1 // Copyright (c) 2012 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/paced_sender.h" 6 7 #include "net/quic/quic_protocol.h" 8 9 namespace net { 10 11 // To prevent too aggressive pacing we allow the following packet burst size. 12 const int64 kMinPacketBurstSize = 2; 13 // Max estimated time between calls to TimeUntilSend and 14 // AvailableCongestionWindow. 15 const int64 kMaxSchedulingDelayUs = 2000; 16 17 PacedSender::PacedSender(QuicBandwidth estimate) 18 : leaky_bucket_(estimate), 19 pace_(estimate) { 20 } 21 22 void PacedSender::UpdateBandwidthEstimate(QuicTime now, 23 QuicBandwidth estimate) { 24 leaky_bucket_.SetDrainingRate(now, estimate); 25 pace_ = estimate; 26 } 27 28 void PacedSender::SentPacket(QuicTime now, QuicByteCount bytes) { 29 leaky_bucket_.Add(now, bytes); 30 } 31 32 QuicTime::Delta PacedSender::TimeUntilSend(QuicTime now, 33 QuicTime::Delta time_until_send) { 34 if (time_until_send.ToMicroseconds() >= kMaxSchedulingDelayUs) { 35 return time_until_send; 36 } 37 // Pace the data. 38 QuicByteCount pacing_window = pace_.ToBytesPerPeriod( 39 QuicTime::Delta::FromMicroseconds(kMaxSchedulingDelayUs)); 40 QuicByteCount min_window_size = kMinPacketBurstSize * kMaxPacketSize; 41 pacing_window = std::max(pacing_window, min_window_size); 42 43 if (pacing_window > leaky_bucket_.BytesPending(now)) { 44 // We have not filled our pacing window yet. 45 return time_until_send; 46 } 47 return leaky_bucket_.TimeRemaining(now); 48 } 49 50 } // namespace net 51
