && it->sent_time.IsInitialized()) | |
| 51 << "All packets less than largest observed should have been nacked." | |
| 52 << " packet_number:" << packet_number | |
| 53 << " largest_observed:" << largest_observed; | |
| 54 | |
| 55 // Packets are sent in order, so break when we haven't waited long enough | |
| 56 // to lose any more packets and leave the loss_time_ set for the timeout. | |
| 57 QuicTime when_lost = it->sent_time.Add(loss_delay); | |
| 58 if (time < when_lost) { | |
| 59 loss_detection_timeout_ = when_lost; | |
| 60 break; | |
| 61 } | |
| 62 lost_packets.insert(packet_number); | |
| 63 } | |
| 64 | |
| 65 return lost_packets; | |
| 66 } | |
| 67 | |
| 68 void TimeLossAlgorithm::DetectLosses( | |
| 69 const QuicUnackedPacketMap& unacked_packets, | |
| 70 const QuicTime& time, | |
| 71 const RttStats& rtt_stats, | |
| 72 SendAlgorithmInterface::CongestionVector* packets_lost) { | |
| 73 QUIC_BUG << "DetectLoss is unsupported by TimeLossAlgorithm."; | |
| 74 } | |
| 75 | |
| 76 // loss_time_ is updated in DetectLostPackets, which must be called every time | |
| 77 // an ack is received or the timeout expires. | |
| 78 QuicTime TimeLossAlgorithm::GetLossTimeout() const { | |
| 79 return loss_detection_timeout_; | |
| 80 } | |
| 81 | |
| 82 } // namespace net | |
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Chromium Code Reviews
Issue 1660593004:
Landing Recent QUIC changes until 01/28/2016 18:41 UTC (Closed)
Base URL: https://chromium.googlesource.com/chromium/src.git@Final_0202