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
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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.
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38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
42 * John Bicket's SampleRate control algorithm.
49 #include <sys/param.h>
50 #include <sys/systm.h>
51 #include <sys/sysctl.h>
52 #include <sys/kernel.h>
54 #include <sys/malloc.h>
55 #include <sys/mutex.h>
56 #include <sys/errno.h>
58 #include <machine/bus.h>
59 #include <machine/resource.h>
62 #include <sys/socket.h>
65 #include <net/if_var.h>
66 #include <net/if_media.h>
67 #include <net/if_arp.h>
68 #include <net/ethernet.h> /* XXX for ether_sprintf */
70 #include <net80211/ieee80211_var.h>
75 #include <netinet/in.h>
76 #include <netinet/if_ether.h>
79 #include <dev/ath/if_athvar.h>
80 #include <dev/ath/ath_rate/sample/sample.h>
81 #include <dev/ath/ath_hal/ah_desc.h>
82 #include <dev/ath/ath_rate/sample/tx_schedules.h>
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 static void ath_rate_ctl_reset(struct ath_softc *, struct ieee80211_node *);
111 size_to_bin(int size)
113 #if NUM_PACKET_SIZE_BINS > 1
114 if (size <= packet_size_bins[0])
117 #if NUM_PACKET_SIZE_BINS > 2
118 if (size <= packet_size_bins[1])
121 #if NUM_PACKET_SIZE_BINS > 3
122 if (size <= packet_size_bins[2])
125 #if NUM_PACKET_SIZE_BINS > 4
126 #error "add support for more packet sizes"
128 return NUM_PACKET_SIZE_BINS-1;
132 ath_rate_node_init(struct ath_softc *sc, struct ath_node *an)
134 /* NB: assumed to be zero'd by caller */
138 ath_rate_node_cleanup(struct ath_softc *sc, struct ath_node *an)
143 dot11rate(const HAL_RATE_TABLE *rt, int rix)
147 return rt->info[rix].phy == IEEE80211_T_HT ?
148 rt->info[rix].dot11Rate : (rt->info[rix].dot11Rate & IEEE80211_RATE_VAL) / 2;
152 dot11rate_label(const HAL_RATE_TABLE *rt, int rix)
156 return rt->info[rix].phy == IEEE80211_T_HT ? "MCS" : "Mb ";
160 * Return the rix with the lowest average_tx_time,
161 * or -1 if all the average_tx_times are 0.
164 pick_best_rate(struct ath_node *an, const HAL_RATE_TABLE *rt,
165 int size_bin, int require_acked_before)
167 struct sample_node *sn = ATH_NODE_SAMPLE(an);
168 int best_rate_rix, best_rate_tt, best_rate_pct;
175 for (mask = sn->ratemask, rix = 0; mask != 0; mask >>= 1, rix++) {
176 if ((mask & 1) == 0) /* not a supported rate */
179 /* Don't pick a non-HT rate for a HT node */
180 if ((an->an_node.ni_flags & IEEE80211_NODE_HT) &&
181 (rt->info[rix].phy != IEEE80211_T_HT)) {
185 tt = sn->stats[size_bin][rix].average_tx_time;
187 (require_acked_before &&
188 !sn->stats[size_bin][rix].packets_acked))
191 /* Calculate percentage if possible */
192 if (sn->stats[size_bin][rix].total_packets > 0) {
193 pct = sn->stats[size_bin][rix].ewma_pct;
195 /* XXX for now, assume 95% ok */
199 /* don't use a bit-rate that has been failing */
200 if (sn->stats[size_bin][rix].successive_failures > 3)
204 * For HT, Don't use a bit rate that is much more
205 * lossy than the best.
207 * XXX this isn't optimal; it's just designed to
208 * eliminate rates that are going to be obviously
211 if (an->an_node.ni_flags & IEEE80211_NODE_HT) {
212 if (best_rate_pct > (pct + 50))
217 * For non-MCS rates, use the current average txtime for
220 if (! (an->an_node.ni_flags & IEEE80211_NODE_HT)) {
221 if (best_rate_tt == 0 || tt <= best_rate_tt) {
229 * Since 2 stream rates have slightly higher TX times,
230 * allow a little bit of leeway. This should later
231 * be abstracted out and properly handled.
233 if (an->an_node.ni_flags & IEEE80211_NODE_HT) {
234 if (best_rate_tt == 0 || (tt * 8 <= best_rate_tt * 10)) {
241 return (best_rate_tt ? best_rate_rix : -1);
245 * Pick a good "random" bit-rate to sample other than the current one.
248 pick_sample_rate(struct sample_softc *ssc , struct ath_node *an,
249 const HAL_RATE_TABLE *rt, int size_bin)
251 #define DOT11RATE(ix) (rt->info[ix].dot11Rate & IEEE80211_RATE_VAL)
252 #define MCS(ix) (rt->info[ix].dot11Rate | IEEE80211_RATE_MCS)
253 struct sample_node *sn = ATH_NODE_SAMPLE(an);
254 int current_rix, rix;
258 current_rix = sn->current_rix[size_bin];
259 if (current_rix < 0) {
260 /* no successes yet, send at the lowest bit-rate */
261 /* XXX should return MCS0 if HT */
265 current_tt = sn->stats[size_bin][current_rix].average_tx_time;
267 rix = sn->last_sample_rix[size_bin]+1; /* next sample rate */
268 mask = sn->ratemask &~ ((uint64_t) 1<<current_rix);/* don't sample current rate */
270 if ((mask & ((uint64_t) 1<<rix)) == 0) { /* not a supported rate */
272 if (++rix >= rt->rateCount)
278 * The following code stops trying to sample
279 * non-MCS rates when speaking to an MCS node.
280 * However, at least for CCK rates in 2.4GHz mode,
281 * the non-MCS rates MAY actually provide better
282 * PER at the very far edge of reception.
284 * However! Until ath_rate_form_aggr() grows
285 * some logic to not form aggregates if the
286 * selected rate is non-MCS, this won't work.
288 * So don't disable this code until you've taught
289 * ath_rate_form_aggr() to drop out if any of
290 * the selected rates are non-MCS.
293 /* if the node is HT and the rate isn't HT, don't bother sample */
294 if ((an->an_node.ni_flags & IEEE80211_NODE_HT) &&
295 (rt->info[rix].phy != IEEE80211_T_HT)) {
296 mask &= ~((uint64_t) 1<<rix);
301 /* this bit-rate is always worse than the current one */
302 if (sn->stats[size_bin][rix].perfect_tx_time > current_tt) {
303 mask &= ~((uint64_t) 1<<rix);
307 /* rarely sample bit-rates that fail a lot */
308 if (sn->stats[size_bin][rix].successive_failures > ssc->max_successive_failures &&
309 ticks - sn->stats[size_bin][rix].last_tx < ssc->stale_failure_timeout) {
310 mask &= ~((uint64_t) 1<<rix);
315 * For HT, only sample a few rates on either side of the
316 * current rix; there's quite likely a lot of them.
318 if (an->an_node.ni_flags & IEEE80211_NODE_HT) {
319 if (rix < (current_rix - 3) ||
320 rix > (current_rix + 3)) {
321 mask &= ~((uint64_t) 1<<rix);
326 /* Don't sample more than 2 rates higher for rates > 11M for non-HT rates */
327 if (! (an->an_node.ni_flags & IEEE80211_NODE_HT)) {
328 if (DOT11RATE(rix) > 2*11 && rix > current_rix + 2) {
329 mask &= ~((uint64_t) 1<<rix);
334 sn->last_sample_rix[size_bin] = rix;
343 ath_rate_get_static_rix(struct ath_softc *sc, const struct ieee80211_node *ni)
345 #define RATE(_ix) (ni->ni_rates.rs_rates[(_ix)] & IEEE80211_RATE_VAL)
346 #define DOT11RATE(_ix) (rt->info[(_ix)].dot11Rate & IEEE80211_RATE_VAL)
347 #define MCS(_ix) (ni->ni_htrates.rs_rates[_ix] | IEEE80211_RATE_MCS)
348 const struct ieee80211_txparam *tp = ni->ni_txparms;
351 /* Check MCS rates */
352 for (srate = ni->ni_htrates.rs_nrates - 1; srate >= 0; srate--) {
353 if (MCS(srate) == tp->ucastrate)
354 return sc->sc_rixmap[tp->ucastrate];
357 /* Check legacy rates */
358 for (srate = ni->ni_rates.rs_nrates - 1; srate >= 0; srate--) {
359 if (RATE(srate) == tp->ucastrate)
360 return sc->sc_rixmap[tp->ucastrate];
369 ath_rate_update_static_rix(struct ath_softc *sc, struct ieee80211_node *ni)
371 struct ath_node *an = ATH_NODE(ni);
372 const struct ieee80211_txparam *tp = ni->ni_txparms;
373 struct sample_node *sn = ATH_NODE_SAMPLE(an);
375 if (tp != NULL && tp->ucastrate != IEEE80211_FIXED_RATE_NONE) {
377 * A fixed rate is to be used; ucastrate is the IEEE code
378 * for this rate (sans basic bit). Check this against the
379 * negotiated rate set for the node. Note the fixed rate
380 * may not be available for various reasons so we only
381 * setup the static rate index if the lookup is successful.
383 sn->static_rix = ath_rate_get_static_rix(sc, ni);
390 * Pick a non-HT rate to begin using.
393 ath_rate_pick_seed_rate_legacy(struct ath_softc *sc, struct ath_node *an,
396 #define DOT11RATE(ix) (rt->info[ix].dot11Rate & IEEE80211_RATE_VAL)
397 #define MCS(ix) (rt->info[ix].dot11Rate | IEEE80211_RATE_MCS)
398 #define RATE(ix) (DOT11RATE(ix) / 2)
400 const HAL_RATE_TABLE *rt = sc->sc_currates;
401 struct sample_node *sn = ATH_NODE_SAMPLE(an);
402 const int size_bin = size_to_bin(frameLen);
404 /* no packet has been sent successfully yet */
405 for (rix = rt->rateCount-1; rix > 0; rix--) {
406 if ((sn->ratemask & ((uint64_t) 1<<rix)) == 0)
410 if (rt->info[rix].phy == IEEE80211_T_HT)
414 * Pick the highest rate <= 36 Mbps
415 * that hasn't failed.
417 if (DOT11RATE(rix) <= 72 &&
418 sn->stats[size_bin][rix].successive_failures == 0) {
429 * Pick a HT rate to begin using.
431 * Don't use any non-HT rates; only consider HT rates.
434 ath_rate_pick_seed_rate_ht(struct ath_softc *sc, struct ath_node *an,
437 #define DOT11RATE(ix) (rt->info[ix].dot11Rate & IEEE80211_RATE_VAL)
438 #define MCS(ix) (rt->info[ix].dot11Rate | IEEE80211_RATE_MCS)
439 #define RATE(ix) (DOT11RATE(ix) / 2)
440 int rix = -1, ht_rix = -1;
441 const HAL_RATE_TABLE *rt = sc->sc_currates;
442 struct sample_node *sn = ATH_NODE_SAMPLE(an);
443 const int size_bin = size_to_bin(frameLen);
445 /* no packet has been sent successfully yet */
446 for (rix = rt->rateCount-1; rix > 0; rix--) {
447 /* Skip rates we can't use */
448 if ((sn->ratemask & ((uint64_t) 1<<rix)) == 0)
451 /* Keep a copy of the last seen HT rate index */
452 if (rt->info[rix].phy == IEEE80211_T_HT)
455 /* Skip non-HT rates */
456 if (rt->info[rix].phy != IEEE80211_T_HT)
460 * Pick a medium-speed rate regardless of stream count
461 * which has not seen any failures. Higher rates may fail;
462 * we'll try them later.
464 if (((MCS(rix) & 0x7) <= 4) &&
465 sn->stats[size_bin][rix].successive_failures == 0) {
471 * If all the MCS rates have successive failures, rix should be
472 * > 0; otherwise use the lowest MCS rix (hopefully MCS 0.)
474 return MAX(rix, ht_rix);
482 ath_rate_findrate(struct ath_softc *sc, struct ath_node *an,
483 int shortPreamble, size_t frameLen,
484 u_int8_t *rix0, int *try0, u_int8_t *txrate)
486 #define DOT11RATE(ix) (rt->info[ix].dot11Rate & IEEE80211_RATE_VAL)
487 #define MCS(ix) (rt->info[ix].dot11Rate | IEEE80211_RATE_MCS)
488 #define RATE(ix) (DOT11RATE(ix) / 2)
489 struct sample_node *sn = ATH_NODE_SAMPLE(an);
490 struct sample_softc *ssc = ATH_SOFTC_SAMPLE(sc);
491 struct ieee80211com *ic = &sc->sc_ic;
492 const HAL_RATE_TABLE *rt = sc->sc_currates;
493 const int size_bin = size_to_bin(frameLen);
494 int rix, mrr, best_rix, change_rates;
495 unsigned average_tx_time;
497 ath_rate_update_static_rix(sc, &an->an_node);
499 if (sn->currates != sc->sc_currates) {
500 device_printf(sc->sc_dev, "%s: currates != sc_currates!\n",
503 *try0 = ATH_TXMAXTRY;
507 if (sn->static_rix != -1) {
508 rix = sn->static_rix;
509 *try0 = ATH_TXMAXTRY;
513 mrr = sc->sc_mrretry;
514 /* XXX check HT protmode too */
515 if (mrr && (ic->ic_flags & IEEE80211_F_USEPROT && !sc->sc_mrrprot))
518 best_rix = pick_best_rate(an, rt, size_bin, !mrr);
520 average_tx_time = sn->stats[size_bin][best_rix].average_tx_time;
525 * Limit the time measuring the performance of other tx
526 * rates to sample_rate% of the total transmission time.
528 if (sn->sample_tt[size_bin] < average_tx_time * (sn->packets_since_sample[size_bin]*ssc->sample_rate/100)) {
529 rix = pick_sample_rate(ssc, an, rt, size_bin);
530 IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
531 &an->an_node, "att %d sample_tt %d size %u sample rate %d %s current rate %d %s",
533 sn->sample_tt[size_bin],
534 bin_to_size(size_bin),
536 dot11rate_label(rt, rix),
537 dot11rate(rt, sn->current_rix[size_bin]),
538 dot11rate_label(rt, sn->current_rix[size_bin]));
539 if (rix != sn->current_rix[size_bin]) {
540 sn->current_sample_rix[size_bin] = rix;
542 sn->current_sample_rix[size_bin] = -1;
544 sn->packets_since_sample[size_bin] = 0;
547 if (!sn->packets_sent[size_bin] || best_rix == -1) {
548 /* no packet has been sent successfully yet */
550 if (an->an_node.ni_flags & IEEE80211_NODE_HT)
552 ath_rate_pick_seed_rate_ht(sc, an, frameLen);
555 ath_rate_pick_seed_rate_legacy(sc, an, frameLen);
556 } else if (sn->packets_sent[size_bin] < 20) {
557 /* let the bit-rate switch quickly during the first few packets */
558 IEEE80211_NOTE(an->an_node.ni_vap,
559 IEEE80211_MSG_RATECTL, &an->an_node,
560 "%s: switching quickly..", __func__);
562 } else if (ticks - ssc->min_switch > sn->ticks_since_switch[size_bin]) {
563 /* min_switch seconds have gone by */
564 IEEE80211_NOTE(an->an_node.ni_vap,
565 IEEE80211_MSG_RATECTL, &an->an_node,
566 "%s: min_switch %d > ticks_since_switch %d..",
567 __func__, ticks - ssc->min_switch, sn->ticks_since_switch[size_bin]);
569 } else if ((! (an->an_node.ni_flags & IEEE80211_NODE_HT)) &&
570 (2*average_tx_time < sn->stats[size_bin][sn->current_rix[size_bin]].average_tx_time)) {
571 /* the current bit-rate is twice as slow as the best one */
572 IEEE80211_NOTE(an->an_node.ni_vap,
573 IEEE80211_MSG_RATECTL, &an->an_node,
574 "%s: 2x att (= %d) < cur_rix att %d",
576 2 * average_tx_time, sn->stats[size_bin][sn->current_rix[size_bin]].average_tx_time);
578 } else if ((an->an_node.ni_flags & IEEE80211_NODE_HT)) {
579 int cur_rix = sn->current_rix[size_bin];
580 int cur_att = sn->stats[size_bin][cur_rix].average_tx_time;
582 * If the node is HT, upgrade it if the MCS rate is
583 * higher and the average tx time is within 20% of
584 * the current rate. It can fail a little.
586 * This is likely not optimal!
589 printf("cur rix/att %x/%d, best rix/att %x/%d\n",
590 MCS(cur_rix), cur_att, MCS(best_rix), average_tx_time);
592 if ((MCS(best_rix) > MCS(cur_rix)) &&
593 (average_tx_time * 8) <= (cur_att * 10)) {
594 IEEE80211_NOTE(an->an_node.ni_vap,
595 IEEE80211_MSG_RATECTL, &an->an_node,
596 "%s: HT: best_rix 0x%d > cur_rix 0x%x, average_tx_time %d, cur_att %d",
598 MCS(best_rix), MCS(cur_rix), average_tx_time, cur_att);
603 sn->packets_since_sample[size_bin]++;
606 if (best_rix != sn->current_rix[size_bin]) {
607 IEEE80211_NOTE(an->an_node.ni_vap,
608 IEEE80211_MSG_RATECTL,
610 "%s: size %d switch rate %d (%d/%d) -> %d (%d/%d) after %d packets mrr %d",
612 bin_to_size(size_bin),
613 RATE(sn->current_rix[size_bin]),
614 sn->stats[size_bin][sn->current_rix[size_bin]].average_tx_time,
615 sn->stats[size_bin][sn->current_rix[size_bin]].perfect_tx_time,
617 sn->stats[size_bin][best_rix].average_tx_time,
618 sn->stats[size_bin][best_rix].perfect_tx_time,
619 sn->packets_since_switch[size_bin],
622 sn->packets_since_switch[size_bin] = 0;
623 sn->current_rix[size_bin] = best_rix;
624 sn->ticks_since_switch[size_bin] = ticks;
626 * Set the visible txrate for this node.
628 an->an_node.ni_txrate = (rt->info[best_rix].phy == IEEE80211_T_HT) ? MCS(best_rix) : DOT11RATE(best_rix);
630 rix = sn->current_rix[size_bin];
631 sn->packets_since_switch[size_bin]++;
633 *try0 = mrr ? sn->sched[rix].t0 : ATH_TXMAXTRY;
637 * This bug totally sucks and should be fixed.
639 * For now though, let's not panic, so we can start to figure
640 * out how to better reproduce it.
642 if (rix < 0 || rix >= rt->rateCount) {
643 printf("%s: ERROR: rix %d out of bounds (rateCount=%d)\n",
647 rix = 0; /* XXX just default for now */
649 KASSERT(rix >= 0 && rix < rt->rateCount, ("rix is %d", rix));
652 *txrate = rt->info[rix].rateCode
653 | (shortPreamble ? rt->info[rix].shortPreamble : 0);
654 sn->packets_sent[size_bin]++;
661 * Get the TX rates. Don't fiddle with short preamble flags for them;
662 * the caller can do that.
665 ath_rate_getxtxrates(struct ath_softc *sc, struct ath_node *an,
666 uint8_t rix0, struct ath_rc_series *rc)
668 struct sample_node *sn = ATH_NODE_SAMPLE(an);
669 const struct txschedule *sched = &sn->sched[rix0];
671 KASSERT(rix0 == sched->r0, ("rix0 (%x) != sched->r0 (%x)!\n",
674 rc[0].flags = rc[1].flags = rc[2].flags = rc[3].flags = 0;
676 rc[0].rix = sched->r0;
677 rc[1].rix = sched->r1;
678 rc[2].rix = sched->r2;
679 rc[3].rix = sched->r3;
681 rc[0].tries = sched->t0;
682 rc[1].tries = sched->t1;
683 rc[2].tries = sched->t2;
684 rc[3].tries = sched->t3;
688 ath_rate_setupxtxdesc(struct ath_softc *sc, struct ath_node *an,
689 struct ath_desc *ds, int shortPreamble, u_int8_t rix)
691 struct sample_node *sn = ATH_NODE_SAMPLE(an);
692 const struct txschedule *sched = &sn->sched[rix];
693 const HAL_RATE_TABLE *rt = sc->sc_currates;
694 uint8_t rix1, s1code, rix2, s2code, rix3, s3code;
696 /* XXX precalculate short preamble tables */
698 s1code = rt->info[rix1].rateCode
699 | (shortPreamble ? rt->info[rix1].shortPreamble : 0);
701 s2code = rt->info[rix2].rateCode
702 | (shortPreamble ? rt->info[rix2].shortPreamble : 0);
704 s3code = rt->info[rix3].rateCode
705 | (shortPreamble ? rt->info[rix3].shortPreamble : 0);
706 ath_hal_setupxtxdesc(sc->sc_ah, ds,
707 s1code, sched->t1, /* series 1 */
708 s2code, sched->t2, /* series 2 */
709 s3code, sched->t3); /* series 3 */
713 update_stats(struct ath_softc *sc, struct ath_node *an,
715 int rix0, int tries0,
716 int rix1, int tries1,
717 int rix2, int tries2,
718 int rix3, int tries3,
719 int short_tries, int tries, int status,
720 int nframes, int nbad)
722 struct sample_node *sn = ATH_NODE_SAMPLE(an);
723 struct sample_softc *ssc = ATH_SOFTC_SAMPLE(sc);
724 #ifdef IEEE80211_DEBUG
725 const HAL_RATE_TABLE *rt = sc->sc_currates;
727 const int size_bin = size_to_bin(frame_size);
728 const int size = bin_to_size(size_bin);
729 int tt, tries_so_far;
730 int is_ht40 = (an->an_node.ni_chw == 40);
733 if (!IS_RATE_DEFINED(sn, rix0))
735 tt = calc_usecs_unicast_packet(sc, size, rix0, short_tries,
736 MIN(tries0, tries) - 1, is_ht40);
737 tries_so_far = tries0;
739 if (tries1 && tries_so_far < tries) {
740 if (!IS_RATE_DEFINED(sn, rix1))
742 tt += calc_usecs_unicast_packet(sc, size, rix1, short_tries,
743 MIN(tries1 + tries_so_far, tries) - tries_so_far - 1, is_ht40);
744 tries_so_far += tries1;
747 if (tries2 && tries_so_far < tries) {
748 if (!IS_RATE_DEFINED(sn, rix2))
750 tt += calc_usecs_unicast_packet(sc, size, rix2, short_tries,
751 MIN(tries2 + tries_so_far, tries) - tries_so_far - 1, is_ht40);
752 tries_so_far += tries2;
755 if (tries3 && tries_so_far < tries) {
756 if (!IS_RATE_DEFINED(sn, rix3))
758 tt += calc_usecs_unicast_packet(sc, size, rix3, short_tries,
759 MIN(tries3 + tries_so_far, tries) - tries_so_far - 1, is_ht40);
762 if (sn->stats[size_bin][rix0].total_packets < ssc->smoothing_minpackets) {
763 /* just average the first few packets */
764 int avg_tx = sn->stats[size_bin][rix0].average_tx_time;
765 int packets = sn->stats[size_bin][rix0].total_packets;
766 sn->stats[size_bin][rix0].average_tx_time = (tt+(avg_tx*packets))/(packets+nframes);
769 sn->stats[size_bin][rix0].average_tx_time =
770 ((sn->stats[size_bin][rix0].average_tx_time * ssc->smoothing_rate) +
771 (tt * (100 - ssc->smoothing_rate))) / 100;
775 * XXX Don't mark the higher bit rates as also having failed; as this
776 * unfortunately stops those rates from being tasted when trying to
777 * TX. This happens with 11n aggregation.
779 if (nframes == nbad) {
783 sn->stats[size_bin][rix0].successive_failures += nbad;
785 for (y = size_bin+1; y < NUM_PACKET_SIZE_BINS; y++) {
787 * Also say larger packets failed since we
788 * assume if a small packet fails at a
789 * bit-rate then a larger one will also.
791 sn->stats[y][rix0].successive_failures += nbad;
792 sn->stats[y][rix0].last_tx = ticks;
793 sn->stats[y][rix0].tries += tries;
794 sn->stats[y][rix0].total_packets += nframes;
798 sn->stats[size_bin][rix0].packets_acked += (nframes - nbad);
799 sn->stats[size_bin][rix0].successive_failures = 0;
801 sn->stats[size_bin][rix0].tries += tries;
802 sn->stats[size_bin][rix0].last_tx = ticks;
803 sn->stats[size_bin][rix0].total_packets += nframes;
805 /* update EWMA for this rix */
807 /* Calculate percentage based on current rate */
810 pct = ((nframes - nbad) * 1000) / nframes;
812 if (sn->stats[size_bin][rix0].total_packets <
813 ssc->smoothing_minpackets) {
814 /* just average the first few packets */
815 int a_pct = (sn->stats[size_bin][rix0].packets_acked * 1000) /
816 (sn->stats[size_bin][rix0].total_packets);
817 sn->stats[size_bin][rix0].ewma_pct = a_pct;
820 sn->stats[size_bin][rix0].ewma_pct =
821 ((sn->stats[size_bin][rix0].ewma_pct * ssc->smoothing_rate) +
822 (pct * (100 - ssc->smoothing_rate))) / 100;
826 if (rix0 == sn->current_sample_rix[size_bin]) {
827 IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
829 "%s: size %d %s sample rate %d %s tries (%d/%d) tt %d avg_tt (%d/%d) nfrm %d nbad %d",
832 status ? "FAIL" : "OK",
834 dot11rate_label(rt, rix0),
835 short_tries, tries, tt,
836 sn->stats[size_bin][rix0].average_tx_time,
837 sn->stats[size_bin][rix0].perfect_tx_time,
839 sn->sample_tt[size_bin] = tt;
840 sn->current_sample_rix[size_bin] = -1;
845 badrate(struct ath_softc *sc, int series, int hwrate, int tries, int status)
848 device_printf(sc->sc_dev,
849 "bad series%d hwrate 0x%x, tries %u ts_status 0x%x\n",
850 series, hwrate, tries, status);
854 ath_rate_tx_complete(struct ath_softc *sc, struct ath_node *an,
855 const struct ath_rc_series *rc, const struct ath_tx_status *ts,
856 int frame_size, int nframes, int nbad)
858 struct ieee80211com *ic = &sc->sc_ic;
859 struct sample_node *sn = ATH_NODE_SAMPLE(an);
860 int final_rix, short_tries, long_tries;
861 const HAL_RATE_TABLE *rt = sc->sc_currates;
862 int status = ts->ts_status;
865 final_rix = rt->rateCodeToIndex[ts->ts_rate];
866 short_tries = ts->ts_shortretry;
867 long_tries = ts->ts_longretry + 1;
870 device_printf(sc->sc_dev, "%s: nframes=0?\n", __func__);
874 if (frame_size == 0) /* NB: should not happen */
877 if (sn->ratemask == 0) {
878 IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
880 "%s: size %d %s rate/try %d/%d no rates yet",
882 bin_to_size(size_to_bin(frame_size)),
883 status ? "FAIL" : "OK",
884 short_tries, long_tries);
887 mrr = sc->sc_mrretry;
888 /* XXX check HT protmode too */
889 if (mrr && (ic->ic_flags & IEEE80211_F_USEPROT && !sc->sc_mrrprot))
892 if (!mrr || ts->ts_finaltsi == 0) {
893 if (!IS_RATE_DEFINED(sn, final_rix)) {
894 device_printf(sc->sc_dev,
895 "%s: ts_rate=%d ts_finaltsi=%d, final_rix=%d\n",
896 __func__, ts->ts_rate, ts->ts_finaltsi, final_rix);
897 badrate(sc, 0, ts->ts_rate, long_tries, status);
901 * Only one rate was used; optimize work.
903 IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
904 &an->an_node, "%s: size %d (%d bytes) %s rate/short/long %d %s/%d/%d nframes/nbad [%d/%d]",
906 bin_to_size(size_to_bin(frame_size)),
908 status ? "FAIL" : "OK",
909 dot11rate(rt, final_rix), dot11rate_label(rt, final_rix),
910 short_tries, long_tries, nframes, nbad);
911 update_stats(sc, an, frame_size,
912 final_rix, long_tries,
916 short_tries, long_tries, status,
920 int finalTSIdx = ts->ts_finaltsi;
924 * Process intermediate rates that failed.
927 IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
929 "%s: size %d (%d bytes) finaltsidx %d short %d long %d %s rate/try [%d %s/%d %d %s/%d %d %s/%d %d %s/%d] nframes/nbad [%d/%d]",
931 bin_to_size(size_to_bin(frame_size)),
936 status ? "FAIL" : "OK",
937 dot11rate(rt, rc[0].rix),
938 dot11rate_label(rt, rc[0].rix), rc[0].tries,
939 dot11rate(rt, rc[1].rix),
940 dot11rate_label(rt, rc[1].rix), rc[1].tries,
941 dot11rate(rt, rc[2].rix),
942 dot11rate_label(rt, rc[2].rix), rc[2].tries,
943 dot11rate(rt, rc[3].rix),
944 dot11rate_label(rt, rc[3].rix), rc[3].tries,
947 for (i = 0; i < 4; i++) {
948 if (rc[i].tries && !IS_RATE_DEFINED(sn, rc[i].rix))
949 badrate(sc, 0, rc[i].ratecode, rc[i].tries,
954 * NB: series > 0 are not penalized for failure
955 * based on the try counts under the assumption
956 * that losses are often bursty and since we
957 * sample higher rates 1 try at a time doing so
958 * may unfairly penalize them.
961 update_stats(sc, an, frame_size,
962 rc[0].rix, rc[0].tries,
963 rc[1].rix, rc[1].tries,
964 rc[2].rix, rc[2].tries,
965 rc[3].rix, rc[3].tries,
966 short_tries, long_tries,
967 long_tries > rc[0].tries,
969 long_tries -= rc[0].tries;
972 if (rc[1].tries && finalTSIdx > 0) {
973 update_stats(sc, an, frame_size,
974 rc[1].rix, rc[1].tries,
975 rc[2].rix, rc[2].tries,
976 rc[3].rix, rc[3].tries,
978 short_tries, long_tries,
981 long_tries -= rc[1].tries;
984 if (rc[2].tries && finalTSIdx > 1) {
985 update_stats(sc, an, frame_size,
986 rc[2].rix, rc[2].tries,
987 rc[3].rix, rc[3].tries,
990 short_tries, long_tries,
993 long_tries -= rc[2].tries;
996 if (rc[3].tries && finalTSIdx > 2) {
997 update_stats(sc, an, frame_size,
998 rc[3].rix, rc[3].tries,
1002 short_tries, long_tries,
1010 ath_rate_newassoc(struct ath_softc *sc, struct ath_node *an, int isnew)
1013 ath_rate_ctl_reset(sc, &an->an_node);
1016 static const struct txschedule *mrr_schedules[IEEE80211_MODE_MAX+2] = {
1017 NULL, /* IEEE80211_MODE_AUTO */
1018 series_11a, /* IEEE80211_MODE_11A */
1019 series_11g, /* IEEE80211_MODE_11B */
1020 series_11g, /* IEEE80211_MODE_11G */
1021 NULL, /* IEEE80211_MODE_FH */
1022 series_11a, /* IEEE80211_MODE_TURBO_A */
1023 series_11g, /* IEEE80211_MODE_TURBO_G */
1024 series_11a, /* IEEE80211_MODE_STURBO_A */
1025 series_11na, /* IEEE80211_MODE_11NA */
1026 series_11ng, /* IEEE80211_MODE_11NG */
1027 series_half, /* IEEE80211_MODE_HALF */
1028 series_quarter, /* IEEE80211_MODE_QUARTER */
1032 * Initialize the tables for a node.
1035 ath_rate_ctl_reset(struct ath_softc *sc, struct ieee80211_node *ni)
1037 #define RATE(_ix) (ni->ni_rates.rs_rates[(_ix)] & IEEE80211_RATE_VAL)
1038 #define DOT11RATE(_ix) (rt->info[(_ix)].dot11Rate & IEEE80211_RATE_VAL)
1039 #define MCS(_ix) (ni->ni_htrates.rs_rates[_ix] | IEEE80211_RATE_MCS)
1040 struct ath_node *an = ATH_NODE(ni);
1041 struct sample_node *sn = ATH_NODE_SAMPLE(an);
1042 const HAL_RATE_TABLE *rt = sc->sc_currates;
1045 KASSERT(rt != NULL, ("no rate table, mode %u", sc->sc_curmode));
1047 KASSERT(sc->sc_curmode < IEEE80211_MODE_MAX+2,
1048 ("curmode %u", sc->sc_curmode));
1050 sn->sched = mrr_schedules[sc->sc_curmode];
1051 KASSERT(sn->sched != NULL,
1052 ("no mrr schedule for mode %u", sc->sc_curmode));
1054 sn->static_rix = -1;
1055 ath_rate_update_static_rix(sc, ni);
1057 sn->currates = sc->sc_currates;
1060 * Construct a bitmask of usable rates. This has all
1061 * negotiated rates minus those marked by the hal as
1062 * to be ignored for doing rate control.
1066 if (ni->ni_flags & IEEE80211_NODE_HT) {
1067 for (x = 0; x < ni->ni_htrates.rs_nrates; x++) {
1068 rix = sc->sc_rixmap[MCS(x)];
1071 /* skip rates marked broken by hal */
1072 if (!rt->info[rix].valid)
1074 KASSERT(rix < SAMPLE_MAXRATES,
1075 ("mcs %u has rix %d", MCS(x), rix));
1076 sn->ratemask |= (uint64_t) 1<<rix;
1081 for (x = 0; x < ni->ni_rates.rs_nrates; x++) {
1082 rix = sc->sc_rixmap[RATE(x)];
1085 /* skip rates marked broken by hal */
1086 if (!rt->info[rix].valid)
1088 KASSERT(rix < SAMPLE_MAXRATES,
1089 ("rate %u has rix %d", RATE(x), rix));
1090 sn->ratemask |= (uint64_t) 1<<rix;
1092 #ifdef IEEE80211_DEBUG
1093 if (ieee80211_msg(ni->ni_vap, IEEE80211_MSG_RATECTL)) {
1096 ieee80211_note(ni->ni_vap, "[%6D] %s: size 1600 rate/tt",
1097 ni->ni_macaddr, ":", __func__);
1098 for (mask = sn->ratemask, rix = 0; mask != 0; mask >>= 1, rix++) {
1099 if ((mask & 1) == 0)
1101 printf(" %d %s/%d", dot11rate(rt, rix), dot11rate_label(rt, rix),
1102 calc_usecs_unicast_packet(sc, 1600, rix, 0,0,
1103 (ni->ni_chw == 40)));
1108 for (y = 0; y < NUM_PACKET_SIZE_BINS; y++) {
1109 int size = bin_to_size(y);
1112 sn->packets_sent[y] = 0;
1113 sn->current_sample_rix[y] = -1;
1114 sn->last_sample_rix[y] = 0;
1115 /* XXX start with first valid rate */
1116 sn->current_rix[y] = ffs(sn->ratemask)-1;
1119 * Initialize the statistics buckets; these are
1120 * indexed by the rate code index.
1122 for (rix = 0, mask = sn->ratemask; mask != 0; rix++, mask >>= 1) {
1123 if ((mask & 1) == 0) /* not a valid rate */
1125 sn->stats[y][rix].successive_failures = 0;
1126 sn->stats[y][rix].tries = 0;
1127 sn->stats[y][rix].total_packets = 0;
1128 sn->stats[y][rix].packets_acked = 0;
1129 sn->stats[y][rix].last_tx = 0;
1130 sn->stats[y][rix].ewma_pct = 0;
1132 sn->stats[y][rix].perfect_tx_time =
1133 calc_usecs_unicast_packet(sc, size, rix, 0, 0,
1134 (ni->ni_chw == 40));
1135 sn->stats[y][rix].average_tx_time =
1136 sn->stats[y][rix].perfect_tx_time;
1140 /* XXX 0, num_rates-1 are wrong */
1141 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
1142 "%s: %d rates %d%sMbps (%dus)- %d%sMbps (%dus)", __func__,
1144 DOT11RATE(0)/2, DOT11RATE(0) % 1 ? ".5" : "",
1145 sn->stats[1][0].perfect_tx_time,
1146 DOT11RATE(sn->num_rates-1)/2, DOT11RATE(sn->num_rates-1) % 1 ? ".5" : "",
1147 sn->stats[1][sn->num_rates-1].perfect_tx_time
1150 /* set the visible bit-rate */
1151 if (sn->static_rix != -1)
1152 ni->ni_txrate = DOT11RATE(sn->static_rix);
1154 ni->ni_txrate = RATE(0);
1160 * Fetch the statistics for the given node.
1162 * The ieee80211 node must be referenced and unlocked, however the ath_node
1165 * The main difference here is that we convert the rate indexes
1166 * to 802.11 rates, or the userland output won't make much sense
1167 * as it has no access to the rix table.
1170 ath_rate_fetch_node_stats(struct ath_softc *sc, struct ath_node *an,
1171 struct ath_rateioctl *rs)
1173 struct sample_node *sn = ATH_NODE_SAMPLE(an);
1174 const HAL_RATE_TABLE *rt = sc->sc_currates;
1175 struct ath_rateioctl_tlv av;
1176 struct ath_rateioctl_rt *tv;
1180 ATH_NODE_LOCK_ASSERT(an);
1183 * Ensure there's enough space for the statistics.
1186 sizeof(struct ath_rateioctl_tlv) +
1187 sizeof(struct ath_rateioctl_rt) +
1188 sizeof(struct ath_rateioctl_tlv) +
1189 sizeof(struct sample_node)) {
1190 device_printf(sc->sc_dev, "%s: len=%d, too short\n",
1197 * Take a temporary copy of the sample node state so we can
1198 * modify it before we copy it.
1200 tv = malloc(sizeof(struct ath_rateioctl_rt), M_TEMP,
1207 * Populate the rate table mapping TLV.
1209 tv->nentries = rt->rateCount;
1210 for (y = 0; y < rt->rateCount; y++) {
1211 tv->ratecode[y] = rt->info[y].dot11Rate & IEEE80211_RATE_VAL;
1212 if (rt->info[y].phy == IEEE80211_T_HT)
1213 tv->ratecode[y] |= IEEE80211_RATE_MCS;
1218 * First TLV - rate code mapping
1220 av.tlv_id = ATH_RATE_TLV_RATETABLE;
1221 av.tlv_len = sizeof(struct ath_rateioctl_rt);
1222 copyout(&av, rs->buf + o, sizeof(struct ath_rateioctl_tlv));
1223 o += sizeof(struct ath_rateioctl_tlv);
1224 copyout(tv, rs->buf + o, sizeof(struct ath_rateioctl_rt));
1225 o += sizeof(struct ath_rateioctl_rt);
1228 * Second TLV - sample node statistics
1230 av.tlv_id = ATH_RATE_TLV_SAMPLENODE;
1231 av.tlv_len = sizeof(struct sample_node);
1232 copyout(&av, rs->buf + o, sizeof(struct ath_rateioctl_tlv));
1233 o += sizeof(struct ath_rateioctl_tlv);
1236 * Copy the statistics over to the provided buffer.
1238 copyout(sn, rs->buf + o, sizeof(struct sample_node));
1239 o += sizeof(struct sample_node);
1247 sample_stats(void *arg, struct ieee80211_node *ni)
1249 struct ath_softc *sc = arg;
1250 const HAL_RATE_TABLE *rt = sc->sc_currates;
1251 struct sample_node *sn = ATH_NODE_SAMPLE(ATH_NODE(ni));
1255 printf("\n[%s] refcnt %d static_rix (%d %s) ratemask 0x%jx\n",
1256 ether_sprintf(ni->ni_macaddr), ieee80211_node_refcnt(ni),
1257 dot11rate(rt, sn->static_rix),
1258 dot11rate_label(rt, sn->static_rix),
1259 (uintmax_t)sn->ratemask);
1260 for (y = 0; y < NUM_PACKET_SIZE_BINS; y++) {
1261 printf("[%4u] cur rix %d (%d %s) since switch: packets %d ticks %u\n",
1262 bin_to_size(y), sn->current_rix[y],
1263 dot11rate(rt, sn->current_rix[y]),
1264 dot11rate_label(rt, sn->current_rix[y]),
1265 sn->packets_since_switch[y], sn->ticks_since_switch[y]);
1266 printf("[%4u] last sample (%d %s) cur sample (%d %s) packets sent %d\n",
1268 dot11rate(rt, sn->last_sample_rix[y]),
1269 dot11rate_label(rt, sn->last_sample_rix[y]),
1270 dot11rate(rt, sn->current_sample_rix[y]),
1271 dot11rate_label(rt, sn->current_sample_rix[y]),
1272 sn->packets_sent[y]);
1273 printf("[%4u] packets since sample %d sample tt %u\n",
1274 bin_to_size(y), sn->packets_since_sample[y],
1277 for (mask = sn->ratemask, rix = 0; mask != 0; mask >>= 1, rix++) {
1278 if ((mask & 1) == 0)
1280 for (y = 0; y < NUM_PACKET_SIZE_BINS; y++) {
1281 if (sn->stats[y][rix].total_packets == 0)
1283 printf("[%2u %s:%4u] %8ju:%-8ju (%3d%%) (EWMA %3d.%1d%%) T %8ju F %4d avg %5u last %u\n",
1284 dot11rate(rt, rix), dot11rate_label(rt, rix),
1286 (uintmax_t) sn->stats[y][rix].total_packets,
1287 (uintmax_t) sn->stats[y][rix].packets_acked,
1288 (int) ((sn->stats[y][rix].packets_acked * 100ULL) /
1289 sn->stats[y][rix].total_packets),
1290 sn->stats[y][rix].ewma_pct / 10,
1291 sn->stats[y][rix].ewma_pct % 10,
1292 (uintmax_t) sn->stats[y][rix].tries,
1293 sn->stats[y][rix].successive_failures,
1294 sn->stats[y][rix].average_tx_time,
1295 ticks - sn->stats[y][rix].last_tx);
1301 ath_rate_sysctl_stats(SYSCTL_HANDLER_ARGS)
1303 struct ath_softc *sc = arg1;
1304 struct ieee80211com *ic = &sc->sc_ic;
1308 error = sysctl_handle_int(oidp, &v, 0, req);
1309 if (error || !req->newptr)
1311 ieee80211_iterate_nodes(&ic->ic_sta, sample_stats, sc);
1316 ath_rate_sysctl_smoothing_rate(SYSCTL_HANDLER_ARGS)
1318 struct sample_softc *ssc = arg1;
1321 rate = ssc->smoothing_rate;
1322 error = sysctl_handle_int(oidp, &rate, 0, req);
1323 if (error || !req->newptr)
1325 if (!(0 <= rate && rate < 100))
1327 ssc->smoothing_rate = rate;
1328 ssc->smoothing_minpackets = 100 / (100 - rate);
1333 ath_rate_sysctl_sample_rate(SYSCTL_HANDLER_ARGS)
1335 struct sample_softc *ssc = arg1;
1338 rate = ssc->sample_rate;
1339 error = sysctl_handle_int(oidp, &rate, 0, req);
1340 if (error || !req->newptr)
1342 if (!(2 <= rate && rate <= 100))
1344 ssc->sample_rate = rate;
1349 ath_rate_sysctlattach(struct ath_softc *sc, struct sample_softc *ssc)
1351 struct sysctl_ctx_list *ctx = device_get_sysctl_ctx(sc->sc_dev);
1352 struct sysctl_oid *tree = device_get_sysctl_tree(sc->sc_dev);
1354 SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
1355 "smoothing_rate", CTLTYPE_INT | CTLFLAG_RW, ssc, 0,
1356 ath_rate_sysctl_smoothing_rate, "I",
1357 "sample: smoothing rate for avg tx time (%%)");
1358 SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
1359 "sample_rate", CTLTYPE_INT | CTLFLAG_RW, ssc, 0,
1360 ath_rate_sysctl_sample_rate, "I",
1361 "sample: percent air time devoted to sampling new rates (%%)");
1362 /* XXX max_successive_failures, stale_failure_timeout, min_switch */
1363 SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
1364 "sample_stats", CTLTYPE_INT | CTLFLAG_RW, sc, 0,
1365 ath_rate_sysctl_stats, "I", "sample: print statistics");
1368 struct ath_ratectrl *
1369 ath_rate_attach(struct ath_softc *sc)
1371 struct sample_softc *ssc;
1373 ssc = malloc(sizeof(struct sample_softc), M_DEVBUF, M_NOWAIT|M_ZERO);
1376 ssc->arc.arc_space = sizeof(struct sample_node);
1377 ssc->smoothing_rate = 75; /* ewma percentage ([0..99]) */
1378 ssc->smoothing_minpackets = 100 / (100 - ssc->smoothing_rate);
1379 ssc->sample_rate = 10; /* %time to try diff tx rates */
1380 ssc->max_successive_failures = 3; /* threshold for rate sampling*/
1381 ssc->stale_failure_timeout = 10 * hz; /* 10 seconds */
1382 ssc->min_switch = hz; /* 1 second */
1383 ath_rate_sysctlattach(sc, ssc);
1388 ath_rate_detach(struct ath_ratectrl *arc)
1390 struct sample_softc *ssc = (struct sample_softc *) arc;
1392 free(ssc, M_DEVBUF);