36729c1a73
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com> Signed-off-by: David S. Miller <davem@davemloft.net>
644 lines
15 KiB
C
644 lines
15 KiB
C
/*
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* net/dccp/ccids/lib/tfrc_equation.c
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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/config.h>
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#include <linux/module.h>
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#include <asm/bug.h>
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#include <asm/div64.h>
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#include "tfrc.h"
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#define TFRC_CALC_X_ARRSIZE 500
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#define TFRC_CALC_X_SPLIT 50000
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/* equivalent to 0.05 */
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static const u32 tfrc_calc_x_lookup[TFRC_CALC_X_ARRSIZE][2] = {
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{ 37172, 8172 },
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{ 53499, 11567 },
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{ 66664, 14180 },
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{ 78298, 16388 },
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{ 89021, 18339 },
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{ 99147, 20108 },
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{ 108858, 21738 },
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{ 118273, 23260 },
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{ 127474, 24693 },
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{ 136520, 26052 },
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{ 145456, 27348 },
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{ 154316, 28589 },
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{ 163130, 29783 },
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{ 171919, 30935 },
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{ 180704, 32049 },
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{ 189502, 33130 },
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{ 198328, 34180 },
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{ 207194, 35202 },
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{ 216114, 36198 },
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{ 225097, 37172 },
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{ 234153, 38123 },
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{ 243294, 39055 },
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{ 252527, 39968 },
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{ 261861, 40864 },
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{ 271305, 41743 },
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{ 280866, 42607 },
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{ 290553, 43457 },
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{ 300372, 44293 },
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{ 310333, 45117 },
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{ 320441, 45929 },
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{ 330705, 46729 },
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{ 341131, 47518 },
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{ 351728, 48297 },
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{ 362501, 49066 },
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{ 373460, 49826 },
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{ 384609, 50577 },
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{ 395958, 51320 },
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{ 407513, 52054 },
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{ 419281, 52780 },
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{ 431270, 53499 },
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{ 443487, 54211 },
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{ 455940, 54916 },
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{ 468635, 55614 },
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{ 481581, 56306 },
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{ 494785, 56991 },
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{ 508254, 57671 },
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{ 521996, 58345 },
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{ 536019, 59014 },
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{ 550331, 59677 },
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{ 564939, 60335 },
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{ 579851, 60988 },
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{ 595075, 61636 },
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{ 610619, 62279 },
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{ 626491, 62918 },
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{ 642700, 63553 },
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{ 659253, 64183 },
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{ 676158, 64809 },
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{ 693424, 65431 },
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{ 711060, 66050 },
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{ 729073, 66664 },
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{ 747472, 67275 },
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{ 766266, 67882 },
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{ 785464, 68486 },
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{ 805073, 69087 },
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{ 825103, 69684 },
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{ 845562, 70278 },
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{ 866460, 70868 },
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{ 887805, 71456 },
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{ 909606, 72041 },
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{ 931873, 72623 },
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{ 954614, 73202 },
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{ 977839, 73778 },
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{ 1001557, 74352 },
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{ 1025777, 74923 },
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{ 1050508, 75492 },
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{ 1075761, 76058 },
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{ 1101544, 76621 },
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{ 1127867, 77183 },
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{ 1154739, 77741 },
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{ 1182172, 78298 },
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{ 1210173, 78852 },
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{ 1238753, 79405 },
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{ 1267922, 79955 },
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{ 1297689, 80503 },
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{ 1328066, 81049 },
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{ 1359060, 81593 },
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{ 1390684, 82135 },
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{ 1422947, 82675 },
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{ 1455859, 83213 },
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{ 1489430, 83750 },
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{ 1523671, 84284 },
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{ 1558593, 84817 },
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{ 1594205, 85348 },
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{ 1630518, 85878 },
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{ 1667543, 86406 },
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{ 1705290, 86932 },
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{ 1743770, 87457 },
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{ 1782994, 87980 },
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{ 1822973, 88501 },
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{ 1863717, 89021 },
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{ 1905237, 89540 },
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{ 1947545, 90057 },
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{ 1990650, 90573 },
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{ 2034566, 91087 },
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{ 2079301, 91600 },
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{ 2124869, 92111 },
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{ 2171279, 92622 },
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{ 2218543, 93131 },
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{ 2266673, 93639 },
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{ 2315680, 94145 },
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{ 2365575, 94650 },
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{ 2416371, 95154 },
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{ 2468077, 95657 },
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{ 2520707, 96159 },
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{ 2574271, 96660 },
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{ 2628782, 97159 },
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{ 2684250, 97658 },
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{ 2740689, 98155 },
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{ 2798110, 98651 },
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{ 2856524, 99147 },
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{ 2915944, 99641 },
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{ 2976382, 100134 },
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{ 3037850, 100626 },
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{ 3100360, 101117 },
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{ 3163924, 101608 },
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{ 3228554, 102097 },
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{ 3294263, 102586 },
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{ 3361063, 103073 },
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{ 3428966, 103560 },
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{ 3497984, 104045 },
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{ 3568131, 104530 },
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{ 3639419, 105014 },
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{ 3711860, 105498 },
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{ 3785467, 105980 },
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{ 3860253, 106462 },
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{ 3936229, 106942 },
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{ 4013410, 107422 },
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{ 4091808, 107902 },
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{ 4171435, 108380 },
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{ 4252306, 108858 },
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{ 4334431, 109335 },
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{ 4417825, 109811 },
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{ 4502501, 110287 },
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{ 4588472, 110762 },
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{ 4675750, 111236 },
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{ 4764349, 111709 },
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{ 4854283, 112182 },
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{ 4945564, 112654 },
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{ 5038206, 113126 },
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{ 5132223, 113597 },
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{ 5227627, 114067 },
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{ 5324432, 114537 },
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{ 5422652, 115006 },
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{ 5522299, 115474 },
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{ 5623389, 115942 },
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{ 5725934, 116409 },
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{ 5829948, 116876 },
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{ 5935446, 117342 },
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{ 6042439, 117808 },
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{ 6150943, 118273 },
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{ 6260972, 118738 },
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{ 6372538, 119202 },
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{ 6485657, 119665 },
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{ 6600342, 120128 },
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{ 6716607, 120591 },
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{ 6834467, 121053 },
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{ 6953935, 121514 },
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{ 7075025, 121976 },
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{ 7197752, 122436 },
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{ 7322131, 122896 },
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{ 7448175, 123356 },
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{ 7575898, 123815 },
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{ 7705316, 124274 },
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{ 7836442, 124733 },
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{ 7969291, 125191 },
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{ 8103877, 125648 },
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{ 8240216, 126105 },
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{ 8378321, 126562 },
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{ 8518208, 127018 },
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{ 8659890, 127474 },
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{ 8803384, 127930 },
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{ 8948702, 128385 },
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{ 9095861, 128840 },
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{ 9244875, 129294 },
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{ 9395760, 129748 },
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{ 9548529, 130202 },
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{ 9703198, 130655 },
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{ 9859782, 131108 },
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{ 10018296, 131561 },
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{ 10178755, 132014 },
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{ 10341174, 132466 },
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{ 10505569, 132917 },
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{ 10671954, 133369 },
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{ 10840345, 133820 },
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{ 11010757, 134271 },
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{ 11183206, 134721 },
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{ 11357706, 135171 },
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{ 11534274, 135621 },
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{ 11712924, 136071 },
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{ 11893673, 136520 },
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{ 12076536, 136969 },
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{ 12261527, 137418 },
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{ 12448664, 137867 },
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{ 12637961, 138315 },
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{ 12829435, 138763 },
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{ 13023101, 139211 },
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{ 13218974, 139658 },
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{ 13417071, 140106 },
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{ 13819999, 140999 },
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{ 14024862, 141446 },
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{ 14232012, 141892 },
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{ 14441465, 142339 },
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{ 14653238, 142785 },
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{ 14867346, 143230 },
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{ 15083805, 143676 },
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{ 15302632, 144121 },
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{ 15523842, 144566 },
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{ 15747453, 145011 },
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{ 15973479, 145456 },
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{ 16201939, 145900 },
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{ 16432847, 146345 },
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{ 16666221, 146789 },
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{ 16902076, 147233 },
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{ 17140429, 147677 },
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{ 17381297, 148121 },
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{ 17624696, 148564 },
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{ 17870643, 149007 },
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{ 18119154, 149451 },
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{ 18370247, 149894 },
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{ 18623936, 150336 },
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{ 18880241, 150779 },
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{ 19139176, 151222 },
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{ 19400759, 151664 },
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{ 19665007, 152107 },
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{ 19931936, 152549 },
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{ 20201564, 152991 },
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{ 20473907, 153433 },
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{ 20748982, 153875 },
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{ 21026807, 154316 },
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{ 21307399, 154758 },
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{ 21590773, 155199 },
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{ 21876949, 155641 },
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{ 22165941, 156082 },
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{ 22457769, 156523 },
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{ 22752449, 156964 },
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{ 23049999, 157405 },
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{ 23350435, 157846 },
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{ 23653774, 158287 },
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{ 23960036, 158727 },
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{ 24896521, 160049 },
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{ 27187165, 163130 },
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{ 37937673, 175433 },
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{ 38371773, 175872 },
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{ 178857621, 251136 },
|
|
{ 180197813, 251599 },
|
|
{ 181545242, 252063 },
|
|
{ 182899933, 252527 },
|
|
{ 184261908, 252991 },
|
|
{ 185631191, 253456 },
|
|
{ 187007807, 253920 },
|
|
{ 188391778, 254385 },
|
|
{ 189783129, 254851 },
|
|
{ 191181884, 255316 },
|
|
{ 192588065, 255782 },
|
|
{ 194001698, 256248 },
|
|
{ 195422805, 256714 },
|
|
{ 196851411, 257181 },
|
|
{ 198287540, 257648 },
|
|
{ 199731215, 258115 },
|
|
{ 201182461, 258582 },
|
|
{ 202641302, 259050 },
|
|
{ 204107760, 259518 },
|
|
{ 205581862, 259986 },
|
|
{ 207063630, 260454 },
|
|
{ 208553088, 260923 },
|
|
{ 210050262, 261392 },
|
|
{ 211555174, 261861 },
|
|
{ 213067849, 262331 },
|
|
{ 214588312, 262800 },
|
|
{ 216116586, 263270 },
|
|
{ 217652696, 263741 },
|
|
{ 219196666, 264211 },
|
|
{ 220748520, 264682 },
|
|
{ 222308282, 265153 },
|
|
{ 223875978, 265625 },
|
|
{ 225451630, 266097 },
|
|
{ 227035265, 266569 },
|
|
{ 228626905, 267041 },
|
|
{ 230226576, 267514 },
|
|
{ 231834302, 267986 },
|
|
{ 233450107, 268460 },
|
|
{ 235074016, 268933 },
|
|
{ 236706054, 269407 },
|
|
{ 238346244, 269881 },
|
|
{ 239994613, 270355 },
|
|
{ 241651183, 270830 },
|
|
{ 243315981, 271305 }
|
|
};
|
|
|
|
/* Calculate the send rate as per section 3.1 of RFC3448
|
|
|
|
Returns send rate in bytes per second
|
|
|
|
Integer maths and lookups are used as not allowed floating point in kernel
|
|
|
|
The function for Xcalc as per section 3.1 of RFC3448 is:
|
|
|
|
X = s
|
|
-------------------------------------------------------------
|
|
R*sqrt(2*b*p/3) + (t_RTO * (3*sqrt(3*b*p/8) * p * (1+32*p^2)))
|
|
|
|
where
|
|
X is the trasmit rate in bytes/second
|
|
s is the packet size in bytes
|
|
R is the round trip time in seconds
|
|
p is the loss event rate, between 0 and 1.0, of the number of loss events
|
|
as a fraction of the number of packets transmitted
|
|
t_RTO is the TCP retransmission timeout value in seconds
|
|
b is the number of packets acknowledged by a single TCP acknowledgement
|
|
|
|
we can assume that b = 1 and t_RTO is 4 * R. With this the equation becomes:
|
|
|
|
X = s
|
|
-----------------------------------------------------------------------
|
|
R * sqrt(2 * p / 3) + (12 * R * (sqrt(3 * p / 8) * p * (1 + 32 * p^2)))
|
|
|
|
|
|
which we can break down into:
|
|
|
|
X = s
|
|
--------
|
|
R * f(p)
|
|
|
|
where f(p) = sqrt(2 * p / 3) + (12 * sqrt(3 * p / 8) * p * (1 + 32 * p * p))
|
|
|
|
Function parameters:
|
|
s - bytes
|
|
R - RTT in usecs
|
|
p - loss rate (decimal fraction multiplied by 1,000,000)
|
|
|
|
Returns Xcalc in bytes per second
|
|
|
|
DON'T alter this code unless you run test cases against it as the code
|
|
has been manipulated to stop underflow/overlow.
|
|
|
|
*/
|
|
u32 tfrc_calc_x(u16 s, u32 R, u32 p)
|
|
{
|
|
int index;
|
|
u32 f;
|
|
u64 tmp1, tmp2;
|
|
|
|
if (p < TFRC_CALC_X_SPLIT)
|
|
index = (p / (TFRC_CALC_X_SPLIT / TFRC_CALC_X_ARRSIZE)) - 1;
|
|
else
|
|
index = (p / (1000000 / TFRC_CALC_X_ARRSIZE)) - 1;
|
|
|
|
if (index < 0)
|
|
/* p should be 0 unless there is a bug in my code */
|
|
index = 0;
|
|
|
|
if (R == 0)
|
|
R = 1; /* RTT can't be zero or else divide by zero */
|
|
|
|
BUG_ON(index >= TFRC_CALC_X_ARRSIZE);
|
|
|
|
if (p >= TFRC_CALC_X_SPLIT)
|
|
f = tfrc_calc_x_lookup[index][0];
|
|
else
|
|
f = tfrc_calc_x_lookup[index][1];
|
|
|
|
tmp1 = ((u64)s * 100000000);
|
|
tmp2 = ((u64)R * (u64)f);
|
|
do_div(tmp2, 10000);
|
|
do_div(tmp1, tmp2);
|
|
/* Don't alter above math unless you test due to overflow on 32 bit */
|
|
|
|
return (u32)tmp1;
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(tfrc_calc_x);
|
|
|
|
/*
|
|
* args: fvalue - function value to match
|
|
* returns: p closest to that value
|
|
*
|
|
* both fvalue and p are multiplied by 1,000,000 to use ints
|
|
*/
|
|
u32 tfrc_calc_x_reverse_lookup(u32 fvalue)
|
|
{
|
|
int ctr = 0;
|
|
int small;
|
|
|
|
if (fvalue < tfrc_calc_x_lookup[0][1])
|
|
return 0;
|
|
|
|
if (fvalue <= tfrc_calc_x_lookup[TFRC_CALC_X_ARRSIZE - 1][1])
|
|
small = 1;
|
|
else if (fvalue > tfrc_calc_x_lookup[TFRC_CALC_X_ARRSIZE - 1][0])
|
|
return 1000000;
|
|
else
|
|
small = 0;
|
|
|
|
while (fvalue > tfrc_calc_x_lookup[ctr][small])
|
|
ctr++;
|
|
|
|
if (small)
|
|
return TFRC_CALC_X_SPLIT * ctr / TFRC_CALC_X_ARRSIZE;
|
|
else
|
|
return 1000000 * ctr / TFRC_CALC_X_ARRSIZE;
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(tfrc_calc_x_reverse_lookup);
|