xref: /freebsd/sys/dev/ath/ath_rate/sample/sample.c (revision 2e1417489338b971e5fd599ff48b5f65df9e8d3b)
1 /*-
2  * Copyright (c) 2005 John Bicket
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer,
10  *    without modification.
11  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
12  *    similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
13  *    redistribution must be conditioned upon including a substantially
14  *    similar Disclaimer requirement for further binary redistribution.
15  * 3. Neither the names of the above-listed copyright holders nor the names
16  *    of any contributors may be used to endorse or promote products derived
17  *    from this software without specific prior written permission.
18  *
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.
22  *
23  * NO WARRANTY
24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
25  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
26  * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
27  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
28  * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
29  * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
32  * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
34  * THE POSSIBILITY OF SUCH DAMAGES.
35  *
36  */
37 
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40 
41 /*
42  * John Bicket's SampleRate control algorithm.
43  */
44 #include "opt_inet.h"
45 #include "opt_wlan.h"
46 #include "opt_ah.h"
47 
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/sysctl.h>
51 #include <sys/kernel.h>
52 #include <sys/lock.h>
53 #include <sys/mutex.h>
54 #include <sys/errno.h>
55 
56 #include <machine/bus.h>
57 #include <machine/resource.h>
58 #include <sys/bus.h>
59 
60 #include <sys/socket.h>
61 
62 #include <net/if.h>
63 #include <net/if_media.h>
64 #include <net/if_arp.h>
65 #include <net/ethernet.h>		/* XXX for ether_sprintf */
66 
67 #include <net80211/ieee80211_var.h>
68 
69 #include <net/bpf.h>
70 
71 #ifdef INET
72 #include <netinet/in.h>
73 #include <netinet/if_ether.h>
74 #endif
75 
76 #include <dev/ath/if_athvar.h>
77 #include <dev/ath/ath_rate/sample/sample.h>
78 #include <dev/ath/ath_hal/ah_desc.h>
79 #include <dev/ath/ath_rate/sample/tx_schedules.h>
80 
81 /*
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)
85  *
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.
97  *
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.
100  *
101  * Also, this implementation tracks the average transmission time for
102  * a few different packet sizes independently for each link.
103  */
104 
105 static void	ath_rate_ctl_reset(struct ath_softc *, struct ieee80211_node *);
106 
107 static const int packet_size_bins[NUM_PACKET_SIZE_BINS] = { 250, 1600 };
108 
109 static __inline int
110 size_to_bin(int size)
111 {
112 #if NUM_PACKET_SIZE_BINS > 1
113 	if (size <= packet_size_bins[0])
114 		return 0;
115 #endif
116 #if NUM_PACKET_SIZE_BINS > 2
117 	if (size <= packet_size_bins[1])
118 		return 1;
119 #endif
120 #if NUM_PACKET_SIZE_BINS > 3
121 	if (size <= packet_size_bins[2])
122 		return 2;
123 #endif
124 #if NUM_PACKET_SIZE_BINS > 4
125 #error "add support for more packet sizes"
126 #endif
127 	return NUM_PACKET_SIZE_BINS-1;
128 }
129 
130 static __inline int
131 bin_to_size(int index)
132 {
133 	return packet_size_bins[index];
134 }
135 
136 void
137 ath_rate_node_init(struct ath_softc *sc, struct ath_node *an)
138 {
139 	/* NB: assumed to be zero'd by caller */
140 }
141 
142 void
143 ath_rate_node_cleanup(struct ath_softc *sc, struct ath_node *an)
144 {
145 }
146 
147 static int
148 dot11rate(const HAL_RATE_TABLE *rt, int rix)
149 {
150 	if (rix < 0)
151 		return -1;
152 	return rt->info[rix].phy == IEEE80211_T_HT ?
153 	    rt->info[rix].dot11Rate : (rt->info[rix].dot11Rate & IEEE80211_RATE_VAL) / 2;
154 }
155 
156 static const char *
157 dot11rate_label(const HAL_RATE_TABLE *rt, int rix)
158 {
159 	if (rix < 0)
160 		return "";
161 	return rt->info[rix].phy == IEEE80211_T_HT ? "MCS" : "Mb ";
162 }
163 
164 /*
165  * Return the rix with the lowest average_tx_time,
166  * or -1 if all the average_tx_times are 0.
167  */
168 static __inline int
169 pick_best_rate(struct ath_node *an, const HAL_RATE_TABLE *rt,
170     int size_bin, int require_acked_before)
171 {
172 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
173         int best_rate_rix, best_rate_tt, best_rate_pct;
174 	uint32_t mask;
175 	int rix, tt, pct;
176 
177         best_rate_rix = 0;
178         best_rate_tt = 0;
179 	best_rate_pct = 0;
180 	for (mask = sn->ratemask, rix = 0; mask != 0; mask >>= 1, rix++) {
181 		if ((mask & 1) == 0)		/* not a supported rate */
182 			continue;
183 
184 		/* Don't pick a non-HT rate for a HT node */
185 		if ((an->an_node.ni_flags & IEEE80211_NODE_HT) &&
186 		    (rt->info[rix].phy != IEEE80211_T_HT)) {
187 			continue;
188 		}
189 
190 		tt = sn->stats[size_bin][rix].average_tx_time;
191 		if (tt <= 0 ||
192 		    (require_acked_before &&
193 		     !sn->stats[size_bin][rix].packets_acked))
194 			continue;
195 
196 		/* Calculate percentage if possible */
197 		if (sn->stats[size_bin][rix].total_packets > 0) {
198 			pct = sn->stats[size_bin][rix].ewma_pct;
199 		} else {
200 			/* XXX for now, assume 95% ok */
201 			pct = 95;
202 		}
203 
204 		/* don't use a bit-rate that has been failing */
205 		if (sn->stats[size_bin][rix].successive_failures > 3)
206 			continue;
207 
208 		/*
209 		 * For HT, Don't use a bit rate that is much more
210 		 * lossy than the best.
211 		 *
212 		 * XXX this isn't optimal; it's just designed to
213 		 * eliminate rates that are going to be obviously
214 		 * worse.
215 		 */
216 		if (an->an_node.ni_flags & IEEE80211_NODE_HT) {
217 			if (best_rate_pct > (pct + 50))
218 				continue;
219 		}
220 
221 		/*
222 		 * For non-MCS rates, use the current average txtime for
223 		 * comparison.
224 		 */
225 		if (! (an->an_node.ni_flags & IEEE80211_NODE_HT)) {
226 			if (best_rate_tt == 0 || tt <= best_rate_tt) {
227 				best_rate_tt = tt;
228 				best_rate_rix = rix;
229 				best_rate_pct = pct;
230 			}
231 		}
232 
233 		/*
234 		 * Since 2 stream rates have slightly higher TX times,
235 		 * allow a little bit of leeway. This should later
236 		 * be abstracted out and properly handled.
237 		 */
238 		if (an->an_node.ni_flags & IEEE80211_NODE_HT) {
239 			if (best_rate_tt == 0 || (tt * 8 <= best_rate_tt * 10)) {
240 				best_rate_tt = tt;
241 				best_rate_rix = rix;
242 				best_rate_pct = pct;
243 			}
244 		}
245         }
246         return (best_rate_tt ? best_rate_rix : -1);
247 }
248 
249 /*
250  * Pick a good "random" bit-rate to sample other than the current one.
251  */
252 static __inline int
253 pick_sample_rate(struct sample_softc *ssc , struct ath_node *an,
254     const HAL_RATE_TABLE *rt, int size_bin)
255 {
256 #define	DOT11RATE(ix)	(rt->info[ix].dot11Rate & IEEE80211_RATE_VAL)
257 #define	MCS(ix)		(rt->info[ix].dot11Rate | IEEE80211_RATE_MCS)
258 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
259 	int current_rix, rix;
260 	unsigned current_tt;
261 	uint32_t mask;
262 
263 	current_rix = sn->current_rix[size_bin];
264 	if (current_rix < 0) {
265 		/* no successes yet, send at the lowest bit-rate */
266 		/* XXX should return MCS0 if HT */
267 		return 0;
268 	}
269 
270 	current_tt = sn->stats[size_bin][current_rix].average_tx_time;
271 
272 	rix = sn->last_sample_rix[size_bin]+1;	/* next sample rate */
273 	mask = sn->ratemask &~ (1<<current_rix);/* don't sample current rate */
274 	while (mask != 0) {
275 		if ((mask & (1<<rix)) == 0) {	/* not a supported rate */
276 	nextrate:
277 			if (++rix >= rt->rateCount)
278 				rix = 0;
279 			continue;
280 		}
281 
282 		/* if the node is HT and the rate isn't HT, don't bother sample */
283 		if ((an->an_node.ni_flags & IEEE80211_NODE_HT) &&
284 		    (rt->info[rix].phy != IEEE80211_T_HT)) {
285 			mask &= ~(1<<rix);
286 			goto nextrate;
287 		}
288 
289 		/* this bit-rate is always worse than the current one */
290 		if (sn->stats[size_bin][rix].perfect_tx_time > current_tt) {
291 			mask &= ~(1<<rix);
292 			goto nextrate;
293 		}
294 
295 		/* rarely sample bit-rates that fail a lot */
296 		if (sn->stats[size_bin][rix].successive_failures > ssc->max_successive_failures &&
297 		    ticks - sn->stats[size_bin][rix].last_tx < ssc->stale_failure_timeout) {
298 			mask &= ~(1<<rix);
299 			goto nextrate;
300 		}
301 
302 		/*
303 		 * When doing aggregation, successive failures don't happen
304 		 * as often, as sometimes some of the sub-frames get through.
305 		 *
306 		 * If the sample rix average tx time is greater than the
307 		 * average tx time of the current rix, don't immediately use
308 		 * the rate for sampling.
309 		 */
310 		if (an->an_node.ni_flags & IEEE80211_NODE_HT) {
311 			if ((sn->stats[size_bin][rix].average_tx_time * 10 >
312 			    sn->stats[size_bin][current_rix].average_tx_time * 9) &&
313 			    (ticks - sn->stats[size_bin][rix].last_tx < ssc->stale_failure_timeout)) {
314 				mask &= ~(1<<rix);
315 				goto nextrate;
316 			}
317 		}
318 
319 		/*
320 		 * XXX TODO
321 		 * For HT, limit sample somehow?
322 		 */
323 
324 		/* Don't sample more than 2 rates higher for rates > 11M for non-HT rates */
325 		if (! (an->an_node.ni_flags & IEEE80211_NODE_HT)) {
326 			if (DOT11RATE(rix) > 2*11 && rix > current_rix + 2) {
327 				mask &= ~(1<<rix);
328 				goto nextrate;
329 			}
330 		}
331 
332 		sn->last_sample_rix[size_bin] = rix;
333 		return rix;
334 	}
335 	return current_rix;
336 #undef DOT11RATE
337 #undef	MCS
338 }
339 
340 static int
341 ath_rate_get_static_rix(struct ath_softc *sc, const struct ieee80211_node *ni)
342 {
343 #define	RATE(_ix)	(ni->ni_rates.rs_rates[(_ix)] & IEEE80211_RATE_VAL)
344 #define	DOT11RATE(_ix)	(rt->info[(_ix)].dot11Rate & IEEE80211_RATE_VAL)
345 #define	MCS(_ix)	(ni->ni_htrates.rs_rates[_ix] | IEEE80211_RATE_MCS)
346 	const struct ieee80211_txparam *tp = ni->ni_txparms;
347 	int srate;
348 
349 	/* Check MCS rates */
350 	for (srate = ni->ni_htrates.rs_nrates - 1; srate >= 0; srate--) {
351 		if (MCS(srate) == tp->ucastrate)
352 			return sc->sc_rixmap[tp->ucastrate];
353 	}
354 
355 	/* Check legacy rates */
356 	for (srate = ni->ni_rates.rs_nrates - 1; srate >= 0; srate--) {
357 		if (RATE(srate) == tp->ucastrate)
358 			return sc->sc_rixmap[tp->ucastrate];
359 	}
360 	return -1;
361 #undef	RATE
362 #undef	DOT11RATE
363 #undef	MCS
364 }
365 
366 static void
367 ath_rate_update_static_rix(struct ath_softc *sc, struct ieee80211_node *ni)
368 {
369 	struct ath_node *an = ATH_NODE(ni);
370 	const struct ieee80211_txparam *tp = ni->ni_txparms;
371 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
372 
373 	if (tp != NULL && tp->ucastrate != IEEE80211_FIXED_RATE_NONE) {
374 		/*
375 		 * A fixed rate is to be used; ucastrate is the IEEE code
376 		 * for this rate (sans basic bit).  Check this against the
377 		 * negotiated rate set for the node.  Note the fixed rate
378 		 * may not be available for various reasons so we only
379 		 * setup the static rate index if the lookup is successful.
380 		 */
381 		sn->static_rix = ath_rate_get_static_rix(sc, ni);
382 	} else {
383 		sn->static_rix = -1;
384 	}
385 }
386 
387 /*
388  * Pick a non-HT rate to begin using.
389  */
390 static int
391 ath_rate_pick_seed_rate_legacy(struct ath_softc *sc, struct ath_node *an,
392     int frameLen)
393 {
394 #define	DOT11RATE(ix)	(rt->info[ix].dot11Rate & IEEE80211_RATE_VAL)
395 #define	MCS(ix)		(rt->info[ix].dot11Rate | IEEE80211_RATE_MCS)
396 #define	RATE(ix)	(DOT11RATE(ix) / 2)
397 	int rix = -1;
398 	const HAL_RATE_TABLE *rt = sc->sc_currates;
399 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
400 	const int size_bin = size_to_bin(frameLen);
401 
402 	/* no packet has been sent successfully yet */
403 	for (rix = rt->rateCount-1; rix > 0; rix--) {
404 		if ((sn->ratemask & (1<<rix)) == 0)
405 			continue;
406 
407 		/* Skip HT rates */
408 		if (rt->info[rix].phy == IEEE80211_T_HT)
409 			continue;
410 
411 		/*
412 		 * Pick the highest rate <= 36 Mbps
413 		 * that hasn't failed.
414 		 */
415 		if (DOT11RATE(rix) <= 72 &&
416 		    sn->stats[size_bin][rix].successive_failures == 0) {
417 			break;
418 		}
419 	}
420 	return rix;
421 #undef	RATE
422 #undef	MCS
423 #undef	DOT11RATE
424 }
425 
426 /*
427  * Pick a HT rate to begin using.
428  *
429  * Don't use any non-HT rates; only consider HT rates.
430  */
431 static int
432 ath_rate_pick_seed_rate_ht(struct ath_softc *sc, struct ath_node *an,
433     int frameLen)
434 {
435 #define	DOT11RATE(ix)	(rt->info[ix].dot11Rate & IEEE80211_RATE_VAL)
436 #define	MCS(ix)		(rt->info[ix].dot11Rate | IEEE80211_RATE_MCS)
437 #define	RATE(ix)	(DOT11RATE(ix) / 2)
438 	int rix = -1, ht_rix = -1;
439 	const HAL_RATE_TABLE *rt = sc->sc_currates;
440 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
441 	const int size_bin = size_to_bin(frameLen);
442 
443 	/* no packet has been sent successfully yet */
444 	for (rix = rt->rateCount-1; rix > 0; rix--) {
445 		/* Skip rates we can't use */
446 		if ((sn->ratemask & (1<<rix)) == 0)
447 			continue;
448 
449 		/* Keep a copy of the last seen HT rate index */
450 		if (rt->info[rix].phy == IEEE80211_T_HT)
451 			ht_rix = rix;
452 
453 		/* Skip non-HT rates */
454 		if (rt->info[rix].phy != IEEE80211_T_HT)
455 			continue;
456 
457 		/*
458 		 * Pick a medium-speed rate regardless of stream count
459 		 * which has not seen any failures. Higher rates may fail;
460 		 * we'll try them later.
461 		 */
462 		if (((MCS(rix) & 0x7) <= 4) &&
463 		    sn->stats[size_bin][rix].successive_failures == 0) {
464 			break;
465 		}
466 	}
467 
468 	/*
469 	 * If all the MCS rates have successive failures, rix should be
470 	 * > 0; otherwise use the lowest MCS rix (hopefully MCS 0.)
471 	 */
472 	return MAX(rix, ht_rix);
473 #undef	RATE
474 #undef	MCS
475 #undef	DOT11RATE
476 }
477 
478 
479 void
480 ath_rate_findrate(struct ath_softc *sc, struct ath_node *an,
481 		  int shortPreamble, size_t frameLen,
482 		  u_int8_t *rix0, int *try0, u_int8_t *txrate)
483 {
484 #define	DOT11RATE(ix)	(rt->info[ix].dot11Rate & IEEE80211_RATE_VAL)
485 #define	MCS(ix)		(rt->info[ix].dot11Rate | IEEE80211_RATE_MCS)
486 #define	RATE(ix)	(DOT11RATE(ix) / 2)
487 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
488 	struct sample_softc *ssc = ATH_SOFTC_SAMPLE(sc);
489 	struct ifnet *ifp = sc->sc_ifp;
490 	struct ieee80211com *ic = ifp->if_l2com;
491 	const HAL_RATE_TABLE *rt = sc->sc_currates;
492 	const int size_bin = size_to_bin(frameLen);
493 	int rix, mrr, best_rix, change_rates;
494 	unsigned average_tx_time;
495 
496 	ath_rate_update_static_rix(sc, &an->an_node);
497 
498 	if (sn->static_rix != -1) {
499 		rix = sn->static_rix;
500 		*try0 = ATH_TXMAXTRY;
501 		goto done;
502 	}
503 
504 	/* XXX TODO: this doesn't know about 11gn vs 11g protection; teach it */
505 	mrr = sc->sc_mrretry && !(ic->ic_flags & IEEE80211_F_USEPROT);
506 
507 	best_rix = pick_best_rate(an, rt, size_bin, !mrr);
508 	if (best_rix >= 0) {
509 		average_tx_time = sn->stats[size_bin][best_rix].average_tx_time;
510 	} else {
511 		average_tx_time = 0;
512 	}
513 	/*
514 	 * Limit the time measuring the performance of other tx
515 	 * rates to sample_rate% of the total transmission time.
516 	 */
517 	if (sn->sample_tt[size_bin] < average_tx_time * (sn->packets_since_sample[size_bin]*ssc->sample_rate/100)) {
518 		rix = pick_sample_rate(ssc, an, rt, size_bin);
519 		IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
520 		     &an->an_node, "att %d sample_tt %d size %u sample rate %d %s current rate %d %s",
521 		     average_tx_time,
522 		     sn->sample_tt[size_bin],
523 		     bin_to_size(size_bin),
524 		     dot11rate(rt, rix),
525 		     dot11rate_label(rt, rix),
526 		     dot11rate(rt, sn->current_rix[size_bin]),
527 		     dot11rate_label(rt, sn->current_rix[size_bin]));
528 		if (rix != sn->current_rix[size_bin]) {
529 			sn->current_sample_rix[size_bin] = rix;
530 		} else {
531 			sn->current_sample_rix[size_bin] = -1;
532 		}
533 		sn->packets_since_sample[size_bin] = 0;
534 	} else {
535 		change_rates = 0;
536 		if (!sn->packets_sent[size_bin] || best_rix == -1) {
537 			/* no packet has been sent successfully yet */
538 			change_rates = 1;
539 			if (an->an_node.ni_flags & IEEE80211_NODE_HT)
540 				best_rix =
541 				    ath_rate_pick_seed_rate_ht(sc, an, frameLen);
542 			else
543 				best_rix =
544 				    ath_rate_pick_seed_rate_legacy(sc, an, frameLen);
545 		} else if (sn->packets_sent[size_bin] < 20) {
546 			/* let the bit-rate switch quickly during the first few packets */
547 			IEEE80211_NOTE(an->an_node.ni_vap,
548 			    IEEE80211_MSG_RATECTL, &an->an_node,
549 			    "%s: switching quickly..", __func__);
550 			change_rates = 1;
551 		} else if (ticks - ssc->min_switch > sn->ticks_since_switch[size_bin]) {
552 			/* min_switch seconds have gone by */
553 			IEEE80211_NOTE(an->an_node.ni_vap,
554 			    IEEE80211_MSG_RATECTL, &an->an_node,
555 			    "%s: min_switch %d > ticks_since_switch %d..",
556 			    __func__, ticks - ssc->min_switch, sn->ticks_since_switch[size_bin]);
557 			change_rates = 1;
558 		} else if ((! (an->an_node.ni_flags & IEEE80211_NODE_HT)) &&
559 		    (2*average_tx_time < sn->stats[size_bin][sn->current_rix[size_bin]].average_tx_time)) {
560 			/* the current bit-rate is twice as slow as the best one */
561 			IEEE80211_NOTE(an->an_node.ni_vap,
562 			    IEEE80211_MSG_RATECTL, &an->an_node,
563 			    "%s: 2x att (= %d) < cur_rix att %d",
564 			    __func__,
565 			    2 * average_tx_time, sn->stats[size_bin][sn->current_rix[size_bin]].average_tx_time);
566 			change_rates = 1;
567 		} else if ((an->an_node.ni_flags & IEEE80211_NODE_HT)) {
568 			int cur_rix = sn->current_rix[size_bin];
569 			int cur_att = sn->stats[size_bin][cur_rix].average_tx_time;
570 			/*
571 			 * If the node is HT, upgrade it if the MCS rate is
572 			 * higher and the average tx time is within 20% of
573 			 * the current rate. It can fail a little.
574 			 *
575 			 * This is likely not optimal!
576 			 */
577 #if 0
578 			printf("cur rix/att %x/%d, best rix/att %x/%d\n",
579 			    MCS(cur_rix), cur_att, MCS(best_rix), average_tx_time);
580 #endif
581 			if ((MCS(best_rix) > MCS(cur_rix)) &&
582 			    (average_tx_time * 8) <= (cur_att * 10)) {
583 				IEEE80211_NOTE(an->an_node.ni_vap,
584 				    IEEE80211_MSG_RATECTL, &an->an_node,
585 				    "%s: HT: best_rix 0x%d > cur_rix 0x%x, average_tx_time %d, cur_att %d",
586 				    __func__,
587 				    MCS(best_rix), MCS(cur_rix), average_tx_time, cur_att);
588 				change_rates = 1;
589 			}
590 		}
591 
592 		sn->packets_since_sample[size_bin]++;
593 
594 		if (change_rates) {
595 			if (best_rix != sn->current_rix[size_bin]) {
596 				IEEE80211_NOTE(an->an_node.ni_vap,
597 				    IEEE80211_MSG_RATECTL,
598 				    &an->an_node,
599 "%s: size %d switch rate %d (%d/%d) -> %d (%d/%d) after %d packets mrr %d",
600 				    __func__,
601 				    bin_to_size(size_bin),
602 				    RATE(sn->current_rix[size_bin]),
603 				    sn->stats[size_bin][sn->current_rix[size_bin]].average_tx_time,
604 				    sn->stats[size_bin][sn->current_rix[size_bin]].perfect_tx_time,
605 				    RATE(best_rix),
606 				    sn->stats[size_bin][best_rix].average_tx_time,
607 				    sn->stats[size_bin][best_rix].perfect_tx_time,
608 				    sn->packets_since_switch[size_bin],
609 				    mrr);
610 			}
611 			sn->packets_since_switch[size_bin] = 0;
612 			sn->current_rix[size_bin] = best_rix;
613 			sn->ticks_since_switch[size_bin] = ticks;
614 			/*
615 			 * Set the visible txrate for this node.
616 			 */
617 			an->an_node.ni_txrate = (rt->info[best_rix].phy == IEEE80211_T_HT) ?  MCS(best_rix) : DOT11RATE(best_rix);
618 		}
619 		rix = sn->current_rix[size_bin];
620 		sn->packets_since_switch[size_bin]++;
621 	}
622 	*try0 = mrr ? sn->sched[rix].t0 : ATH_TXMAXTRY;
623 done:
624 	KASSERT(rix >= 0 && rix < rt->rateCount, ("rix is %d", rix));
625 
626 	*rix0 = rix;
627 	*txrate = rt->info[rix].rateCode
628 		| (shortPreamble ? rt->info[rix].shortPreamble : 0);
629 	sn->packets_sent[size_bin]++;
630 #undef DOT11RATE
631 #undef MCS
632 #undef RATE
633 }
634 
635 /*
636  * Get the TX rates. Don't fiddle with short preamble flags for them;
637  * the caller can do that.
638  */
639 void
640 ath_rate_getxtxrates(struct ath_softc *sc, struct ath_node *an,
641     uint8_t rix0, struct ath_rc_series *rc)
642 {
643 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
644 	const struct txschedule *sched = &sn->sched[rix0];
645 
646 	KASSERT(rix0 == sched->r0, ("rix0 (%x) != sched->r0 (%x)!\n", rix0, sched->r0));
647 
648 	rc[0].flags = rc[1].flags = rc[2].flags = rc[3].flags = 0;
649 
650 	rc[0].rix = sched->r0;
651 	rc[1].rix = sched->r1;
652 	rc[2].rix = sched->r2;
653 	rc[3].rix = sched->r3;
654 
655 	rc[0].tries = sched->t0;
656 	rc[1].tries = sched->t1;
657 	rc[2].tries = sched->t2;
658 	rc[3].tries = sched->t3;
659 }
660 
661 void
662 ath_rate_setupxtxdesc(struct ath_softc *sc, struct ath_node *an,
663 		      struct ath_desc *ds, int shortPreamble, u_int8_t rix)
664 {
665 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
666 	const struct txschedule *sched = &sn->sched[rix];
667 	const HAL_RATE_TABLE *rt = sc->sc_currates;
668 	uint8_t rix1, s1code, rix2, s2code, rix3, s3code;
669 
670 	/* XXX precalculate short preamble tables */
671 	rix1 = sched->r1;
672 	s1code = rt->info[rix1].rateCode
673 	       | (shortPreamble ? rt->info[rix1].shortPreamble : 0);
674 	rix2 = sched->r2;
675 	s2code = rt->info[rix2].rateCode
676 	       | (shortPreamble ? rt->info[rix2].shortPreamble : 0);
677 	rix3 = sched->r3;
678 	s3code = rt->info[rix3].rateCode
679 	       | (shortPreamble ? rt->info[rix3].shortPreamble : 0);
680 	ath_hal_setupxtxdesc(sc->sc_ah, ds,
681 	    s1code, sched->t1,		/* series 1 */
682 	    s2code, sched->t2,		/* series 2 */
683 	    s3code, sched->t3);		/* series 3 */
684 }
685 
686 /*
687  * Update the EWMA percentage.
688  *
689  * This is a simple hack to track an EWMA based on the current
690  * rate scenario. For the rate codes which failed, this will
691  * record a 0% against it. For the rate code which succeeded,
692  * EWMA will record the nbad*100/nframes percentage against it.
693  */
694 static void
695 update_ewma_stats(struct ath_softc *sc, struct ath_node *an,
696     int frame_size,
697     int rix0, int tries0,
698     int rix1, int tries1,
699     int rix2, int tries2,
700     int rix3, int tries3,
701     int short_tries, int tries, int status,
702     int nframes, int nbad)
703 {
704 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
705 	struct sample_softc *ssc = ATH_SOFTC_SAMPLE(sc);
706 	const int size_bin = size_to_bin(frame_size);
707 	int tries_so_far;
708 	int pct;
709 	int rix = rix0;
710 
711 	/* Calculate percentage based on current rate */
712 	if (nframes == 0)
713 		nframes = nbad = 1;
714 	pct = ((nframes - nbad) * 1000) / nframes;
715 
716 	/* Figure out which rate index succeeded */
717 	tries_so_far = tries0;
718 
719 	if (tries1 && tries_so_far < tries) {
720 		tries_so_far += tries1;
721 		rix = rix1;
722 		/* XXX bump ewma pct */
723 	}
724 
725 	if (tries2 && tries_so_far < tries) {
726 		tries_so_far += tries2;
727 		rix = rix2;
728 		/* XXX bump ewma pct */
729 	}
730 
731 	if (tries3 && tries_so_far < tries) {
732 		rix = rix3;
733 		/* XXX bump ewma pct */
734 	}
735 
736 	/* rix is the successful rate, update EWMA for final rix */
737 	if (sn->stats[size_bin][rix].total_packets <
738 	    ssc->smoothing_minpackets) {
739 		/* just average the first few packets */
740 		int a_pct = (sn->stats[size_bin][rix].packets_acked * 1000) /
741 		    (sn->stats[size_bin][rix].total_packets);
742 		sn->stats[size_bin][rix].ewma_pct = a_pct;
743 	} else {
744 		/* use a ewma */
745 		sn->stats[size_bin][rix].ewma_pct =
746 			((sn->stats[size_bin][rix].ewma_pct * ssc->smoothing_rate) +
747 			 (pct * (100 - ssc->smoothing_rate))) / 100;
748 	}
749 }
750 
751 static void
752 update_stats(struct ath_softc *sc, struct ath_node *an,
753 		  int frame_size,
754 		  int rix0, int tries0,
755 		  int rix1, int tries1,
756 		  int rix2, int tries2,
757 		  int rix3, int tries3,
758 		  int short_tries, int tries, int status,
759 		  int nframes, int nbad)
760 {
761 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
762 	struct sample_softc *ssc = ATH_SOFTC_SAMPLE(sc);
763 #ifdef IEEE80211_DEBUG
764 	const HAL_RATE_TABLE *rt = sc->sc_currates;
765 #endif
766 	const int size_bin = size_to_bin(frame_size);
767 	const int size = bin_to_size(size_bin);
768 	int tt, tries_so_far;
769 	int is_ht40 = (an->an_node.ni_chw == 40);
770 
771 	if (!IS_RATE_DEFINED(sn, rix0))
772 		return;
773 	tt = calc_usecs_unicast_packet(sc, size, rix0, short_tries,
774 		MIN(tries0, tries) - 1, is_ht40);
775 	tries_so_far = tries0;
776 
777 	if (tries1 && tries_so_far < tries) {
778 		if (!IS_RATE_DEFINED(sn, rix1))
779 			return;
780 		tt += calc_usecs_unicast_packet(sc, size, rix1, short_tries,
781 			MIN(tries1 + tries_so_far, tries) - tries_so_far - 1, is_ht40);
782 		tries_so_far += tries1;
783 	}
784 
785 	if (tries2 && tries_so_far < tries) {
786 		if (!IS_RATE_DEFINED(sn, rix2))
787 			return;
788 		tt += calc_usecs_unicast_packet(sc, size, rix2, short_tries,
789 			MIN(tries2 + tries_so_far, tries) - tries_so_far - 1, is_ht40);
790 		tries_so_far += tries2;
791 	}
792 
793 	if (tries3 && tries_so_far < tries) {
794 		if (!IS_RATE_DEFINED(sn, rix3))
795 			return;
796 		tt += calc_usecs_unicast_packet(sc, size, rix3, short_tries,
797 			MIN(tries3 + tries_so_far, tries) - tries_so_far - 1, is_ht40);
798 	}
799 
800 	if (sn->stats[size_bin][rix0].total_packets < ssc->smoothing_minpackets) {
801 		/* just average the first few packets */
802 		int avg_tx = sn->stats[size_bin][rix0].average_tx_time;
803 		int packets = sn->stats[size_bin][rix0].total_packets;
804 		sn->stats[size_bin][rix0].average_tx_time = (tt+(avg_tx*packets))/(packets+nframes);
805 	} else {
806 		/* use a ewma */
807 		sn->stats[size_bin][rix0].average_tx_time =
808 			((sn->stats[size_bin][rix0].average_tx_time * ssc->smoothing_rate) +
809 			 (tt * (100 - ssc->smoothing_rate))) / 100;
810 	}
811 
812 	/*
813 	 * XXX Don't mark the higher bit rates as also having failed; as this
814 	 * unfortunately stops those rates from being tasted when trying to
815 	 * TX. This happens with 11n aggregation.
816 	 */
817 	if (nframes == nbad) {
818 #if 0
819 		int y;
820 #endif
821 		sn->stats[size_bin][rix0].successive_failures += nbad;
822 #if 0
823 		for (y = size_bin+1; y < NUM_PACKET_SIZE_BINS; y++) {
824 			/*
825 			 * Also say larger packets failed since we
826 			 * assume if a small packet fails at a
827 			 * bit-rate then a larger one will also.
828 			 */
829 			sn->stats[y][rix0].successive_failures += nbad;
830 			sn->stats[y][rix0].last_tx = ticks;
831 			sn->stats[y][rix0].tries += tries;
832 			sn->stats[y][rix0].total_packets += nframes;
833 		}
834 #endif
835 	} else {
836 		sn->stats[size_bin][rix0].packets_acked += (nframes - nbad);
837 		sn->stats[size_bin][rix0].successive_failures = 0;
838 	}
839 	sn->stats[size_bin][rix0].tries += tries;
840 	sn->stats[size_bin][rix0].last_tx = ticks;
841 	sn->stats[size_bin][rix0].total_packets += nframes;
842 
843 	if (rix0 == sn->current_sample_rix[size_bin]) {
844 		IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
845 		   &an->an_node,
846 "%s: size %d %s sample rate %d %s tries (%d/%d) tt %d avg_tt (%d/%d) nfrm %d nbad %d",
847 		    __func__,
848 		    size,
849 		    status ? "FAIL" : "OK",
850 		    dot11rate(rt, rix0),
851 		    dot11rate_label(rt, rix0),
852 		    short_tries, tries, tt,
853 		    sn->stats[size_bin][rix0].average_tx_time,
854 		    sn->stats[size_bin][rix0].perfect_tx_time,
855 		    nframes, nbad);
856 		sn->sample_tt[size_bin] = tt;
857 		sn->current_sample_rix[size_bin] = -1;
858 	}
859 }
860 
861 static void
862 badrate(struct ifnet *ifp, int series, int hwrate, int tries, int status)
863 {
864 	if_printf(ifp, "bad series%d hwrate 0x%x, tries %u ts_status 0x%x\n",
865 	    series, hwrate, tries, status);
866 }
867 
868 void
869 ath_rate_tx_complete(struct ath_softc *sc, struct ath_node *an,
870 	const struct ath_rc_series *rc, const struct ath_tx_status *ts,
871 	int frame_size, int nframes, int nbad)
872 {
873 	struct ifnet *ifp = sc->sc_ifp;
874 	struct ieee80211com *ic = ifp->if_l2com;
875 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
876 	int final_rix, short_tries, long_tries;
877 	const HAL_RATE_TABLE *rt = sc->sc_currates;
878 	int status = ts->ts_status;
879 	int mrr;
880 
881 	final_rix = rt->rateCodeToIndex[ts->ts_rate];
882 	short_tries = ts->ts_shortretry;
883 	long_tries = ts->ts_longretry + 1;
884 
885 	if (frame_size == 0)		    /* NB: should not happen */
886 		frame_size = 1500;
887 
888 	if (sn->ratemask == 0) {
889 		IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
890 		    &an->an_node,
891 		    "%s: size %d %s rate/try %d/%d no rates yet",
892 		    __func__,
893 		    bin_to_size(size_to_bin(frame_size)),
894 		    status ? "FAIL" : "OK",
895 		    short_tries, long_tries);
896 		return;
897 	}
898 	mrr = sc->sc_mrretry && !(ic->ic_flags & IEEE80211_F_USEPROT);
899 	if (!mrr || ts->ts_finaltsi == 0) {
900 		if (!IS_RATE_DEFINED(sn, final_rix)) {
901 			badrate(ifp, 0, ts->ts_rate, long_tries, status);
902 			return;
903 		}
904 		/*
905 		 * Only one rate was used; optimize work.
906 		 */
907 		IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
908 		     &an->an_node, "%s: size %d (%d bytes) %s rate/try %d %s/%d/%d nframes/nbad [%d/%d]",
909 		     __func__,
910 		     bin_to_size(size_to_bin(frame_size)),
911 		     frame_size,
912 		     status ? "FAIL" : "OK",
913 		     dot11rate(rt, final_rix), dot11rate_label(rt, final_rix),
914 		     short_tries, long_tries, nframes, nbad);
915 		update_stats(sc, an, frame_size,
916 			     final_rix, long_tries,
917 			     0, 0,
918 			     0, 0,
919 			     0, 0,
920 			     short_tries, long_tries, status,
921 			     nframes, nbad);
922 		update_ewma_stats(sc, an, frame_size,
923 			     final_rix, long_tries,
924 			     0, 0,
925 			     0, 0,
926 			     0, 0,
927 			     short_tries, long_tries, status,
928 			     nframes, nbad);
929 
930 	} else {
931 		int finalTSIdx = ts->ts_finaltsi;
932 		int i;
933 
934 		/*
935 		 * Process intermediate rates that failed.
936 		 */
937 
938 		IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
939 		    &an->an_node,
940 "%s: size %d (%d bytes) finaltsidx %d tries %d %s rate/try [%d %s/%d %d %s/%d %d %s/%d %d %s/%d] nframes/nbad [%d/%d]",
941 		     __func__,
942 		     bin_to_size(size_to_bin(frame_size)),
943 		     frame_size,
944 		     finalTSIdx,
945 		     long_tries,
946 		     status ? "FAIL" : "OK",
947 		     dot11rate(rt, rc[0].rix),
948 		      dot11rate_label(rt, rc[0].rix), rc[0].tries,
949 		     dot11rate(rt, rc[1].rix),
950 		      dot11rate_label(rt, rc[1].rix), rc[1].tries,
951 		     dot11rate(rt, rc[2].rix),
952 		      dot11rate_label(rt, rc[2].rix), rc[2].tries,
953 		     dot11rate(rt, rc[3].rix),
954 		      dot11rate_label(rt, rc[3].rix), rc[3].tries,
955 		     nframes, nbad);
956 
957 		for (i = 0; i < 4; i++) {
958 			if (rc[i].tries && !IS_RATE_DEFINED(sn, rc[i].rix))
959 				badrate(ifp, 0, rc[i].ratecode, rc[i].tries,
960 				    status);
961 		}
962 
963 		/*
964 		 * NB: series > 0 are not penalized for failure
965 		 * based on the try counts under the assumption
966 		 * that losses are often bursty and since we
967 		 * sample higher rates 1 try at a time doing so
968 		 * may unfairly penalize them.
969 		 */
970 		if (rc[0].tries) {
971 			update_stats(sc, an, frame_size,
972 				     rc[0].rix, rc[0].tries,
973 				     rc[1].rix, rc[1].tries,
974 				     rc[2].rix, rc[2].tries,
975 				     rc[3].rix, rc[3].tries,
976 				     short_tries, long_tries,
977 				     long_tries > rc[0].tries,
978 				     nframes, nbad);
979 			long_tries -= rc[0].tries;
980 		}
981 
982 		if (rc[1].tries && finalTSIdx > 0) {
983 			update_stats(sc, an, frame_size,
984 				     rc[1].rix, rc[1].tries,
985 				     rc[2].rix, rc[2].tries,
986 				     rc[3].rix, rc[3].tries,
987 				     0, 0,
988 				     short_tries, long_tries,
989 				     status,
990 				     nframes, nbad);
991 			long_tries -= rc[1].tries;
992 		}
993 
994 		if (rc[2].tries && finalTSIdx > 1) {
995 			update_stats(sc, an, frame_size,
996 				     rc[2].rix, rc[2].tries,
997 				     rc[3].rix, rc[3].tries,
998 				     0, 0,
999 				     0, 0,
1000 				     short_tries, long_tries,
1001 				     status,
1002 				     nframes, nbad);
1003 			long_tries -= rc[2].tries;
1004 		}
1005 
1006 		if (rc[3].tries && finalTSIdx > 2) {
1007 			update_stats(sc, an, frame_size,
1008 				     rc[3].rix, rc[3].tries,
1009 				     0, 0,
1010 				     0, 0,
1011 				     0, 0,
1012 				     short_tries, long_tries,
1013 				     status,
1014 				     nframes, nbad);
1015 		}
1016 
1017 		update_ewma_stats(sc, an, frame_size,
1018 			     rc[0].rix, rc[0].tries,
1019 			     rc[1].rix, rc[1].tries,
1020 			     rc[2].rix, rc[2].tries,
1021 			     rc[3].rix, rc[3].tries,
1022 			     short_tries, long_tries,
1023 			     long_tries > rc[0].tries,
1024 			     nframes, nbad);
1025 
1026 	}
1027 }
1028 
1029 void
1030 ath_rate_newassoc(struct ath_softc *sc, struct ath_node *an, int isnew)
1031 {
1032 	if (isnew)
1033 		ath_rate_ctl_reset(sc, &an->an_node);
1034 }
1035 
1036 static const struct txschedule *mrr_schedules[IEEE80211_MODE_MAX+2] = {
1037 	NULL,		/* IEEE80211_MODE_AUTO */
1038 	series_11a,	/* IEEE80211_MODE_11A */
1039 	series_11g,	/* IEEE80211_MODE_11B */
1040 	series_11g,	/* IEEE80211_MODE_11G */
1041 	NULL,		/* IEEE80211_MODE_FH */
1042 	series_11a,	/* IEEE80211_MODE_TURBO_A */
1043 	series_11g,	/* IEEE80211_MODE_TURBO_G */
1044 	series_11a,	/* IEEE80211_MODE_STURBO_A */
1045 	series_11na,	/* IEEE80211_MODE_11NA */
1046 	series_11ng,	/* IEEE80211_MODE_11NG */
1047 	series_half,	/* IEEE80211_MODE_HALF */
1048 	series_quarter,	/* IEEE80211_MODE_QUARTER */
1049 };
1050 
1051 /*
1052  * Initialize the tables for a node.
1053  */
1054 static void
1055 ath_rate_ctl_reset(struct ath_softc *sc, struct ieee80211_node *ni)
1056 {
1057 #define	RATE(_ix)	(ni->ni_rates.rs_rates[(_ix)] & IEEE80211_RATE_VAL)
1058 #define	DOT11RATE(_ix)	(rt->info[(_ix)].dot11Rate & IEEE80211_RATE_VAL)
1059 #define	MCS(_ix)	(ni->ni_htrates.rs_rates[_ix] | IEEE80211_RATE_MCS)
1060 	struct ath_node *an = ATH_NODE(ni);
1061 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
1062 	const HAL_RATE_TABLE *rt = sc->sc_currates;
1063 	int x, y, rix;
1064 
1065 	KASSERT(rt != NULL, ("no rate table, mode %u", sc->sc_curmode));
1066 
1067 	KASSERT(sc->sc_curmode < IEEE80211_MODE_MAX+2,
1068 	    ("curmode %u", sc->sc_curmode));
1069 	sn->sched = mrr_schedules[sc->sc_curmode];
1070 	KASSERT(sn->sched != NULL,
1071 	    ("no mrr schedule for mode %u", sc->sc_curmode));
1072 
1073         sn->static_rix = -1;
1074 	ath_rate_update_static_rix(sc, ni);
1075 
1076 	/*
1077 	 * Construct a bitmask of usable rates.  This has all
1078 	 * negotiated rates minus those marked by the hal as
1079 	 * to be ignored for doing rate control.
1080 	 */
1081 	sn->ratemask = 0;
1082 	/* MCS rates */
1083 	if (ni->ni_flags & IEEE80211_NODE_HT) {
1084 		for (x = 0; x < ni->ni_htrates.rs_nrates; x++) {
1085 			rix = sc->sc_rixmap[MCS(x)];
1086 			if (rix == 0xff)
1087 				continue;
1088 			/* skip rates marked broken by hal */
1089 			if (!rt->info[rix].valid)
1090 				continue;
1091 			KASSERT(rix < SAMPLE_MAXRATES,
1092 			    ("mcs %u has rix %d", MCS(x), rix));
1093 			sn->ratemask |= 1<<rix;
1094 		}
1095 	}
1096 
1097 	/* Legacy rates */
1098 	for (x = 0; x < ni->ni_rates.rs_nrates; x++) {
1099 		rix = sc->sc_rixmap[RATE(x)];
1100 		if (rix == 0xff)
1101 			continue;
1102 		/* skip rates marked broken by hal */
1103 		if (!rt->info[rix].valid)
1104 			continue;
1105 		KASSERT(rix < SAMPLE_MAXRATES,
1106 		    ("rate %u has rix %d", RATE(x), rix));
1107 		sn->ratemask |= 1<<rix;
1108 	}
1109 #ifdef IEEE80211_DEBUG
1110 	if (ieee80211_msg(ni->ni_vap, IEEE80211_MSG_RATECTL)) {
1111 		uint32_t mask;
1112 
1113 		ieee80211_note(ni->ni_vap, "[%6D] %s: size 1600 rate/tt",
1114 		    ni->ni_macaddr, ":", __func__);
1115 		for (mask = sn->ratemask, rix = 0; mask != 0; mask >>= 1, rix++) {
1116 			if ((mask & 1) == 0)
1117 				continue;
1118 			printf(" %d %s/%d", dot11rate(rt, rix), dot11rate_label(rt, rix),
1119 			    calc_usecs_unicast_packet(sc, 1600, rix, 0,0,
1120 			        (ni->ni_chw == 40)));
1121 		}
1122 		printf("\n");
1123 	}
1124 #endif
1125 	for (y = 0; y < NUM_PACKET_SIZE_BINS; y++) {
1126 		int size = bin_to_size(y);
1127 		uint32_t mask;
1128 
1129 		sn->packets_sent[y] = 0;
1130 		sn->current_sample_rix[y] = -1;
1131 		sn->last_sample_rix[y] = 0;
1132 		/* XXX start with first valid rate */
1133 		sn->current_rix[y] = ffs(sn->ratemask)-1;
1134 
1135 		/*
1136 		 * Initialize the statistics buckets; these are
1137 		 * indexed by the rate code index.
1138 		 */
1139 		for (rix = 0, mask = sn->ratemask; mask != 0; rix++, mask >>= 1) {
1140 			if ((mask & 1) == 0)		/* not a valid rate */
1141 				continue;
1142 			sn->stats[y][rix].successive_failures = 0;
1143 			sn->stats[y][rix].tries = 0;
1144 			sn->stats[y][rix].total_packets = 0;
1145 			sn->stats[y][rix].packets_acked = 0;
1146 			sn->stats[y][rix].last_tx = 0;
1147 			sn->stats[y][rix].ewma_pct = 0;
1148 
1149 			sn->stats[y][rix].perfect_tx_time =
1150 			    calc_usecs_unicast_packet(sc, size, rix, 0, 0,
1151 			    (ni->ni_chw == 40));
1152 			sn->stats[y][rix].average_tx_time =
1153 			    sn->stats[y][rix].perfect_tx_time;
1154 		}
1155 	}
1156 #if 0
1157 	/* XXX 0, num_rates-1 are wrong */
1158 	IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
1159 	    "%s: %d rates %d%sMbps (%dus)- %d%sMbps (%dus)", __func__,
1160 	    sn->num_rates,
1161 	    DOT11RATE(0)/2, DOT11RATE(0) % 1 ? ".5" : "",
1162 	    sn->stats[1][0].perfect_tx_time,
1163 	    DOT11RATE(sn->num_rates-1)/2, DOT11RATE(sn->num_rates-1) % 1 ? ".5" : "",
1164 	    sn->stats[1][sn->num_rates-1].perfect_tx_time
1165 	);
1166 #endif
1167 	/* set the visible bit-rate */
1168 	if (sn->static_rix != -1)
1169 		ni->ni_txrate = DOT11RATE(sn->static_rix);
1170 	else
1171 		ni->ni_txrate = RATE(0);
1172 #undef RATE
1173 #undef DOT11RATE
1174 }
1175 
1176 static void
1177 sample_stats(void *arg, struct ieee80211_node *ni)
1178 {
1179 	struct ath_softc *sc = arg;
1180 	const HAL_RATE_TABLE *rt = sc->sc_currates;
1181 	struct sample_node *sn = ATH_NODE_SAMPLE(ATH_NODE(ni));
1182 	uint32_t mask;
1183 	int rix, y;
1184 
1185 	printf("\n[%s] refcnt %d static_rix (%d %s) ratemask 0x%x\n",
1186 	    ether_sprintf(ni->ni_macaddr), ieee80211_node_refcnt(ni),
1187 	    dot11rate(rt, sn->static_rix),
1188 	    dot11rate_label(rt, sn->static_rix),
1189 	    sn->ratemask);
1190 	for (y = 0; y < NUM_PACKET_SIZE_BINS; y++) {
1191 		printf("[%4u] cur rix %d (%d %s) since switch: packets %d ticks %u\n",
1192 		    bin_to_size(y), sn->current_rix[y],
1193 		    dot11rate(rt, sn->current_rix[y]),
1194 		    dot11rate_label(rt, sn->current_rix[y]),
1195 		    sn->packets_since_switch[y], sn->ticks_since_switch[y]);
1196 		printf("[%4u] last sample (%d %s) cur sample (%d %s) packets sent %d\n",
1197 		    bin_to_size(y),
1198 		    dot11rate(rt, sn->last_sample_rix[y]),
1199 		    dot11rate_label(rt, sn->last_sample_rix[y]),
1200 		    dot11rate(rt, sn->current_sample_rix[y]),
1201 		    dot11rate_label(rt, sn->current_sample_rix[y]),
1202 		    sn->packets_sent[y]);
1203 		printf("[%4u] packets since sample %d sample tt %u\n",
1204 		    bin_to_size(y), sn->packets_since_sample[y],
1205 		    sn->sample_tt[y]);
1206 	}
1207 	for (mask = sn->ratemask, rix = 0; mask != 0; mask >>= 1, rix++) {
1208 		if ((mask & 1) == 0)
1209 				continue;
1210 		for (y = 0; y < NUM_PACKET_SIZE_BINS; y++) {
1211 			if (sn->stats[y][rix].total_packets == 0)
1212 				continue;
1213 			printf("[%2u %s:%4u] %8ju:%-8ju (%3d%%) (EWMA %3d.%1d%%) T %8ju F %4d avg %5u last %u\n",
1214 			    dot11rate(rt, rix), dot11rate_label(rt, rix),
1215 			    bin_to_size(y),
1216 			    (uintmax_t) sn->stats[y][rix].total_packets,
1217 			    (uintmax_t) sn->stats[y][rix].packets_acked,
1218 			    (int) ((sn->stats[y][rix].packets_acked * 100ULL) /
1219 			     sn->stats[y][rix].total_packets),
1220 			    sn->stats[y][rix].ewma_pct / 10,
1221 			    sn->stats[y][rix].ewma_pct % 10,
1222 			    (uintmax_t) sn->stats[y][rix].tries,
1223 			    sn->stats[y][rix].successive_failures,
1224 			    sn->stats[y][rix].average_tx_time,
1225 			    ticks - sn->stats[y][rix].last_tx);
1226 		}
1227 	}
1228 }
1229 
1230 static int
1231 ath_rate_sysctl_stats(SYSCTL_HANDLER_ARGS)
1232 {
1233 	struct ath_softc *sc = arg1;
1234 	struct ifnet *ifp = sc->sc_ifp;
1235 	struct ieee80211com *ic = ifp->if_l2com;
1236 	int error, v;
1237 
1238 	v = 0;
1239 	error = sysctl_handle_int(oidp, &v, 0, req);
1240 	if (error || !req->newptr)
1241 		return error;
1242 	ieee80211_iterate_nodes(&ic->ic_sta, sample_stats, sc);
1243 	return 0;
1244 }
1245 
1246 static int
1247 ath_rate_sysctl_smoothing_rate(SYSCTL_HANDLER_ARGS)
1248 {
1249 	struct sample_softc *ssc = arg1;
1250 	int rate, error;
1251 
1252 	rate = ssc->smoothing_rate;
1253 	error = sysctl_handle_int(oidp, &rate, 0, req);
1254 	if (error || !req->newptr)
1255 		return error;
1256 	if (!(0 <= rate && rate < 100))
1257 		return EINVAL;
1258 	ssc->smoothing_rate = rate;
1259 	ssc->smoothing_minpackets = 100 / (100 - rate);
1260 	return 0;
1261 }
1262 
1263 static int
1264 ath_rate_sysctl_sample_rate(SYSCTL_HANDLER_ARGS)
1265 {
1266 	struct sample_softc *ssc = arg1;
1267 	int rate, error;
1268 
1269 	rate = ssc->sample_rate;
1270 	error = sysctl_handle_int(oidp, &rate, 0, req);
1271 	if (error || !req->newptr)
1272 		return error;
1273 	if (!(2 <= rate && rate <= 100))
1274 		return EINVAL;
1275 	ssc->sample_rate = rate;
1276 	return 0;
1277 }
1278 
1279 static void
1280 ath_rate_sysctlattach(struct ath_softc *sc, struct sample_softc *ssc)
1281 {
1282 	struct sysctl_ctx_list *ctx = device_get_sysctl_ctx(sc->sc_dev);
1283 	struct sysctl_oid *tree = device_get_sysctl_tree(sc->sc_dev);
1284 
1285 	SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
1286 	    "smoothing_rate", CTLTYPE_INT | CTLFLAG_RW, ssc, 0,
1287 	    ath_rate_sysctl_smoothing_rate, "I",
1288 	    "sample: smoothing rate for avg tx time (%%)");
1289 	SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
1290 	    "sample_rate", CTLTYPE_INT | CTLFLAG_RW, ssc, 0,
1291 	    ath_rate_sysctl_sample_rate, "I",
1292 	    "sample: percent air time devoted to sampling new rates (%%)");
1293 	/* XXX max_successive_failures, stale_failure_timeout, min_switch */
1294 	SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
1295 	    "sample_stats", CTLTYPE_INT | CTLFLAG_RW, sc, 0,
1296 	    ath_rate_sysctl_stats, "I", "sample: print statistics");
1297 }
1298 
1299 struct ath_ratectrl *
1300 ath_rate_attach(struct ath_softc *sc)
1301 {
1302 	struct sample_softc *ssc;
1303 
1304 	ssc = malloc(sizeof(struct sample_softc), M_DEVBUF, M_NOWAIT|M_ZERO);
1305 	if (ssc == NULL)
1306 		return NULL;
1307 	ssc->arc.arc_space = sizeof(struct sample_node);
1308 	ssc->smoothing_rate = 95;		/* ewma percentage ([0..99]) */
1309 	ssc->smoothing_minpackets = 100 / (100 - ssc->smoothing_rate);
1310 	ssc->sample_rate = 10;			/* %time to try diff tx rates */
1311 	ssc->max_successive_failures = 3;	/* threshold for rate sampling*/
1312 	ssc->stale_failure_timeout = 10 * hz;	/* 10 seconds */
1313 	ssc->min_switch = hz;			/* 1 second */
1314 	ath_rate_sysctlattach(sc, ssc);
1315 	return &ssc->arc;
1316 }
1317 
1318 void
1319 ath_rate_detach(struct ath_ratectrl *arc)
1320 {
1321 	struct sample_softc *ssc = (struct sample_softc *) arc;
1322 
1323 	free(ssc, M_DEVBUF);
1324 }
1325