2 * Copyright (c) 2005 John Bicket
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer,
10 * without modification.
11 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
12 * similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
13 * redistribution must be conditioned upon including a substantially
14 * similar Disclaimer requirement for further binary redistribution.
15 * 3. Neither the names of the above-listed copyright holders nor the names
16 * of any contributors may be used to endorse or promote products derived
17 * from this software without specific prior written permission.
19 * Alternatively, this software may be distributed under the terms of the
20 * GNU General Public License ("GPL") version 2 as published by the Free
21 * Software Foundation.
24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
25 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
26 * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
27 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
28 * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
29 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
32 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
34 * THE POSSIBILITY OF SUCH DAMAGES.
36 * $FreeBSD: src/sys/dev/ath/ath_rate/sample/sample.c,v 1.8.2.3 2006/03/14 23:22:27 sam Exp $
37 * $DragonFly: src/sys/dev/netif/ath/rate_sample/sample.c,v 1.6 2007/02/22 05:17:10 sephe Exp $
41 * John Bicket's SampleRate control algorithm.
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/sysctl.h>
47 #include <sys/module.h>
48 #include <sys/kernel.h>
50 #include <sys/errno.h>
53 #include <sys/socket.h>
56 #include <net/if_media.h>
57 #include <net/if_arp.h>
59 #include <netproto/802_11/ieee80211_var.h>
63 #include <dev/netif/ath/ath/if_athvar.h>
64 #include <dev/netif/ath/rate_sample/sample.h>
65 #include <dev/netif/ath/hal/ath_hal/ah_desc.h>
70 ATH_DEBUG_NODE = 0x00080000, /* node management */
71 ATH_DEBUG_RATE = 0x00000010, /* rate control */
72 ATH_DEBUG_ANY = 0xffffffff
74 #define DPRINTF(sc, m, _fmt, ...) do { \
75 if (sc->sc_debug & (m)) \
76 kprintf(_fmt, __VA_ARGS__); \
79 #define DPRINTF(sc, m, _fmt, ...) do { \
85 * This file is an implementation of the SampleRate algorithm
86 * in "Bit-rate Selection in Wireless Networks"
87 * (http://www.pdos.lcs.mit.edu/papers/jbicket-ms.ps)
89 * SampleRate chooses the bit-rate it predicts will provide the most
90 * throughput based on estimates of the expected per-packet
91 * transmission time for each bit-rate. SampleRate periodically sends
92 * packets at bit-rates other than the current one to estimate when
93 * another bit-rate will provide better performance. SampleRate
94 * switches to another bit-rate when its estimated per-packet
95 * transmission time becomes smaller than the current bit-rate's.
96 * SampleRate reduces the number of bit-rates it must sample by
97 * eliminating those that could not perform better than the one
98 * currently being used. SampleRate also stops probing at a bit-rate
99 * if it experiences several successive losses.
101 * The difference between the algorithm in the thesis and the one in this
102 * file is that the one in this file uses a ewma instead of a window.
104 * Also, this implementation tracks the average transmission time for
105 * a few different packet sizes independently for each link.
108 #define STALE_FAILURE_TIMEOUT_MS 10000
109 #define MIN_SWITCH_MS 1000
111 static void ath_rate_ctl_reset(struct ath_softc *, struct ieee80211_node *);
114 size_to_bin(int size)
117 for (x = 0; x < NUM_PACKET_SIZE_BINS; x++) {
118 if (size <= packet_size_bins[x]) {
122 return NUM_PACKET_SIZE_BINS-1;
125 bin_to_size(int index) {
126 return packet_size_bins[index];
130 rate_to_ndx(struct sample_node *sn, int rate) {
132 for (x = 0; x < sn->num_rates; x++) {
133 if (sn->rates[x].rate == rate) {
141 ath_rate_node_init(struct ath_softc *sc, struct ath_node *an)
143 DPRINTF(sc, ATH_DEBUG_NODE, "%s:\n", __func__);
144 /* NB: assumed to be zero'd by caller */
148 ath_rate_node_cleanup(struct ath_softc *sc, struct ath_node *an)
150 DPRINTF(sc, ATH_DEBUG_NODE, "%s:\n", __func__);
155 * returns the ndx with the lowest average_tx_time,
156 * or -1 if all the average_tx_times are 0.
159 best_rate_ndx(struct sample_node *sn, int size_bin, int require_acked_before)
162 int best_rate_ndx = 0;
163 int best_rate_tt = 0;
164 for (x = 0; x < sn->num_rates; x++) {
165 int tt = sn->stats[size_bin][x].average_tx_time;
166 if (tt <= 0 || (require_acked_before &&
167 !sn->stats[size_bin][x].packets_acked)) {
171 /* 9 megabits never works better than 12 */
172 if (sn->rates[x].rate == 18)
175 /* don't use a bit-rate that has been failing */
176 if (sn->stats[size_bin][x].successive_failures > 3)
179 if (!best_rate_tt || best_rate_tt > tt) {
184 return (best_rate_tt) ? best_rate_ndx : -1;
188 * pick a good "random" bit-rate to sample other than the current one
191 pick_sample_ndx(struct sample_node *sn, int size_bin)
195 unsigned current_tt = 0;
197 current_ndx = sn->current_rate[size_bin];
198 if (current_ndx < 0) {
199 /* no successes yet, send at the lowest bit-rate */
203 current_tt = sn->stats[size_bin][current_ndx].average_tx_time;
205 for (x = 0; x < sn->num_rates; x++) {
206 int ndx = (sn->last_sample_ndx[size_bin]+1+x) % sn->num_rates;
208 /* don't sample the current bit-rate */
209 if (ndx == current_ndx)
212 /* this bit-rate is always worse than the current one */
213 if (sn->stats[size_bin][ndx].perfect_tx_time > current_tt)
216 /* rarely sample bit-rates that fail a lot */
217 if (ticks - sn->stats[size_bin][ndx].last_tx < ((hz * STALE_FAILURE_TIMEOUT_MS)/1000) &&
218 sn->stats[size_bin][ndx].successive_failures > 3)
221 /* don't sample more than 2 indexes higher
222 * for rates higher than 11 megabits
224 if (sn->rates[ndx].rate > 22 && ndx > current_ndx + 2)
227 /* 9 megabits never works better than 12 */
228 if (sn->rates[ndx].rate == 18)
231 /* if we're using 11 megabits, only sample up to 12 megabits
233 if (sn->rates[current_ndx].rate == 22 && ndx > current_ndx + 1)
236 sn->last_sample_ndx[size_bin] = ndx;
243 ath_rate_findrate(struct ath_softc *sc, struct ath_node *an,
244 int shortPreamble, size_t frameLen,
245 u_int8_t *rix, int *try0, u_int8_t *txrate)
247 struct sample_node *sn = ATH_NODE_SAMPLE(an);
248 struct sample_softc *ssc = ATH_SOFTC_SAMPLE(sc);
249 struct ieee80211com *ic = &sc->sc_ic;
250 int ndx, size_bin, mrr, best_ndx, change_rates;
251 unsigned average_tx_time;
253 mrr = sc->sc_mrretry && !(ic->ic_flags & IEEE80211_F_USEPROT);
254 size_bin = size_to_bin(frameLen);
255 best_ndx = best_rate_ndx(sn, size_bin, !mrr);
258 average_tx_time = sn->stats[size_bin][best_ndx].average_tx_time;
263 if (sn->static_rate_ndx != -1) {
264 ndx = sn->static_rate_ndx;
265 *try0 = ATH_TXMAXTRY;
267 *try0 = mrr ? 2 : ATH_TXMAXTRY;
269 if (sn->sample_tt[size_bin] < average_tx_time * (sn->packets_since_sample[size_bin]*ssc->ath_sample_rate/100)) {
271 * we want to limit the time measuring the performance
272 * of other bit-rates to ath_sample_rate% of the
273 * total transmission time.
275 ndx = pick_sample_ndx(sn, size_bin);
276 if (ndx != sn->current_rate[size_bin]) {
277 sn->current_sample_ndx[size_bin] = ndx;
279 sn->current_sample_ndx[size_bin] = -1;
281 sn->packets_since_sample[size_bin] = 0;
285 if (!sn->packets_sent[size_bin] || best_ndx == -1) {
286 /* no packet has been sent successfully yet */
287 for (ndx = sn->num_rates-1; ndx > 0; ndx--) {
289 * pick the highest rate <= 36 Mbps
290 * that hasn't failed.
292 if (sn->rates[ndx].rate <= 72 &&
293 sn->stats[size_bin][ndx].successive_failures == 0) {
299 } else if (sn->packets_sent[size_bin] < 20) {
300 /* let the bit-rate switch quickly during the first few packets */
302 } else if (ticks - ((hz*MIN_SWITCH_MS)/1000) > sn->ticks_since_switch[size_bin]) {
303 /* 2 seconds have gone by */
305 } else if (average_tx_time * 2 < sn->stats[size_bin][sn->current_rate[size_bin]].average_tx_time) {
306 /* the current bit-rate is twice as slow as the best one */
310 sn->packets_since_sample[size_bin]++;
313 if (best_ndx != sn->current_rate[size_bin]) {
314 DPRINTF(sc, ATH_DEBUG_RATE,
315 "%s: %6D size %d switch rate %d (%d/%d) -> %d (%d/%d) after %d packets mrr %d\n",
317 an->an_node.ni_macaddr, ":",
318 packet_size_bins[size_bin],
319 sn->rates[sn->current_rate[size_bin]].rate,
320 sn->stats[size_bin][sn->current_rate[size_bin]].average_tx_time,
321 sn->stats[size_bin][sn->current_rate[size_bin]].perfect_tx_time,
322 sn->rates[best_ndx].rate,
323 sn->stats[size_bin][best_ndx].average_tx_time,
324 sn->stats[size_bin][best_ndx].perfect_tx_time,
325 sn->packets_since_switch[size_bin],
328 sn->packets_since_switch[size_bin] = 0;
329 sn->current_rate[size_bin] = best_ndx;
330 sn->ticks_since_switch[size_bin] = ticks;
332 ndx = sn->current_rate[size_bin];
333 sn->packets_since_switch[size_bin]++;
336 * set the visible txrate for this node
337 * to the rate of small packets
339 an->an_node.ni_txrate = ndx;
344 KASSERT(ndx >= 0 && ndx < sn->num_rates, ("ndx is %d", ndx));
346 *rix = sn->rates[ndx].rix;
348 *txrate = sn->rates[ndx].shortPreambleRateCode;
350 *txrate = sn->rates[ndx].rateCode;
352 sn->packets_sent[size_bin]++;
356 ath_rate_setupxtxdesc(struct ath_softc *sc, struct ath_node *an,
357 struct ath_desc *ds, int shortPreamble, u_int8_t rix)
359 struct sample_node *sn = ATH_NODE_SAMPLE(an);
365 /* TODO: it's correct that frame_size alway 0 ? */
366 size_bin = size_to_bin(frame_size);
368 ndx = sn->current_rate[size_bin]; /* retry at the current bit-rate */
370 if (!sn->stats[size_bin][ndx].packets_acked) {
371 ndx = 0; /* use the lowest bit-rate */
375 rateCode = sn->rates[ndx].shortPreambleRateCode;
377 rateCode = sn->rates[ndx].rateCode;
379 ath_hal_setupxtxdesc(sc->sc_ah, ds
380 , rateCode, 3 /* series 1 */
381 , sn->rates[0].rateCode, 3 /* series 2 */
382 , 0, 0 /* series 3 */
387 update_stats(struct ath_softc *sc, struct ath_node *an,
389 int ndx0, int tries0,
390 int ndx1, int tries1,
391 int ndx2, int tries2,
392 int ndx3, int tries3,
393 int short_tries, int tries, int status)
395 struct sample_node *sn = ATH_NODE_SAMPLE(an);
396 struct sample_softc *ssc = ATH_SOFTC_SAMPLE(sc);
398 int tries_so_far = 0;
403 size_bin = size_to_bin(frame_size);
404 size = bin_to_size(size_bin);
406 if (!(0 <= ndx0 && ndx0 < sn->num_rates)) {
407 kprintf("%s: bogus ndx0 %d, max %u, mode %u\n",
408 __func__, ndx0, sn->num_rates, sc->sc_curmode);
411 rate = sn->rates[ndx0].rate;
413 tt += calc_usecs_unicast_packet(sc, size, sn->rates[ndx0].rix,
415 MIN(tries0, tries) - 1);
416 tries_so_far += tries0;
417 if (tries1 && tries0 < tries) {
418 if (!(0 <= ndx1 && ndx1 < sn->num_rates)) {
419 kprintf("%s: bogus ndx1 %d, max %u, mode %u\n",
420 __func__, ndx1, sn->num_rates, sc->sc_curmode);
423 tt += calc_usecs_unicast_packet(sc, size, sn->rates[ndx1].rix,
425 MIN(tries1 + tries_so_far, tries) - tries_so_far - 1);
427 tries_so_far += tries1;
429 if (tries2 && tries0 + tries1 < tries) {
430 if (!(0 <= ndx2 && ndx2 < sn->num_rates)) {
431 kprintf("%s: bogus ndx2 %d, max %u, mode %u\n",
432 __func__, ndx2, sn->num_rates, sc->sc_curmode);
435 tt += calc_usecs_unicast_packet(sc, size, sn->rates[ndx2].rix,
437 MIN(tries2 + tries_so_far, tries) - tries_so_far - 1);
440 tries_so_far += tries2;
442 if (tries3 && tries0 + tries1 + tries2 < tries) {
443 if (!(0 <= ndx3 && ndx3 < sn->num_rates)) {
444 kprintf("%s: bogus ndx3 %d, max %u, mode %u\n",
445 __func__, ndx3, sn->num_rates, sc->sc_curmode);
448 tt += calc_usecs_unicast_packet(sc, size, sn->rates[ndx3].rix,
450 MIN(tries3 + tries_so_far, tries) - tries_so_far - 1);
452 if (sn->stats[size_bin][ndx0].total_packets < (100 / (100 - ssc->ath_smoothing_rate))) {
453 /* just average the first few packets */
454 int avg_tx = sn->stats[size_bin][ndx0].average_tx_time;
455 int packets = sn->stats[size_bin][ndx0].total_packets;
456 sn->stats[size_bin][ndx0].average_tx_time = (tt+(avg_tx*packets))/(packets+1);
459 sn->stats[size_bin][ndx0].average_tx_time =
460 ((sn->stats[size_bin][ndx0].average_tx_time * ssc->ath_smoothing_rate) +
461 (tt * (100 - ssc->ath_smoothing_rate))) / 100;
466 sn->stats[size_bin][ndx0].successive_failures++;
467 for (y = size_bin+1; y < NUM_PACKET_SIZE_BINS; y++) {
468 /* also say larger packets failed since we
469 * assume if a small packet fails at a lower
470 * bit-rate then a larger one will also.
472 sn->stats[y][ndx0].successive_failures++;
473 sn->stats[y][ndx0].last_tx = ticks;
474 sn->stats[y][ndx0].tries += tries;
475 sn->stats[y][ndx0].total_packets++;
478 sn->stats[size_bin][ndx0].packets_acked++;
479 sn->stats[size_bin][ndx0].successive_failures = 0;
481 sn->stats[size_bin][ndx0].tries += tries;
482 sn->stats[size_bin][ndx0].last_tx = ticks;
483 sn->stats[size_bin][ndx0].total_packets++;
486 if (ndx0 == sn->current_sample_ndx[size_bin]) {
487 DPRINTF(sc, ATH_DEBUG_RATE,
488 "%s: %6D size %d %s sample rate %d tries (%d/%d) tt %d avg_tt (%d/%d)\n",
489 __func__, an->an_node.ni_macaddr, ":",
491 status ? "FAIL" : "OK",
492 rate, short_tries, tries, tt,
493 sn->stats[size_bin][ndx0].average_tx_time,
494 sn->stats[size_bin][ndx0].perfect_tx_time);
495 sn->sample_tt[size_bin] = tt;
496 sn->current_sample_ndx[size_bin] = -1;
501 ath_rate_tx_complete(struct ath_softc *sc, struct ath_node *an,
502 const struct ath_buf *bf)
504 struct ieee80211com *ic = &sc->sc_ic;
505 struct sample_node *sn = ATH_NODE_SAMPLE(an);
506 const struct ath_tx_status *ts = &bf->bf_status.ds_txstat;
507 const struct ath_desc *ds0 = &bf->bf_desc[0];
508 int final_rate, short_tries, long_tries, frame_size;
511 final_rate = sc->sc_hwmap[ts->ts_rate &~ HAL_TXSTAT_ALTRATE].ieeerate;
512 short_tries = ts->ts_shortretry;
513 long_tries = ts->ts_longretry + 1;
514 frame_size = ds0->ds_ctl0 & 0x0fff; /* low-order 12 bits of ds_ctl0 */
515 if (frame_size == 0) /* NB: should not happen */
518 if (sn->num_rates <= 0) {
519 DPRINTF(sc, ATH_DEBUG_RATE,
520 "%s: %6D size %d %s rate/try %d/%d no rates yet\n",
521 __func__, an->an_node.ni_macaddr, ":",
522 bin_to_size(size_to_bin(frame_size)),
523 ts->ts_status ? "FAIL" : "OK",
524 short_tries, long_tries);
528 mrr = sc->sc_mrretry && !(ic->ic_flags & IEEE80211_F_USEPROT);
529 if (!mrr || !(ts->ts_rate & HAL_TXSTAT_ALTRATE)) {
530 int ndx = rate_to_ndx(sn, final_rate);
533 * Only one rate was used; optimize work.
535 DPRINTF(sc, ATH_DEBUG_RATE,
536 "%s: %6D size %d %s rate/try %d/%d/%d\n",
537 __func__, an->an_node.ni_macaddr, ":",
538 bin_to_size(size_to_bin(frame_size)),
539 ts->ts_status ? "FAIL" : "OK",
540 final_rate, short_tries, long_tries);
541 update_stats(sc, an, frame_size,
546 short_tries, long_tries, ts->ts_status);
548 int hwrate0, rate0, tries0, ndx0;
549 int hwrate1, rate1, tries1, ndx1;
550 int hwrate2, rate2, tries2, ndx2;
551 int hwrate3, rate3, tries3, ndx3;
552 int finalTSIdx = ts->ts_finaltsi;
555 * Process intermediate rates that failed.
557 if (sc->sc_ah->ah_magic != 0x20065416) {
558 hwrate0 = MS(ds0->ds_ctl3, AR_XmitRate0);
559 hwrate1 = MS(ds0->ds_ctl3, AR_XmitRate1);
560 hwrate2 = MS(ds0->ds_ctl3, AR_XmitRate2);
561 hwrate3 = MS(ds0->ds_ctl3, AR_XmitRate3);
563 hwrate0 = MS(ds0->ds_ctl3, AR5416_XmitRate0);
564 hwrate1 = MS(ds0->ds_ctl3, AR5416_XmitRate1);
565 hwrate2 = MS(ds0->ds_ctl3, AR5416_XmitRate2);
566 hwrate3 = MS(ds0->ds_ctl3, AR5416_XmitRate3);
569 rate0 = sc->sc_hwmap[hwrate0].ieeerate;
570 tries0 = MS(ds0->ds_ctl2, AR_XmitDataTries0);
571 ndx0 = rate_to_ndx(sn, rate0);
573 rate1 = sc->sc_hwmap[hwrate1].ieeerate;
574 tries1 = MS(ds0->ds_ctl2, AR_XmitDataTries1);
575 ndx1 = rate_to_ndx(sn, rate1);
577 rate2 = sc->sc_hwmap[hwrate2].ieeerate;
578 tries2 = MS(ds0->ds_ctl2, AR_XmitDataTries2);
579 ndx2 = rate_to_ndx(sn, rate2);
581 rate3 = sc->sc_hwmap[hwrate3].ieeerate;
582 tries3 = MS(ds0->ds_ctl2, AR_XmitDataTries3);
583 ndx3 = rate_to_ndx(sn, rate3);
585 DPRINTF(sc, ATH_DEBUG_RATE,
586 "%s: %6D size %d finaltsidx %d tries %d %s rate/try [%d/%d %d/%d %d/%d %d/%d]\n",
587 __func__, an->an_node.ni_macaddr, ":",
588 bin_to_size(size_to_bin(frame_size)),
591 ts->ts_status ? "FAIL" : "OK",
598 * NB: series > 0 are not penalized for failure
599 * based on the try counts under the assumption
600 * that losses are often bursty and since we
601 * sample higher rates 1 try at a time doing so
602 * may unfairly penalize them.
605 update_stats(sc, an, frame_size,
610 short_tries, long_tries,
611 long_tries > tries0);
612 long_tries -= tries0;
615 if (tries1 && finalTSIdx > 0) {
616 update_stats(sc, an, frame_size,
621 short_tries, long_tries,
623 long_tries -= tries1;
626 if (tries2 && finalTSIdx > 1) {
627 update_stats(sc, an, frame_size,
632 short_tries, long_tries,
634 long_tries -= tries2;
637 if (tries3 && finalTSIdx > 2) {
638 update_stats(sc, an, frame_size,
643 short_tries, long_tries,
650 ath_rate_newassoc(struct ath_softc *sc, struct ath_node *an, int isnew)
652 DPRINTF(sc, ATH_DEBUG_NODE, "%s: %6D isnew %d\n", __func__,
653 an->an_node.ni_macaddr, ":", isnew);
655 ath_rate_ctl_reset(sc, &an->an_node);
659 * Initialize the tables for a node.
662 ath_rate_ctl_reset(struct ath_softc *sc, struct ieee80211_node *ni)
664 #define RATE(_ix) (ni->ni_rates.rs_rates[(_ix)] & IEEE80211_RATE_VAL)
665 struct ieee80211com *ic = &sc->sc_ic;
666 struct ath_node *an = ATH_NODE(ni);
667 struct sample_node *sn = ATH_NODE_SAMPLE(an);
668 const HAL_RATE_TABLE *rt = sc->sc_currates;
671 KASSERT(rt != NULL, ("no rate table, mode %u", sc->sc_curmode));
672 sn->static_rate_ndx = -1;
673 if (ic->ic_fixed_rate != IEEE80211_FIXED_RATE_NONE) {
675 * A fixed rate is to be used; ic_fixed_rate is an
676 * index into the supported rate set. Convert this
677 * to the index into the negotiated rate set for
680 const struct ieee80211_rateset *rs =
681 &ic->ic_sup_rates[ic->ic_curmode];
682 int r = rs->rs_rates[ic->ic_fixed_rate] & IEEE80211_RATE_VAL;
683 /* NB: the rate set is assumed sorted */
684 srate = ni->ni_rates.rs_nrates - 1;
685 for (; srate >= 0 && RATE(srate) != r; srate--)
688 ("fixed rate %d not in rate set", ic->ic_fixed_rate));
689 sn->static_rate_ndx = srate;
692 DPRINTF(sc, ATH_DEBUG_RATE, "%s: %6D size 1600 rate/tt", __func__,
693 ni->ni_macaddr, ":");
695 sn->num_rates = ni->ni_rates.rs_nrates;
696 for (x = 0; x < ni->ni_rates.rs_nrates; x++) {
697 sn->rates[x].rate = ni->ni_rates.rs_rates[x] & IEEE80211_RATE_VAL;
698 sn->rates[x].rix = sc->sc_rixmap[sn->rates[x].rate];
699 if (sn->rates[x].rix == 0xff) {
700 DPRINTF(sc, ATH_DEBUG_RATE,
701 "%s: ignore bogus rix at %d\n", __func__, x);
704 sn->rates[x].rateCode = rt->info[sn->rates[x].rix].rateCode;
705 sn->rates[x].shortPreambleRateCode =
706 rt->info[sn->rates[x].rix].rateCode |
707 rt->info[sn->rates[x].rix].shortPreamble;
709 DPRINTF(sc, ATH_DEBUG_RATE, " %d/%d", sn->rates[x].rate,
710 calc_usecs_unicast_packet(sc, 1600, sn->rates[x].rix,
713 DPRINTF(sc, ATH_DEBUG_RATE, "%s\n", "");
715 /* set the visible bit-rate to the lowest one available */
717 sn->num_rates = ni->ni_rates.rs_nrates;
719 for (y = 0; y < NUM_PACKET_SIZE_BINS; y++) {
720 int size = bin_to_size(y);
722 sn->packets_sent[y] = 0;
723 sn->current_sample_ndx[y] = -1;
724 sn->last_sample_ndx[y] = 0;
726 for (x = 0; x < ni->ni_rates.rs_nrates; x++) {
727 sn->stats[y][x].successive_failures = 0;
728 sn->stats[y][x].tries = 0;
729 sn->stats[y][x].total_packets = 0;
730 sn->stats[y][x].packets_acked = 0;
731 sn->stats[y][x].last_tx = 0;
733 sn->stats[y][x].perfect_tx_time =
734 calc_usecs_unicast_packet(sc, size,
737 sn->stats[y][x].average_tx_time = sn->stats[y][x].perfect_tx_time;
740 /* set the initial rate */
741 for (ndx = sn->num_rates-1; ndx > 0; ndx--) {
742 if (sn->rates[ndx].rate <= 72) {
746 sn->current_rate[y] = ndx;
749 DPRINTF(sc, ATH_DEBUG_RATE,
750 "%s: %6D %d rates %d%sMbps (%dus)- %d%sMbps (%dus)\n",
751 __func__, ni->ni_macaddr, ":",
753 sn->rates[0].rate/2, sn->rates[0].rate % 0x1 ? ".5" : "",
754 sn->stats[1][0].perfect_tx_time,
755 sn->rates[sn->num_rates-1].rate/2,
756 sn->rates[sn->num_rates-1].rate % 0x1 ? ".5" : "",
757 sn->stats[1][sn->num_rates-1].perfect_tx_time
760 if (sn->static_rate_ndx != -1)
761 ni->ni_txrate = sn->static_rate_ndx;
763 ni->ni_txrate = sn->current_rate[0];
768 rate_cb(void *arg, struct ieee80211_node *ni)
770 struct ath_softc *sc = arg;
772 ath_rate_newassoc(sc, ATH_NODE(ni), 1);
776 * Reset the rate control state for each 802.11 state transition.
779 ath_rate_newstate(struct ath_softc *sc, enum ieee80211_state state)
781 struct ieee80211com *ic = &sc->sc_ic;
783 ASSERT_SERIALIZED(ic->ic_if.if_serializer);
785 if (state == IEEE80211_S_RUN) {
786 if (ic->ic_opmode != IEEE80211_M_STA) {
788 * Sync rates for associated stations and neighbors.
790 ieee80211_iterate_nodes(&ic->ic_sta, rate_cb, sc);
792 ath_rate_newassoc(sc, ATH_NODE(ic->ic_bss), 1);
797 ath_rate_sysctlattach(struct ath_softc *sc, struct sample_softc *osc)
799 struct sysctl_ctx_list *ctx = &sc->sc_sysctl_ctx;
800 struct sysctl_oid *tree = sc->sc_sysctl_tree;
802 /* XXX bounds check [0..100] */
803 SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
804 "smoothing_rate", CTLFLAG_RW, &osc->ath_smoothing_rate, 0,
805 "rate control: retry threshold to credit rate raise (%%)");
806 /* XXX bounds check [2..100] */
807 SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
808 "sample_rate", CTLFLAG_RW, &osc->ath_sample_rate,0,
809 "rate control: # good periods before raising rate");
812 struct ath_ratectrl *
813 ath_rate_attach(struct ath_softc *sc)
815 struct sample_softc *osc;
817 DPRINTF(sc, ATH_DEBUG_ANY, "%s:\n", __func__);
818 osc = kmalloc(sizeof(struct sample_softc), M_DEVBUF, M_NOWAIT|M_ZERO);
821 osc->arc.arc_space = sizeof(struct sample_node);
822 osc->ath_smoothing_rate = 95; /* ewma percentage (out of 100) */
823 osc->ath_sample_rate = 10; /* send a different bit-rate 1/X packets */
824 ath_rate_sysctlattach(sc, osc);
829 ath_rate_detach(struct ath_ratectrl *arc)
831 struct sample_softc *osc = (struct sample_softc *) arc;
833 kfree(osc, M_DEVBUF);
837 ath_rate_stop(struct ath_ratectrl *arc __unused)
845 sample_modevent(module_t mod, int type, void *unused)
850 kprintf("ath_rate: version 1.2 <SampleRate bit-rate selection algorithm>\n");
858 static moduledata_t sample_mod = {
863 DECLARE_MODULE(ath_rate, sample_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
864 MODULE_VERSION(ath_rate, 1);
865 MODULE_DEPEND(ath_rate, ath_hal, 1, 1, 1); /* Atheros HAL */
866 MODULE_DEPEND(ath_rate, wlan, 1, 1, 1);