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1a21e49a8d
This patch * resolves a bug where packets smaller than 32/64 bytes resulted in sending rates of 0 * supports all sending rates from 1/64 bytes/second up to 4Gbyte/second * simplifies the present overflow problems in calculations Current sending rate X and the cached value X_recv of the receiver-estimated sending rate are both scaled by 64 (2^6) in order to * cope with low sending rates (minimally 1 byte/second) * allow upgrading to use a packets-per-second implementation of CCID 3 * avoid calculation errors due to integer arithmetic cut-off The patch implements a revised strategy from http://www.mail-archive.com/dccp@vger.kernel.org/msg01040.html The only difference with regard to that strategy is that t_ipi is already used in the calculation of the nofeedback timeout, which saves one division. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk> Acked-by: Ian McDonald <ian.mcdonald@jandi.co.nz> Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
56 lines
1.9 KiB
C
56 lines
1.9 KiB
C
#ifndef _LINUX_TFRC_H_
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#define _LINUX_TFRC_H_
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/*
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* TFRC - Data Structures for the TCP-Friendly Rate Control congestion
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* control mechanism as specified in RFC 3448.
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*
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* Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
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* Copyright (c) 2005 Ian McDonald <iam4@cs.waikato.ac.nz>
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* Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
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* Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#include <linux/types.h>
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/** tfrc_rx_info - TFRC Receiver Data Structure
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*
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* @tfrcrx_x_recv: receiver estimate of sending rate (3.2.2)
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* @tfrcrx_rtt: round-trip-time (communicated by sender)
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* @tfrcrx_p: current estimate of loss event rate (3.2.2)
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*/
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struct tfrc_rx_info {
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__u32 tfrcrx_x_recv;
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__u32 tfrcrx_rtt;
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__u32 tfrcrx_p;
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};
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/** tfrc_tx_info - TFRC Sender Data Structure
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*
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* @tfrctx_x: computed transmit rate (4.3 (4))
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* @tfrctx_x_recv: receiver estimate of send rate (4.3)
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* @tfrctx_x_calc: return value of throughput equation (3.1)
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* @tfrctx_rtt: (moving average) estimate of RTT (4.3)
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* @tfrctx_p: current loss event rate (5.4)
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* @tfrctx_rto: estimate of RTO, equals 4*RTT (4.3)
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* @tfrctx_ipi: inter-packet interval (4.6)
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*
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* Note: X and X_recv are both maintained in units of 64 * bytes/second. This
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* enables a finer resolution of sending rates and avoids problems with
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* integer arithmetic; u32 is not sufficient as scaling consumes 6 bits.
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*/
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struct tfrc_tx_info {
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__u64 tfrctx_x;
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__u64 tfrctx_x_recv;
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__u32 tfrctx_x_calc;
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__u32 tfrctx_rtt;
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__u32 tfrctx_p;
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__u32 tfrctx_rto;
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__u32 tfrctx_ipi;
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};
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#endif /* _LINUX_TFRC_H_ */
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