003 File Manager
Current Path:
/usr/src/sys/netinet/cc
usr
/
src
/
sys
/
netinet
/
cc
/
📁
..
📄
cc.c
(8.92 KB)
📄
cc.h
(6.88 KB)
📄
cc_cdg.c
(23.51 KB)
📄
cc_chd.c
(13.87 KB)
📄
cc_cubic.c
(14.72 KB)
📄
cc_cubic.h
(7.43 KB)
📄
cc_dctcp.c
(13.21 KB)
📄
cc_hd.c
(7.42 KB)
📄
cc_htcp.c
(16.62 KB)
📄
cc_module.h
(2.92 KB)
📄
cc_newreno.c
(12.15 KB)
📄
cc_newreno.h
(1.57 KB)
📄
cc_vegas.c
(8.89 KB)
Editing: cc_cdg.c
/*- * SPDX-License-Identifier: BSD-2-Clause-FreeBSD * * Copyright (c) 2009-2013 * Swinburne University of Technology, Melbourne, Australia * All rights reserved. * * This software was developed at the Centre for Advanced Internet * Architectures, Swinburne University of Technology, by David Hayes, made * possible in part by a gift from The Cisco University Research Program Fund, * a corporate advised fund of Silicon Valley Community Foundation. Development * and testing were further assisted by a grant from the FreeBSD Foundation. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ /* * CAIA Delay-Gradient (CDG) congestion control algorithm * * An implemention of the delay-gradient congestion control algorithm proposed * in the following paper: * * D. A. Hayes and G. Armitage, "Revisiting TCP Congestion Control using Delay * Gradients", in IFIP Networking, Valencia, Spain, 9-13 May 2011. * * Developed as part of the NewTCP research project at Swinburne University of * Technology's Centre for Advanced Internet Architectures, Melbourne, * Australia. More details are available at: * http://caia.swin.edu.au/urp/newtcp/ */ #include <sys/cdefs.h> __FBSDID("$FreeBSD$"); #include <sys/param.h> #include <sys/hhook.h> #include <sys/kernel.h> #include <sys/khelp.h> #include <sys/limits.h> #include <sys/lock.h> #include <sys/malloc.h> #include <sys/module.h> #include <sys/queue.h> #include <sys/socket.h> #include <sys/socketvar.h> #include <sys/sysctl.h> #include <sys/systm.h> #include <net/vnet.h> #include <netinet/tcp.h> #include <netinet/tcp_seq.h> #include <netinet/tcp_timer.h> #include <netinet/tcp_var.h> #include <netinet/cc/cc.h> #include <netinet/cc/cc_module.h> #include <netinet/khelp/h_ertt.h> #include <vm/uma.h> #define CDG_VERSION "0.1" /* Private delay-gradient induced congestion control signal. */ #define CC_CDG_DELAY 0x01000000 /* NewReno window deflation factor on loss (as a percentage). */ #define RENO_BETA 50 /* Queue states. */ #define CDG_Q_EMPTY 1 #define CDG_Q_RISING 2 #define CDG_Q_FALLING 3 #define CDG_Q_FULL 4 #define CDG_Q_UNKNOWN 9999 /* Number of bit shifts used in probexp lookup table. */ #define EXP_PREC 15 /* Largest gradient represented in probexp lookup table. */ #define MAXGRAD 5 /* * Delay Precision Enhance - number of bit shifts used for qtrend related * integer arithmetic precision. */ #define D_P_E 7 struct qdiff_sample { long qdiff; STAILQ_ENTRY(qdiff_sample) qdiff_lnk; }; struct cdg { long max_qtrend; long min_qtrend; STAILQ_HEAD(minrtts_head, qdiff_sample) qdiffmin_q; STAILQ_HEAD(maxrtts_head, qdiff_sample) qdiffmax_q; long window_incr; /* rttcount for window increase when in congestion avoidance */ long rtt_count; /* maximum measured rtt within an rtt period */ int maxrtt_in_rtt; /* maximum measured rtt within prev rtt period */ int maxrtt_in_prevrtt; /* minimum measured rtt within an rtt period */ int minrtt_in_rtt; /* minimum measured rtt within prev rtt period */ int minrtt_in_prevrtt; /* consecutive congestion episode counter */ uint32_t consec_cong_cnt; /* when tracking a new reno type loss window */ uint32_t shadow_w; /* maximum number of samples in the moving average queue */ int sample_q_size; /* number of samples in the moving average queue */ int num_samples; /* estimate of the queue state of the path */ int queue_state; }; /* * Lookup table for: * (1 - exp(-x)) << EXP_PREC, where x = [0,MAXGRAD] in 2^-7 increments * * Note: probexp[0] is set to 10 (not 0) as a safety for very low increase * gradients. */ static const int probexp[641] = { 10,255,508,759,1008,1255,1501,1744,1985,2225,2463,2698,2932,3165,3395,3624, 3850,4075,4299,4520,4740,4958,5175,5389,5602,5814,6024,6232,6438,6643,6846, 7048,7248,7447,7644,7839,8033,8226,8417,8606,8794,8981,9166,9350,9532,9713, 9892,10070,10247,10422,10596,10769,10940,11110,11278,11445,11611,11776,11939, 12101,12262,12422,12580,12737,12893,13048,13201,13354,13505,13655,13803,13951, 14097,14243,14387,14530,14672,14813,14952,15091,15229,15365,15500,15635,15768, 15900,16032,16162,16291,16419,16547,16673,16798,16922,17046,17168,17289,17410, 17529,17648,17766,17882,17998,18113,18227,18340,18453,18564,18675,18784,18893, 19001,19108,19215,19320,19425,19529,19632,19734,19835,19936,20036,20135,20233, 20331,20427,20523,20619,20713,20807,20900,20993,21084,21175,21265,21355,21444, 21532,21619,21706,21792,21878,21962,22046,22130,22213,22295,22376,22457,22537, 22617,22696,22774,22852,22929,23006,23082,23157,23232,23306,23380,23453,23525, 23597,23669,23739,23810,23879,23949,24017,24085,24153,24220,24286,24352,24418, 24483,24547,24611,24675,24738,24800,24862,24924,24985,25045,25106,25165,25224, 25283,25341,25399,25456,25513,25570,25626,25681,25737,25791,25846,25899,25953, 26006,26059,26111,26163,26214,26265,26316,26366,26416,26465,26514,26563,26611, 26659,26707,26754,26801,26847,26893,26939,26984,27029,27074,27118,27162,27206, 27249,27292,27335,27377,27419,27460,27502,27543,27583,27624,27664,27703,27743, 27782,27821,27859,27897,27935,27973,28010,28047,28084,28121,28157,28193,28228, 28263,28299,28333,28368,28402,28436,28470,28503,28536,28569,28602,28634,28667, 28699,28730,28762,28793,28824,28854,28885,28915,28945,28975,29004,29034,29063, 29092,29120,29149,29177,29205,29232,29260,29287,29314,29341,29368,29394,29421, 29447,29472,29498,29524,29549,29574,29599,29623,29648,29672,29696,29720,29744, 29767,29791,29814,29837,29860,29882,29905,29927,29949,29971,29993,30014,30036, 30057,30078,30099,30120,30141,30161,30181,30201,30221,30241,30261,30280,30300, 30319,30338,30357,30376,30394,30413,30431,30449,30467,30485,30503,30521,30538, 30555,30573,30590,30607,30624,30640,30657,30673,30690,30706,30722,30738,30753, 30769,30785,30800,30815,30831,30846,30861,30876,30890,30905,30919,30934,30948, 30962,30976,30990,31004,31018,31031,31045,31058,31072,31085,31098,31111,31124, 31137,31149,31162,31174,31187,31199,31211,31223,31235,31247,31259,31271,31283, 31294,31306,31317,31328,31339,31351,31362,31373,31383,31394,31405,31416,31426, 31436,31447,31457,31467,31477,31487,31497,31507,31517,31527,31537,31546,31556, 31565,31574,31584,31593,31602,31611,31620,31629,31638,31647,31655,31664,31673, 31681,31690,31698,31706,31715,31723,31731,31739,31747,31755,31763,31771,31778, 31786,31794,31801,31809,31816,31824,31831,31838,31846,31853,31860,31867,31874, 31881,31888,31895,31902,31908,31915,31922,31928,31935,31941,31948,31954,31960, 31967,31973,31979,31985,31991,31997,32003,32009,32015,32021,32027,32033,32038, 32044,32050,32055,32061,32066,32072,32077,32083,32088,32093,32098,32104,32109, 32114,32119,32124,32129,32134,32139,32144,32149,32154,32158,32163,32168,32173, 32177,32182,32186,32191,32195,32200,32204,32209,32213,32217,32222,32226,32230, 32234,32238,32242,32247,32251,32255,32259,32263,32267,32270,32274,32278,32282, 32286,32290,32293,32297,32301,32304,32308,32311,32315,32318,32322,32325,32329, 32332,32336,32339,32342,32346,32349,32352,32356,32359,32362,32365,32368,32371, 32374,32377,32381,32384,32387,32389,32392,32395,32398,32401,32404,32407,32410, 32412,32415,32418,32421,32423,32426,32429,32431,32434,32437,32439,32442,32444, 32447,32449,32452,32454,32457,32459,32461,32464,32466,32469,32471,32473,32476, 32478,32480,32482,32485,32487,32489,32491,32493,32495,32497,32500,32502,32504, 32506,32508,32510,32512,32514,32516,32518,32520,32522,32524,32526,32527,32529, 32531,32533,32535,32537,32538,32540,32542,32544,32545,32547}; static uma_zone_t qdiffsample_zone; static MALLOC_DEFINE(M_CDG, "cdg data", "Per connection data required for the CDG congestion control algorithm"); static int ertt_id; VNET_DEFINE_STATIC(uint32_t, cdg_alpha_inc); VNET_DEFINE_STATIC(uint32_t, cdg_beta_delay); VNET_DEFINE_STATIC(uint32_t, cdg_beta_loss); VNET_DEFINE_STATIC(uint32_t, cdg_smoothing_factor); VNET_DEFINE_STATIC(uint32_t, cdg_exp_backoff_scale); VNET_DEFINE_STATIC(uint32_t, cdg_consec_cong); VNET_DEFINE_STATIC(uint32_t, cdg_hold_backoff); #define V_cdg_alpha_inc VNET(cdg_alpha_inc) #define V_cdg_beta_delay VNET(cdg_beta_delay) #define V_cdg_beta_loss VNET(cdg_beta_loss) #define V_cdg_smoothing_factor VNET(cdg_smoothing_factor) #define V_cdg_exp_backoff_scale VNET(cdg_exp_backoff_scale) #define V_cdg_consec_cong VNET(cdg_consec_cong) #define V_cdg_hold_backoff VNET(cdg_hold_backoff) /* Function prototypes. */ static int cdg_mod_init(void); static int cdg_mod_destroy(void); static void cdg_conn_init(struct cc_var *ccv); static int cdg_cb_init(struct cc_var *ccv); static void cdg_cb_destroy(struct cc_var *ccv); static void cdg_cong_signal(struct cc_var *ccv, uint32_t signal_type); static void cdg_ack_received(struct cc_var *ccv, uint16_t ack_type); struct cc_algo cdg_cc_algo = { .name = "cdg", .mod_init = cdg_mod_init, .ack_received = cdg_ack_received, .cb_destroy = cdg_cb_destroy, .cb_init = cdg_cb_init, .conn_init = cdg_conn_init, .cong_signal = cdg_cong_signal, .mod_destroy = cdg_mod_destroy }; /* Vnet created and being initialised. */ static void cdg_init_vnet(const void *unused __unused) { V_cdg_alpha_inc = 0; V_cdg_beta_delay = 70; V_cdg_beta_loss = 50; V_cdg_smoothing_factor = 8; V_cdg_exp_backoff_scale = 3; V_cdg_consec_cong = 5; V_cdg_hold_backoff = 5; } static int cdg_mod_init(void) { VNET_ITERATOR_DECL(v); ertt_id = khelp_get_id("ertt"); if (ertt_id <= 0) return (EINVAL); qdiffsample_zone = uma_zcreate("cdg_qdiffsample", sizeof(struct qdiff_sample), NULL, NULL, NULL, NULL, 0, 0); VNET_LIST_RLOCK(); VNET_FOREACH(v) { CURVNET_SET(v); cdg_init_vnet(NULL); CURVNET_RESTORE(); } VNET_LIST_RUNLOCK(); cdg_cc_algo.post_recovery = newreno_cc_algo.post_recovery; cdg_cc_algo.after_idle = newreno_cc_algo.after_idle; return (0); } static int cdg_mod_destroy(void) { uma_zdestroy(qdiffsample_zone); return (0); } static int cdg_cb_init(struct cc_var *ccv) { struct cdg *cdg_data; cdg_data = malloc(sizeof(struct cdg), M_CDG, M_NOWAIT); if (cdg_data == NULL) return (ENOMEM); cdg_data->shadow_w = 0; cdg_data->max_qtrend = 0; cdg_data->min_qtrend = 0; cdg_data->queue_state = CDG_Q_UNKNOWN; cdg_data->maxrtt_in_rtt = 0; cdg_data->maxrtt_in_prevrtt = 0; cdg_data->minrtt_in_rtt = INT_MAX; cdg_data->minrtt_in_prevrtt = 0; cdg_data->window_incr = 0; cdg_data->rtt_count = 0; cdg_data->consec_cong_cnt = 0; cdg_data->sample_q_size = V_cdg_smoothing_factor; cdg_data->num_samples = 0; STAILQ_INIT(&cdg_data->qdiffmin_q); STAILQ_INIT(&cdg_data->qdiffmax_q); ccv->cc_data = cdg_data; return (0); } static void cdg_conn_init(struct cc_var *ccv) { struct cdg *cdg_data = ccv->cc_data; /* * Initialise the shadow_cwnd in case we are competing with loss based * flows from the start */ cdg_data->shadow_w = CCV(ccv, snd_cwnd); } static void cdg_cb_destroy(struct cc_var *ccv) { struct cdg *cdg_data; struct qdiff_sample *qds, *qds_n; cdg_data = ccv->cc_data; qds = STAILQ_FIRST(&cdg_data->qdiffmin_q); while (qds != NULL) { qds_n = STAILQ_NEXT(qds, qdiff_lnk); uma_zfree(qdiffsample_zone,qds); qds = qds_n; } qds = STAILQ_FIRST(&cdg_data->qdiffmax_q); while (qds != NULL) { qds_n = STAILQ_NEXT(qds, qdiff_lnk); uma_zfree(qdiffsample_zone,qds); qds = qds_n; } free(ccv->cc_data, M_CDG); } static int cdg_beta_handler(SYSCTL_HANDLER_ARGS) { int error; uint32_t new; new = *(uint32_t *)arg1; error = sysctl_handle_int(oidp, &new, 0, req); if (error == 0 && req->newptr != NULL) { if (new == 0 || new > 100) error = EINVAL; else *(uint32_t *)arg1 = new; } return (error); } static int cdg_exp_backoff_scale_handler(SYSCTL_HANDLER_ARGS) { int error; uint32_t new; new = *(uint32_t *)arg1; error = sysctl_handle_int(oidp, &new, 0, req); if (error == 0 && req->newptr != NULL) { if (new < 1) error = EINVAL; else *(uint32_t *)arg1 = new; } return (error); } static inline uint32_t cdg_window_decrease(struct cc_var *ccv, unsigned long owin, unsigned int beta) { return ((ulmin(CCV(ccv, snd_wnd), owin) * beta) / 100); } /* * Window increase function * This window increase function is independent of the initial window size * to ensure small window flows are not discriminated against (i.e. fairness). * It increases at 1pkt/rtt like Reno for alpha_inc rtts, and then 2pkts/rtt for * the next alpha_inc rtts, etc. */ static void cdg_window_increase(struct cc_var *ccv, int new_measurement) { struct cdg *cdg_data; int incr, s_w_incr; cdg_data = ccv->cc_data; incr = s_w_incr = 0; if (CCV(ccv, snd_cwnd) <= CCV(ccv, snd_ssthresh)) { /* Slow start. */ incr = CCV(ccv, t_maxseg); s_w_incr = incr; cdg_data->window_incr = cdg_data->rtt_count = 0; } else { /* Congestion avoidance. */ if (new_measurement) { s_w_incr = CCV(ccv, t_maxseg); if (V_cdg_alpha_inc == 0) { incr = CCV(ccv, t_maxseg); } else { if (++cdg_data->rtt_count >= V_cdg_alpha_inc) { cdg_data->window_incr++; cdg_data->rtt_count = 0; } incr = CCV(ccv, t_maxseg) * cdg_data->window_incr; } } } if (cdg_data->shadow_w > 0) cdg_data->shadow_w = ulmin(cdg_data->shadow_w + s_w_incr, TCP_MAXWIN << CCV(ccv, snd_scale)); CCV(ccv, snd_cwnd) = ulmin(CCV(ccv, snd_cwnd) + incr, TCP_MAXWIN << CCV(ccv, snd_scale)); } static void cdg_cong_signal(struct cc_var *ccv, uint32_t signal_type) { struct cdg *cdg_data = ccv->cc_data; switch(signal_type) { case CC_CDG_DELAY: CCV(ccv, snd_ssthresh) = cdg_window_decrease(ccv, CCV(ccv, snd_cwnd), V_cdg_beta_delay); CCV(ccv, snd_cwnd) = CCV(ccv, snd_ssthresh); CCV(ccv, snd_recover) = CCV(ccv, snd_max); cdg_data->window_incr = cdg_data->rtt_count = 0; ENTER_CONGRECOVERY(CCV(ccv, t_flags)); break; case CC_NDUPACK: /* * If already responding to congestion OR we have guessed no * queue in the path is full. */ if (IN_CONGRECOVERY(CCV(ccv, t_flags)) || cdg_data->queue_state < CDG_Q_FULL) { CCV(ccv, snd_ssthresh) = CCV(ccv, snd_cwnd); CCV(ccv, snd_recover) = CCV(ccv, snd_max); } else { /* * Loss is likely to be congestion related. We have * inferred a queue full state, so have shadow window * react to loss as NewReno would. */ if (cdg_data->shadow_w > 0) cdg_data->shadow_w = cdg_window_decrease(ccv, cdg_data->shadow_w, RENO_BETA); CCV(ccv, snd_ssthresh) = max(cdg_data->shadow_w, cdg_window_decrease(ccv, CCV(ccv, snd_cwnd), V_cdg_beta_loss)); cdg_data->window_incr = cdg_data->rtt_count = 0; } ENTER_RECOVERY(CCV(ccv, t_flags)); break; default: newreno_cc_algo.cong_signal(ccv, signal_type); break; } } /* * Using a negative exponential probabilistic backoff so that sources with * varying RTTs which share the same link will, on average, have the same * probability of backoff over time. * * Prob_backoff = 1 - exp(-qtrend / V_cdg_exp_backoff_scale), where * V_cdg_exp_backoff_scale is the average qtrend for the exponential backoff. */ static inline int prob_backoff(long qtrend) { int backoff, idx, p; backoff = (qtrend > ((MAXGRAD * V_cdg_exp_backoff_scale) << D_P_E)); if (!backoff) { if (V_cdg_exp_backoff_scale > 1) idx = (qtrend + V_cdg_exp_backoff_scale / 2) / V_cdg_exp_backoff_scale; else idx = qtrend; /* Backoff probability proportional to rate of queue growth. */ p = (INT_MAX / (1 << EXP_PREC)) * probexp[idx]; backoff = (random() < p); } return (backoff); } static inline void calc_moving_average(struct cdg *cdg_data, long qdiff_max, long qdiff_min) { struct qdiff_sample *qds; ++cdg_data->num_samples; if (cdg_data->num_samples > cdg_data->sample_q_size) { /* Minimum RTT. */ qds = STAILQ_FIRST(&cdg_data->qdiffmin_q); cdg_data->min_qtrend = cdg_data->min_qtrend + (qdiff_min - qds->qdiff) / cdg_data->sample_q_size; STAILQ_REMOVE_HEAD(&cdg_data->qdiffmin_q, qdiff_lnk); qds->qdiff = qdiff_min; STAILQ_INSERT_TAIL(&cdg_data->qdiffmin_q, qds, qdiff_lnk); /* Maximum RTT. */ qds = STAILQ_FIRST(&cdg_data->qdiffmax_q); cdg_data->max_qtrend = cdg_data->max_qtrend + (qdiff_max - qds->qdiff) / cdg_data->sample_q_size; STAILQ_REMOVE_HEAD(&cdg_data->qdiffmax_q, qdiff_lnk); qds->qdiff = qdiff_max; STAILQ_INSERT_TAIL(&cdg_data->qdiffmax_q, qds, qdiff_lnk); --cdg_data->num_samples; } else { qds = uma_zalloc(qdiffsample_zone, M_NOWAIT); if (qds != NULL) { cdg_data->min_qtrend = cdg_data->min_qtrend + qdiff_min / cdg_data->sample_q_size; qds->qdiff = qdiff_min; STAILQ_INSERT_TAIL(&cdg_data->qdiffmin_q, qds, qdiff_lnk); } qds = uma_zalloc(qdiffsample_zone, M_NOWAIT); if (qds) { cdg_data->max_qtrend = cdg_data->max_qtrend + qdiff_max / cdg_data->sample_q_size; qds->qdiff = qdiff_max; STAILQ_INSERT_TAIL(&cdg_data->qdiffmax_q, qds, qdiff_lnk); } } } static void cdg_ack_received(struct cc_var *ccv, uint16_t ack_type) { struct cdg *cdg_data; struct ertt *e_t; long qdiff_max, qdiff_min; int congestion, new_measurement, slowstart; cdg_data = ccv->cc_data; e_t = (struct ertt *)khelp_get_osd(CCV(ccv, osd), ertt_id); new_measurement = e_t->flags & ERTT_NEW_MEASUREMENT; congestion = 0; cdg_data->maxrtt_in_rtt = imax(e_t->rtt, cdg_data->maxrtt_in_rtt); cdg_data->minrtt_in_rtt = imin(e_t->rtt, cdg_data->minrtt_in_rtt); if (new_measurement) { slowstart = (CCV(ccv, snd_cwnd) <= CCV(ccv, snd_ssthresh)); /* * Update smoothed gradient measurements. Since we are only * using one measurement per RTT, use max or min rtt_in_rtt. * This is also less noisy than a sample RTT measurement. Max * RTT measurements can have trouble due to OS issues. */ if (cdg_data->maxrtt_in_prevrtt) { qdiff_max = ((long)(cdg_data->maxrtt_in_rtt - cdg_data->maxrtt_in_prevrtt) << D_P_E ); qdiff_min = ((long)(cdg_data->minrtt_in_rtt - cdg_data->minrtt_in_prevrtt) << D_P_E ); if (cdg_data->sample_q_size == 0) { cdg_data->max_qtrend = qdiff_max; cdg_data->min_qtrend = qdiff_min; } else calc_moving_average(cdg_data, qdiff_max, qdiff_min); /* Probabilistic backoff with respect to gradient. */ if (slowstart && qdiff_min > 0) congestion = prob_backoff(qdiff_min); else if (cdg_data->min_qtrend > 0) congestion = prob_backoff(cdg_data->min_qtrend); else if (slowstart && qdiff_max > 0) congestion = prob_backoff(qdiff_max); else if (cdg_data->max_qtrend > 0) congestion = prob_backoff(cdg_data->max_qtrend); /* Update estimate of queue state. */ if (cdg_data->min_qtrend > 0 && cdg_data->max_qtrend <= 0) { cdg_data->queue_state = CDG_Q_FULL; } else if (cdg_data->min_qtrend >= 0 && cdg_data->max_qtrend < 0) { cdg_data->queue_state = CDG_Q_EMPTY; cdg_data->shadow_w = 0; } else if (cdg_data->min_qtrend > 0 && cdg_data->max_qtrend > 0) { cdg_data->queue_state = CDG_Q_RISING; } else if (cdg_data->min_qtrend < 0 && cdg_data->max_qtrend < 0) { cdg_data->queue_state = CDG_Q_FALLING; } if (cdg_data->min_qtrend < 0 || cdg_data->max_qtrend < 0) cdg_data->consec_cong_cnt = 0; } cdg_data->minrtt_in_prevrtt = cdg_data->minrtt_in_rtt; cdg_data->minrtt_in_rtt = INT_MAX; cdg_data->maxrtt_in_prevrtt = cdg_data->maxrtt_in_rtt; cdg_data->maxrtt_in_rtt = 0; e_t->flags &= ~ERTT_NEW_MEASUREMENT; } if (congestion) { cdg_data->consec_cong_cnt++; if (!IN_RECOVERY(CCV(ccv, t_flags))) { if (cdg_data->consec_cong_cnt <= V_cdg_consec_cong) cdg_cong_signal(ccv, CC_CDG_DELAY); else /* * We have been backing off but the queue is not * falling. Assume we are competing with * loss-based flows and don't back off for the * next V_cdg_hold_backoff RTT periods. */ if (cdg_data->consec_cong_cnt >= V_cdg_consec_cong + V_cdg_hold_backoff) cdg_data->consec_cong_cnt = 0; /* Won't see effect until 2nd RTT. */ cdg_data->maxrtt_in_prevrtt = 0; /* * Resync shadow window in case we are competing with a * loss based flow */ cdg_data->shadow_w = ulmax(CCV(ccv, snd_cwnd), cdg_data->shadow_w); } } else if (ack_type == CC_ACK) cdg_window_increase(ccv, new_measurement); } /* When a vnet is created and being initialised, init the per-stack CDG vars. */ VNET_SYSINIT(cdg_init_vnet, SI_SUB_PROTO_BEGIN, SI_ORDER_FIRST, cdg_init_vnet, NULL); SYSCTL_DECL(_net_inet_tcp_cc_cdg); SYSCTL_NODE(_net_inet_tcp_cc, OID_AUTO, cdg, CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, "CAIA delay-gradient congestion control related settings"); SYSCTL_STRING(_net_inet_tcp_cc_cdg, OID_AUTO, version, CTLFLAG_RD, CDG_VERSION, sizeof(CDG_VERSION) - 1, "Current algorithm/implementation version number"); SYSCTL_UINT(_net_inet_tcp_cc_cdg, OID_AUTO, alpha_inc, CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(cdg_alpha_inc), 0, "Increment the window increase factor alpha by 1 MSS segment every " "alpha_inc RTTs during congestion avoidance mode."); SYSCTL_PROC(_net_inet_tcp_cc_cdg, OID_AUTO, beta_delay, CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, &VNET_NAME(cdg_beta_delay), 70, &cdg_beta_handler, "IU", "Delay-based window decrease factor as a percentage " "(on delay-based backoff, w = w * beta_delay / 100)"); SYSCTL_PROC(_net_inet_tcp_cc_cdg, OID_AUTO, beta_loss, CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, &VNET_NAME(cdg_beta_loss), 50, &cdg_beta_handler, "IU", "Loss-based window decrease factor as a percentage " "(on loss-based backoff, w = w * beta_loss / 100)"); SYSCTL_PROC(_net_inet_tcp_cc_cdg, OID_AUTO, exp_backoff_scale, CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, &VNET_NAME(cdg_exp_backoff_scale), 2, &cdg_exp_backoff_scale_handler, "IU", "Scaling parameter for the probabilistic exponential backoff"); SYSCTL_UINT(_net_inet_tcp_cc_cdg, OID_AUTO, smoothing_factor, CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(cdg_smoothing_factor), 8, "Number of samples used for moving average smoothing (0 = no smoothing)"); SYSCTL_UINT(_net_inet_tcp_cc_cdg, OID_AUTO, loss_compete_consec_cong, CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(cdg_consec_cong), 5, "Number of consecutive delay-gradient based congestion episodes which will " "trigger loss based CC compatibility"); SYSCTL_UINT(_net_inet_tcp_cc_cdg, OID_AUTO, loss_compete_hold_backoff, CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(cdg_hold_backoff), 5, "Number of consecutive delay-gradient based congestion episodes to hold " "the window backoff for loss based CC compatibility"); DECLARE_CC_MODULE(cdg, &cdg_cc_algo); MODULE_VERSION(cdg, 1); MODULE_DEPEND(cdg, ertt, 1, 1, 1);
Upload File
Create Folder