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1 // Copyright (c) 2013 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/pacing_sender.h" | |
6 | |
7 namespace net { | |
8 | |
9 PacingSender::PacingSender(SendAlgorithmInterface* sender, | |
10 QuicTime::Delta alarm_granularity, | |
11 uint32 initial_packet_burst) | |
12 : sender_(sender), | |
13 alarm_granularity_(alarm_granularity), | |
14 initial_packet_burst_(initial_packet_burst), | |
15 burst_tokens_(initial_packet_burst), | |
16 last_delayed_packet_sent_time_(QuicTime::Zero()), | |
17 ideal_next_packet_send_time_(QuicTime::Zero()), | |
18 was_last_send_delayed_(false) { | |
19 } | |
20 | |
21 PacingSender::~PacingSender() {} | |
22 | |
23 void PacingSender::SetFromConfig(const QuicConfig& config, | |
24 bool is_server, | |
25 bool using_pacing) { | |
26 DCHECK(using_pacing); | |
27 sender_->SetFromConfig(config, is_server, using_pacing); | |
28 } | |
29 | |
30 bool PacingSender::ResumeConnectionState( | |
31 const CachedNetworkParameters& cached_network_params) { | |
32 return sender_->ResumeConnectionState(cached_network_params); | |
33 } | |
34 | |
35 void PacingSender::SetNumEmulatedConnections(int num_connections) { | |
36 sender_->SetNumEmulatedConnections(num_connections); | |
37 } | |
38 | |
39 void PacingSender::OnCongestionEvent(bool rtt_updated, | |
40 QuicByteCount bytes_in_flight, | |
41 const CongestionVector& acked_packets, | |
42 const CongestionVector& lost_packets) { | |
43 sender_->OnCongestionEvent( | |
44 rtt_updated, bytes_in_flight, acked_packets, lost_packets); | |
45 } | |
46 | |
47 bool PacingSender::OnPacketSent( | |
48 QuicTime sent_time, | |
49 QuicByteCount bytes_in_flight, | |
50 QuicPacketSequenceNumber sequence_number, | |
51 QuicByteCount bytes, | |
52 HasRetransmittableData has_retransmittable_data) { | |
53 const bool in_flight = | |
54 sender_->OnPacketSent(sent_time, bytes_in_flight, sequence_number, | |
55 bytes, has_retransmittable_data); | |
56 if (has_retransmittable_data != HAS_RETRANSMITTABLE_DATA) { | |
57 return in_flight; | |
58 } | |
59 if (bytes_in_flight == 0) { | |
60 // Add more burst tokens anytime the connection is leaving quiescence. | |
61 burst_tokens_ = initial_packet_burst_; | |
62 } | |
63 if (burst_tokens_ > 0) { | |
64 --burst_tokens_; | |
65 was_last_send_delayed_ = false; | |
66 last_delayed_packet_sent_time_ = QuicTime::Zero(); | |
67 ideal_next_packet_send_time_ = QuicTime::Zero(); | |
68 return in_flight; | |
69 } | |
70 // The next packet should be sent as soon as the current packets has been | |
71 // transferred. | |
72 QuicTime::Delta delay = PacingRate().TransferTime(bytes); | |
73 // If the last send was delayed, and the alarm took a long time to get | |
74 // invoked, allow the connection to make up for lost time. | |
75 if (was_last_send_delayed_) { | |
76 ideal_next_packet_send_time_ = ideal_next_packet_send_time_.Add(delay); | |
77 // The send was application limited if it takes longer than the | |
78 // pacing delay between sent packets. | |
79 const bool application_limited = | |
80 last_delayed_packet_sent_time_.IsInitialized() && | |
81 sent_time > last_delayed_packet_sent_time_.Add(delay); | |
82 const bool making_up_for_lost_time = | |
83 ideal_next_packet_send_time_ <= sent_time; | |
84 // As long as we're making up time and not application limited, | |
85 // continue to consider the packets delayed, allowing the packets to be | |
86 // sent immediately. | |
87 if (making_up_for_lost_time && !application_limited) { | |
88 last_delayed_packet_sent_time_ = sent_time; | |
89 } else { | |
90 was_last_send_delayed_ = false; | |
91 last_delayed_packet_sent_time_ = QuicTime::Zero(); | |
92 } | |
93 } else { | |
94 ideal_next_packet_send_time_ = QuicTime::Max( | |
95 ideal_next_packet_send_time_.Add(delay), sent_time.Add(delay)); | |
96 } | |
97 return in_flight; | |
98 } | |
99 | |
100 void PacingSender::OnRetransmissionTimeout(bool packets_retransmitted) { | |
101 sender_->OnRetransmissionTimeout(packets_retransmitted); | |
102 } | |
103 | |
104 void PacingSender::RevertRetransmissionTimeout() { | |
105 sender_->RevertRetransmissionTimeout(); | |
106 } | |
107 | |
108 QuicTime::Delta PacingSender::TimeUntilSend( | |
109 QuicTime now, | |
110 QuicByteCount bytes_in_flight, | |
111 HasRetransmittableData has_retransmittable_data) const { | |
112 QuicTime::Delta time_until_send = | |
113 sender_->TimeUntilSend(now, bytes_in_flight, has_retransmittable_data); | |
114 if (burst_tokens_ > 0 || bytes_in_flight == 0) { | |
115 // Don't pace if we have burst tokens available or leaving quiescence. | |
116 return time_until_send; | |
117 } | |
118 | |
119 if (!time_until_send.IsZero()) { | |
120 DCHECK(time_until_send.IsInfinite()); | |
121 // The underlying sender prevents sending. | |
122 return time_until_send; | |
123 } | |
124 | |
125 if (has_retransmittable_data == NO_RETRANSMITTABLE_DATA) { | |
126 // Don't pace ACK packets, since they do not count against CWND and do not | |
127 // cause CWND to grow. | |
128 return QuicTime::Delta::Zero(); | |
129 } | |
130 | |
131 // If the next send time is within the alarm granularity, send immediately. | |
132 if (ideal_next_packet_send_time_ > now.Add(alarm_granularity_)) { | |
133 DVLOG(1) << "Delaying packet: " | |
134 << ideal_next_packet_send_time_.Subtract(now).ToMicroseconds(); | |
135 was_last_send_delayed_ = true; | |
136 return ideal_next_packet_send_time_.Subtract(now); | |
137 } | |
138 | |
139 DVLOG(1) << "Sending packet now"; | |
140 return QuicTime::Delta::Zero(); | |
141 } | |
142 | |
143 QuicBandwidth PacingSender::PacingRate() const { | |
144 return sender_->PacingRate(); | |
145 } | |
146 | |
147 QuicBandwidth PacingSender::BandwidthEstimate() const { | |
148 return sender_->BandwidthEstimate(); | |
149 } | |
150 | |
151 bool PacingSender::HasReliableBandwidthEstimate() const { | |
152 return sender_->HasReliableBandwidthEstimate(); | |
153 } | |
154 | |
155 QuicTime::Delta PacingSender::RetransmissionDelay() const { | |
156 return sender_->RetransmissionDelay(); | |
157 } | |
158 | |
159 QuicByteCount PacingSender::GetCongestionWindow() const { | |
160 return sender_->GetCongestionWindow(); | |
161 } | |
162 | |
163 bool PacingSender::InSlowStart() const { | |
164 return sender_->InSlowStart(); | |
165 } | |
166 | |
167 bool PacingSender::InRecovery() const { | |
168 return sender_->InRecovery(); | |
169 } | |
170 | |
171 QuicByteCount PacingSender::GetSlowStartThreshold() const { | |
172 return sender_->GetSlowStartThreshold(); | |
173 } | |
174 | |
175 CongestionControlType PacingSender::GetCongestionControlType() const { | |
176 return sender_->GetCongestionControlType(); | |
177 } | |
178 | |
179 } // namespace net | |
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