2 * Copyright (c) 2005 John Bicket
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6 * modification, are permitted provided that the following conditions
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38 #include <sys/cdefs.h>
41 * John Bicket's SampleRate control algorithm.
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/sysctl.h>
51 #include <sys/kernel.h>
53 #include <sys/malloc.h>
54 #include <sys/mutex.h>
55 #include <sys/errno.h>
57 #include <sys/socket.h>
60 #include <net/if_var.h>
61 #include <net/if_media.h>
62 #include <net/if_arp.h>
63 #include <net/ethernet.h> /* XXX for ether_sprintf */
65 #include <netproto/802_11/ieee80211_var.h>
70 #include <netinet/in.h>
71 #include <netinet/if_ether.h>
74 #include <dev/netif/ath/ath/if_athvar.h>
75 #include <dev/netif/ath/ath_rate/sample/sample.h>
76 #include <dev/netif/ath/ath_hal/ah_desc.h>
77 #include <dev/netif/ath/ath_rate/sample/tx_schedules.h>
79 extern const char* ath_hal_ether_sprintf(const uint8_t *mac);
82 * This file is an implementation of the SampleRate algorithm
83 * in "Bit-rate Selection in Wireless Networks"
84 * (http://www.pdos.lcs.mit.edu/papers/jbicket-ms.ps)
86 * SampleRate chooses the bit-rate it predicts will provide the most
87 * throughput based on estimates of the expected per-packet
88 * transmission time for each bit-rate. SampleRate periodically sends
89 * packets at bit-rates other than the current one to estimate when
90 * another bit-rate will provide better performance. SampleRate
91 * switches to another bit-rate when its estimated per-packet
92 * transmission time becomes smaller than the current bit-rate's.
93 * SampleRate reduces the number of bit-rates it must sample by
94 * eliminating those that could not perform better than the one
95 * currently being used. SampleRate also stops probing at a bit-rate
96 * if it experiences several successive losses.
98 * The difference between the algorithm in the thesis and the one in this
99 * file is that the one in this file uses a ewma instead of a window.
101 * Also, this implementation tracks the average transmission time for
102 * a few different packet sizes independently for each link.
105 static void ath_rate_ctl_reset(struct ath_softc *, struct ieee80211_node *);
108 size_to_bin(int size)
110 #if NUM_PACKET_SIZE_BINS > 1
111 if (size <= packet_size_bins[0])
114 #if NUM_PACKET_SIZE_BINS > 2
115 if (size <= packet_size_bins[1])
118 #if NUM_PACKET_SIZE_BINS > 3
119 if (size <= packet_size_bins[2])
122 #if NUM_PACKET_SIZE_BINS > 4
123 #error "add support for more packet sizes"
125 return NUM_PACKET_SIZE_BINS-1;
129 ath_rate_node_init(struct ath_softc *sc, struct ath_node *an)
131 /* NB: assumed to be zero'd by caller */
135 ath_rate_node_cleanup(struct ath_softc *sc, struct ath_node *an)
140 dot11rate(const HAL_RATE_TABLE *rt, int rix)
144 return rt->info[rix].phy == IEEE80211_T_HT ?
145 rt->info[rix].dot11Rate : (rt->info[rix].dot11Rate & IEEE80211_RATE_VAL) / 2;
149 dot11rate_label(const HAL_RATE_TABLE *rt, int rix)
153 return rt->info[rix].phy == IEEE80211_T_HT ? "MCS" : "Mb ";
157 * Return the rix with the lowest average_tx_time,
158 * or -1 if all the average_tx_times are 0.
161 pick_best_rate(struct ath_node *an, const HAL_RATE_TABLE *rt,
162 int size_bin, int require_acked_before)
164 struct sample_node *sn = ATH_NODE_SAMPLE(an);
165 int best_rate_rix, best_rate_tt, best_rate_pct;
172 for (mask = sn->ratemask, rix = 0; mask != 0; mask >>= 1, rix++) {
173 if ((mask & 1) == 0) /* not a supported rate */
176 /* Don't pick a non-HT rate for a HT node */
177 if ((an->an_node.ni_flags & IEEE80211_NODE_HT) &&
178 (rt->info[rix].phy != IEEE80211_T_HT)) {
182 tt = sn->stats[size_bin][rix].average_tx_time;
184 (require_acked_before &&
185 !sn->stats[size_bin][rix].packets_acked))
188 /* Calculate percentage if possible */
189 if (sn->stats[size_bin][rix].total_packets > 0) {
190 pct = sn->stats[size_bin][rix].ewma_pct;
192 /* XXX for now, assume 95% ok */
196 /* don't use a bit-rate that has been failing */
197 if (sn->stats[size_bin][rix].successive_failures > 3)
201 * For HT, Don't use a bit rate that is much more
202 * lossy than the best.
204 * XXX this isn't optimal; it's just designed to
205 * eliminate rates that are going to be obviously
208 if (an->an_node.ni_flags & IEEE80211_NODE_HT) {
209 if (best_rate_pct > (pct + 50))
214 * For non-MCS rates, use the current average txtime for
217 if (! (an->an_node.ni_flags & IEEE80211_NODE_HT)) {
218 if (best_rate_tt == 0 || tt <= best_rate_tt) {
226 * Since 2 stream rates have slightly higher TX times,
227 * allow a little bit of leeway. This should later
228 * be abstracted out and properly handled.
230 if (an->an_node.ni_flags & IEEE80211_NODE_HT) {
231 if (best_rate_tt == 0 || (tt * 8 <= best_rate_tt * 10)) {
238 return (best_rate_tt ? best_rate_rix : -1);
242 * Pick a good "random" bit-rate to sample other than the current one.
245 pick_sample_rate(struct sample_softc *ssc , struct ath_node *an,
246 const HAL_RATE_TABLE *rt, int size_bin)
248 #define DOT11RATE(ix) (rt->info[ix].dot11Rate & IEEE80211_RATE_VAL)
249 #define MCS(ix) (rt->info[ix].dot11Rate | IEEE80211_RATE_MCS)
250 struct sample_node *sn = ATH_NODE_SAMPLE(an);
251 int current_rix, rix;
255 current_rix = sn->current_rix[size_bin];
256 if (current_rix < 0) {
257 /* no successes yet, send at the lowest bit-rate */
258 /* XXX should return MCS0 if HT */
262 current_tt = sn->stats[size_bin][current_rix].average_tx_time;
264 rix = sn->last_sample_rix[size_bin]+1; /* next sample rate */
265 mask = sn->ratemask &~ ((uint64_t) 1<<current_rix);/* don't sample current rate */
267 if ((mask & ((uint64_t) 1<<rix)) == 0) { /* not a supported rate */
269 if (++rix >= rt->rateCount)
275 * The following code stops trying to sample
276 * non-MCS rates when speaking to an MCS node.
277 * However, at least for CCK rates in 2.4GHz mode,
278 * the non-MCS rates MAY actually provide better
279 * PER at the very far edge of reception.
281 * However! Until ath_rate_form_aggr() grows
282 * some logic to not form aggregates if the
283 * selected rate is non-MCS, this won't work.
285 * So don't disable this code until you've taught
286 * ath_rate_form_aggr() to drop out if any of
287 * the selected rates are non-MCS.
290 /* if the node is HT and the rate isn't HT, don't bother sample */
291 if ((an->an_node.ni_flags & IEEE80211_NODE_HT) &&
292 (rt->info[rix].phy != IEEE80211_T_HT)) {
293 mask &= ~((uint64_t) 1<<rix);
298 /* this bit-rate is always worse than the current one */
299 if (sn->stats[size_bin][rix].perfect_tx_time > current_tt) {
300 mask &= ~((uint64_t) 1<<rix);
304 /* rarely sample bit-rates that fail a lot */
305 if (sn->stats[size_bin][rix].successive_failures > ssc->max_successive_failures &&
306 ticks - sn->stats[size_bin][rix].last_tx < ssc->stale_failure_timeout) {
307 mask &= ~((uint64_t) 1<<rix);
312 * For HT, only sample a few rates on either side of the
313 * current rix; there's quite likely a lot of them.
315 if (an->an_node.ni_flags & IEEE80211_NODE_HT) {
316 if (rix < (current_rix - 3) ||
317 rix > (current_rix + 3)) {
318 mask &= ~((uint64_t) 1<<rix);
323 /* Don't sample more than 2 rates higher for rates > 11M for non-HT rates */
324 if (! (an->an_node.ni_flags & IEEE80211_NODE_HT)) {
325 if (DOT11RATE(rix) > 2*11 && rix > current_rix + 2) {
326 mask &= ~((uint64_t) 1<<rix);
331 sn->last_sample_rix[size_bin] = rix;
340 ath_rate_get_static_rix(struct ath_softc *sc, const struct ieee80211_node *ni)
342 #define RATE(_ix) (ni->ni_rates.rs_rates[(_ix)] & IEEE80211_RATE_VAL)
343 #define DOT11RATE(_ix) (rt->info[(_ix)].dot11Rate & IEEE80211_RATE_VAL)
344 #define MCS(_ix) (ni->ni_htrates.rs_rates[_ix] | IEEE80211_RATE_MCS)
345 const struct ieee80211_txparam *tp = ni->ni_txparms;
348 /* Check MCS rates */
349 for (srate = ni->ni_htrates.rs_nrates - 1; srate >= 0; srate--) {
350 if (MCS(srate) == tp->ucastrate)
351 return sc->sc_rixmap[tp->ucastrate];
354 /* Check legacy rates */
355 for (srate = ni->ni_rates.rs_nrates - 1; srate >= 0; srate--) {
356 if (RATE(srate) == tp->ucastrate)
357 return sc->sc_rixmap[tp->ucastrate];
366 ath_rate_update_static_rix(struct ath_softc *sc, struct ieee80211_node *ni)
368 struct ath_node *an = ATH_NODE(ni);
369 const struct ieee80211_txparam *tp = ni->ni_txparms;
370 struct sample_node *sn = ATH_NODE_SAMPLE(an);
372 if (tp != NULL && tp->ucastrate != IEEE80211_FIXED_RATE_NONE) {
374 * A fixed rate is to be used; ucastrate is the IEEE code
375 * for this rate (sans basic bit). Check this against the
376 * negotiated rate set for the node. Note the fixed rate
377 * may not be available for various reasons so we only
378 * setup the static rate index if the lookup is successful.
380 sn->static_rix = ath_rate_get_static_rix(sc, ni);
387 * Pick a non-HT rate to begin using.
390 ath_rate_pick_seed_rate_legacy(struct ath_softc *sc, struct ath_node *an,
393 #define DOT11RATE(ix) (rt->info[ix].dot11Rate & IEEE80211_RATE_VAL)
394 #define MCS(ix) (rt->info[ix].dot11Rate | IEEE80211_RATE_MCS)
395 #define RATE(ix) (DOT11RATE(ix) / 2)
397 const HAL_RATE_TABLE *rt = sc->sc_currates;
398 struct sample_node *sn = ATH_NODE_SAMPLE(an);
399 const int size_bin = size_to_bin(frameLen);
401 /* no packet has been sent successfully yet */
402 for (rix = rt->rateCount-1; rix > 0; rix--) {
403 if ((sn->ratemask & ((uint64_t) 1<<rix)) == 0)
407 if (rt->info[rix].phy == IEEE80211_T_HT)
411 * Pick the highest rate <= 36 Mbps
412 * that hasn't failed.
414 if (DOT11RATE(rix) <= 72 &&
415 sn->stats[size_bin][rix].successive_failures == 0) {
426 * Pick a HT rate to begin using.
428 * Don't use any non-HT rates; only consider HT rates.
431 ath_rate_pick_seed_rate_ht(struct ath_softc *sc, struct ath_node *an,
434 #define DOT11RATE(ix) (rt->info[ix].dot11Rate & IEEE80211_RATE_VAL)
435 #define MCS(ix) (rt->info[ix].dot11Rate | IEEE80211_RATE_MCS)
436 #define RATE(ix) (DOT11RATE(ix) / 2)
437 int rix = -1, ht_rix = -1;
438 const HAL_RATE_TABLE *rt = sc->sc_currates;
439 struct sample_node *sn = ATH_NODE_SAMPLE(an);
440 const int size_bin = size_to_bin(frameLen);
442 /* no packet has been sent successfully yet */
443 for (rix = rt->rateCount-1; rix > 0; rix--) {
444 /* Skip rates we can't use */
445 if ((sn->ratemask & ((uint64_t) 1<<rix)) == 0)
448 /* Keep a copy of the last seen HT rate index */
449 if (rt->info[rix].phy == IEEE80211_T_HT)
452 /* Skip non-HT rates */
453 if (rt->info[rix].phy != IEEE80211_T_HT)
457 * Pick a medium-speed rate regardless of stream count
458 * which has not seen any failures. Higher rates may fail;
459 * we'll try them later.
461 if (((MCS(rix) & 0x7) <= 4) &&
462 sn->stats[size_bin][rix].successive_failures == 0) {
468 * If all the MCS rates have successive failures, rix should be
469 * > 0; otherwise use the lowest MCS rix (hopefully MCS 0.)
471 return MAX(rix, ht_rix);
479 ath_rate_findrate(struct ath_softc *sc, struct ath_node *an,
480 int shortPreamble, size_t frameLen,
481 u_int8_t *rix0, int *try0, u_int8_t *txrate)
483 #define DOT11RATE(ix) (rt->info[ix].dot11Rate & IEEE80211_RATE_VAL)
484 #define MCS(ix) (rt->info[ix].dot11Rate | IEEE80211_RATE_MCS)
485 #define RATE(ix) (DOT11RATE(ix) / 2)
486 struct sample_node *sn = ATH_NODE_SAMPLE(an);
487 struct sample_softc *ssc = ATH_SOFTC_SAMPLE(sc);
488 struct ifnet *ifp = sc->sc_ifp;
489 struct ieee80211com *ic = ifp->if_l2com;
490 const HAL_RATE_TABLE *rt = sc->sc_currates;
491 const int size_bin = size_to_bin(frameLen);
492 int rix, mrr, best_rix, change_rates;
493 unsigned average_tx_time;
495 ath_rate_update_static_rix(sc, &an->an_node);
497 if (sn->currates != sc->sc_currates) {
498 device_printf(sc->sc_dev, "%s: currates != sc_currates!\n",
501 *try0 = ATH_TXMAXTRY;
505 if (sn->static_rix != -1) {
506 rix = sn->static_rix;
507 *try0 = ATH_TXMAXTRY;
511 mrr = sc->sc_mrretry;
512 /* XXX check HT protmode too */
513 if (mrr && (ic->ic_flags & IEEE80211_F_USEPROT && !sc->sc_mrrprot))
516 best_rix = pick_best_rate(an, rt, size_bin, !mrr);
518 average_tx_time = sn->stats[size_bin][best_rix].average_tx_time;
523 * Limit the time measuring the performance of other tx
524 * rates to sample_rate% of the total transmission time.
526 if (sn->sample_tt[size_bin] < average_tx_time * (sn->packets_since_sample[size_bin]*ssc->sample_rate/100)) {
527 rix = pick_sample_rate(ssc, an, rt, size_bin);
528 IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
529 &an->an_node, "att %d sample_tt %d size %u sample rate %d %s current rate %d %s",
531 sn->sample_tt[size_bin],
532 bin_to_size(size_bin),
534 dot11rate_label(rt, rix),
535 dot11rate(rt, sn->current_rix[size_bin]),
536 dot11rate_label(rt, sn->current_rix[size_bin]));
537 if (rix != sn->current_rix[size_bin]) {
538 sn->current_sample_rix[size_bin] = rix;
540 sn->current_sample_rix[size_bin] = -1;
542 sn->packets_since_sample[size_bin] = 0;
545 if (!sn->packets_sent[size_bin] || best_rix == -1) {
546 /* no packet has been sent successfully yet */
548 if (an->an_node.ni_flags & IEEE80211_NODE_HT)
550 ath_rate_pick_seed_rate_ht(sc, an, frameLen);
553 ath_rate_pick_seed_rate_legacy(sc, an, frameLen);
554 } else if (sn->packets_sent[size_bin] < 20) {
555 /* let the bit-rate switch quickly during the first few packets */
556 IEEE80211_NOTE(an->an_node.ni_vap,
557 IEEE80211_MSG_RATECTL, &an->an_node,
558 "%s: switching quickly..", __func__);
560 } else if (ticks - ssc->min_switch > sn->ticks_since_switch[size_bin]) {
561 /* min_switch seconds have gone by */
562 IEEE80211_NOTE(an->an_node.ni_vap,
563 IEEE80211_MSG_RATECTL, &an->an_node,
564 "%s: min_switch %d > ticks_since_switch %d..",
565 __func__, ticks - ssc->min_switch, sn->ticks_since_switch[size_bin]);
567 } else if ((! (an->an_node.ni_flags & IEEE80211_NODE_HT)) &&
568 (2*average_tx_time < sn->stats[size_bin][sn->current_rix[size_bin]].average_tx_time)) {
569 /* the current bit-rate is twice as slow as the best one */
570 IEEE80211_NOTE(an->an_node.ni_vap,
571 IEEE80211_MSG_RATECTL, &an->an_node,
572 "%s: 2x att (= %d) < cur_rix att %d",
574 2 * average_tx_time, sn->stats[size_bin][sn->current_rix[size_bin]].average_tx_time);
576 } else if ((an->an_node.ni_flags & IEEE80211_NODE_HT)) {
577 int cur_rix = sn->current_rix[size_bin];
578 int cur_att = sn->stats[size_bin][cur_rix].average_tx_time;
580 * If the node is HT, upgrade it if the MCS rate is
581 * higher and the average tx time is within 20% of
582 * the current rate. It can fail a little.
584 * This is likely not optimal!
587 kprintf("cur rix/att %x/%d, best rix/att %x/%d\n",
588 MCS(cur_rix), cur_att, MCS(best_rix), average_tx_time);
590 if ((MCS(best_rix) > MCS(cur_rix)) &&
591 (average_tx_time * 8) <= (cur_att * 10)) {
592 IEEE80211_NOTE(an->an_node.ni_vap,
593 IEEE80211_MSG_RATECTL, &an->an_node,
594 "%s: HT: best_rix 0x%d > cur_rix 0x%x, average_tx_time %d, cur_att %d",
596 MCS(best_rix), MCS(cur_rix), average_tx_time, cur_att);
601 sn->packets_since_sample[size_bin]++;
604 if (best_rix != sn->current_rix[size_bin]) {
605 IEEE80211_NOTE(an->an_node.ni_vap,
606 IEEE80211_MSG_RATECTL,
608 "%s: size %d switch rate %d (%d/%d) -> %d (%d/%d) after %d packets mrr %d",
610 bin_to_size(size_bin),
611 RATE(sn->current_rix[size_bin]),
612 sn->stats[size_bin][sn->current_rix[size_bin]].average_tx_time,
613 sn->stats[size_bin][sn->current_rix[size_bin]].perfect_tx_time,
615 sn->stats[size_bin][best_rix].average_tx_time,
616 sn->stats[size_bin][best_rix].perfect_tx_time,
617 sn->packets_since_switch[size_bin],
620 sn->packets_since_switch[size_bin] = 0;
621 sn->current_rix[size_bin] = best_rix;
622 sn->ticks_since_switch[size_bin] = ticks;
624 * Set the visible txrate for this node.
626 an->an_node.ni_txrate = (rt->info[best_rix].phy == IEEE80211_T_HT) ? MCS(best_rix) : DOT11RATE(best_rix);
628 rix = sn->current_rix[size_bin];
629 sn->packets_since_switch[size_bin]++;
631 *try0 = mrr ? sn->sched[rix].t0 : ATH_TXMAXTRY;
635 * This bug totally sucks and should be fixed.
637 * For now though, let's not panic, so we can start to figure
638 * out how to better reproduce it.
640 if (rix < 0 || rix >= rt->rateCount) {
641 kprintf("%s: ERROR: rix %d out of bounds (rateCount=%d)\n",
645 rix = 0; /* XXX just default for now */
647 KASSERT(rix >= 0 && rix < rt->rateCount, ("rix is %d", rix));
650 *txrate = rt->info[rix].rateCode
651 | (shortPreamble ? rt->info[rix].shortPreamble : 0);
652 sn->packets_sent[size_bin]++;
659 * Get the TX rates. Don't fiddle with short preamble flags for them;
660 * the caller can do that.
663 ath_rate_getxtxrates(struct ath_softc *sc, struct ath_node *an,
664 uint8_t rix0, struct ath_rc_series *rc)
666 struct sample_node *sn = ATH_NODE_SAMPLE(an);
667 const struct txschedule *sched = &sn->sched[rix0];
669 KASSERT(rix0 == sched->r0, ("rix0 (%x) != sched->r0 (%x)!\n",
672 rc[0].flags = rc[1].flags = rc[2].flags = rc[3].flags = 0;
674 rc[0].rix = sched->r0;
675 rc[1].rix = sched->r1;
676 rc[2].rix = sched->r2;
677 rc[3].rix = sched->r3;
679 rc[0].tries = sched->t0;
680 rc[1].tries = sched->t1;
681 rc[2].tries = sched->t2;
682 rc[3].tries = sched->t3;
686 ath_rate_setupxtxdesc(struct ath_softc *sc, struct ath_node *an,
687 struct ath_desc *ds, int shortPreamble, u_int8_t rix)
689 struct sample_node *sn = ATH_NODE_SAMPLE(an);
690 const struct txschedule *sched = &sn->sched[rix];
691 const HAL_RATE_TABLE *rt = sc->sc_currates;
692 uint8_t rix1, s1code, rix2, s2code, rix3, s3code;
694 /* XXX precalculate short preamble tables */
696 s1code = rt->info[rix1].rateCode
697 | (shortPreamble ? rt->info[rix1].shortPreamble : 0);
699 s2code = rt->info[rix2].rateCode
700 | (shortPreamble ? rt->info[rix2].shortPreamble : 0);
702 s3code = rt->info[rix3].rateCode
703 | (shortPreamble ? rt->info[rix3].shortPreamble : 0);
704 ath_hal_setupxtxdesc(sc->sc_ah, ds,
705 s1code, sched->t1, /* series 1 */
706 s2code, sched->t2, /* series 2 */
707 s3code, sched->t3); /* series 3 */
711 update_stats(struct ath_softc *sc, struct ath_node *an,
713 int rix0, int tries0,
714 int rix1, int tries1,
715 int rix2, int tries2,
716 int rix3, int tries3,
717 int short_tries, int tries, int status,
718 int nframes, int nbad)
720 struct sample_node *sn = ATH_NODE_SAMPLE(an);
721 struct sample_softc *ssc = ATH_SOFTC_SAMPLE(sc);
722 #ifdef IEEE80211_DEBUG
723 const HAL_RATE_TABLE *rt = sc->sc_currates;
725 const int size_bin = size_to_bin(frame_size);
726 const int size = bin_to_size(size_bin);
727 int tt, tries_so_far;
728 int is_ht40 = (an->an_node.ni_chw == 40);
731 if (!IS_RATE_DEFINED(sn, rix0))
733 tt = calc_usecs_unicast_packet(sc, size, rix0, short_tries,
734 MIN(tries0, tries) - 1, is_ht40);
735 tries_so_far = tries0;
737 if (tries1 && tries_so_far < tries) {
738 if (!IS_RATE_DEFINED(sn, rix1))
740 tt += calc_usecs_unicast_packet(sc, size, rix1, short_tries,
741 MIN(tries1 + tries_so_far, tries) - tries_so_far - 1, is_ht40);
742 tries_so_far += tries1;
745 if (tries2 && tries_so_far < tries) {
746 if (!IS_RATE_DEFINED(sn, rix2))
748 tt += calc_usecs_unicast_packet(sc, size, rix2, short_tries,
749 MIN(tries2 + tries_so_far, tries) - tries_so_far - 1, is_ht40);
750 tries_so_far += tries2;
753 if (tries3 && tries_so_far < tries) {
754 if (!IS_RATE_DEFINED(sn, rix3))
756 tt += calc_usecs_unicast_packet(sc, size, rix3, short_tries,
757 MIN(tries3 + tries_so_far, tries) - tries_so_far - 1, is_ht40);
760 if (sn->stats[size_bin][rix0].total_packets < ssc->smoothing_minpackets) {
761 /* just average the first few packets */
762 int avg_tx = sn->stats[size_bin][rix0].average_tx_time;
763 int packets = sn->stats[size_bin][rix0].total_packets;
764 sn->stats[size_bin][rix0].average_tx_time = (tt+(avg_tx*packets))/(packets+nframes);
767 sn->stats[size_bin][rix0].average_tx_time =
768 ((sn->stats[size_bin][rix0].average_tx_time * ssc->smoothing_rate) +
769 (tt * (100 - ssc->smoothing_rate))) / 100;
773 * XXX Don't mark the higher bit rates as also having failed; as this
774 * unfortunately stops those rates from being tasted when trying to
775 * TX. This happens with 11n aggregation.
777 if (nframes == nbad) {
781 sn->stats[size_bin][rix0].successive_failures += nbad;
783 for (y = size_bin+1; y < NUM_PACKET_SIZE_BINS; y++) {
785 * Also say larger packets failed since we
786 * assume if a small packet fails at a
787 * bit-rate then a larger one will also.
789 sn->stats[y][rix0].successive_failures += nbad;
790 sn->stats[y][rix0].last_tx = ticks;
791 sn->stats[y][rix0].tries += tries;
792 sn->stats[y][rix0].total_packets += nframes;
796 sn->stats[size_bin][rix0].packets_acked += (nframes - nbad);
797 sn->stats[size_bin][rix0].successive_failures = 0;
799 sn->stats[size_bin][rix0].tries += tries;
800 sn->stats[size_bin][rix0].last_tx = ticks;
801 sn->stats[size_bin][rix0].total_packets += nframes;
803 /* update EWMA for this rix */
805 /* Calculate percentage based on current rate */
808 pct = ((nframes - nbad) * 1000) / nframes;
810 if (sn->stats[size_bin][rix0].total_packets <
811 ssc->smoothing_minpackets) {
812 /* just average the first few packets */
813 int a_pct = (sn->stats[size_bin][rix0].packets_acked * 1000) /
814 (sn->stats[size_bin][rix0].total_packets);
815 sn->stats[size_bin][rix0].ewma_pct = a_pct;
818 sn->stats[size_bin][rix0].ewma_pct =
819 ((sn->stats[size_bin][rix0].ewma_pct * ssc->smoothing_rate) +
820 (pct * (100 - ssc->smoothing_rate))) / 100;
824 if (rix0 == sn->current_sample_rix[size_bin]) {
825 IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
827 "%s: size %d %s sample rate %d %s tries (%d/%d) tt %d avg_tt (%d/%d) nfrm %d nbad %d",
830 status ? "FAIL" : "OK",
832 dot11rate_label(rt, rix0),
833 short_tries, tries, tt,
834 sn->stats[size_bin][rix0].average_tx_time,
835 sn->stats[size_bin][rix0].perfect_tx_time,
837 sn->sample_tt[size_bin] = tt;
838 sn->current_sample_rix[size_bin] = -1;
843 badrate(struct ifnet *ifp, int series, int hwrate, int tries, int status)
845 if_printf(ifp, "bad series%d hwrate 0x%x, tries %u ts_status 0x%x\n",
846 series, hwrate, tries, status);
850 ath_rate_tx_complete(struct ath_softc *sc, struct ath_node *an,
851 const struct ath_rc_series *rc, const struct ath_tx_status *ts,
852 int frame_size, int nframes, int nbad)
854 struct ifnet *ifp = sc->sc_ifp;
855 struct ieee80211com *ic = ifp->if_l2com;
856 struct sample_node *sn = ATH_NODE_SAMPLE(an);
857 int final_rix, short_tries, long_tries;
858 const HAL_RATE_TABLE *rt = sc->sc_currates;
859 int status = ts->ts_status;
862 final_rix = rt->rateCodeToIndex[ts->ts_rate];
863 short_tries = ts->ts_shortretry;
864 long_tries = ts->ts_longretry + 1;
867 device_printf(sc->sc_dev, "%s: nframes=0?\n", __func__);
871 if (frame_size == 0) /* NB: should not happen */
874 if (sn->ratemask == 0) {
875 IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
877 "%s: size %d %s rate/try %d/%d no rates yet",
879 bin_to_size(size_to_bin(frame_size)),
880 status ? "FAIL" : "OK",
881 short_tries, long_tries);
884 mrr = sc->sc_mrretry;
885 /* XXX check HT protmode too */
886 if (mrr && (ic->ic_flags & IEEE80211_F_USEPROT && !sc->sc_mrrprot))
889 if (!mrr || ts->ts_finaltsi == 0) {
890 if (!IS_RATE_DEFINED(sn, final_rix)) {
891 device_printf(sc->sc_dev, "%s: ts_rate=%d ts_finaltsi=%d\n",
892 __func__, ts->ts_rate, ts->ts_finaltsi);
893 badrate(ifp, 0, ts->ts_rate, long_tries, status);
897 * Only one rate was used; optimize work.
899 IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
900 &an->an_node, "%s: size %d (%d bytes) %s rate/short/long %d %s/%d/%d nframes/nbad [%d/%d]",
902 bin_to_size(size_to_bin(frame_size)),
904 status ? "FAIL" : "OK",
905 dot11rate(rt, final_rix), dot11rate_label(rt, final_rix),
906 short_tries, long_tries, nframes, nbad);
907 update_stats(sc, an, frame_size,
908 final_rix, long_tries,
912 short_tries, long_tries, status,
916 int finalTSIdx = ts->ts_finaltsi;
920 * Process intermediate rates that failed.
923 IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
925 "%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]",
927 bin_to_size(size_to_bin(frame_size)),
932 status ? "FAIL" : "OK",
933 dot11rate(rt, rc[0].rix),
934 dot11rate_label(rt, rc[0].rix), rc[0].tries,
935 dot11rate(rt, rc[1].rix),
936 dot11rate_label(rt, rc[1].rix), rc[1].tries,
937 dot11rate(rt, rc[2].rix),
938 dot11rate_label(rt, rc[2].rix), rc[2].tries,
939 dot11rate(rt, rc[3].rix),
940 dot11rate_label(rt, rc[3].rix), rc[3].tries,
943 for (i = 0; i < 4; i++) {
944 if (rc[i].tries && !IS_RATE_DEFINED(sn, rc[i].rix))
945 badrate(ifp, 0, rc[i].ratecode, rc[i].tries,
950 * NB: series > 0 are not penalized for failure
951 * based on the try counts under the assumption
952 * that losses are often bursty and since we
953 * sample higher rates 1 try at a time doing so
954 * may unfairly penalize them.
957 update_stats(sc, an, frame_size,
958 rc[0].rix, rc[0].tries,
959 rc[1].rix, rc[1].tries,
960 rc[2].rix, rc[2].tries,
961 rc[3].rix, rc[3].tries,
962 short_tries, long_tries,
963 long_tries > rc[0].tries,
965 long_tries -= rc[0].tries;
968 if (rc[1].tries && finalTSIdx > 0) {
969 update_stats(sc, an, frame_size,
970 rc[1].rix, rc[1].tries,
971 rc[2].rix, rc[2].tries,
972 rc[3].rix, rc[3].tries,
974 short_tries, long_tries,
977 long_tries -= rc[1].tries;
980 if (rc[2].tries && finalTSIdx > 1) {
981 update_stats(sc, an, frame_size,
982 rc[2].rix, rc[2].tries,
983 rc[3].rix, rc[3].tries,
986 short_tries, long_tries,
989 long_tries -= rc[2].tries;
992 if (rc[3].tries && finalTSIdx > 2) {
993 update_stats(sc, an, frame_size,
994 rc[3].rix, rc[3].tries,
998 short_tries, long_tries,
1006 ath_rate_newassoc(struct ath_softc *sc, struct ath_node *an, int isnew)
1009 ath_rate_ctl_reset(sc, &an->an_node);
1012 static const struct txschedule *mrr_schedules[IEEE80211_MODE_MAX+2] = {
1013 NULL, /* IEEE80211_MODE_AUTO */
1014 series_11a, /* IEEE80211_MODE_11A */
1015 series_11g, /* IEEE80211_MODE_11B */
1016 series_11g, /* IEEE80211_MODE_11G */
1017 NULL, /* IEEE80211_MODE_FH */
1018 series_11a, /* IEEE80211_MODE_TURBO_A */
1019 series_11g, /* IEEE80211_MODE_TURBO_G */
1020 series_11a, /* IEEE80211_MODE_STURBO_A */
1021 series_11na, /* IEEE80211_MODE_11NA */
1022 series_11ng, /* IEEE80211_MODE_11NG */
1023 series_half, /* IEEE80211_MODE_HALF */
1024 series_quarter, /* IEEE80211_MODE_QUARTER */
1028 * Initialize the tables for a node.
1031 ath_rate_ctl_reset(struct ath_softc *sc, struct ieee80211_node *ni)
1033 #define RATE(_ix) (ni->ni_rates.rs_rates[(_ix)] & IEEE80211_RATE_VAL)
1034 #define DOT11RATE(_ix) (rt->info[(_ix)].dot11Rate & IEEE80211_RATE_VAL)
1035 #define MCS(_ix) (ni->ni_htrates.rs_rates[_ix] | IEEE80211_RATE_MCS)
1036 struct ath_node *an = ATH_NODE(ni);
1037 struct sample_node *sn = ATH_NODE_SAMPLE(an);
1038 const HAL_RATE_TABLE *rt = sc->sc_currates;
1041 KASSERT(rt != NULL, ("no rate table, mode %u", sc->sc_curmode));
1043 KASSERT(sc->sc_curmode < IEEE80211_MODE_MAX+2,
1044 ("curmode %u", sc->sc_curmode));
1046 sn->sched = mrr_schedules[sc->sc_curmode];
1047 KASSERT(sn->sched != NULL,
1048 ("no mrr schedule for mode %u", sc->sc_curmode));
1050 sn->static_rix = -1;
1051 ath_rate_update_static_rix(sc, ni);
1053 sn->currates = sc->sc_currates;
1056 * Construct a bitmask of usable rates. This has all
1057 * negotiated rates minus those marked by the hal as
1058 * to be ignored for doing rate control.
1062 if (ni->ni_flags & IEEE80211_NODE_HT) {
1063 for (x = 0; x < ni->ni_htrates.rs_nrates; x++) {
1064 rix = sc->sc_rixmap[MCS(x)];
1067 /* skip rates marked broken by hal */
1068 if (!rt->info[rix].valid)
1070 KASSERT(rix < SAMPLE_MAXRATES,
1071 ("mcs %u has rix %d", MCS(x), rix));
1072 sn->ratemask |= (uint64_t) 1<<rix;
1077 for (x = 0; x < ni->ni_rates.rs_nrates; x++) {
1078 rix = sc->sc_rixmap[RATE(x)];
1081 /* skip rates marked broken by hal */
1082 if (!rt->info[rix].valid)
1084 KASSERT(rix < SAMPLE_MAXRATES,
1085 ("rate %u has rix %d", RATE(x), rix));
1086 sn->ratemask |= (uint64_t) 1<<rix;
1088 #ifdef IEEE80211_DEBUG
1089 if (ieee80211_msg(ni->ni_vap, IEEE80211_MSG_RATECTL)) {
1092 ieee80211_note(ni->ni_vap, "[%6D] %s: size 1600 rate/tt",
1093 ni->ni_macaddr, ":", __func__);
1094 for (mask = sn->ratemask, rix = 0; mask != 0; mask >>= 1, rix++) {
1095 if ((mask & 1) == 0)
1097 kprintf(" %d %s/%d", dot11rate(rt, rix), dot11rate_label(rt, rix),
1098 calc_usecs_unicast_packet(sc, 1600, rix, 0,0,
1099 (ni->ni_chw == 40)));
1104 for (y = 0; y < NUM_PACKET_SIZE_BINS; y++) {
1105 int size = bin_to_size(y);
1108 sn->packets_sent[y] = 0;
1109 sn->current_sample_rix[y] = -1;
1110 sn->last_sample_rix[y] = 0;
1111 /* XXX start with first valid rate */
1112 sn->current_rix[y] = ffs(sn->ratemask)-1;
1115 * Initialize the statistics buckets; these are
1116 * indexed by the rate code index.
1118 for (rix = 0, mask = sn->ratemask; mask != 0; rix++, mask >>= 1) {
1119 if ((mask & 1) == 0) /* not a valid rate */
1121 sn->stats[y][rix].successive_failures = 0;
1122 sn->stats[y][rix].tries = 0;
1123 sn->stats[y][rix].total_packets = 0;
1124 sn->stats[y][rix].packets_acked = 0;
1125 sn->stats[y][rix].last_tx = 0;
1126 sn->stats[y][rix].ewma_pct = 0;
1128 sn->stats[y][rix].perfect_tx_time =
1129 calc_usecs_unicast_packet(sc, size, rix, 0, 0,
1130 (ni->ni_chw == 40));
1131 sn->stats[y][rix].average_tx_time =
1132 sn->stats[y][rix].perfect_tx_time;
1136 /* XXX 0, num_rates-1 are wrong */
1137 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
1138 "%s: %d rates %d%sMbps (%dus)- %d%sMbps (%dus)", __func__,
1140 DOT11RATE(0)/2, DOT11RATE(0) % 1 ? ".5" : "",
1141 sn->stats[1][0].perfect_tx_time,
1142 DOT11RATE(sn->num_rates-1)/2, DOT11RATE(sn->num_rates-1) % 1 ? ".5" : "",
1143 sn->stats[1][sn->num_rates-1].perfect_tx_time
1146 /* set the visible bit-rate */
1147 if (sn->static_rix != -1)
1148 ni->ni_txrate = DOT11RATE(sn->static_rix);
1150 ni->ni_txrate = RATE(0);
1156 * Fetch the statistics for the given node.
1158 * The ieee80211 node must be referenced and unlocked, however the ath_node
1161 * The main difference here is that we convert the rate indexes
1162 * to 802.11 rates, or the userland output won't make much sense
1163 * as it has no access to the rix table.
1166 ath_rate_fetch_node_stats(struct ath_softc *sc, struct ath_node *an,
1167 struct ath_rateioctl *rs)
1169 struct sample_node *sn = ATH_NODE_SAMPLE(an);
1170 const HAL_RATE_TABLE *rt = sc->sc_currates;
1171 struct ath_rateioctl_tlv av;
1172 struct ath_rateioctl_rt *tv;
1176 ATH_NODE_LOCK_ASSERT(an);
1179 * Ensure there's enough space for the statistics.
1182 sizeof(struct ath_rateioctl_tlv) +
1183 sizeof(struct ath_rateioctl_rt) +
1184 sizeof(struct ath_rateioctl_tlv) +
1185 sizeof(struct sample_node)) {
1186 device_printf(sc->sc_dev, "%s: len=%d, too short\n",
1193 * Take a temporary copy of the sample node state so we can
1194 * modify it before we copy it.
1196 tv = kmalloc(sizeof(struct ath_rateioctl_rt), M_TEMP,
1197 M_INTWAIT | M_ZERO);
1203 * Populate the rate table mapping TLV.
1205 tv->nentries = rt->rateCount;
1206 for (y = 0; y < rt->rateCount; y++) {
1207 tv->ratecode[y] = rt->info[y].dot11Rate & IEEE80211_RATE_VAL;
1208 if (rt->info[y].phy == IEEE80211_T_HT)
1209 tv->ratecode[y] |= IEEE80211_RATE_MCS;
1214 * First TLV - rate code mapping
1216 av.tlv_id = ATH_RATE_TLV_RATETABLE;
1217 av.tlv_len = sizeof(struct ath_rateioctl_rt);
1218 copyout(&av, rs->buf + o, sizeof(struct ath_rateioctl_tlv));
1219 o += sizeof(struct ath_rateioctl_tlv);
1220 copyout(tv, rs->buf + o, sizeof(struct ath_rateioctl_rt));
1221 o += sizeof(struct ath_rateioctl_rt);
1224 * Second TLV - sample node statistics
1226 av.tlv_id = ATH_RATE_TLV_SAMPLENODE;
1227 av.tlv_len = sizeof(struct sample_node);
1228 copyout(&av, rs->buf + o, sizeof(struct ath_rateioctl_tlv));
1229 o += sizeof(struct ath_rateioctl_tlv);
1232 * Copy the statistics over to the provided buffer.
1234 copyout(sn, rs->buf + o, sizeof(struct sample_node));
1235 o += sizeof(struct sample_node);
1243 sample_stats(void *arg, struct ieee80211_node *ni)
1245 struct ath_softc *sc = arg;
1246 const HAL_RATE_TABLE *rt = sc->sc_currates;
1247 struct sample_node *sn = ATH_NODE_SAMPLE(ATH_NODE(ni));
1251 kprintf("\n[%s] refcnt %d static_rix (%d %s) ratemask 0x%jx\n",
1252 ath_hal_ether_sprintf(ni->ni_macaddr),
1253 ieee80211_node_refcnt(ni),
1254 dot11rate(rt, sn->static_rix),
1255 dot11rate_label(rt, sn->static_rix),
1256 (uintmax_t)sn->ratemask);
1257 for (y = 0; y < NUM_PACKET_SIZE_BINS; y++) {
1258 kprintf("[%4u] cur rix %d (%d %s) since switch: packets %d ticks %u\n",
1259 bin_to_size(y), sn->current_rix[y],
1260 dot11rate(rt, sn->current_rix[y]),
1261 dot11rate_label(rt, sn->current_rix[y]),
1262 sn->packets_since_switch[y], sn->ticks_since_switch[y]);
1263 kprintf("[%4u] last sample (%d %s) cur sample (%d %s) packets sent %d\n",
1265 dot11rate(rt, sn->last_sample_rix[y]),
1266 dot11rate_label(rt, sn->last_sample_rix[y]),
1267 dot11rate(rt, sn->current_sample_rix[y]),
1268 dot11rate_label(rt, sn->current_sample_rix[y]),
1269 sn->packets_sent[y]);
1270 kprintf("[%4u] packets since sample %d sample tt %u\n",
1271 bin_to_size(y), sn->packets_since_sample[y],
1274 for (mask = sn->ratemask, rix = 0; mask != 0; mask >>= 1, rix++) {
1275 if ((mask & 1) == 0)
1277 for (y = 0; y < NUM_PACKET_SIZE_BINS; y++) {
1278 if (sn->stats[y][rix].total_packets == 0)
1280 kprintf("[%2u %s:%4u] %8ju:%-8ju (%3d%%) (EWMA %3d.%1d%%) T %8ju F %4d avg %5u last %u\n",
1281 dot11rate(rt, rix), dot11rate_label(rt, rix),
1283 (uintmax_t) sn->stats[y][rix].total_packets,
1284 (uintmax_t) sn->stats[y][rix].packets_acked,
1285 (int) ((sn->stats[y][rix].packets_acked * 100ULL) /
1286 sn->stats[y][rix].total_packets),
1287 sn->stats[y][rix].ewma_pct / 10,
1288 sn->stats[y][rix].ewma_pct % 10,
1289 (uintmax_t) sn->stats[y][rix].tries,
1290 sn->stats[y][rix].successive_failures,
1291 sn->stats[y][rix].average_tx_time,
1292 ticks - sn->stats[y][rix].last_tx);
1298 ath_rate_sysctl_stats(SYSCTL_HANDLER_ARGS)
1300 struct ath_softc *sc = arg1;
1301 struct ifnet *ifp = sc->sc_ifp;
1302 struct ieee80211com *ic = ifp->if_l2com;
1306 error = sysctl_handle_int(oidp, &v, 0, req);
1307 if (error || !req->newptr)
1309 ieee80211_iterate_nodes(&ic->ic_sta, sample_stats, sc);
1314 ath_rate_sysctl_smoothing_rate(SYSCTL_HANDLER_ARGS)
1316 struct sample_softc *ssc = arg1;
1319 rate = ssc->smoothing_rate;
1320 error = sysctl_handle_int(oidp, &rate, 0, req);
1321 if (error || !req->newptr)
1323 if (!(0 <= rate && rate < 100))
1325 ssc->smoothing_rate = rate;
1326 ssc->smoothing_minpackets = 100 / (100 - rate);
1331 ath_rate_sysctl_sample_rate(SYSCTL_HANDLER_ARGS)
1333 struct sample_softc *ssc = arg1;
1336 rate = ssc->sample_rate;
1337 error = sysctl_handle_int(oidp, &rate, 0, req);
1338 if (error || !req->newptr)
1340 if (!(2 <= rate && rate <= 100))
1342 ssc->sample_rate = rate;
1347 ath_rate_sysctlattach(struct ath_softc *sc, struct sample_softc *ssc)
1349 struct sysctl_ctx_list *ctx = &sc->sc_sysctl_ctx;
1350 struct sysctl_oid *tree = sc->sc_sysctl_tree;
1352 SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
1353 "smoothing_rate", CTLTYPE_INT | CTLFLAG_RW, ssc, 0,
1354 ath_rate_sysctl_smoothing_rate, "I",
1355 "sample: smoothing rate for avg tx time (%%)");
1356 SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
1357 "sample_rate", CTLTYPE_INT | CTLFLAG_RW, ssc, 0,
1358 ath_rate_sysctl_sample_rate, "I",
1359 "sample: percent air time devoted to sampling new rates (%%)");
1360 /* XXX max_successive_failures, stale_failure_timeout, min_switch */
1361 SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
1362 "sample_stats", CTLTYPE_INT | CTLFLAG_RW, sc, 0,
1363 ath_rate_sysctl_stats, "I", "sample: print statistics");
1366 struct ath_ratectrl *
1367 ath_rate_attach(struct ath_softc *sc)
1369 struct sample_softc *ssc;
1371 ssc = kmalloc(sizeof(struct sample_softc), M_DEVBUF, M_INTWAIT|M_ZERO);
1374 ssc->arc.arc_space = sizeof(struct sample_node);
1375 ssc->smoothing_rate = 75; /* ewma percentage ([0..99]) */
1376 ssc->smoothing_minpackets = 100 / (100 - ssc->smoothing_rate);
1377 ssc->sample_rate = 10; /* %time to try diff tx rates */
1378 ssc->max_successive_failures = 3; /* threshold for rate sampling*/
1379 ssc->stale_failure_timeout = 10 * hz; /* 10 seconds */
1380 ssc->min_switch = hz; /* 1 second */
1381 ath_rate_sysctlattach(sc, ssc);
1386 ath_rate_detach(struct ath_ratectrl *arc)
1388 struct sample_softc *ssc = (struct sample_softc *) arc;
1390 kfree(ssc, M_DEVBUF);
1397 sample_modevent(module_t mod, int type, void *unused)
1401 wlan_serialize_enter();
1406 kprintf("ath_rate: <SampleRate bit-rate "
1407 "selection algorithm>\n");
1418 wlan_serialize_exit();
1423 static moduledata_t sample_mod = {
1429 DECLARE_MODULE(ath_rate, sample_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
1430 MODULE_VERSION(ath_rate, 1);
1431 MODULE_DEPEND(ath_rate, ath_hal, 1, 1, 1);
1432 MODULE_DEPEND(ath_rate, wlan, 1, 1, 1);