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Side by Side Diff: net/quic/congestion_control/time_loss_algorithm.cc

Issue 992733002: Remove //net (except for Android test stuff) and sdch (Closed) Base URL: git@github.com:domokit/mojo.git@master
Patch Set: Created 5 years, 9 months ago
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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_protocol.h"
9
10 namespace net {
11 namespace {
12
13 // The minimum delay before a packet will be considered lost,
14 // regardless of SRTT. Half of the minimum TLP, since the loss algorithm only
15 // triggers when a nack has been receieved for the packet.
16 static const size_t kMinLossDelayMs = 5;
17
18 // How many RTTs the algorithm waits before determining a packet is lost.
19 static const double kLossDelayMultiplier = 1.25;
20
21 } // namespace
22
23 TimeLossAlgorithm::TimeLossAlgorithm()
24 : loss_detection_timeout_(QuicTime::Zero()) { }
25
26 LossDetectionType TimeLossAlgorithm::GetLossDetectionType() const {
27 return kTime;
28 }
29
30 SequenceNumberSet TimeLossAlgorithm::DetectLostPackets(
31 const QuicUnackedPacketMap& unacked_packets,
32 const QuicTime& time,
33 QuicPacketSequenceNumber largest_observed,
34 const RttStats& rtt_stats) {
35 SequenceNumberSet lost_packets;
36 loss_detection_timeout_ = QuicTime::Zero();
37 QuicTime::Delta loss_delay = QuicTime::Delta::Max(
38 QuicTime::Delta::FromMilliseconds(kMinLossDelayMs),
39 QuicTime::Delta::Max(rtt_stats.smoothed_rtt(), rtt_stats.latest_rtt())
40 .Multiply(kLossDelayMultiplier));
41
42 QuicPacketSequenceNumber sequence_number = unacked_packets.GetLeastUnacked();
43 for (QuicUnackedPacketMap::const_iterator it = unacked_packets.begin();
44 it != unacked_packets.end() && sequence_number <= largest_observed;
45 ++it, ++sequence_number) {
46 if (!it->in_flight) {
47 continue;
48 }
49 LOG_IF(DFATAL, it->nack_count == 0 && it->sent_time.IsInitialized())
50 << "All packets less than largest observed should have been nacked."
51 << "sequence_number:" << sequence_number
52 << " largest_observed:" << largest_observed;
53
54 // Packets are sent in order, so break when we haven't waited long enough
55 // to lose any more packets and leave the loss_time_ set for the timeout.
56 QuicTime when_lost = it->sent_time.Add(loss_delay);
57 if (time < when_lost) {
58 loss_detection_timeout_ = when_lost;
59 break;
60 }
61 lost_packets.insert(sequence_number);
62 }
63
64 return lost_packets;
65 }
66
67 // loss_time_ is updated in DetectLostPackets, which must be called every time
68 // an ack is received or the timeout expires.
69 QuicTime TimeLossAlgorithm::GetLossTimeout() const {
70 return loss_detection_timeout_;
71 }
72
73 } // namespace net
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