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>
60 #include <sys/socket.h>
63 #include <net/if_var.h>
64 #include <net/if_media.h>
65 #include <net/if_arp.h>
66 #include <net/ethernet.h> /* XXX for ether_sprintf */
68 #include <netproto/802_11/ieee80211_var.h>
73 #include <netinet/in.h>
74 #include <netinet/if_ether.h>
77 #include <dev/netif/ath/ath/if_athvar.h>
78 #include <dev/netif/ath/ath_rate/sample/sample.h>
79 #include <dev/netif/ath/ath_hal/ah_desc.h>
80 #include <dev/netif/ath/ath_rate/sample/tx_schedules.h>
82 extern const char* ath_hal_ether_sprintf(const uint8_t *mac);
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 ifnet *ifp = sc->sc_ifp;
492 struct ieee80211com *ic = ifp->if_l2com;
493 const HAL_RATE_TABLE *rt = sc->sc_currates;
494 const int size_bin = size_to_bin(frameLen);
495 int rix, mrr, best_rix, change_rates;
496 unsigned average_tx_time;
498 ath_rate_update_static_rix(sc, &an->an_node);
500 if (sn->currates != sc->sc_currates) {
501 device_printf(sc->sc_dev, "%s: currates != sc_currates!\n",
504 *try0 = ATH_TXMAXTRY;
508 if (sn->static_rix != -1) {
509 rix = sn->static_rix;
510 *try0 = ATH_TXMAXTRY;
514 mrr = sc->sc_mrretry;
515 /* XXX check HT protmode too */
516 if (mrr && (ic->ic_flags & IEEE80211_F_USEPROT && !sc->sc_mrrprot))
519 best_rix = pick_best_rate(an, rt, size_bin, !mrr);
521 average_tx_time = sn->stats[size_bin][best_rix].average_tx_time;
526 * Limit the time measuring the performance of other tx
527 * rates to sample_rate% of the total transmission time.
529 if (sn->sample_tt[size_bin] < average_tx_time * (sn->packets_since_sample[size_bin]*ssc->sample_rate/100)) {
530 rix = pick_sample_rate(ssc, an, rt, size_bin);
531 IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
532 &an->an_node, "att %d sample_tt %d size %u sample rate %d %s current rate %d %s",
534 sn->sample_tt[size_bin],
535 bin_to_size(size_bin),
537 dot11rate_label(rt, rix),
538 dot11rate(rt, sn->current_rix[size_bin]),
539 dot11rate_label(rt, sn->current_rix[size_bin]));
540 if (rix != sn->current_rix[size_bin]) {
541 sn->current_sample_rix[size_bin] = rix;
543 sn->current_sample_rix[size_bin] = -1;
545 sn->packets_since_sample[size_bin] = 0;
548 if (!sn->packets_sent[size_bin] || best_rix == -1) {
549 /* no packet has been sent successfully yet */
551 if (an->an_node.ni_flags & IEEE80211_NODE_HT)
553 ath_rate_pick_seed_rate_ht(sc, an, frameLen);
556 ath_rate_pick_seed_rate_legacy(sc, an, frameLen);
557 } else if (sn->packets_sent[size_bin] < 20) {
558 /* let the bit-rate switch quickly during the first few packets */
559 IEEE80211_NOTE(an->an_node.ni_vap,
560 IEEE80211_MSG_RATECTL, &an->an_node,
561 "%s: switching quickly..", __func__);
563 } else if (ticks - ssc->min_switch > sn->ticks_since_switch[size_bin]) {
564 /* min_switch seconds have gone by */
565 IEEE80211_NOTE(an->an_node.ni_vap,
566 IEEE80211_MSG_RATECTL, &an->an_node,
567 "%s: min_switch %d > ticks_since_switch %d..",
568 __func__, ticks - ssc->min_switch, sn->ticks_since_switch[size_bin]);
570 } else if ((! (an->an_node.ni_flags & IEEE80211_NODE_HT)) &&
571 (2*average_tx_time < sn->stats[size_bin][sn->current_rix[size_bin]].average_tx_time)) {
572 /* the current bit-rate is twice as slow as the best one */
573 IEEE80211_NOTE(an->an_node.ni_vap,
574 IEEE80211_MSG_RATECTL, &an->an_node,
575 "%s: 2x att (= %d) < cur_rix att %d",
577 2 * average_tx_time, sn->stats[size_bin][sn->current_rix[size_bin]].average_tx_time);
579 } else if ((an->an_node.ni_flags & IEEE80211_NODE_HT)) {
580 int cur_rix = sn->current_rix[size_bin];
581 int cur_att = sn->stats[size_bin][cur_rix].average_tx_time;
583 * If the node is HT, upgrade it if the MCS rate is
584 * higher and the average tx time is within 20% of
585 * the current rate. It can fail a little.
587 * This is likely not optimal!
590 kprintf("cur rix/att %x/%d, best rix/att %x/%d\n",
591 MCS(cur_rix), cur_att, MCS(best_rix), average_tx_time);
593 if ((MCS(best_rix) > MCS(cur_rix)) &&
594 (average_tx_time * 8) <= (cur_att * 10)) {
595 IEEE80211_NOTE(an->an_node.ni_vap,
596 IEEE80211_MSG_RATECTL, &an->an_node,
597 "%s: HT: best_rix 0x%d > cur_rix 0x%x, average_tx_time %d, cur_att %d",
599 MCS(best_rix), MCS(cur_rix), average_tx_time, cur_att);
604 sn->packets_since_sample[size_bin]++;
607 if (best_rix != sn->current_rix[size_bin]) {
608 IEEE80211_NOTE(an->an_node.ni_vap,
609 IEEE80211_MSG_RATECTL,
611 "%s: size %d switch rate %d (%d/%d) -> %d (%d/%d) after %d packets mrr %d",
613 bin_to_size(size_bin),
614 RATE(sn->current_rix[size_bin]),
615 sn->stats[size_bin][sn->current_rix[size_bin]].average_tx_time,
616 sn->stats[size_bin][sn->current_rix[size_bin]].perfect_tx_time,
618 sn->stats[size_bin][best_rix].average_tx_time,
619 sn->stats[size_bin][best_rix].perfect_tx_time,
620 sn->packets_since_switch[size_bin],
623 sn->packets_since_switch[size_bin] = 0;
624 sn->current_rix[size_bin] = best_rix;
625 sn->ticks_since_switch[size_bin] = ticks;
627 * Set the visible txrate for this node.
629 an->an_node.ni_txrate = (rt->info[best_rix].phy == IEEE80211_T_HT) ? MCS(best_rix) : DOT11RATE(best_rix);
631 rix = sn->current_rix[size_bin];
632 sn->packets_since_switch[size_bin]++;
634 *try0 = mrr ? sn->sched[rix].t0 : ATH_TXMAXTRY;
638 * This bug totally sucks and should be fixed.
640 * For now though, let's not panic, so we can start to figure
641 * out how to better reproduce it.
643 if (rix < 0 || rix >= rt->rateCount) {
644 kprintf("%s: ERROR: rix %d out of bounds (rateCount=%d)\n",
648 rix = 0; /* XXX just default for now */
650 KASSERT(rix >= 0 && rix < rt->rateCount, ("rix is %d", rix));
653 *txrate = rt->info[rix].rateCode
654 | (shortPreamble ? rt->info[rix].shortPreamble : 0);
655 sn->packets_sent[size_bin]++;
662 * Get the TX rates. Don't fiddle with short preamble flags for them;
663 * the caller can do that.
666 ath_rate_getxtxrates(struct ath_softc *sc, struct ath_node *an,
667 uint8_t rix0, struct ath_rc_series *rc)
669 struct sample_node *sn = ATH_NODE_SAMPLE(an);
670 const struct txschedule *sched = &sn->sched[rix0];
672 KASSERT(rix0 == sched->r0, ("rix0 (%x) != sched->r0 (%x)!\n",
675 rc[0].flags = rc[1].flags = rc[2].flags = rc[3].flags = 0;
677 rc[0].rix = sched->r0;
678 rc[1].rix = sched->r1;
679 rc[2].rix = sched->r2;
680 rc[3].rix = sched->r3;
682 rc[0].tries = sched->t0;
683 rc[1].tries = sched->t1;
684 rc[2].tries = sched->t2;
685 rc[3].tries = sched->t3;
689 ath_rate_setupxtxdesc(struct ath_softc *sc, struct ath_node *an,
690 struct ath_desc *ds, int shortPreamble, u_int8_t rix)
692 struct sample_node *sn = ATH_NODE_SAMPLE(an);
693 const struct txschedule *sched = &sn->sched[rix];
694 const HAL_RATE_TABLE *rt = sc->sc_currates;
695 uint8_t rix1, s1code, rix2, s2code, rix3, s3code;
697 /* XXX precalculate short preamble tables */
699 s1code = rt->info[rix1].rateCode
700 | (shortPreamble ? rt->info[rix1].shortPreamble : 0);
702 s2code = rt->info[rix2].rateCode
703 | (shortPreamble ? rt->info[rix2].shortPreamble : 0);
705 s3code = rt->info[rix3].rateCode
706 | (shortPreamble ? rt->info[rix3].shortPreamble : 0);
707 ath_hal_setupxtxdesc(sc->sc_ah, ds,
708 s1code, sched->t1, /* series 1 */
709 s2code, sched->t2, /* series 2 */
710 s3code, sched->t3); /* series 3 */
714 update_stats(struct ath_softc *sc, struct ath_node *an,
716 int rix0, int tries0,
717 int rix1, int tries1,
718 int rix2, int tries2,
719 int rix3, int tries3,
720 int short_tries, int tries, int status,
721 int nframes, int nbad)
723 struct sample_node *sn = ATH_NODE_SAMPLE(an);
724 struct sample_softc *ssc = ATH_SOFTC_SAMPLE(sc);
725 #ifdef IEEE80211_DEBUG
726 const HAL_RATE_TABLE *rt = sc->sc_currates;
728 const int size_bin = size_to_bin(frame_size);
729 const int size = bin_to_size(size_bin);
730 int tt, tries_so_far;
731 int is_ht40 = (an->an_node.ni_chw == 40);
734 if (!IS_RATE_DEFINED(sn, rix0))
736 tt = calc_usecs_unicast_packet(sc, size, rix0, short_tries,
737 MIN(tries0, tries) - 1, is_ht40);
738 tries_so_far = tries0;
740 if (tries1 && tries_so_far < tries) {
741 if (!IS_RATE_DEFINED(sn, rix1))
743 tt += calc_usecs_unicast_packet(sc, size, rix1, short_tries,
744 MIN(tries1 + tries_so_far, tries) - tries_so_far - 1, is_ht40);
745 tries_so_far += tries1;
748 if (tries2 && tries_so_far < tries) {
749 if (!IS_RATE_DEFINED(sn, rix2))
751 tt += calc_usecs_unicast_packet(sc, size, rix2, short_tries,
752 MIN(tries2 + tries_so_far, tries) - tries_so_far - 1, is_ht40);
753 tries_so_far += tries2;
756 if (tries3 && tries_so_far < tries) {
757 if (!IS_RATE_DEFINED(sn, rix3))
759 tt += calc_usecs_unicast_packet(sc, size, rix3, short_tries,
760 MIN(tries3 + tries_so_far, tries) - tries_so_far - 1, is_ht40);
763 if (sn->stats[size_bin][rix0].total_packets < ssc->smoothing_minpackets) {
764 /* just average the first few packets */
765 int avg_tx = sn->stats[size_bin][rix0].average_tx_time;
766 int packets = sn->stats[size_bin][rix0].total_packets;
767 sn->stats[size_bin][rix0].average_tx_time = (tt+(avg_tx*packets))/(packets+nframes);
770 sn->stats[size_bin][rix0].average_tx_time =
771 ((sn->stats[size_bin][rix0].average_tx_time * ssc->smoothing_rate) +
772 (tt * (100 - ssc->smoothing_rate))) / 100;
776 * XXX Don't mark the higher bit rates as also having failed; as this
777 * unfortunately stops those rates from being tasted when trying to
778 * TX. This happens with 11n aggregation.
780 if (nframes == nbad) {
784 sn->stats[size_bin][rix0].successive_failures += nbad;
786 for (y = size_bin+1; y < NUM_PACKET_SIZE_BINS; y++) {
788 * Also say larger packets failed since we
789 * assume if a small packet fails at a
790 * bit-rate then a larger one will also.
792 sn->stats[y][rix0].successive_failures += nbad;
793 sn->stats[y][rix0].last_tx = ticks;
794 sn->stats[y][rix0].tries += tries;
795 sn->stats[y][rix0].total_packets += nframes;
799 sn->stats[size_bin][rix0].packets_acked += (nframes - nbad);
800 sn->stats[size_bin][rix0].successive_failures = 0;
802 sn->stats[size_bin][rix0].tries += tries;
803 sn->stats[size_bin][rix0].last_tx = ticks;
804 sn->stats[size_bin][rix0].total_packets += nframes;
806 /* update EWMA for this rix */
808 /* Calculate percentage based on current rate */
811 pct = ((nframes - nbad) * 1000) / nframes;
813 if (sn->stats[size_bin][rix0].total_packets <
814 ssc->smoothing_minpackets) {
815 /* just average the first few packets */
816 int a_pct = (sn->stats[size_bin][rix0].packets_acked * 1000) /
817 (sn->stats[size_bin][rix0].total_packets);
818 sn->stats[size_bin][rix0].ewma_pct = a_pct;
821 sn->stats[size_bin][rix0].ewma_pct =
822 ((sn->stats[size_bin][rix0].ewma_pct * ssc->smoothing_rate) +
823 (pct * (100 - ssc->smoothing_rate))) / 100;
827 if (rix0 == sn->current_sample_rix[size_bin]) {
828 IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
830 "%s: size %d %s sample rate %d %s tries (%d/%d) tt %d avg_tt (%d/%d) nfrm %d nbad %d",
833 status ? "FAIL" : "OK",
835 dot11rate_label(rt, rix0),
836 short_tries, tries, tt,
837 sn->stats[size_bin][rix0].average_tx_time,
838 sn->stats[size_bin][rix0].perfect_tx_time,
840 sn->sample_tt[size_bin] = tt;
841 sn->current_sample_rix[size_bin] = -1;
846 badrate(struct ifnet *ifp, int series, int hwrate, int tries, int status)
848 if_printf(ifp, "bad series%d hwrate 0x%x, tries %u ts_status 0x%x\n",
849 series, hwrate, tries, status);
853 ath_rate_tx_complete(struct ath_softc *sc, struct ath_node *an,
854 const struct ath_rc_series *rc, const struct ath_tx_status *ts,
855 int frame_size, int nframes, int nbad)
857 struct ifnet *ifp = sc->sc_ifp;
858 struct ieee80211com *ic = ifp->if_l2com;
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, "%s: ts_rate=%d ts_finaltsi=%d\n",
895 __func__, ts->ts_rate, ts->ts_finaltsi);
896 badrate(ifp, 0, ts->ts_rate, long_tries, status);
900 * Only one rate was used; optimize work.
902 IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
903 &an->an_node, "%s: size %d (%d bytes) %s rate/short/long %d %s/%d/%d nframes/nbad [%d/%d]",
905 bin_to_size(size_to_bin(frame_size)),
907 status ? "FAIL" : "OK",
908 dot11rate(rt, final_rix), dot11rate_label(rt, final_rix),
909 short_tries, long_tries, nframes, nbad);
910 update_stats(sc, an, frame_size,
911 final_rix, long_tries,
915 short_tries, long_tries, status,
919 int finalTSIdx = ts->ts_finaltsi;
923 * Process intermediate rates that failed.
926 IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
928 "%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]",
930 bin_to_size(size_to_bin(frame_size)),
935 status ? "FAIL" : "OK",
936 dot11rate(rt, rc[0].rix),
937 dot11rate_label(rt, rc[0].rix), rc[0].tries,
938 dot11rate(rt, rc[1].rix),
939 dot11rate_label(rt, rc[1].rix), rc[1].tries,
940 dot11rate(rt, rc[2].rix),
941 dot11rate_label(rt, rc[2].rix), rc[2].tries,
942 dot11rate(rt, rc[3].rix),
943 dot11rate_label(rt, rc[3].rix), rc[3].tries,
946 for (i = 0; i < 4; i++) {
947 if (rc[i].tries && !IS_RATE_DEFINED(sn, rc[i].rix))
948 badrate(ifp, 0, rc[i].ratecode, rc[i].tries,
953 * NB: series > 0 are not penalized for failure
954 * based on the try counts under the assumption
955 * that losses are often bursty and since we
956 * sample higher rates 1 try at a time doing so
957 * may unfairly penalize them.
960 update_stats(sc, an, frame_size,
961 rc[0].rix, rc[0].tries,
962 rc[1].rix, rc[1].tries,
963 rc[2].rix, rc[2].tries,
964 rc[3].rix, rc[3].tries,
965 short_tries, long_tries,
966 long_tries > rc[0].tries,
968 long_tries -= rc[0].tries;
971 if (rc[1].tries && finalTSIdx > 0) {
972 update_stats(sc, an, frame_size,
973 rc[1].rix, rc[1].tries,
974 rc[2].rix, rc[2].tries,
975 rc[3].rix, rc[3].tries,
977 short_tries, long_tries,
980 long_tries -= rc[1].tries;
983 if (rc[2].tries && finalTSIdx > 1) {
984 update_stats(sc, an, frame_size,
985 rc[2].rix, rc[2].tries,
986 rc[3].rix, rc[3].tries,
989 short_tries, long_tries,
992 long_tries -= rc[2].tries;
995 if (rc[3].tries && finalTSIdx > 2) {
996 update_stats(sc, an, frame_size,
997 rc[3].rix, rc[3].tries,
1001 short_tries, long_tries,
1009 ath_rate_newassoc(struct ath_softc *sc, struct ath_node *an, int isnew)
1012 ath_rate_ctl_reset(sc, &an->an_node);
1015 static const struct txschedule *mrr_schedules[IEEE80211_MODE_MAX+2] = {
1016 NULL, /* IEEE80211_MODE_AUTO */
1017 series_11a, /* IEEE80211_MODE_11A */
1018 series_11g, /* IEEE80211_MODE_11B */
1019 series_11g, /* IEEE80211_MODE_11G */
1020 NULL, /* IEEE80211_MODE_FH */
1021 series_11a, /* IEEE80211_MODE_TURBO_A */
1022 series_11g, /* IEEE80211_MODE_TURBO_G */
1023 series_11a, /* IEEE80211_MODE_STURBO_A */
1024 series_11na, /* IEEE80211_MODE_11NA */
1025 series_11ng, /* IEEE80211_MODE_11NG */
1026 series_half, /* IEEE80211_MODE_HALF */
1027 series_quarter, /* IEEE80211_MODE_QUARTER */
1031 * Initialize the tables for a node.
1034 ath_rate_ctl_reset(struct ath_softc *sc, struct ieee80211_node *ni)
1036 #define RATE(_ix) (ni->ni_rates.rs_rates[(_ix)] & IEEE80211_RATE_VAL)
1037 #define DOT11RATE(_ix) (rt->info[(_ix)].dot11Rate & IEEE80211_RATE_VAL)
1038 #define MCS(_ix) (ni->ni_htrates.rs_rates[_ix] | IEEE80211_RATE_MCS)
1039 struct ath_node *an = ATH_NODE(ni);
1040 struct sample_node *sn = ATH_NODE_SAMPLE(an);
1041 const HAL_RATE_TABLE *rt = sc->sc_currates;
1044 KASSERT(rt != NULL, ("no rate table, mode %u", sc->sc_curmode));
1046 KASSERT(sc->sc_curmode < IEEE80211_MODE_MAX+2,
1047 ("curmode %u", sc->sc_curmode));
1049 sn->sched = mrr_schedules[sc->sc_curmode];
1050 KASSERT(sn->sched != NULL,
1051 ("no mrr schedule for mode %u", sc->sc_curmode));
1053 sn->static_rix = -1;
1054 ath_rate_update_static_rix(sc, ni);
1056 sn->currates = sc->sc_currates;
1059 * Construct a bitmask of usable rates. This has all
1060 * negotiated rates minus those marked by the hal as
1061 * to be ignored for doing rate control.
1065 if (ni->ni_flags & IEEE80211_NODE_HT) {
1066 for (x = 0; x < ni->ni_htrates.rs_nrates; x++) {
1067 rix = sc->sc_rixmap[MCS(x)];
1070 /* skip rates marked broken by hal */
1071 if (!rt->info[rix].valid)
1073 KASSERT(rix < SAMPLE_MAXRATES,
1074 ("mcs %u has rix %d", MCS(x), rix));
1075 sn->ratemask |= (uint64_t) 1<<rix;
1080 for (x = 0; x < ni->ni_rates.rs_nrates; x++) {
1081 rix = sc->sc_rixmap[RATE(x)];
1084 /* skip rates marked broken by hal */
1085 if (!rt->info[rix].valid)
1087 KASSERT(rix < SAMPLE_MAXRATES,
1088 ("rate %u has rix %d", RATE(x), rix));
1089 sn->ratemask |= (uint64_t) 1<<rix;
1091 #ifdef IEEE80211_DEBUG
1092 if (ieee80211_msg(ni->ni_vap, IEEE80211_MSG_RATECTL)) {
1095 ieee80211_note(ni->ni_vap, "[%s] %s: size 1600 rate/tt",
1096 ath_hal_ether_sprintf(ni->ni_macaddr), __func__);
1097 for (mask = sn->ratemask, rix = 0; mask != 0; mask >>= 1, rix++) {
1098 if ((mask & 1) == 0)
1100 kprintf(" %d %s/%d", dot11rate(rt, rix), dot11rate_label(rt, rix),
1101 calc_usecs_unicast_packet(sc, 1600, rix, 0,0,
1102 (ni->ni_chw == 40)));
1107 for (y = 0; y < NUM_PACKET_SIZE_BINS; y++) {
1108 int size = bin_to_size(y);
1111 sn->packets_sent[y] = 0;
1112 sn->current_sample_rix[y] = -1;
1113 sn->last_sample_rix[y] = 0;
1114 /* XXX start with first valid rate */
1115 sn->current_rix[y] = ffs(sn->ratemask)-1;
1118 * Initialize the statistics buckets; these are
1119 * indexed by the rate code index.
1121 for (rix = 0, mask = sn->ratemask; mask != 0; rix++, mask >>= 1) {
1122 if ((mask & 1) == 0) /* not a valid rate */
1124 sn->stats[y][rix].successive_failures = 0;
1125 sn->stats[y][rix].tries = 0;
1126 sn->stats[y][rix].total_packets = 0;
1127 sn->stats[y][rix].packets_acked = 0;
1128 sn->stats[y][rix].last_tx = 0;
1129 sn->stats[y][rix].ewma_pct = 0;
1131 sn->stats[y][rix].perfect_tx_time =
1132 calc_usecs_unicast_packet(sc, size, rix, 0, 0,
1133 (ni->ni_chw == 40));
1134 sn->stats[y][rix].average_tx_time =
1135 sn->stats[y][rix].perfect_tx_time;
1139 /* XXX 0, num_rates-1 are wrong */
1140 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
1141 "%s: %d rates %d%sMbps (%dus)- %d%sMbps (%dus)", __func__,
1143 DOT11RATE(0)/2, DOT11RATE(0) % 1 ? ".5" : "",
1144 sn->stats[1][0].perfect_tx_time,
1145 DOT11RATE(sn->num_rates-1)/2, DOT11RATE(sn->num_rates-1) % 1 ? ".5" : "",
1146 sn->stats[1][sn->num_rates-1].perfect_tx_time
1149 /* set the visible bit-rate */
1150 if (sn->static_rix != -1)
1151 ni->ni_txrate = DOT11RATE(sn->static_rix);
1153 ni->ni_txrate = RATE(0);
1159 * Fetch the statistics for the given node.
1161 * The ieee80211 node must be referenced and unlocked, however the ath_node
1164 * The main difference here is that we convert the rate indexes
1165 * to 802.11 rates, or the userland output won't make much sense
1166 * as it has no access to the rix table.
1169 ath_rate_fetch_node_stats(struct ath_softc *sc, struct ath_node *an,
1170 struct ath_rateioctl *rs)
1172 struct sample_node *sn = ATH_NODE_SAMPLE(an);
1173 const HAL_RATE_TABLE *rt = sc->sc_currates;
1174 struct ath_rateioctl_tlv av;
1175 struct ath_rateioctl_rt *tv;
1179 ATH_NODE_LOCK_ASSERT(an);
1182 * Ensure there's enough space for the statistics.
1185 sizeof(struct ath_rateioctl_tlv) +
1186 sizeof(struct ath_rateioctl_rt) +
1187 sizeof(struct ath_rateioctl_tlv) +
1188 sizeof(struct sample_node)) {
1189 device_printf(sc->sc_dev, "%s: len=%d, too short\n",
1196 * Take a temporary copy of the sample node state so we can
1197 * modify it before we copy it.
1199 tv = kmalloc(sizeof(struct ath_rateioctl_rt), M_TEMP,
1200 M_INTWAIT | M_ZERO);
1206 * Populate the rate table mapping TLV.
1208 tv->nentries = rt->rateCount;
1209 for (y = 0; y < rt->rateCount; y++) {
1210 tv->ratecode[y] = rt->info[y].dot11Rate & IEEE80211_RATE_VAL;
1211 if (rt->info[y].phy == IEEE80211_T_HT)
1212 tv->ratecode[y] |= IEEE80211_RATE_MCS;
1217 * First TLV - rate code mapping
1219 av.tlv_id = ATH_RATE_TLV_RATETABLE;
1220 av.tlv_len = sizeof(struct ath_rateioctl_rt);
1221 copyout(&av, rs->buf + o, sizeof(struct ath_rateioctl_tlv));
1222 o += sizeof(struct ath_rateioctl_tlv);
1223 copyout(tv, rs->buf + o, sizeof(struct ath_rateioctl_rt));
1224 o += sizeof(struct ath_rateioctl_rt);
1227 * Second TLV - sample node statistics
1229 av.tlv_id = ATH_RATE_TLV_SAMPLENODE;
1230 av.tlv_len = sizeof(struct sample_node);
1231 copyout(&av, rs->buf + o, sizeof(struct ath_rateioctl_tlv));
1232 o += sizeof(struct ath_rateioctl_tlv);
1235 * Copy the statistics over to the provided buffer.
1237 copyout(sn, rs->buf + o, sizeof(struct sample_node));
1238 o += sizeof(struct sample_node);
1246 sample_stats(void *arg, struct ieee80211_node *ni)
1248 struct ath_softc *sc = arg;
1249 const HAL_RATE_TABLE *rt = sc->sc_currates;
1250 struct sample_node *sn = ATH_NODE_SAMPLE(ATH_NODE(ni));
1254 kprintf("\n[%s] refcnt %d static_rix (%d %s) ratemask 0x%jx\n",
1255 ether_sprintf(ni->ni_macaddr), ieee80211_node_refcnt(ni),
1256 dot11rate(rt, sn->static_rix),
1257 dot11rate_label(rt, sn->static_rix),
1258 (uintmax_t)sn->ratemask);
1259 for (y = 0; y < NUM_PACKET_SIZE_BINS; y++) {
1260 kprintf("[%4u] cur rix %d (%d %s) since switch: packets %d ticks %u\n",
1261 bin_to_size(y), sn->current_rix[y],
1262 dot11rate(rt, sn->current_rix[y]),
1263 dot11rate_label(rt, sn->current_rix[y]),
1264 sn->packets_since_switch[y], sn->ticks_since_switch[y]);
1265 kprintf("[%4u] last sample (%d %s) cur sample (%d %s) packets sent %d\n",
1267 dot11rate(rt, sn->last_sample_rix[y]),
1268 dot11rate_label(rt, sn->last_sample_rix[y]),
1269 dot11rate(rt, sn->current_sample_rix[y]),
1270 dot11rate_label(rt, sn->current_sample_rix[y]),
1271 sn->packets_sent[y]);
1272 kprintf("[%4u] packets since sample %d sample tt %u\n",
1273 bin_to_size(y), sn->packets_since_sample[y],
1276 for (mask = sn->ratemask, rix = 0; mask != 0; mask >>= 1, rix++) {
1277 if ((mask & 1) == 0)
1279 for (y = 0; y < NUM_PACKET_SIZE_BINS; y++) {
1280 if (sn->stats[y][rix].total_packets == 0)
1282 kprintf("[%2u %s:%4u] %8ju:%-8ju (%3d%%) (EWMA %3d.%1d%%) T %8ju F %4d avg %5u last %u\n",
1283 dot11rate(rt, rix), dot11rate_label(rt, rix),
1285 (uintmax_t) sn->stats[y][rix].total_packets,
1286 (uintmax_t) sn->stats[y][rix].packets_acked,
1287 (int) ((sn->stats[y][rix].packets_acked * 100ULL) /
1288 sn->stats[y][rix].total_packets),
1289 sn->stats[y][rix].ewma_pct / 10,
1290 sn->stats[y][rix].ewma_pct % 10,
1291 (uintmax_t) sn->stats[y][rix].tries,
1292 sn->stats[y][rix].successive_failures,
1293 sn->stats[y][rix].average_tx_time,
1294 ticks - sn->stats[y][rix].last_tx);
1300 ath_rate_sysctl_stats(SYSCTL_HANDLER_ARGS)
1302 struct ath_softc *sc = arg1;
1303 struct ifnet *ifp = sc->sc_ifp;
1304 struct ieee80211com *ic = ifp->if_l2com;
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 = kmalloc(sizeof(struct sample_softc), M_DEVBUF, M_INTWAIT|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 kfree(ssc, M_DEVBUF);
1399 sample_modevent(module_t mod, int type, void *unused)
1403 wlan_serialize_enter();
1408 kprintf("ath_rate: <SampleRate bit-rate "
1409 "selection algorithm>\n");
1420 wlan_serialize_exit();
1425 static moduledata_t sample_mod = {
1431 DECLARE_MODULE(ath_rate, sample_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST);
1432 MODULE_VERSION(ath_rate, 1);
1433 MODULE_DEPEND(ath_rate, ath_hal, 1, 1, 1);
1434 MODULE_DEPEND(ath_rate, wlan, 1, 1, 1);