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.
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
42 * John Bicket's SampleRate control algorithm.
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/sysctl.h>
49 #include <sys/kernel.h>
51 #include <sys/mutex.h>
52 #include <sys/errno.h>
54 #include <machine/bus.h>
55 #include <machine/resource.h>
58 #include <sys/socket.h>
61 #include <net/if_media.h>
62 #include <net/if_arp.h>
63 #include <net/ethernet.h> /* XXX for ether_sprintf */
65 #include <net80211/ieee80211_var.h>
70 #include <netinet/in.h>
71 #include <netinet/if_ether.h>
74 #include <dev/ath/if_athvar.h>
75 #include <dev/ath/ath_rate/sample/sample.h>
76 #include <dev/ath/ath_hal/ah_desc.h>
81 ATH_DEBUG_NODE = 0x00080000, /* node management */
82 ATH_DEBUG_RATE = 0x00000010, /* rate control */
83 ATH_DEBUG_ANY = 0xffffffff
85 #define DPRINTF(sc, m, fmt, ...) do { \
86 if (sc->sc_debug & (m)) \
87 printf(fmt, __VA_ARGS__); \
90 #define DPRINTF(sc, m, fmt, ...) do { \
96 * This file is an implementation of the SampleRate algorithm
97 * in "Bit-rate Selection in Wireless Networks"
98 * (http://www.pdos.lcs.mit.edu/papers/jbicket-ms.ps)
100 * SampleRate chooses the bit-rate it predicts will provide the most
101 * throughput based on estimates of the expected per-packet
102 * transmission time for each bit-rate. SampleRate periodically sends
103 * packets at bit-rates other than the current one to estimate when
104 * another bit-rate will provide better performance. SampleRate
105 * switches to another bit-rate when its estimated per-packet
106 * transmission time becomes smaller than the current bit-rate's.
107 * SampleRate reduces the number of bit-rates it must sample by
108 * eliminating those that could not perform better than the one
109 * currently being used. SampleRate also stops probing at a bit-rate
110 * if it experiences several successive losses.
112 * The difference between the algorithm in the thesis and the one in this
113 * file is that the one in this file uses a ewma instead of a window.
115 * Also, this implementation tracks the average transmission time for
116 * a few different packet sizes independently for each link.
119 #define STALE_FAILURE_TIMEOUT_MS 10000
120 #define MIN_SWITCH_MS 1000
122 static void ath_rate_ctl_reset(struct ath_softc *, struct ieee80211_node *);
125 size_to_bin(int size)
128 for (x = 0; x < NUM_PACKET_SIZE_BINS; x++) {
129 if (size <= packet_size_bins[x]) {
133 return NUM_PACKET_SIZE_BINS-1;
136 bin_to_size(int index) {
137 return packet_size_bins[index];
141 rate_to_ndx(struct sample_node *sn, int rate) {
143 for (x = 0; x < sn->num_rates; x++) {
144 if (sn->rates[x].rate == rate) {
152 ath_rate_node_init(struct ath_softc *sc, struct ath_node *an)
154 DPRINTF(sc, ATH_DEBUG_NODE, "%s:\n", __func__);
155 /* NB: assumed to be zero'd by caller */
159 ath_rate_node_cleanup(struct ath_softc *sc, struct ath_node *an)
161 DPRINTF(sc, ATH_DEBUG_NODE, "%s:\n", __func__);
166 * returns the ndx with the lowest average_tx_time,
167 * or -1 if all the average_tx_times are 0.
169 static __inline int best_rate_ndx(struct sample_node *sn, int size_bin,
170 int require_acked_before)
173 int best_rate_ndx = 0;
174 int best_rate_tt = 0;
175 for (x = 0; x < sn->num_rates; x++) {
176 int tt = sn->stats[size_bin][x].average_tx_time;
177 if (tt <= 0 || (require_acked_before &&
178 !sn->stats[size_bin][x].packets_acked)) {
182 /* 9 megabits never works better than 12 */
183 if (sn->rates[x].rate == 18)
186 /* don't use a bit-rate that has been failing */
187 if (sn->stats[size_bin][x].successive_failures > 3)
190 if (!best_rate_tt || best_rate_tt > tt) {
195 return (best_rate_tt) ? best_rate_ndx : -1;
199 * pick a good "random" bit-rate to sample other than the current one
202 pick_sample_ndx(struct sample_node *sn, int size_bin)
206 unsigned current_tt = 0;
208 current_ndx = sn->current_rate[size_bin];
209 if (current_ndx < 0) {
210 /* no successes yet, send at the lowest bit-rate */
214 current_tt = sn->stats[size_bin][current_ndx].average_tx_time;
216 for (x = 0; x < sn->num_rates; x++) {
217 int ndx = (sn->last_sample_ndx[size_bin]+1+x) % sn->num_rates;
219 /* don't sample the current bit-rate */
220 if (ndx == current_ndx)
223 /* this bit-rate is always worse than the current one */
224 if (sn->stats[size_bin][ndx].perfect_tx_time > current_tt)
227 /* rarely sample bit-rates that fail a lot */
228 if (ticks - sn->stats[size_bin][ndx].last_tx < ((hz * STALE_FAILURE_TIMEOUT_MS)/1000) &&
229 sn->stats[size_bin][ndx].successive_failures > 3)
232 /* don't sample more than 2 indexes higher
233 * for rates higher than 11 megabits
235 if (sn->rates[ndx].rate > 22 && ndx > current_ndx + 2)
238 /* 9 megabits never works better than 12 */
239 if (sn->rates[ndx].rate == 18)
242 /* if we're using 11 megabits, only sample up to 12 megabits
244 if (sn->rates[current_ndx].rate == 22 && ndx > current_ndx + 1)
247 sn->last_sample_ndx[size_bin] = ndx;
254 ath_rate_findrate(struct ath_softc *sc, struct ath_node *an,
255 int shortPreamble, size_t frameLen,
256 u_int8_t *rix, int *try0, u_int8_t *txrate)
258 struct sample_node *sn = ATH_NODE_SAMPLE(an);
259 struct sample_softc *ssc = ATH_SOFTC_SAMPLE(sc);
260 struct ieee80211com *ic = &sc->sc_ic;
261 int ndx, size_bin, mrr, best_ndx, change_rates;
262 unsigned average_tx_time;
264 mrr = sc->sc_mrretry && !(ic->ic_flags & IEEE80211_F_USEPROT);
265 size_bin = size_to_bin(frameLen);
266 best_ndx = best_rate_ndx(sn, size_bin, !mrr);
269 average_tx_time = sn->stats[size_bin][best_ndx].average_tx_time;
274 if (sn->static_rate_ndx != -1) {
275 ndx = sn->static_rate_ndx;
276 *try0 = ATH_TXMAXTRY;
278 *try0 = mrr ? 2 : ATH_TXMAXTRY;
280 if (sn->sample_tt[size_bin] < average_tx_time * (sn->packets_since_sample[size_bin]*ssc->ath_sample_rate/100)) {
282 * we want to limit the time measuring the performance
283 * of other bit-rates to ath_sample_rate% of the
284 * total transmission time.
286 ndx = pick_sample_ndx(sn, size_bin);
287 if (ndx != sn->current_rate[size_bin]) {
288 sn->current_sample_ndx[size_bin] = ndx;
290 sn->current_sample_ndx[size_bin] = -1;
292 sn->packets_since_sample[size_bin] = 0;
296 if (!sn->packets_sent[size_bin] || best_ndx == -1) {
297 /* no packet has been sent successfully yet */
298 for (ndx = sn->num_rates-1; ndx > 0; ndx--) {
300 * pick the highest rate <= 36 Mbps
301 * that hasn't failed.
303 if (sn->rates[ndx].rate <= 72 &&
304 sn->stats[size_bin][ndx].successive_failures == 0) {
310 } else if (sn->packets_sent[size_bin] < 20) {
311 /* let the bit-rate switch quickly during the first few packets */
313 } else if (ticks - ((hz*MIN_SWITCH_MS)/1000) > sn->ticks_since_switch[size_bin]) {
314 /* 2 seconds have gone by */
316 } else if (average_tx_time * 2 < sn->stats[size_bin][sn->current_rate[size_bin]].average_tx_time) {
317 /* the current bit-rate is twice as slow as the best one */
321 sn->packets_since_sample[size_bin]++;
324 if (best_ndx != sn->current_rate[size_bin]) {
325 DPRINTF(sc, ATH_DEBUG_RATE,
326 "%s: %s size %d switch rate %d (%d/%d) -> %d (%d/%d) after %d packets mrr %d\n",
328 ether_sprintf(an->an_node.ni_macaddr),
329 packet_size_bins[size_bin],
330 sn->rates[sn->current_rate[size_bin]].rate,
331 sn->stats[size_bin][sn->current_rate[size_bin]].average_tx_time,
332 sn->stats[size_bin][sn->current_rate[size_bin]].perfect_tx_time,
333 sn->rates[best_ndx].rate,
334 sn->stats[size_bin][best_ndx].average_tx_time,
335 sn->stats[size_bin][best_ndx].perfect_tx_time,
336 sn->packets_since_switch[size_bin],
339 sn->packets_since_switch[size_bin] = 0;
340 sn->current_rate[size_bin] = best_ndx;
341 sn->ticks_since_switch[size_bin] = ticks;
343 ndx = sn->current_rate[size_bin];
344 sn->packets_since_switch[size_bin]++;
347 * set the visible txrate for this node
348 * to the rate of small packets
350 an->an_node.ni_txrate = ndx;
355 KASSERT(ndx >= 0 && ndx < sn->num_rates, ("ndx is %d", ndx));
357 *rix = sn->rates[ndx].rix;
359 *txrate = sn->rates[ndx].shortPreambleRateCode;
361 *txrate = sn->rates[ndx].rateCode;
363 sn->packets_sent[size_bin]++;
367 ath_rate_setupxtxdesc(struct ath_softc *sc, struct ath_node *an,
368 struct ath_desc *ds, int shortPreamble, u_int8_t rix)
370 struct sample_node *sn = ATH_NODE_SAMPLE(an);
376 size_bin = size_to_bin(frame_size); // TODO: it's correct that frame_size alway 0 ?
377 ndx = sn->current_rate[size_bin]; /* retry at the current bit-rate */
379 if (!sn->stats[size_bin][ndx].packets_acked) {
380 ndx = 0; /* use the lowest bit-rate */
384 rateCode = sn->rates[ndx].shortPreambleRateCode;
386 rateCode = sn->rates[ndx].rateCode;
388 ath_hal_setupxtxdesc(sc->sc_ah, ds
389 , rateCode, 3 /* series 1 */
390 , sn->rates[0].rateCode, 3 /* series 2 */
391 , 0, 0 /* series 3 */
396 update_stats(struct ath_softc *sc, struct ath_node *an,
398 int ndx0, int tries0,
399 int ndx1, int tries1,
400 int ndx2, int tries2,
401 int ndx3, int tries3,
402 int short_tries, int tries, int status)
404 struct sample_node *sn = ATH_NODE_SAMPLE(an);
405 struct sample_softc *ssc = ATH_SOFTC_SAMPLE(sc);
407 int tries_so_far = 0;
412 size_bin = size_to_bin(frame_size);
413 size = bin_to_size(size_bin);
415 if (!(0 <= ndx0 && ndx0 < sn->num_rates)) {
416 printf("%s: bogus ndx0 %d, max %u, mode %u\n",
417 __func__, ndx0, sn->num_rates, sc->sc_curmode);
420 rate = sn->rates[ndx0].rate;
422 tt += calc_usecs_unicast_packet(sc, size, sn->rates[ndx0].rix,
424 MIN(tries0, tries) - 1);
425 tries_so_far += tries0;
426 if (tries1 && tries0 < tries) {
427 if (!(0 <= ndx1 && ndx1 < sn->num_rates)) {
428 printf("%s: bogus ndx1 %d, max %u, mode %u\n",
429 __func__, ndx1, sn->num_rates, sc->sc_curmode);
432 tt += calc_usecs_unicast_packet(sc, size, sn->rates[ndx1].rix,
434 MIN(tries1 + tries_so_far, tries) - tries_so_far - 1);
436 tries_so_far += tries1;
438 if (tries2 && tries0 + tries1 < tries) {
439 if (!(0 <= ndx2 && ndx2 < sn->num_rates)) {
440 printf("%s: bogus ndx2 %d, max %u, mode %u\n",
441 __func__, ndx2, sn->num_rates, sc->sc_curmode);
444 tt += calc_usecs_unicast_packet(sc, size, sn->rates[ndx2].rix,
446 MIN(tries2 + tries_so_far, tries) - tries_so_far - 1);
449 tries_so_far += tries2;
451 if (tries3 && tries0 + tries1 + tries2 < tries) {
452 if (!(0 <= ndx3 && ndx3 < sn->num_rates)) {
453 printf("%s: bogus ndx3 %d, max %u, mode %u\n",
454 __func__, ndx3, sn->num_rates, sc->sc_curmode);
457 tt += calc_usecs_unicast_packet(sc, size, sn->rates[ndx3].rix,
459 MIN(tries3 + tries_so_far, tries) - tries_so_far - 1);
461 if (sn->stats[size_bin][ndx0].total_packets < (100 / (100 - ssc->ath_smoothing_rate))) {
462 /* just average the first few packets */
463 int avg_tx = sn->stats[size_bin][ndx0].average_tx_time;
464 int packets = sn->stats[size_bin][ndx0].total_packets;
465 sn->stats[size_bin][ndx0].average_tx_time = (tt+(avg_tx*packets))/(packets+1);
468 sn->stats[size_bin][ndx0].average_tx_time =
469 ((sn->stats[size_bin][ndx0].average_tx_time * ssc->ath_smoothing_rate) +
470 (tt * (100 - ssc->ath_smoothing_rate))) / 100;
475 sn->stats[size_bin][ndx0].successive_failures++;
476 for (y = size_bin+1; y < NUM_PACKET_SIZE_BINS; y++) {
477 /* also say larger packets failed since we
478 * assume if a small packet fails at a lower
479 * bit-rate then a larger one will also.
481 sn->stats[y][ndx0].successive_failures++;
482 sn->stats[y][ndx0].last_tx = ticks;
483 sn->stats[y][ndx0].tries += tries;
484 sn->stats[y][ndx0].total_packets++;
487 sn->stats[size_bin][ndx0].packets_acked++;
488 sn->stats[size_bin][ndx0].successive_failures = 0;
490 sn->stats[size_bin][ndx0].tries += tries;
491 sn->stats[size_bin][ndx0].last_tx = ticks;
492 sn->stats[size_bin][ndx0].total_packets++;
495 if (ndx0 == sn->current_sample_ndx[size_bin]) {
496 DPRINTF(sc, ATH_DEBUG_RATE,
497 "%s: %s size %d %s sample rate %d tries (%d/%d) tt %d avg_tt (%d/%d)\n",
498 __func__, ether_sprintf(an->an_node.ni_macaddr),
500 status ? "FAIL" : "OK",
501 rate, short_tries, tries, tt,
502 sn->stats[size_bin][ndx0].average_tx_time,
503 sn->stats[size_bin][ndx0].perfect_tx_time);
504 sn->sample_tt[size_bin] = tt;
505 sn->current_sample_ndx[size_bin] = -1;
510 ath_rate_tx_complete(struct ath_softc *sc, struct ath_node *an,
511 const struct ath_buf *bf)
513 struct ieee80211com *ic = &sc->sc_ic;
514 struct sample_node *sn = ATH_NODE_SAMPLE(an);
515 const struct ath_tx_status *ts = &bf->bf_status.ds_txstat;
516 const struct ath_desc *ds0 = &bf->bf_desc[0];
517 int final_rate, short_tries, long_tries, frame_size;
520 final_rate = sc->sc_hwmap[ts->ts_rate &~ HAL_TXSTAT_ALTRATE].ieeerate;
521 short_tries = ts->ts_shortretry;
522 long_tries = ts->ts_longretry + 1;
523 frame_size = ds0->ds_ctl0 & 0x0fff; /* low-order 12 bits of ds_ctl0 */
524 if (frame_size == 0) /* NB: should not happen */
527 if (sn->num_rates <= 0) {
528 DPRINTF(sc, ATH_DEBUG_RATE,
529 "%s: %s size %d %s rate/try %d/%d no rates yet\n",
530 __func__, ether_sprintf(an->an_node.ni_macaddr),
531 bin_to_size(size_to_bin(frame_size)),
532 ts->ts_status ? "FAIL" : "OK",
533 short_tries, long_tries);
536 mrr = sc->sc_mrretry && !(ic->ic_flags & IEEE80211_F_USEPROT);
537 if (!mrr || !(ts->ts_rate & HAL_TXSTAT_ALTRATE)) {
538 int ndx = rate_to_ndx(sn, final_rate);
541 * Only one rate was used; optimize work.
543 DPRINTF(sc, ATH_DEBUG_RATE,
544 "%s: %s size %d %s rate/try %d/%d/%d\n",
545 __func__, ether_sprintf(an->an_node.ni_macaddr),
546 bin_to_size(size_to_bin(frame_size)),
547 ts->ts_status ? "FAIL" : "OK",
548 final_rate, short_tries, long_tries);
549 update_stats(sc, an, frame_size,
554 short_tries, long_tries, ts->ts_status);
556 int hwrate0, rate0, tries0, ndx0;
557 int hwrate1, rate1, tries1, ndx1;
558 int hwrate2, rate2, tries2, ndx2;
559 int hwrate3, rate3, tries3, ndx3;
560 int finalTSIdx = ts->ts_finaltsi;
563 * Process intermediate rates that failed.
565 if (sc->sc_ah->ah_magic != 0x20065416) {
566 hwrate0 = MS(ds0->ds_ctl3, AR_XmitRate0);
567 hwrate1 = MS(ds0->ds_ctl3, AR_XmitRate1);
568 hwrate2 = MS(ds0->ds_ctl3, AR_XmitRate2);
569 hwrate3 = MS(ds0->ds_ctl3, AR_XmitRate3);
571 hwrate0 = MS(ds0->ds_ctl3, AR5416_XmitRate0);
572 hwrate1 = MS(ds0->ds_ctl3, AR5416_XmitRate1);
573 hwrate2 = MS(ds0->ds_ctl3, AR5416_XmitRate2);
574 hwrate3 = MS(ds0->ds_ctl3, AR5416_XmitRate3);
577 rate0 = sc->sc_hwmap[hwrate0].ieeerate;
578 tries0 = MS(ds0->ds_ctl2, AR_XmitDataTries0);
579 ndx0 = rate_to_ndx(sn, rate0);
581 rate1 = sc->sc_hwmap[hwrate1].ieeerate;
582 tries1 = MS(ds0->ds_ctl2, AR_XmitDataTries1);
583 ndx1 = rate_to_ndx(sn, rate1);
585 rate2 = sc->sc_hwmap[hwrate2].ieeerate;
586 tries2 = MS(ds0->ds_ctl2, AR_XmitDataTries2);
587 ndx2 = rate_to_ndx(sn, rate2);
589 rate3 = sc->sc_hwmap[hwrate3].ieeerate;
590 tries3 = MS(ds0->ds_ctl2, AR_XmitDataTries3);
591 ndx3 = rate_to_ndx(sn, rate3);
593 DPRINTF(sc, ATH_DEBUG_RATE,
594 "%s: %s size %d finaltsidx %d tries %d %s rate/try [%d/%d %d/%d %d/%d %d/%d]\n",
595 __func__, ether_sprintf(an->an_node.ni_macaddr),
596 bin_to_size(size_to_bin(frame_size)),
599 ts->ts_status ? "FAIL" : "OK",
606 * NB: series > 0 are not penalized for failure
607 * based on the try counts under the assumption
608 * that losses are often bursty and since we
609 * sample higher rates 1 try at a time doing so
610 * may unfairly penalize them.
613 update_stats(sc, an, frame_size,
618 short_tries, long_tries,
619 long_tries > tries0);
620 long_tries -= tries0;
623 if (tries1 && finalTSIdx > 0) {
624 update_stats(sc, an, frame_size,
629 short_tries, long_tries,
631 long_tries -= tries1;
634 if (tries2 && finalTSIdx > 1) {
635 update_stats(sc, an, frame_size,
640 short_tries, long_tries,
642 long_tries -= tries2;
645 if (tries3 && finalTSIdx > 2) {
646 update_stats(sc, an, frame_size,
651 short_tries, long_tries,
658 ath_rate_newassoc(struct ath_softc *sc, struct ath_node *an, int isnew)
660 DPRINTF(sc, ATH_DEBUG_NODE, "%s: %s isnew %d\n", __func__,
661 ether_sprintf(an->an_node.ni_macaddr), isnew);
663 ath_rate_ctl_reset(sc, &an->an_node);
667 * Initialize the tables for a node.
670 ath_rate_ctl_reset(struct ath_softc *sc, struct ieee80211_node *ni)
672 #define RATE(_ix) (ni->ni_rates.rs_rates[(_ix)] & IEEE80211_RATE_VAL)
673 struct ieee80211com *ic = &sc->sc_ic;
674 struct ath_node *an = ATH_NODE(ni);
675 struct sample_node *sn = ATH_NODE_SAMPLE(an);
676 const HAL_RATE_TABLE *rt = sc->sc_currates;
679 KASSERT(rt != NULL, ("no rate table, mode %u", sc->sc_curmode));
680 sn->static_rate_ndx = -1;
681 if (ic->ic_fixed_rate != IEEE80211_FIXED_RATE_NONE) {
683 * A fixed rate is to be used; ic_fixed_rate is the
684 * IEEE code for this rate (sans basic bit). Convert this
685 * to the index into the negotiated rate set for
688 /* NB: the rate set is assumed sorted */
689 srate = ni->ni_rates.rs_nrates - 1;
690 for (; srate >= 0 && RATE(srate) != ic->ic_fixed_rate; srate--)
693 * The fixed rate may not be available due to races
694 * and mode settings. Also orphaned nodes created in
695 * adhoc mode may not have any rate set so this lookup
699 sn->static_rate_ndx = srate;
702 DPRINTF(sc, ATH_DEBUG_RATE, "%s: %s size 1600 rate/tt",
703 __func__, ether_sprintf(ni->ni_macaddr));
705 sn->num_rates = ni->ni_rates.rs_nrates;
706 for (x = 0; x < ni->ni_rates.rs_nrates; x++) {
707 sn->rates[x].rate = ni->ni_rates.rs_rates[x] & IEEE80211_RATE_VAL;
708 sn->rates[x].rix = sc->sc_rixmap[sn->rates[x].rate];
709 if (sn->rates[x].rix == 0xff) {
710 DPRINTF(sc, ATH_DEBUG_RATE,
711 "%s: ignore bogus rix at %d\n", __func__, x);
714 sn->rates[x].rateCode = rt->info[sn->rates[x].rix].rateCode;
715 sn->rates[x].shortPreambleRateCode =
716 rt->info[sn->rates[x].rix].rateCode |
717 rt->info[sn->rates[x].rix].shortPreamble;
719 DPRINTF(sc, ATH_DEBUG_RATE, " %d/%d", sn->rates[x].rate,
720 calc_usecs_unicast_packet(sc, 1600, sn->rates[x].rix, 0,0));
722 DPRINTF(sc, ATH_DEBUG_RATE, "%s\n", "");
724 /* set the visible bit-rate to the lowest one available */
726 sn->num_rates = ni->ni_rates.rs_nrates;
728 for (y = 0; y < NUM_PACKET_SIZE_BINS; y++) {
729 int size = bin_to_size(y);
731 sn->packets_sent[y] = 0;
732 sn->current_sample_ndx[y] = -1;
733 sn->last_sample_ndx[y] = 0;
735 for (x = 0; x < ni->ni_rates.rs_nrates; x++) {
736 sn->stats[y][x].successive_failures = 0;
737 sn->stats[y][x].tries = 0;
738 sn->stats[y][x].total_packets = 0;
739 sn->stats[y][x].packets_acked = 0;
740 sn->stats[y][x].last_tx = 0;
742 sn->stats[y][x].perfect_tx_time =
743 calc_usecs_unicast_packet(sc, size,
746 sn->stats[y][x].average_tx_time = sn->stats[y][x].perfect_tx_time;
749 /* set the initial rate */
750 for (ndx = sn->num_rates-1; ndx > 0; ndx--) {
751 if (sn->rates[ndx].rate <= 72) {
755 sn->current_rate[y] = ndx;
758 DPRINTF(sc, ATH_DEBUG_RATE,
759 "%s: %s %d rates %d%sMbps (%dus)- %d%sMbps (%dus)\n",
760 __func__, ether_sprintf(ni->ni_macaddr),
762 sn->rates[0].rate/2, sn->rates[0].rate % 0x1 ? ".5" : "",
763 sn->stats[1][0].perfect_tx_time,
764 sn->rates[sn->num_rates-1].rate/2,
765 sn->rates[sn->num_rates-1].rate % 0x1 ? ".5" : "",
766 sn->stats[1][sn->num_rates-1].perfect_tx_time
769 if (sn->static_rate_ndx != -1)
770 ni->ni_txrate = sn->static_rate_ndx;
772 ni->ni_txrate = sn->current_rate[0];
777 rate_cb(void *arg, struct ieee80211_node *ni)
779 struct ath_softc *sc = arg;
781 ath_rate_newassoc(sc, ATH_NODE(ni), 1);
785 * Reset the rate control state for each 802.11 state transition.
788 ath_rate_newstate(struct ath_softc *sc, enum ieee80211_state state)
790 struct ieee80211com *ic = &sc->sc_ic;
792 if (state == IEEE80211_S_RUN) {
793 if (ic->ic_opmode != IEEE80211_M_STA) {
795 * Sync rates for associated stations and neighbors.
797 ieee80211_iterate_nodes(&ic->ic_sta, rate_cb, sc);
799 ath_rate_newassoc(sc, ATH_NODE(ic->ic_bss), 1);
804 ath_rate_sysctlattach(struct ath_softc *sc, struct sample_softc *osc)
806 struct sysctl_ctx_list *ctx = device_get_sysctl_ctx(sc->sc_dev);
807 struct sysctl_oid *tree = device_get_sysctl_tree(sc->sc_dev);
809 /* XXX bounds check [0..100] */
810 SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
811 "smoothing_rate", CTLFLAG_RW, &osc->ath_smoothing_rate, 0,
812 "rate control: retry threshold to credit rate raise (%%)");
813 /* XXX bounds check [2..100] */
814 SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
815 "sample_rate", CTLFLAG_RW, &osc->ath_sample_rate,0,
816 "rate control: # good periods before raising rate");
819 struct ath_ratectrl *
820 ath_rate_attach(struct ath_softc *sc)
822 struct sample_softc *osc;
824 DPRINTF(sc, ATH_DEBUG_ANY, "%s:\n", __func__);
825 osc = malloc(sizeof(struct sample_softc), M_DEVBUF, M_NOWAIT|M_ZERO);
828 osc->arc.arc_space = sizeof(struct sample_node);
829 osc->ath_smoothing_rate = 95; /* ewma percentage (out of 100) */
830 osc->ath_sample_rate = 10; /* send a different bit-rate 1/X packets */
831 ath_rate_sysctlattach(sc, osc);
836 ath_rate_detach(struct ath_ratectrl *arc)
838 struct sample_softc *osc = (struct sample_softc *) arc;