1/*-
2 * Copyright (c) 2009-2010
3 * Swinburne University of Technology, Melbourne, Australia
4 * Copyright (c) 2010 Lawrence Stewart <lstewart@freebsd.org>
5 * Copyright (c) 2010-2011 The FreeBSD Foundation
6 * All rights reserved.
7 *
8 * This software was developed at the Centre for Advanced Internet
9 * Architectures, Swinburne University of Technology, by David Hayes and
10 * Lawrence Stewart, made possible in part by a grant from the Cisco University
11 * Research Program Fund at Community Foundation Silicon Valley.
12 *
13 * Portions of this software were developed at the Centre for Advanced Internet
14 * Architectures, Swinburne University of Technology, Melbourne, Australia by
15 * David Hayes under sponsorship from the FreeBSD Foundation.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions
19 * are met:
20 * 1. Redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer.
22 * 2. Redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 */
38
39/*
40 * An implementation of the Vegas congestion control algorithm for FreeBSD,
41 * based on L. S. Brakmo and L. L. Peterson, "TCP Vegas: end to end congestion
42 * avoidance on a global internet", IEEE J. Sel. Areas Commun., vol. 13, no. 8,
43 * pp. 1465-1480, Oct. 1995. The original Vegas duplicate ack policy has not
44 * been implemented, since clock ticks are not as coarse as they were (i.e.
45 * 500ms) when Vegas was designed. Also, packets are timed once per RTT as in
46 * the original paper.
47 *
48 * Originally released as part of the NewTCP research project at Swinburne
49 * University of Technology's Centre for Advanced Internet Architectures,
50 * Melbourne, Australia, which was made possible in part by a grant from the
51 * Cisco University Research Program Fund at Community Foundation Silicon
52 * Valley. More details are available at:
53 * http://caia.swin.edu.au/urp/newtcp/
54 */
55
56#include <sys/cdefs.h>
| 1/*-
2 * Copyright (c) 2009-2010
3 * Swinburne University of Technology, Melbourne, Australia
4 * Copyright (c) 2010 Lawrence Stewart <lstewart@freebsd.org>
5 * Copyright (c) 2010-2011 The FreeBSD Foundation
6 * All rights reserved.
7 *
8 * This software was developed at the Centre for Advanced Internet
9 * Architectures, Swinburne University of Technology, by David Hayes and
10 * Lawrence Stewart, made possible in part by a grant from the Cisco University
11 * Research Program Fund at Community Foundation Silicon Valley.
12 *
13 * Portions of this software were developed at the Centre for Advanced Internet
14 * Architectures, Swinburne University of Technology, Melbourne, Australia by
15 * David Hayes under sponsorship from the FreeBSD Foundation.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions
19 * are met:
20 * 1. Redistributions of source code must retain the above copyright
21 * notice, this list of conditions and the following disclaimer.
22 * 2. Redistributions in binary form must reproduce the above copyright
23 * notice, this list of conditions and the following disclaimer in the
24 * documentation and/or other materials provided with the distribution.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 */
38
39/*
40 * An implementation of the Vegas congestion control algorithm for FreeBSD,
41 * based on L. S. Brakmo and L. L. Peterson, "TCP Vegas: end to end congestion
42 * avoidance on a global internet", IEEE J. Sel. Areas Commun., vol. 13, no. 8,
43 * pp. 1465-1480, Oct. 1995. The original Vegas duplicate ack policy has not
44 * been implemented, since clock ticks are not as coarse as they were (i.e.
45 * 500ms) when Vegas was designed. Also, packets are timed once per RTT as in
46 * the original paper.
47 *
48 * Originally released as part of the NewTCP research project at Swinburne
49 * University of Technology's Centre for Advanced Internet Architectures,
50 * Melbourne, Australia, which was made possible in part by a grant from the
51 * Cisco University Research Program Fund at Community Foundation Silicon
52 * Valley. More details are available at:
53 * http://caia.swin.edu.au/urp/newtcp/
54 */
55
56#include <sys/cdefs.h>
|
110 "Per connection data required for the Vegas congestion control algorithm");
111
112struct cc_algo vegas_cc_algo = {
113 .name = "vegas",
114 .ack_received = vegas_ack_received,
115 .cb_destroy = vegas_cb_destroy,
116 .cb_init = vegas_cb_init,
117 .cong_signal = vegas_cong_signal,
118 .conn_init = vegas_conn_init,
119 .mod_init = vegas_mod_init
120};
121
122/*
123 * The vegas window adjustment is done once every RTT, as indicated by the
124 * ERTT_NEW_MEASUREMENT flag. This flag is reset once the new measurment data
125 * has been used.
126 */
127static void
128vegas_ack_received(struct cc_var *ccv, uint16_t ack_type)
129{
130 struct ertt *e_t;
131 struct vegas *vegas_data;
132 long actual_tx_rate, expected_tx_rate, ndiff;
133
134 e_t = khelp_get_osd(CCV(ccv, osd), ertt_id);
135 vegas_data = ccv->cc_data;
136
137 if (e_t->flags & ERTT_NEW_MEASUREMENT) { /* Once per RTT. */
138 if (e_t->minrtt && e_t->markedpkt_rtt) {
139 expected_tx_rate = e_t->marked_snd_cwnd / e_t->minrtt;
140 actual_tx_rate = e_t->bytes_tx_in_marked_rtt /
141 e_t->markedpkt_rtt;
142 ndiff = (expected_tx_rate - actual_tx_rate) *
143 e_t->minrtt / CCV(ccv, t_maxseg);
144
145 if (ndiff < V_vegas_alpha) {
146 if (CCV(ccv, snd_cwnd) <=
147 CCV(ccv, snd_ssthresh)) {
148 vegas_data->slow_start_toggle =
149 vegas_data->slow_start_toggle ?
150 0 : 1;
151 } else {
152 vegas_data->slow_start_toggle = 0;
153 CCV(ccv, snd_cwnd) =
154 min(CCV(ccv, snd_cwnd) +
155 CCV(ccv, t_maxseg),
156 TCP_MAXWIN << CCV(ccv, snd_scale));
157 }
158 } else if (ndiff > V_vegas_beta) {
159 /* Rate-based congestion. */
160 vegas_cong_signal(ccv, CC_VEGAS_RATE);
161 vegas_data->slow_start_toggle = 0;
162 }
163 }
164 e_t->flags &= ~ERTT_NEW_MEASUREMENT;
165 }
166
167 if (vegas_data->slow_start_toggle)
168 newreno_cc_algo.ack_received(ccv, ack_type);
169}
170
171static void
172vegas_cb_destroy(struct cc_var *ccv)
173{
174
175 if (ccv->cc_data != NULL)
176 free(ccv->cc_data, M_VEGAS);
177}
178
179static int
180vegas_cb_init(struct cc_var *ccv)
181{
182 struct vegas *vegas_data;
183
184 vegas_data = malloc(sizeof(struct vegas), M_VEGAS, M_NOWAIT);
185
186 if (vegas_data == NULL)
187 return (ENOMEM);
188
189 vegas_data->slow_start_toggle = 1;
190 ccv->cc_data = vegas_data;
191
192 return (0);
193}
194
195/*
196 * If congestion has been triggered triggered by the Vegas measured rates, it is
197 * handled here, otherwise it falls back to newreno's congestion handling.
198 */
199static void
200vegas_cong_signal(struct cc_var *ccv, uint32_t signal_type)
201{
202 struct vegas *vegas_data;
203 int presignalrecov;
204
205 vegas_data = ccv->cc_data;
206
207 if (IN_RECOVERY(CCV(ccv, t_flags)))
208 presignalrecov = 1;
209 else
210 presignalrecov = 0;
211
212 switch(signal_type) {
213 case CC_VEGAS_RATE:
214 if (!IN_RECOVERY(CCV(ccv, t_flags))) {
215 CCV(ccv, snd_cwnd) = max(2 * CCV(ccv, t_maxseg),
216 CCV(ccv, snd_cwnd) - CCV(ccv, t_maxseg));
217 if (CCV(ccv, snd_cwnd) < CCV(ccv, snd_ssthresh))
218 /* Exit slow start. */
219 CCV(ccv, snd_ssthresh) = CCV(ccv, snd_cwnd);
220 }
221 break;
222
223 default:
224 newreno_cc_algo.cong_signal(ccv, signal_type);
225 }
226
227 if (IN_RECOVERY(CCV(ccv, t_flags)) && !presignalrecov)
228 vegas_data->slow_start_toggle =
229 (CCV(ccv, snd_cwnd) < CCV(ccv, snd_ssthresh)) ? 1 : 0;
230}
231
232static void
233vegas_conn_init(struct cc_var *ccv)
234{
235 struct vegas *vegas_data;
236
237 vegas_data = ccv->cc_data;
238 vegas_data->slow_start_toggle = 1;
239}
240
241static int
242vegas_mod_init(void)
243{
244
245 ertt_id = khelp_get_id("ertt");
246 if (ertt_id <= 0) {
247 printf("%s: h_ertt module not found\n", __func__);
248 return (ENOENT);
249 }
250
251 vegas_cc_algo.after_idle = newreno_cc_algo.after_idle;
252 vegas_cc_algo.post_recovery = newreno_cc_algo.post_recovery;
253
254 return (0);
255}
256
257static int
258vegas_alpha_handler(SYSCTL_HANDLER_ARGS)
259{
260 int error;
261 uint32_t new;
262
263 new = V_vegas_alpha;
264 error = sysctl_handle_int(oidp, &new, 0, req);
265 if (error == 0 && req->newptr != NULL) {
266 if (CAST_PTR_INT(req->newptr) < 1 ||
267 CAST_PTR_INT(req->newptr) > V_vegas_beta)
268 error = EINVAL;
269 else
270 V_vegas_alpha = new;
271 }
272
273 return (error);
274}
275
276static int
277vegas_beta_handler(SYSCTL_HANDLER_ARGS)
278{
279 int error;
280 uint32_t new;
281
282 new = V_vegas_beta;
283 error = sysctl_handle_int(oidp, &new, 0, req);
284 if (error == 0 && req->newptr != NULL) {
285 if (CAST_PTR_INT(req->newptr) < 1 ||
286 CAST_PTR_INT(req->newptr) < V_vegas_alpha)
287 error = EINVAL;
288 else
289 V_vegas_beta = new;
290 }
291
292 return (error);
293}
294
295SYSCTL_DECL(_net_inet_tcp_cc_vegas);
296SYSCTL_NODE(_net_inet_tcp_cc, OID_AUTO, vegas, CTLFLAG_RW, NULL,
297 "Vegas related settings");
298
299SYSCTL_VNET_PROC(_net_inet_tcp_cc_vegas, OID_AUTO, alpha,
300 CTLTYPE_UINT|CTLFLAG_RW, &VNET_NAME(vegas_alpha), 1, &vegas_alpha_handler,
301 "IU", "vegas alpha, specified as number of \"buffers\" (0 < alpha < beta)");
302
303SYSCTL_VNET_PROC(_net_inet_tcp_cc_vegas, OID_AUTO, beta,
304 CTLTYPE_UINT|CTLFLAG_RW, &VNET_NAME(vegas_beta), 3, &vegas_beta_handler,
305 "IU", "vegas beta, specified as number of \"buffers\" (0 < alpha < beta)");
306
307DECLARE_CC_MODULE(vegas, &vegas_cc_algo);
308MODULE_DEPEND(vegas, ertt, 1, 1, 1);
| 109 "Per connection data required for the Vegas congestion control algorithm");
110
111struct cc_algo vegas_cc_algo = {
112 .name = "vegas",
113 .ack_received = vegas_ack_received,
114 .cb_destroy = vegas_cb_destroy,
115 .cb_init = vegas_cb_init,
116 .cong_signal = vegas_cong_signal,
117 .conn_init = vegas_conn_init,
118 .mod_init = vegas_mod_init
119};
120
121/*
122 * The vegas window adjustment is done once every RTT, as indicated by the
123 * ERTT_NEW_MEASUREMENT flag. This flag is reset once the new measurment data
124 * has been used.
125 */
126static void
127vegas_ack_received(struct cc_var *ccv, uint16_t ack_type)
128{
129 struct ertt *e_t;
130 struct vegas *vegas_data;
131 long actual_tx_rate, expected_tx_rate, ndiff;
132
133 e_t = khelp_get_osd(CCV(ccv, osd), ertt_id);
134 vegas_data = ccv->cc_data;
135
136 if (e_t->flags & ERTT_NEW_MEASUREMENT) { /* Once per RTT. */
137 if (e_t->minrtt && e_t->markedpkt_rtt) {
138 expected_tx_rate = e_t->marked_snd_cwnd / e_t->minrtt;
139 actual_tx_rate = e_t->bytes_tx_in_marked_rtt /
140 e_t->markedpkt_rtt;
141 ndiff = (expected_tx_rate - actual_tx_rate) *
142 e_t->minrtt / CCV(ccv, t_maxseg);
143
144 if (ndiff < V_vegas_alpha) {
145 if (CCV(ccv, snd_cwnd) <=
146 CCV(ccv, snd_ssthresh)) {
147 vegas_data->slow_start_toggle =
148 vegas_data->slow_start_toggle ?
149 0 : 1;
150 } else {
151 vegas_data->slow_start_toggle = 0;
152 CCV(ccv, snd_cwnd) =
153 min(CCV(ccv, snd_cwnd) +
154 CCV(ccv, t_maxseg),
155 TCP_MAXWIN << CCV(ccv, snd_scale));
156 }
157 } else if (ndiff > V_vegas_beta) {
158 /* Rate-based congestion. */
159 vegas_cong_signal(ccv, CC_VEGAS_RATE);
160 vegas_data->slow_start_toggle = 0;
161 }
162 }
163 e_t->flags &= ~ERTT_NEW_MEASUREMENT;
164 }
165
166 if (vegas_data->slow_start_toggle)
167 newreno_cc_algo.ack_received(ccv, ack_type);
168}
169
170static void
171vegas_cb_destroy(struct cc_var *ccv)
172{
173
174 if (ccv->cc_data != NULL)
175 free(ccv->cc_data, M_VEGAS);
176}
177
178static int
179vegas_cb_init(struct cc_var *ccv)
180{
181 struct vegas *vegas_data;
182
183 vegas_data = malloc(sizeof(struct vegas), M_VEGAS, M_NOWAIT);
184
185 if (vegas_data == NULL)
186 return (ENOMEM);
187
188 vegas_data->slow_start_toggle = 1;
189 ccv->cc_data = vegas_data;
190
191 return (0);
192}
193
194/*
195 * If congestion has been triggered triggered by the Vegas measured rates, it is
196 * handled here, otherwise it falls back to newreno's congestion handling.
197 */
198static void
199vegas_cong_signal(struct cc_var *ccv, uint32_t signal_type)
200{
201 struct vegas *vegas_data;
202 int presignalrecov;
203
204 vegas_data = ccv->cc_data;
205
206 if (IN_RECOVERY(CCV(ccv, t_flags)))
207 presignalrecov = 1;
208 else
209 presignalrecov = 0;
210
211 switch(signal_type) {
212 case CC_VEGAS_RATE:
213 if (!IN_RECOVERY(CCV(ccv, t_flags))) {
214 CCV(ccv, snd_cwnd) = max(2 * CCV(ccv, t_maxseg),
215 CCV(ccv, snd_cwnd) - CCV(ccv, t_maxseg));
216 if (CCV(ccv, snd_cwnd) < CCV(ccv, snd_ssthresh))
217 /* Exit slow start. */
218 CCV(ccv, snd_ssthresh) = CCV(ccv, snd_cwnd);
219 }
220 break;
221
222 default:
223 newreno_cc_algo.cong_signal(ccv, signal_type);
224 }
225
226 if (IN_RECOVERY(CCV(ccv, t_flags)) && !presignalrecov)
227 vegas_data->slow_start_toggle =
228 (CCV(ccv, snd_cwnd) < CCV(ccv, snd_ssthresh)) ? 1 : 0;
229}
230
231static void
232vegas_conn_init(struct cc_var *ccv)
233{
234 struct vegas *vegas_data;
235
236 vegas_data = ccv->cc_data;
237 vegas_data->slow_start_toggle = 1;
238}
239
240static int
241vegas_mod_init(void)
242{
243
244 ertt_id = khelp_get_id("ertt");
245 if (ertt_id <= 0) {
246 printf("%s: h_ertt module not found\n", __func__);
247 return (ENOENT);
248 }
249
250 vegas_cc_algo.after_idle = newreno_cc_algo.after_idle;
251 vegas_cc_algo.post_recovery = newreno_cc_algo.post_recovery;
252
253 return (0);
254}
255
256static int
257vegas_alpha_handler(SYSCTL_HANDLER_ARGS)
258{
259 int error;
260 uint32_t new;
261
262 new = V_vegas_alpha;
263 error = sysctl_handle_int(oidp, &new, 0, req);
264 if (error == 0 && req->newptr != NULL) {
265 if (CAST_PTR_INT(req->newptr) < 1 ||
266 CAST_PTR_INT(req->newptr) > V_vegas_beta)
267 error = EINVAL;
268 else
269 V_vegas_alpha = new;
270 }
271
272 return (error);
273}
274
275static int
276vegas_beta_handler(SYSCTL_HANDLER_ARGS)
277{
278 int error;
279 uint32_t new;
280
281 new = V_vegas_beta;
282 error = sysctl_handle_int(oidp, &new, 0, req);
283 if (error == 0 && req->newptr != NULL) {
284 if (CAST_PTR_INT(req->newptr) < 1 ||
285 CAST_PTR_INT(req->newptr) < V_vegas_alpha)
286 error = EINVAL;
287 else
288 V_vegas_beta = new;
289 }
290
291 return (error);
292}
293
294SYSCTL_DECL(_net_inet_tcp_cc_vegas);
295SYSCTL_NODE(_net_inet_tcp_cc, OID_AUTO, vegas, CTLFLAG_RW, NULL,
296 "Vegas related settings");
297
298SYSCTL_VNET_PROC(_net_inet_tcp_cc_vegas, OID_AUTO, alpha,
299 CTLTYPE_UINT|CTLFLAG_RW, &VNET_NAME(vegas_alpha), 1, &vegas_alpha_handler,
300 "IU", "vegas alpha, specified as number of \"buffers\" (0 < alpha < beta)");
301
302SYSCTL_VNET_PROC(_net_inet_tcp_cc_vegas, OID_AUTO, beta,
303 CTLTYPE_UINT|CTLFLAG_RW, &VNET_NAME(vegas_beta), 3, &vegas_beta_handler,
304 "IU", "vegas beta, specified as number of \"buffers\" (0 < alpha < beta)");
305
306DECLARE_CC_MODULE(vegas, &vegas_cc_algo);
307MODULE_DEPEND(vegas, ertt, 1, 1, 1);
|