diff options
Diffstat (limited to 'chromium/net/quic/congestion_control/inter_arrival_overuse_detector.h')
| -rw-r--r-- | chromium/net/quic/congestion_control/inter_arrival_overuse_detector.h | 173 |
1 files changed, 0 insertions, 173 deletions
diff --git a/chromium/net/quic/congestion_control/inter_arrival_overuse_detector.h b/chromium/net/quic/congestion_control/inter_arrival_overuse_detector.h deleted file mode 100644 index 185236279bb..00000000000 --- a/chromium/net/quic/congestion_control/inter_arrival_overuse_detector.h +++ /dev/null @@ -1,173 +0,0 @@ -// Copyright (c) 2013 The Chromium Authors. All rights reserved. -// Use of this source code is governed by a BSD-style license that can be -// found in the LICENSE file. - -// This class is a helper class to the inter arrival congestion control. It -// provide a signal to the inter arrival congestion control of the estimated -// state of our transport channel. The estimate is based on the inter arrival -// time of the received packets relative to the time those packets were sent; -// we can estimate the build up of buffers on the network before packets are -// lost. -// -// Note: this class is not thread-safe. - -#ifndef NET_QUIC_CONGESTION_CONTROL_INTER_ARRIVAL_OVERUSE_DETECTOR_H_ -#define NET_QUIC_CONGESTION_CONTROL_INTER_ARRIVAL_OVERUSE_DETECTOR_H_ - -#include "base/basictypes.h" -#include "net/base/net_export.h" -#include "net/quic/quic_protocol.h" -#include "net/quic/quic_time.h" - -namespace net { - -enum NET_EXPORT_PRIVATE RateControlRegion { - kRateControlRegionUnknown = 0, - kRateControlRegionUnderMax = 1, - kRateControlRegionNearMax = 2 -}; - -// Note: Order is important. -enum NET_EXPORT_PRIVATE BandwidthUsage { - kBandwidthSteady = 0, - kBandwidthUnderUsing = 1, - kBandwidthDraining = 2, - kBandwidthOverUsing = 3, -}; - -// Normal state transition diagram -// -// kBandwidthUnderUsing -// | -// | -// kBandwidthSteady -// | ^ -// | | -// kBandwidthOverUsing | -// | | -// | | -// kBandwidthDraining -// -// The above transitions is in normal operation, with extreme values we don't -// enforce the state transitions, hence you could in extreme scenarios go -// between any states. -// -// kBandwidthSteady When the packets arrive in the same pace as we sent -// them. In this state we can increase our send pace. -// -// kBandwidthOverUsing When the packets arrive slower than the pace we sent -// them. In this state we should decrease our send pace. -// When we enter into this state we will also get an -// estimate on how much delay we have built up. The -// reduction in send pace should be chosen to drain the -// built up delay within reasonable time. -// -// kBandwidthUnderUsing When the packets arrive faster than the pace we sent -// them. In this state another stream disappeared from -// a shared link leaving us more available bandwidth. -// In this state we should hold our pace to make sure we -// fully drain the buffers before we start increasing -// our send rate. We do this to avoid operating with -// semi-full buffers. -// -// kBandwidthDraining We can only be in this state after we have been in a -// overuse state. In this state we should hold our pace -// to make sure we fully drain the buffers before we -// start increasing our send rate. We do this to avoid -// operating with semi-full buffers. - -class NET_EXPORT_PRIVATE InterArrivalOveruseDetector { - public: - InterArrivalOveruseDetector(); - - // Update the statistics with the received delta times, call for every - // received delta time. This function assumes that there is no re-orderings. - // If multiple packets are sent at the same time (identical send_time) - // last_of_send_time should be set to false for all but the last calls to - // this function. If there is only one packet sent at a given time - // last_of_send_time must be true. - // received_delta is the time difference between receiving this packet and the - // previously received packet. - void OnAcknowledgedPacket(QuicPacketSequenceNumber sequence_number, - QuicTime send_time, - bool last_of_send_time, - QuicTime receive_time); - - // Get the current estimated state and update the estimated congestion delay. - // |estimated_congestion_delay| will be updated with the estimated built up - // buffer delay; it must not be NULL as it will be updated with the estimate. - // Note 1: estimated_buffer_delay will only be valid when kBandwidthOverUsing - // is returned. - // Note 2: it's assumed that the pacer lower its send pace to drain the - // built up buffer within reasonable time. The pacer should use the - // estimated_buffer_delay as a guidance on how much to back off. - // Note 3: The absolute value of estimated_congestion_delay is less reliable - // than the state itself. It is also biased to low since we can't know - // how full the buffers are when the flow starts. - BandwidthUsage GetState(QuicTime::Delta* estimated_congestion_delay); - - private: - struct PacketGroup { - PacketGroup() - : send_time(QuicTime::Zero()), - last_receive_time(QuicTime::Zero()) { - } - QuicTime send_time; - QuicTime last_receive_time; - }; - - // Update the statistics with the absolute receive time relative to the - // absolute send time. - void UpdateSendReceiveTimeOffset(QuicTime::Delta offset); - - // Update the filter with this new data point. - void UpdateFilter(QuicTime::Delta received_delta, - QuicTime::Delta sent_delta); - - // Update the estimate with this residual. - void UpdateDeltaEstimate(QuicTime::Delta residual); - - // Estimate the state based on the slope of the changes. - void DetectSlope(int64 sigma_delta); - - // Estimate the state based on the accumulated drift of the changes. - void DetectDrift(int64 sigma_delta); - - // Current grouping of packets that were sent at the same time. - PacketGroup current_packet_group_; - // Grouping of packets that were sent at the same time, just before the - // current_packet_group_ above. - PacketGroup previous_packet_group_; - // Sequence number of the last acknowledged packet. - QuicPacketSequenceNumber last_sequence_number_; - // Number of received delta times with unique send time. - int num_of_deltas_; - // Estimated accumulation of received delta times. - // Note: Can be negative and can drift over time which is why we bias it - // towards 0 and reset it given some triggers. - QuicTime::Delta accumulated_deltas_; - // Current running mean of our received delta times. - int delta_mean_; - // Current running variance of our received delta times. - int64 delta_variance_; - // Number of overuse signals currently triggered in this state. - // Note: negative represent underuse. - int delta_overuse_counter_; - // State estimated by the delta times. - BandwidthUsage delta_estimate_; - // Number of overuse signals currently triggered in this state. - // Note: negative represent underuse. - int slope_overuse_counter_; - // State estimated by the slope of the delta times. - BandwidthUsage slope_estimate_; - // Lowest offset between send and receive time ever received in this session. - QuicTime::Delta send_receive_offset_; - // Last received time difference between our normalized send and receive time. - QuicTime::Delta estimated_congestion_delay_; - - DISALLOW_COPY_AND_ASSIGN(InterArrivalOveruseDetector); -}; - -} // namespace net - -#endif // NET_QUIC_CONGESTION_CONTROL_INTER_ARRIVAL_OVERUSE_DETECTOR_H_ |