xref: /freebsd/sys/dev/ath/ath_rate/sample/sample.c (revision bdd1243df58e60e85101c09001d9812a789b6bc4)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 2005 John Bicket
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer,
12  *    without modification.
13  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
14  *    similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
15  *    redistribution must be conditioned upon including a substantially
16  *    similar Disclaimer requirement for further binary redistribution.
17  * 3. Neither the names of the above-listed copyright holders nor the names
18  *    of any contributors may be used to endorse or promote products derived
19  *    from this software without specific prior written permission.
20  *
21  * Alternatively, this software may be distributed under the terms of the
22  * GNU General Public License ("GPL") version 2 as published by the Free
23  * Software Foundation.
24  *
25  * NO WARRANTY
26  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
28  * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
29  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
30  * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY,
31  * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
34  * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
36  * THE POSSIBILITY OF SUCH DAMAGES.
37  *
38  */
39 
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42 
43 /*
44  * John Bicket's SampleRate control algorithm.
45  */
46 #include "opt_ath.h"
47 #include "opt_inet.h"
48 #include "opt_wlan.h"
49 #include "opt_ah.h"
50 
51 #include <sys/param.h>
52 #include <sys/systm.h>
53 #include <sys/sysctl.h>
54 #include <sys/kernel.h>
55 #include <sys/lock.h>
56 #include <sys/malloc.h>
57 #include <sys/mutex.h>
58 #include <sys/errno.h>
59 
60 #include <machine/bus.h>
61 #include <machine/resource.h>
62 #include <sys/bus.h>
63 
64 #include <sys/socket.h>
65 
66 #include <net/if.h>
67 #include <net/if_var.h>
68 #include <net/if_media.h>
69 #include <net/if_arp.h>
70 #include <net/ethernet.h>		/* XXX for ether_sprintf */
71 
72 #include <net80211/ieee80211_var.h>
73 
74 #include <net/bpf.h>
75 
76 #ifdef INET
77 #include <netinet/in.h>
78 #include <netinet/if_ether.h>
79 #endif
80 
81 #include <dev/ath/if_athvar.h>
82 #include <dev/ath/ath_rate/sample/sample.h>
83 #include <dev/ath/ath_hal/ah_desc.h>
84 #include <dev/ath/ath_rate/sample/tx_schedules.h>
85 
86 /*
87  * This file is an implementation of the SampleRate algorithm
88  * in "Bit-rate Selection in Wireless Networks"
89  * (http://www.pdos.lcs.mit.edu/papers/jbicket-ms.ps)
90  *
91  * SampleRate chooses the bit-rate it predicts will provide the most
92  * throughput based on estimates of the expected per-packet
93  * transmission time for each bit-rate.  SampleRate periodically sends
94  * packets at bit-rates other than the current one to estimate when
95  * another bit-rate will provide better performance. SampleRate
96  * switches to another bit-rate when its estimated per-packet
97  * transmission time becomes smaller than the current bit-rate's.
98  * SampleRate reduces the number of bit-rates it must sample by
99  * eliminating those that could not perform better than the one
100  * currently being used.  SampleRate also stops probing at a bit-rate
101  * if it experiences several successive losses.
102  *
103  * The difference between the algorithm in the thesis and the one in this
104  * file is that the one in this file uses a ewma instead of a window.
105  *
106  * Also, this implementation tracks the average transmission time for
107  * a few different packet sizes independently for each link.
108  */
109 
110 /* XXX TODO: move this into ath_hal/net80211 so it can be shared */
111 
112 #define	MCS_HT20	0
113 #define	MCS_HT20_SGI	1
114 #define	MCS_HT40	2
115 #define	MCS_HT40_SGI	3
116 
117 /*
118  * This is currently a copy/paste from the 11n tx code.
119  *
120  * It's used to determine the maximum frame length allowed for the
121  * given rate.  For now this ignores SGI/LGI and will assume long-GI.
122  * This only matters for lower rates that can't fill a full 64k A-MPDU.
123  *
124  * (But it's also important because right now rate control doesn't set
125  * flags like SGI/LGI, STBC, LDPC, TX power, etc.)
126  *
127  * When selecting a set of rates the rate control code will iterate
128  * over the HT20/HT40 max frame length and tell the caller the maximum
129  * length (@ LGI.)  It will also choose a bucket that's the minimum
130  * of this value and the provided aggregate length.  That way the
131  * rate selection will closely match what the eventual formed aggregate
132  * will be rather than "not at all".
133  */
134 
135 static int ath_rate_sample_max_4ms_framelen[4][32] = {
136         [MCS_HT20] = {
137                 3212,  6432,  9648,  12864,  19300,  25736,  28952,  32172,
138                 6424,  12852, 19280, 25708,  38568,  51424,  57852,  64280,
139                 9628,  19260, 28896, 38528,  57792,  65532,  65532,  65532,
140                 12828, 25656, 38488, 51320,  65532,  65532,  65532,  65532,
141         },
142         [MCS_HT20_SGI] = {
143                 3572,  7144,  10720,  14296,  21444,  28596,  32172,  35744,
144                 7140,  14284, 21428,  28568,  42856,  57144,  64288,  65532,
145                 10700, 21408, 32112,  42816,  64228,  65532,  65532,  65532,
146                 14256, 28516, 42780,  57040,  65532,  65532,  65532,  65532,
147         },
148         [MCS_HT40] = {
149                 6680,  13360,  20044,  26724,  40092,  53456,  60140,  65532,
150                 13348, 26700,  40052,  53400,  65532,  65532,  65532,  65532,
151                 20004, 40008,  60016,  65532,  65532,  65532,  65532,  65532,
152                 26644, 53292,  65532,  65532,  65532,  65532,  65532,  65532,
153         },
154         [MCS_HT40_SGI] = {
155                 7420,  14844,  22272,  29696,  44544,  59396,  65532,  65532,
156                 14832, 29668,  44504,  59340,  65532,  65532,  65532,  65532,
157                 22232, 44464,  65532,  65532,  65532,  65532,  65532,  65532,
158                 29616, 59232,  65532,  65532,  65532,  65532,  65532,  65532,
159         }
160 };
161 
162 /*
163  * Given the (potentially MRR) transmit schedule, calculate the maximum
164  * allowed packet size for forming aggregates based on the lowest
165  * MCS rate in the transmit schedule.
166  *
167  * Returns -1 if it's a legacy rate or no MRR.
168  *
169  * XXX TODO: this needs to be limited by the RTS/CTS AR5416 8KB bug limit!
170  * (by checking rts/cts flags and applying sc_rts_aggr_limit)
171  *
172  * XXX TODO: apply per-node max-ampdu size and driver ampdu size limits too.
173  */
174 static int
175 ath_rate_sample_find_min_pktlength(struct ath_softc *sc,
176     struct ath_node *an, uint8_t rix0, int is_aggr)
177 {
178 #define	MCS_IDX(ix)		(rt->info[ix].dot11Rate)
179 	const HAL_RATE_TABLE *rt = sc->sc_currates;
180 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
181 	const struct txschedule *sched = &sn->sched[rix0];
182 	int max_pkt_length = 65530; // ATH_AGGR_MAXSIZE
183 	// Note: this may not be true in all cases; need to check?
184 	int is_ht40 = (an->an_node.ni_chw == 40);
185 	// Note: not great, but good enough..
186 	int idx = is_ht40 ? MCS_HT40 : MCS_HT20;
187 
188 	if (rt->info[rix0].phy != IEEE80211_T_HT) {
189 		return -1;
190 	}
191 
192 	if (! sc->sc_mrretry) {
193 		return -1;
194 	}
195 
196 	KASSERT(rix0 == sched->r0, ("rix0 (%x) != sched->r0 (%x)!\n",
197 	    rix0, sched->r0));
198 
199 	/*
200 	 * Update based on sched->r{0,1,2,3} if sched->t{0,1,2,3}
201 	 * is not zero.
202 	 *
203 	 * Note: assuming all four PHYs are HT!
204 	 *
205 	 * XXX TODO: right now I hardcode here and in getxtxrates() that
206 	 * rates 2 and 3 in the tx schedule are ignored.  This is important
207 	 * for forming larger aggregates because right now (a) the tx schedule
208 	 * per rate is fixed, and (b) reliable packet transmission at those
209 	 * higher rates kinda needs a lower MCS rate in there somewhere.
210 	 * However, this means we can only form shorter aggregates.
211 	 * If we've negotiated aggregation then we can actually just
212 	 * rely on software retransmit rather than having things fall
213 	 * back to like MCS0/1 in hardware, and rate control will hopefully
214 	 * do the right thing.
215 	 *
216 	 * Once the whole rate schedule is passed into ath_rate_findrate(),
217 	 * the ath_rc_series is populated ,the fixed tx schedule stuff
218 	 * is removed AND getxtxrates() is removed then we can remove this
219 	 * check as it can just NOT populate t2/t3.  It also means
220 	 * probing can actually use rix0 for probeing and rix1 for the
221 	 * current best rate..
222 	 */
223 	if (sched->t0 != 0) {
224 		max_pkt_length = MIN(max_pkt_length,
225 		    ath_rate_sample_max_4ms_framelen[idx][MCS_IDX(sched->r0)]);
226 	}
227 	if (sched->t1 != 0) {
228 		max_pkt_length = MIN(max_pkt_length,
229 		    ath_rate_sample_max_4ms_framelen[idx][MCS_IDX(sched->r1)]);
230 	}
231 	if (sched->t2 != 0 && (! is_aggr)) {
232 		max_pkt_length = MIN(max_pkt_length,
233 		    ath_rate_sample_max_4ms_framelen[idx][MCS_IDX(sched->r2)]);
234 	}
235 	if (sched->t3 != 0 && (! is_aggr)) {
236 		max_pkt_length = MIN(max_pkt_length,
237 		    ath_rate_sample_max_4ms_framelen[idx][MCS_IDX(sched->r3)]);
238 	}
239 
240 	return max_pkt_length;
241 #undef	MCS
242 }
243 
244 static void	ath_rate_ctl_reset(struct ath_softc *, struct ieee80211_node *);
245 
246 static __inline int
247 size_to_bin(int size)
248 {
249 #if NUM_PACKET_SIZE_BINS > 1
250 	if (size <= packet_size_bins[0])
251 		return 0;
252 #endif
253 #if NUM_PACKET_SIZE_BINS > 2
254 	if (size <= packet_size_bins[1])
255 		return 1;
256 #endif
257 #if NUM_PACKET_SIZE_BINS > 3
258 	if (size <= packet_size_bins[2])
259 		return 2;
260 #endif
261 #if NUM_PACKET_SIZE_BINS > 4
262 	if (size <= packet_size_bins[3])
263 		return 3;
264 #endif
265 #if NUM_PACKET_SIZE_BINS > 5
266 	if (size <= packet_size_bins[4])
267 		return 4;
268 #endif
269 #if NUM_PACKET_SIZE_BINS > 6
270 	if (size <= packet_size_bins[5])
271 		return 5;
272 #endif
273 #if NUM_PACKET_SIZE_BINS > 7
274 	if (size <= packet_size_bins[6])
275 		return 6;
276 #endif
277 #if NUM_PACKET_SIZE_BINS > 8
278 #error "add support for more packet sizes"
279 #endif
280 	return NUM_PACKET_SIZE_BINS-1;
281 }
282 
283 void
284 ath_rate_node_init(struct ath_softc *sc, struct ath_node *an)
285 {
286 	/* NB: assumed to be zero'd by caller */
287 }
288 
289 void
290 ath_rate_node_cleanup(struct ath_softc *sc, struct ath_node *an)
291 {
292 }
293 
294 static int
295 dot11rate(const HAL_RATE_TABLE *rt, int rix)
296 {
297 	if (rix < 0)
298 		return -1;
299 	return rt->info[rix].phy == IEEE80211_T_HT ?
300 	    rt->info[rix].dot11Rate : (rt->info[rix].dot11Rate & IEEE80211_RATE_VAL) / 2;
301 }
302 
303 static const char *
304 dot11rate_label(const HAL_RATE_TABLE *rt, int rix)
305 {
306 	if (rix < 0)
307 		return "";
308 	return rt->info[rix].phy == IEEE80211_T_HT ? "MCS" : "Mb ";
309 }
310 
311 /*
312  * Return the rix with the lowest average_tx_time,
313  * or -1 if all the average_tx_times are 0.
314  */
315 static __inline int
316 pick_best_rate(struct ath_node *an, const HAL_RATE_TABLE *rt,
317     int size_bin, int require_acked_before)
318 {
319 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
320 	int best_rate_rix, best_rate_tt, best_rate_pct;
321 	uint64_t mask;
322 	int rix, tt, pct;
323 
324 	best_rate_rix = 0;
325 	best_rate_tt = 0;
326 	best_rate_pct = 0;
327 	for (mask = sn->ratemask, rix = 0; mask != 0; mask >>= 1, rix++) {
328 		if ((mask & 1) == 0)		/* not a supported rate */
329 			continue;
330 
331 		/* Don't pick a non-HT rate for a HT node */
332 		if ((an->an_node.ni_flags & IEEE80211_NODE_HT) &&
333 		    (rt->info[rix].phy != IEEE80211_T_HT)) {
334 			continue;
335 		}
336 
337 		tt = sn->stats[size_bin][rix].average_tx_time;
338 		if (tt <= 0 ||
339 		    (require_acked_before &&
340 		     !sn->stats[size_bin][rix].packets_acked))
341 			continue;
342 
343 		/* Calculate percentage if possible */
344 		if (sn->stats[size_bin][rix].total_packets > 0) {
345 			pct = sn->stats[size_bin][rix].ewma_pct;
346 		} else {
347 			pct = -1; /* No percent yet to compare against! */
348 		}
349 
350 		/* don't use a bit-rate that has been failing */
351 		if (sn->stats[size_bin][rix].successive_failures > 3)
352 			continue;
353 
354 		/*
355 		 * For HT, Don't use a bit rate that is more
356 		 * lossy than the best.  Give a bit of leeway.
357 		 *
358 		 * Don't consider best rates that we haven't seen
359 		 * packets for yet; let sampling start inflence that.
360 		 */
361 		if (an->an_node.ni_flags & IEEE80211_NODE_HT) {
362 			if (pct == -1)
363 				continue;
364 #if 0
365 			IEEE80211_NOTE(an->an_node.ni_vap,
366 			    IEEE80211_MSG_RATECTL,
367 			    &an->an_node,
368 			    "%s: size %d comparing best rate 0x%x pkts/ewma/tt (%ju/%d/%d) "
369 			    "to 0x%x pkts/ewma/tt (%ju/%d/%d)",
370 			    __func__,
371 			    bin_to_size(size_bin),
372 			    rt->info[best_rate_rix].dot11Rate,
373 			    sn->stats[size_bin][best_rate_rix].total_packets,
374 			    best_rate_pct,
375 			    best_rate_tt,
376 			    rt->info[rix].dot11Rate,
377 			    sn->stats[size_bin][rix].total_packets,
378 			    pct,
379 			    tt);
380 #endif
381 			if (best_rate_pct > (pct + 50))
382 				continue;
383 		}
384 		/*
385 		 * For non-MCS rates, use the current average txtime for
386 		 * comparison.
387 		 */
388 		if (! (an->an_node.ni_flags & IEEE80211_NODE_HT)) {
389 			if (best_rate_tt == 0 || tt <= best_rate_tt) {
390 				best_rate_tt = tt;
391 				best_rate_rix = rix;
392 				best_rate_pct = pct;
393 			}
394 		}
395 
396 		/*
397 		 * Since 2 and 3 stream rates have slightly higher TX times,
398 		 * allow a little bit of leeway. This should later
399 		 * be abstracted out and properly handled.
400 		 */
401 		if (an->an_node.ni_flags & IEEE80211_NODE_HT) {
402 			if (best_rate_tt == 0 || ((tt * 10) <= (best_rate_tt * 10))) {
403 				best_rate_tt = tt;
404 				best_rate_rix = rix;
405 				best_rate_pct = pct;
406 			}
407 		}
408 	}
409 	return (best_rate_tt ? best_rate_rix : -1);
410 }
411 
412 /*
413  * Pick a good "random" bit-rate to sample other than the current one.
414  */
415 static __inline int
416 pick_sample_rate(struct sample_softc *ssc , struct ath_node *an,
417     const HAL_RATE_TABLE *rt, int size_bin)
418 {
419 #define	DOT11RATE(ix)	(rt->info[ix].dot11Rate & IEEE80211_RATE_VAL)
420 #define	MCS(ix)		(rt->info[ix].dot11Rate | IEEE80211_RATE_MCS)
421 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
422 	int current_rix, rix;
423 	unsigned current_tt;
424 	uint64_t mask;
425 
426 	current_rix = sn->current_rix[size_bin];
427 	if (current_rix < 0) {
428 		/* no successes yet, send at the lowest bit-rate */
429 		/* XXX TODO should return MCS0 if HT */
430 		return 0;
431 	}
432 
433 	current_tt = sn->stats[size_bin][current_rix].average_tx_time;
434 
435 	rix = sn->last_sample_rix[size_bin]+1;	/* next sample rate */
436 	mask = sn->ratemask &~ ((uint64_t) 1<<current_rix);/* don't sample current rate */
437 	while (mask != 0) {
438 		if ((mask & ((uint64_t) 1<<rix)) == 0) {	/* not a supported rate */
439 	nextrate:
440 			if (++rix >= rt->rateCount)
441 				rix = 0;
442 			continue;
443 		}
444 
445 		/*
446 		 * The following code stops trying to sample
447 		 * non-MCS rates when speaking to an MCS node.
448 		 * However, at least for CCK rates in 2.4GHz mode,
449 		 * the non-MCS rates MAY actually provide better
450 		 * PER at the very far edge of reception.
451 		 *
452 		 * However! Until ath_rate_form_aggr() grows
453 		 * some logic to not form aggregates if the
454 		 * selected rate is non-MCS, this won't work.
455 		 *
456 		 * So don't disable this code until you've taught
457 		 * ath_rate_form_aggr() to drop out if any of
458 		 * the selected rates are non-MCS.
459 		 */
460 #if 1
461 		/* if the node is HT and the rate isn't HT, don't bother sample */
462 		if ((an->an_node.ni_flags & IEEE80211_NODE_HT) &&
463 		    (rt->info[rix].phy != IEEE80211_T_HT)) {
464 			mask &= ~((uint64_t) 1<<rix);
465 			goto nextrate;
466 		}
467 #endif
468 
469 		/* this bit-rate is always worse than the current one */
470 		if (sn->stats[size_bin][rix].perfect_tx_time > current_tt) {
471 			mask &= ~((uint64_t) 1<<rix);
472 			goto nextrate;
473 		}
474 
475 		/* rarely sample bit-rates that fail a lot */
476 		if (sn->stats[size_bin][rix].successive_failures > ssc->max_successive_failures &&
477 		    ticks - sn->stats[size_bin][rix].last_tx < ssc->stale_failure_timeout) {
478 			mask &= ~((uint64_t) 1<<rix);
479 			goto nextrate;
480 		}
481 
482 		/*
483 		 * For HT, only sample a few rates on either side of the
484 		 * current rix; there's quite likely a lot of them.
485 		 *
486 		 * This is limited to testing rate indexes on either side of
487 		 * this MCS, but for all spatial streams.
488 		 *
489 		 * Otherwise we'll (a) never really sample higher MCS
490 		 * rates if we're stuck low, and we'll make weird moves
491 		 * like sample MCS8 if we're using MCS7.
492 		 */
493 		if (an->an_node.ni_flags & IEEE80211_NODE_HT) {
494 			uint8_t current_mcs, rix_mcs;
495 
496 			current_mcs = MCS(current_rix) & 0x7;
497 			rix_mcs = MCS(rix) & 0x7;
498 
499 			if (rix_mcs < (current_mcs - 2) ||
500 			    rix_mcs > (current_mcs + 2)) {
501 				mask &= ~((uint64_t) 1<<rix);
502 				goto nextrate;
503 			}
504 		}
505 
506 		/* Don't sample more than 2 rates higher for rates > 11M for non-HT rates */
507 		if (! (an->an_node.ni_flags & IEEE80211_NODE_HT)) {
508 			if (DOT11RATE(rix) > 2*11 && rix > current_rix + 2) {
509 				mask &= ~((uint64_t) 1<<rix);
510 				goto nextrate;
511 			}
512 		}
513 
514 		sn->last_sample_rix[size_bin] = rix;
515 		return rix;
516 	}
517 	return current_rix;
518 #undef DOT11RATE
519 #undef	MCS
520 }
521 
522 static int
523 ath_rate_get_static_rix(struct ath_softc *sc, const struct ieee80211_node *ni)
524 {
525 #define	RATE(_ix)	(ni->ni_rates.rs_rates[(_ix)] & IEEE80211_RATE_VAL)
526 #define	DOT11RATE(_ix)	(rt->info[(_ix)].dot11Rate & IEEE80211_RATE_VAL)
527 #define	MCS(_ix)	(ni->ni_htrates.rs_rates[_ix] | IEEE80211_RATE_MCS)
528 	const struct ieee80211_txparam *tp = ni->ni_txparms;
529 	int srate;
530 
531 	/* Check MCS rates */
532 	for (srate = ni->ni_htrates.rs_nrates - 1; srate >= 0; srate--) {
533 		if (MCS(srate) == tp->ucastrate)
534 			return sc->sc_rixmap[tp->ucastrate];
535 	}
536 
537 	/* Check legacy rates */
538 	for (srate = ni->ni_rates.rs_nrates - 1; srate >= 0; srate--) {
539 		if (RATE(srate) == tp->ucastrate)
540 			return sc->sc_rixmap[tp->ucastrate];
541 	}
542 	return -1;
543 #undef	RATE
544 #undef	DOT11RATE
545 #undef	MCS
546 }
547 
548 static void
549 ath_rate_update_static_rix(struct ath_softc *sc, struct ieee80211_node *ni)
550 {
551 	struct ath_node *an = ATH_NODE(ni);
552 	const struct ieee80211_txparam *tp = ni->ni_txparms;
553 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
554 
555 	if (tp != NULL && tp->ucastrate != IEEE80211_FIXED_RATE_NONE) {
556 		/*
557 		 * A fixed rate is to be used; ucastrate is the IEEE code
558 		 * for this rate (sans basic bit).  Check this against the
559 		 * negotiated rate set for the node.  Note the fixed rate
560 		 * may not be available for various reasons so we only
561 		 * setup the static rate index if the lookup is successful.
562 		 */
563 		sn->static_rix = ath_rate_get_static_rix(sc, ni);
564 	} else {
565 		sn->static_rix = -1;
566 	}
567 }
568 
569 /*
570  * Pick a non-HT rate to begin using.
571  */
572 static int
573 ath_rate_pick_seed_rate_legacy(struct ath_softc *sc, struct ath_node *an,
574     int frameLen)
575 {
576 #define	DOT11RATE(ix)	(rt->info[ix].dot11Rate & IEEE80211_RATE_VAL)
577 #define	MCS(ix)		(rt->info[ix].dot11Rate | IEEE80211_RATE_MCS)
578 #define	RATE(ix)	(DOT11RATE(ix) / 2)
579 	int rix = -1;
580 	const HAL_RATE_TABLE *rt = sc->sc_currates;
581 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
582 	const int size_bin = size_to_bin(frameLen);
583 
584 	/* no packet has been sent successfully yet */
585 	for (rix = rt->rateCount-1; rix > 0; rix--) {
586 		if ((sn->ratemask & ((uint64_t) 1<<rix)) == 0)
587 			continue;
588 
589 		/* Skip HT rates */
590 		if (rt->info[rix].phy == IEEE80211_T_HT)
591 			continue;
592 
593 		/*
594 		 * Pick the highest rate <= 36 Mbps
595 		 * that hasn't failed.
596 		 */
597 		if (DOT11RATE(rix) <= 72 &&
598 		    sn->stats[size_bin][rix].successive_failures == 0) {
599 			break;
600 		}
601 	}
602 	return rix;
603 #undef	RATE
604 #undef	MCS
605 #undef	DOT11RATE
606 }
607 
608 /*
609  * Pick a HT rate to begin using.
610  *
611  * Don't use any non-HT rates; only consider HT rates.
612  */
613 static int
614 ath_rate_pick_seed_rate_ht(struct ath_softc *sc, struct ath_node *an,
615     int frameLen)
616 {
617 #define	DOT11RATE(ix)	(rt->info[ix].dot11Rate & IEEE80211_RATE_VAL)
618 #define	MCS(ix)		(rt->info[ix].dot11Rate | IEEE80211_RATE_MCS)
619 #define	RATE(ix)	(DOT11RATE(ix) / 2)
620 	int rix = -1, ht_rix = -1;
621 	const HAL_RATE_TABLE *rt = sc->sc_currates;
622 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
623 	const int size_bin = size_to_bin(frameLen);
624 
625 	/* no packet has been sent successfully yet */
626 	for (rix = rt->rateCount-1; rix > 0; rix--) {
627 		/* Skip rates we can't use */
628 		if ((sn->ratemask & ((uint64_t) 1<<rix)) == 0)
629 			continue;
630 
631 		/* Keep a copy of the last seen HT rate index */
632 		if (rt->info[rix].phy == IEEE80211_T_HT)
633 			ht_rix = rix;
634 
635 		/* Skip non-HT rates */
636 		if (rt->info[rix].phy != IEEE80211_T_HT)
637 			continue;
638 
639 		/*
640 		 * Pick a medium-speed rate at 1 spatial stream
641 		 * which has not seen any failures.
642 		 * Higher rates may fail; we'll try them later.
643 		 */
644 		if (((MCS(rix)& 0x7f) <= 4) &&
645 		    sn->stats[size_bin][rix].successive_failures == 0) {
646 			break;
647 		}
648 	}
649 
650 	/*
651 	 * If all the MCS rates have successive failures, rix should be
652 	 * > 0; otherwise use the lowest MCS rix (hopefully MCS 0.)
653 	 */
654 	return MAX(rix, ht_rix);
655 #undef	RATE
656 #undef	MCS
657 #undef	DOT11RATE
658 }
659 
660 void
661 ath_rate_findrate(struct ath_softc *sc, struct ath_node *an,
662 		  int shortPreamble, size_t frameLen, int tid,
663 		  int is_aggr, u_int8_t *rix0, int *try0,
664 		  u_int8_t *txrate, int *maxdur, int *maxpktlen)
665 {
666 #define	DOT11RATE(ix)	(rt->info[ix].dot11Rate & IEEE80211_RATE_VAL)
667 #define	MCS(ix)		(rt->info[ix].dot11Rate | IEEE80211_RATE_MCS)
668 #define	RATE(ix)	(DOT11RATE(ix) / 2)
669 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
670 	struct sample_softc *ssc = ATH_SOFTC_SAMPLE(sc);
671 	struct ieee80211com *ic = &sc->sc_ic;
672 	const HAL_RATE_TABLE *rt = sc->sc_currates;
673 	int size_bin = size_to_bin(frameLen);
674 	int rix, mrr, best_rix, change_rates;
675 	unsigned average_tx_time;
676 	int max_pkt_len;
677 
678 	ath_rate_update_static_rix(sc, &an->an_node);
679 
680 	/* For now don't take TID, is_aggr into account */
681 	/* Also for now don't calculate a max duration; that'll come later */
682 	*maxdur = -1;
683 
684 	/*
685 	 * For now just set it to the frame length; we'll optimise it later.
686 	 */
687 	*maxpktlen = frameLen;
688 
689 	if (sn->currates != sc->sc_currates) {
690 		device_printf(sc->sc_dev, "%s: currates != sc_currates!\n",
691 		    __func__);
692 		rix = 0;
693 		*try0 = ATH_TXMAXTRY;
694 		goto done;
695 	}
696 
697 	if (sn->static_rix != -1) {
698 		rix = sn->static_rix;
699 		*try0 = ATH_TXMAXTRY;
700 
701 		/*
702 		 * Ensure we limit max packet length here too!
703 		 */
704 		max_pkt_len = ath_rate_sample_find_min_pktlength(sc, an,
705 		    sn->static_rix,
706 		    is_aggr);
707 		if (max_pkt_len > 0) {
708 			*maxpktlen = frameLen = MIN(frameLen, max_pkt_len);
709 			size_bin = size_to_bin(frameLen);
710 		}
711 		goto done;
712 	}
713 
714 	mrr = sc->sc_mrretry;
715 	/* XXX check HT protmode too */
716 	/* XXX turn into a cap; 11n MACs support MRR+RTSCTS */
717 	if (mrr && (ic->ic_flags & IEEE80211_F_USEPROT && !sc->sc_mrrprot))
718 		mrr = 0;
719 
720 	best_rix = pick_best_rate(an, rt, size_bin, !mrr);
721 
722 	/*
723 	 * At this point we've chosen the best rix, so now we
724 	 * need to potentially update our maximum packet length
725 	 * and size_bin if we're doing 11n rates.
726 	 */
727 	max_pkt_len = ath_rate_sample_find_min_pktlength(sc, an, best_rix,
728 	    is_aggr);
729 	if (max_pkt_len > 0) {
730 #if 0
731 		device_printf(sc->sc_dev,
732 		    "Limiting maxpktlen from %d to %d bytes\n",
733 		    (int) frameLen, max_pkt_len);
734 #endif
735 		*maxpktlen = frameLen = MIN(frameLen, max_pkt_len);
736 		size_bin = size_to_bin(frameLen);
737 	}
738 
739 	if (best_rix >= 0) {
740 		average_tx_time = sn->stats[size_bin][best_rix].average_tx_time;
741 	} else {
742 		average_tx_time = 0;
743 	}
744 
745 	/*
746 	 * Limit the time measuring the performance of other tx
747 	 * rates to sample_rate% of the total transmission time.
748 	 */
749 	if (sn->sample_tt[size_bin] <
750 	    average_tx_time *
751 	    (sn->packets_since_sample[size_bin]*ssc->sample_rate/100)) {
752 		rix = pick_sample_rate(ssc, an, rt, size_bin);
753 		IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
754 		     &an->an_node, "att %d sample_tt %d size %u "
755 		     "sample rate %d %s current rate %d %s",
756 		     average_tx_time,
757 		     sn->sample_tt[size_bin],
758 		     bin_to_size(size_bin),
759 		     dot11rate(rt, rix),
760 		     dot11rate_label(rt, rix),
761 		     dot11rate(rt, sn->current_rix[size_bin]),
762 		     dot11rate_label(rt, sn->current_rix[size_bin]));
763 		if (rix != sn->current_rix[size_bin]) {
764 			sn->current_sample_rix[size_bin] = rix;
765 		} else {
766 			sn->current_sample_rix[size_bin] = -1;
767 		}
768 		sn->packets_since_sample[size_bin] = 0;
769 	} else {
770 		change_rates = 0;
771 		if (!sn->packets_sent[size_bin] || best_rix == -1) {
772 			/* no packet has been sent successfully yet */
773 			change_rates = 1;
774 			if (an->an_node.ni_flags & IEEE80211_NODE_HT)
775 				best_rix =
776 				    ath_rate_pick_seed_rate_ht(sc, an, frameLen);
777 			else
778 				best_rix =
779 				    ath_rate_pick_seed_rate_legacy(sc, an, frameLen);
780 		} else if (sn->packets_sent[size_bin] < 20) {
781 			/* let the bit-rate switch quickly during the first few packets */
782 			IEEE80211_NOTE(an->an_node.ni_vap,
783 			    IEEE80211_MSG_RATECTL, &an->an_node,
784 			    "%s: switching quickly..", __func__);
785 			change_rates = 1;
786 		} else if (ticks - ssc->min_switch > sn->ticks_since_switch[size_bin]) {
787 			/* min_switch seconds have gone by */
788 			IEEE80211_NOTE(an->an_node.ni_vap,
789 			    IEEE80211_MSG_RATECTL, &an->an_node,
790 			    "%s: min_switch %d > ticks_since_switch %d..",
791 			    __func__, ticks - ssc->min_switch, sn->ticks_since_switch[size_bin]);
792 			change_rates = 1;
793 		} else if ((! (an->an_node.ni_flags & IEEE80211_NODE_HT)) &&
794 		    (2*average_tx_time < sn->stats[size_bin][sn->current_rix[size_bin]].average_tx_time)) {
795 			/* the current bit-rate is twice as slow as the best one */
796 			IEEE80211_NOTE(an->an_node.ni_vap,
797 			    IEEE80211_MSG_RATECTL, &an->an_node,
798 			    "%s: 2x att (= %d) < cur_rix att %d",
799 			    __func__,
800 			    2 * average_tx_time, sn->stats[size_bin][sn->current_rix[size_bin]].average_tx_time);
801 			change_rates = 1;
802 		} else if ((an->an_node.ni_flags & IEEE80211_NODE_HT)) {
803 			int cur_rix = sn->current_rix[size_bin];
804 			int cur_att = sn->stats[size_bin][cur_rix].average_tx_time;
805 			/*
806 			 * If the node is HT, it if the rate isn't the
807 			 * same and the average tx time is within 10%
808 			 * of the current rate. It can fail a little.
809 			 *
810 			 * This is likely not optimal!
811 			 */
812 #if 0
813 			printf("cur rix/att %x/%d, best rix/att %x/%d\n",
814 			    MCS(cur_rix), cur_att, MCS(best_rix), average_tx_time);
815 #endif
816 			if ((best_rix != cur_rix) &&
817 			    (average_tx_time * 9) <= (cur_att * 10)) {
818 				IEEE80211_NOTE(an->an_node.ni_vap,
819 				    IEEE80211_MSG_RATECTL, &an->an_node,
820 				    "%s: HT: size %d best_rix 0x%x > "
821 				    " cur_rix 0x%x, average_tx_time %d,"
822 				    " cur_att %d",
823 				    __func__, bin_to_size(size_bin),
824 				    MCS(best_rix), MCS(cur_rix),
825 				    average_tx_time, cur_att);
826 				change_rates = 1;
827 			}
828 		}
829 
830 		sn->packets_since_sample[size_bin]++;
831 
832 		if (change_rates) {
833 			if (best_rix != sn->current_rix[size_bin]) {
834 				IEEE80211_NOTE(an->an_node.ni_vap,
835 				    IEEE80211_MSG_RATECTL,
836 				    &an->an_node,
837 "%s: size %d switch rate %d %s (%d/%d) EWMA %d -> %d %s (%d/%d) EWMA %d after %d packets mrr %d",
838 				    __func__,
839 				    bin_to_size(size_bin),
840 				    dot11rate(rt, sn->current_rix[size_bin]),
841 				    dot11rate_label(rt, sn->current_rix[size_bin]),
842 				    sn->stats[size_bin][sn->current_rix[size_bin]].average_tx_time,
843 				    sn->stats[size_bin][sn->current_rix[size_bin]].perfect_tx_time,
844 				    sn->stats[size_bin][sn->current_rix[size_bin]].ewma_pct,
845 				    dot11rate(rt, best_rix),
846 				    dot11rate_label(rt, best_rix),
847 				    sn->stats[size_bin][best_rix].average_tx_time,
848 				    sn->stats[size_bin][best_rix].perfect_tx_time,
849 				    sn->stats[size_bin][best_rix].ewma_pct,
850 				    sn->packets_since_switch[size_bin],
851 				    mrr);
852 			}
853 			sn->packets_since_switch[size_bin] = 0;
854 			sn->current_rix[size_bin] = best_rix;
855 			sn->ticks_since_switch[size_bin] = ticks;
856 			/*
857 			 * Set the visible txrate for this node.
858 			 */
859 			an->an_node.ni_txrate =
860 			    (rt->info[best_rix].phy == IEEE80211_T_HT) ?
861 			     MCS(best_rix) : DOT11RATE(best_rix);
862 		}
863 		rix = sn->current_rix[size_bin];
864 		sn->packets_since_switch[size_bin]++;
865 	}
866 	*try0 = mrr ? sn->sched[rix].t0 : ATH_TXMAXTRY;
867 done:
868 
869 	/*
870 	 * This bug totally sucks and should be fixed.
871 	 *
872 	 * For now though, let's not panic, so we can start to figure
873 	 * out how to better reproduce it.
874 	 */
875 	if (rix < 0 || rix >= rt->rateCount) {
876 		printf("%s: ERROR: rix %d out of bounds (rateCount=%d)\n",
877 		    __func__,
878 		    rix,
879 		    rt->rateCount);
880 		    rix = 0;	/* XXX just default for now */
881 	}
882 	KASSERT(rix >= 0 && rix < rt->rateCount, ("rix is %d", rix));
883 
884 	*rix0 = rix;
885 	*txrate = rt->info[rix].rateCode
886 		| (shortPreamble ? rt->info[rix].shortPreamble : 0);
887 	sn->packets_sent[size_bin]++;
888 
889 #undef DOT11RATE
890 #undef MCS
891 #undef RATE
892 }
893 
894 /*
895  * Get the TX rates. Don't fiddle with short preamble flags for them;
896  * the caller can do that.
897  */
898 void
899 ath_rate_getxtxrates(struct ath_softc *sc, struct ath_node *an,
900     uint8_t rix0, int is_aggr, struct ath_rc_series *rc)
901 {
902 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
903 	const struct txschedule *sched = &sn->sched[rix0];
904 
905 	KASSERT(rix0 == sched->r0, ("rix0 (%x) != sched->r0 (%x)!\n",
906 	    rix0, sched->r0));
907 
908 	rc[0].flags = rc[1].flags = rc[2].flags = rc[3].flags = 0;
909 
910 	rc[0].rix = sched->r0;
911 	rc[1].rix = sched->r1;
912 	rc[2].rix = sched->r2;
913 	rc[3].rix = sched->r3;
914 
915 	rc[0].tries = sched->t0;
916 	rc[1].tries = sched->t1;
917 
918 	if (is_aggr) {
919 		rc[2].tries = rc[3].tries = 0;
920 	} else {
921 		rc[2].tries = sched->t2;
922 		rc[3].tries = sched->t3;
923 	}
924 }
925 
926 void
927 ath_rate_setupxtxdesc(struct ath_softc *sc, struct ath_node *an,
928 		      struct ath_desc *ds, int shortPreamble, u_int8_t rix)
929 {
930 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
931 	const struct txschedule *sched = &sn->sched[rix];
932 	const HAL_RATE_TABLE *rt = sc->sc_currates;
933 	uint8_t rix1, s1code, rix2, s2code, rix3, s3code;
934 
935 	/* XXX precalculate short preamble tables */
936 	rix1 = sched->r1;
937 	s1code = rt->info[rix1].rateCode
938 	       | (shortPreamble ? rt->info[rix1].shortPreamble : 0);
939 	rix2 = sched->r2;
940 	s2code = rt->info[rix2].rateCode
941 	       | (shortPreamble ? rt->info[rix2].shortPreamble : 0);
942 	rix3 = sched->r3;
943 	s3code = rt->info[rix3].rateCode
944 	       | (shortPreamble ? rt->info[rix3].shortPreamble : 0);
945 	ath_hal_setupxtxdesc(sc->sc_ah, ds,
946 	    s1code, sched->t1,		/* series 1 */
947 	    s2code, sched->t2,		/* series 2 */
948 	    s3code, sched->t3);		/* series 3 */
949 }
950 
951 /*
952  * Update the current statistics.
953  *
954  * Note that status is for the FINAL transmit status, not this
955  * particular attempt.  So, check if tries > tries0 and if so
956  * assume this status failed.
957  *
958  * This is important because some failures are due to both
959  * short AND long retries; if the final issue was a short
960  * retry failure then we still want to account for the
961  * bad long retry attempts.
962  */
963 static void
964 update_stats(struct ath_softc *sc, struct ath_node *an,
965 		  int frame_size,
966 		  int rix0, int tries0,
967 		  int short_tries, int tries, int status,
968 		  int nframes, int nbad)
969 {
970 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
971 	struct sample_softc *ssc = ATH_SOFTC_SAMPLE(sc);
972 #ifdef IEEE80211_DEBUG
973 	const HAL_RATE_TABLE *rt = sc->sc_currates;
974 #endif
975 	const int size_bin = size_to_bin(frame_size);
976 	const int size = bin_to_size(size_bin);
977 	int tt;
978 	int is_ht40 = (an->an_node.ni_chw == 40);
979 	int pct;
980 
981 	if (!IS_RATE_DEFINED(sn, rix0))
982 		return;
983 
984 	/*
985 	 * Treat long retries as us exceeding retries, even
986 	 * if the eventual attempt at some other MRR schedule
987 	 * succeeded.
988 	 */
989 	if (tries > tries0) {
990 		status = HAL_TXERR_XRETRY;
991 	}
992 
993 	/*
994 	 * If status is FAIL then we treat all frames as bad.
995 	 * This better accurately tracks EWMA and average TX time
996 	 * because even if the eventual transmission succeeded,
997 	 * transmission at this rate did not.
998 	 */
999 	if (status != 0)
1000 		nbad = nframes;
1001 
1002 	/*
1003 	 * Ignore short tries count as contributing to failure.
1004 	 * Right now there's no way to know if it's part of any
1005 	 * given rate attempt, and outside of the RTS/CTS management
1006 	 * rate, it doesn't /really/ help.
1007 	 */
1008 	tt = calc_usecs_unicast_packet(sc, size, rix0,
1009 	    0 /* short_tries */, MIN(tries0, tries) - 1, is_ht40);
1010 
1011 	if (sn->stats[size_bin][rix0].total_packets < ssc->smoothing_minpackets) {
1012 		/* just average the first few packets */
1013 		int avg_tx = sn->stats[size_bin][rix0].average_tx_time;
1014 		int packets = sn->stats[size_bin][rix0].total_packets;
1015 		sn->stats[size_bin][rix0].average_tx_time = (tt+(avg_tx*packets))/(packets+nframes);
1016 	} else {
1017 		/* use a ewma */
1018 		sn->stats[size_bin][rix0].average_tx_time =
1019 			((sn->stats[size_bin][rix0].average_tx_time * ssc->smoothing_rate) +
1020 			 (tt * (100 - ssc->smoothing_rate))) / 100;
1021 	}
1022 
1023 	if (nframes == nbad) {
1024 		sn->stats[size_bin][rix0].successive_failures += nbad;
1025 	} else {
1026 		sn->stats[size_bin][rix0].packets_acked += (nframes - nbad);
1027 		sn->stats[size_bin][rix0].successive_failures = 0;
1028 	}
1029 	sn->stats[size_bin][rix0].tries += tries;
1030 	sn->stats[size_bin][rix0].last_tx = ticks;
1031 	sn->stats[size_bin][rix0].total_packets += nframes;
1032 
1033 	/* update EWMA for this rix */
1034 
1035 	/* Calculate percentage based on current rate */
1036 	if (nframes == 0)
1037 		nframes = nbad = 1;
1038 	pct = ((nframes - nbad) * 1000) / nframes;
1039 
1040 	if (sn->stats[size_bin][rix0].total_packets <
1041 	    ssc->smoothing_minpackets) {
1042 		/* just average the first few packets */
1043 		int a_pct = (sn->stats[size_bin][rix0].packets_acked * 1000) /
1044 		    (sn->stats[size_bin][rix0].total_packets);
1045 		sn->stats[size_bin][rix0].ewma_pct = a_pct;
1046 	} else {
1047 		/* use a ewma */
1048 		sn->stats[size_bin][rix0].ewma_pct =
1049 			((sn->stats[size_bin][rix0].ewma_pct * ssc->smoothing_rate) +
1050 			 (pct * (100 - ssc->smoothing_rate))) / 100;
1051 	}
1052 
1053 	/*
1054 	 * Only update the sample time for the initial sample rix.
1055 	 * We've updated the statistics on each of the other retries
1056 	 * fine, but we should only update the sample_tt with what
1057 	 * was actually sampled.
1058 	 *
1059 	 * However, to aide in debugging, log all the failures for
1060 	 * each of the buckets
1061 	 */
1062 	IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
1063 	   &an->an_node,
1064 	    "%s: size %d %s %s rate %d %s tries (%d/%d) tt %d "
1065 	    "avg_tt (%d/%d) nfrm %d nbad %d",
1066 	    __func__,
1067 	    size,
1068 	    status ? "FAIL" : "OK",
1069 	    rix0 == sn->current_sample_rix[size_bin] ? "sample" : "mrr",
1070 	    dot11rate(rt, rix0),
1071 	    dot11rate_label(rt, rix0),
1072 	    short_tries, tries, tt,
1073 	    sn->stats[size_bin][rix0].average_tx_time,
1074 	    sn->stats[size_bin][rix0].perfect_tx_time,
1075 	    nframes, nbad);
1076 
1077 	if (rix0 == sn->current_sample_rix[size_bin]) {
1078 		sn->sample_tt[size_bin] = tt;
1079 		sn->current_sample_rix[size_bin] = -1;
1080 	}
1081 }
1082 
1083 static void
1084 badrate(struct ath_softc *sc, int series, int hwrate, int tries, int status)
1085 {
1086 
1087 	device_printf(sc->sc_dev,
1088 	    "bad series%d hwrate 0x%x, tries %u ts_status 0x%x\n",
1089 	    series, hwrate, tries, status);
1090 }
1091 
1092 void
1093 ath_rate_tx_complete(struct ath_softc *sc, struct ath_node *an,
1094 	const struct ath_rc_series *rc, const struct ath_tx_status *ts,
1095 	int frame_size, int rc_framesize, int nframes, int nbad)
1096 {
1097 	struct ieee80211com *ic = &sc->sc_ic;
1098 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
1099 	int final_rix, short_tries, long_tries;
1100 	const HAL_RATE_TABLE *rt = sc->sc_currates;
1101 	int status = ts->ts_status;
1102 	int mrr;
1103 
1104 	final_rix = rt->rateCodeToIndex[ts->ts_rate];
1105 	short_tries = ts->ts_shortretry;
1106 	long_tries = ts->ts_longretry + 1;
1107 
1108 	if (nframes == 0) {
1109 		device_printf(sc->sc_dev, "%s: nframes=0?\n", __func__);
1110 		return;
1111 	}
1112 
1113 	if (frame_size == 0)		    /* NB: should not happen */
1114 		frame_size = 1500;
1115 	if (rc_framesize == 0)		    /* NB: should not happen */
1116 		rc_framesize = 1500;
1117 
1118 	/*
1119 	 * There are still some places where what rate control set as
1120 	 * a limit but the hardware decided, for some reason, to transmit
1121 	 * at a smaller size that fell into a different bucket.
1122 	 *
1123 	 * The eternal question here is - which size_bin should it go in?
1124 	 * The one that was requested, or the one that was transmitted?
1125 	 *
1126 	 * Here's the problem - if we use the one that was transmitted,
1127 	 * we may continue to hit corner cases where we make a rate
1128 	 * selection using a higher bin but only update the smaller bin;
1129 	 * thus never really "adapting".
1130 	 *
1131 	 * If however we update the larger bin, we're not accurately
1132 	 * representing the channel state at that frame/aggregate size.
1133 	 * However if we keep hitting the larger request but completing
1134 	 * a smaller size, we at least updates based on what the
1135 	 * request was /for/.
1136 	 *
1137 	 * I'm going to err on the side of caution and choose the
1138 	 * latter.
1139 	 */
1140 	if (size_to_bin(frame_size) != size_to_bin(rc_framesize)) {
1141 #if 0
1142 		device_printf(sc->sc_dev,
1143 		    "%s: completed but frame size buckets mismatch "
1144 		    "(completed %d tx'ed %d)\n",
1145 		    __func__, frame_size, rc_framesize);
1146 #endif
1147 		frame_size = rc_framesize;
1148 	}
1149 
1150 	if (sn->ratemask == 0) {
1151 		IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
1152 		    &an->an_node,
1153 		    "%s: size %d %s rate/try %d/%d no rates yet",
1154 		    __func__,
1155 		    bin_to_size(size_to_bin(frame_size)),
1156 		    status ? "FAIL" : "OK",
1157 		    short_tries, long_tries);
1158 		return;
1159 	}
1160 	mrr = sc->sc_mrretry;
1161 	/* XXX check HT protmode too */
1162 	if (mrr && (ic->ic_flags & IEEE80211_F_USEPROT && !sc->sc_mrrprot))
1163 		mrr = 0;
1164 
1165 	if (!mrr || ts->ts_finaltsi == 0) {
1166 		if (!IS_RATE_DEFINED(sn, final_rix)) {
1167 			device_printf(sc->sc_dev,
1168 			    "%s: ts_rate=%d ts_finaltsi=%d, final_rix=%d\n",
1169 			    __func__, ts->ts_rate, ts->ts_finaltsi, final_rix);
1170 			badrate(sc, 0, ts->ts_rate, long_tries, status);
1171 			return;
1172 		}
1173 		/*
1174 		 * Only one rate was used; optimize work.
1175 		 */
1176 		IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
1177 		     &an->an_node, "%s: size %d (%d bytes) %s rate/short/long %d %s/%d/%d nframes/nbad [%d/%d]",
1178 		     __func__,
1179 		     bin_to_size(size_to_bin(frame_size)),
1180 		     frame_size,
1181 		     status ? "FAIL" : "OK",
1182 		     dot11rate(rt, final_rix), dot11rate_label(rt, final_rix),
1183 		     short_tries, long_tries, nframes, nbad);
1184 		update_stats(sc, an, frame_size,
1185 			     final_rix, long_tries,
1186 			     short_tries, long_tries, status,
1187 			     nframes, nbad);
1188 
1189 	} else {
1190 		int finalTSIdx = ts->ts_finaltsi;
1191 		int i;
1192 
1193 		/*
1194 		 * Process intermediate rates that failed.
1195 		 */
1196 
1197 		IEEE80211_NOTE(an->an_node.ni_vap, IEEE80211_MSG_RATECTL,
1198 		    &an->an_node,
1199 "%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]",
1200 		     __func__,
1201 		     bin_to_size(size_to_bin(frame_size)),
1202 		     frame_size,
1203 		     finalTSIdx,
1204 		     short_tries,
1205 		     long_tries,
1206 		     status ? "FAIL" : "OK",
1207 		     dot11rate(rt, rc[0].rix),
1208 		      dot11rate_label(rt, rc[0].rix), rc[0].tries,
1209 		     dot11rate(rt, rc[1].rix),
1210 		      dot11rate_label(rt, rc[1].rix), rc[1].tries,
1211 		     dot11rate(rt, rc[2].rix),
1212 		      dot11rate_label(rt, rc[2].rix), rc[2].tries,
1213 		     dot11rate(rt, rc[3].rix),
1214 		      dot11rate_label(rt, rc[3].rix), rc[3].tries,
1215 		     nframes, nbad);
1216 
1217 		for (i = 0; i < 4; i++) {
1218 			if (rc[i].tries && !IS_RATE_DEFINED(sn, rc[i].rix))
1219 				badrate(sc, 0, rc[i].ratecode, rc[i].tries,
1220 				    status);
1221 		}
1222 
1223 		/*
1224 		 * This used to not penalise other tries because loss
1225 		 * can be bursty, but it's then not accurately keeping
1226 		 * the avg TX time and EWMA updated.
1227 		 */
1228 		if (rc[0].tries) {
1229 			update_stats(sc, an, frame_size,
1230 				     rc[0].rix, rc[0].tries,
1231 				     short_tries, long_tries,
1232 				     status,
1233 				     nframes, nbad);
1234 			long_tries -= rc[0].tries;
1235 		}
1236 
1237 		if (rc[1].tries && finalTSIdx > 0) {
1238 			update_stats(sc, an, frame_size,
1239 				     rc[1].rix, rc[1].tries,
1240 				     short_tries, long_tries,
1241 				     status,
1242 				     nframes, nbad);
1243 			long_tries -= rc[1].tries;
1244 		}
1245 
1246 		if (rc[2].tries && finalTSIdx > 1) {
1247 			update_stats(sc, an, frame_size,
1248 				     rc[2].rix, rc[2].tries,
1249 				     short_tries, long_tries,
1250 				     status,
1251 				     nframes, nbad);
1252 			long_tries -= rc[2].tries;
1253 		}
1254 
1255 		if (rc[3].tries && finalTSIdx > 2) {
1256 			update_stats(sc, an, frame_size,
1257 				     rc[3].rix, rc[3].tries,
1258 				     short_tries, long_tries,
1259 				     status,
1260 				     nframes, nbad);
1261 		}
1262 	}
1263 }
1264 
1265 void
1266 ath_rate_newassoc(struct ath_softc *sc, struct ath_node *an, int isnew)
1267 {
1268 	if (isnew)
1269 		ath_rate_ctl_reset(sc, &an->an_node);
1270 }
1271 
1272 void
1273 ath_rate_update_rx_rssi(struct ath_softc *sc, struct ath_node *an, int rssi)
1274 {
1275 }
1276 
1277 static const struct txschedule *mrr_schedules[IEEE80211_MODE_MAX+2] = {
1278 	NULL,		/* IEEE80211_MODE_AUTO */
1279 	series_11a,	/* IEEE80211_MODE_11A */
1280 	series_11g,	/* IEEE80211_MODE_11B */
1281 	series_11g,	/* IEEE80211_MODE_11G */
1282 	NULL,		/* IEEE80211_MODE_FH */
1283 	series_11a,	/* IEEE80211_MODE_TURBO_A */
1284 	series_11g,	/* IEEE80211_MODE_TURBO_G */
1285 	series_11a,	/* IEEE80211_MODE_STURBO_A */
1286 	series_11na,	/* IEEE80211_MODE_11NA */
1287 	series_11ng,	/* IEEE80211_MODE_11NG */
1288 	series_half,	/* IEEE80211_MODE_HALF */
1289 	series_quarter,	/* IEEE80211_MODE_QUARTER */
1290 };
1291 
1292 /*
1293  * Initialize the tables for a node.
1294  */
1295 static void
1296 ath_rate_ctl_reset(struct ath_softc *sc, struct ieee80211_node *ni)
1297 {
1298 #define	RATE(_ix)	(ni->ni_rates.rs_rates[(_ix)] & IEEE80211_RATE_VAL)
1299 #define	DOT11RATE(_ix)	(rt->info[(_ix)].dot11Rate & IEEE80211_RATE_VAL)
1300 #define	MCS(_ix)	(ni->ni_htrates.rs_rates[_ix] | IEEE80211_RATE_MCS)
1301 	struct ath_node *an = ATH_NODE(ni);
1302 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
1303 	const HAL_RATE_TABLE *rt = sc->sc_currates;
1304 	int x, y, rix;
1305 
1306 	KASSERT(rt != NULL, ("no rate table, mode %u", sc->sc_curmode));
1307 
1308 	KASSERT(sc->sc_curmode < IEEE80211_MODE_MAX+2,
1309 	    ("curmode %u", sc->sc_curmode));
1310 
1311 	sn->sched = mrr_schedules[sc->sc_curmode];
1312 	KASSERT(sn->sched != NULL,
1313 	    ("no mrr schedule for mode %u", sc->sc_curmode));
1314 
1315         sn->static_rix = -1;
1316 	ath_rate_update_static_rix(sc, ni);
1317 
1318 	sn->currates = sc->sc_currates;
1319 
1320 	/*
1321 	 * Construct a bitmask of usable rates.  This has all
1322 	 * negotiated rates minus those marked by the hal as
1323 	 * to be ignored for doing rate control.
1324 	 */
1325 	sn->ratemask = 0;
1326 	/* MCS rates */
1327 	if (ni->ni_flags & IEEE80211_NODE_HT) {
1328 		for (x = 0; x < ni->ni_htrates.rs_nrates; x++) {
1329 			rix = sc->sc_rixmap[MCS(x)];
1330 			if (rix == 0xff)
1331 				continue;
1332 			/* skip rates marked broken by hal */
1333 			if (!rt->info[rix].valid)
1334 				continue;
1335 			KASSERT(rix < SAMPLE_MAXRATES,
1336 			    ("mcs %u has rix %d", MCS(x), rix));
1337 			sn->ratemask |= (uint64_t) 1<<rix;
1338 		}
1339 	}
1340 
1341 	/* Legacy rates */
1342 	for (x = 0; x < ni->ni_rates.rs_nrates; x++) {
1343 		rix = sc->sc_rixmap[RATE(x)];
1344 		if (rix == 0xff)
1345 			continue;
1346 		/* skip rates marked broken by hal */
1347 		if (!rt->info[rix].valid)
1348 			continue;
1349 		KASSERT(rix < SAMPLE_MAXRATES,
1350 		    ("rate %u has rix %d", RATE(x), rix));
1351 		sn->ratemask |= (uint64_t) 1<<rix;
1352 	}
1353 #ifdef IEEE80211_DEBUG
1354 	if (ieee80211_msg(ni->ni_vap, IEEE80211_MSG_RATECTL)) {
1355 		uint64_t mask;
1356 
1357 		ieee80211_note(ni->ni_vap, "[%6D] %s: size 1600 rate/tt",
1358 		    ni->ni_macaddr, ":", __func__);
1359 		for (mask = sn->ratemask, rix = 0; mask != 0; mask >>= 1, rix++) {
1360 			if ((mask & 1) == 0)
1361 				continue;
1362 			printf(" %d %s/%d", dot11rate(rt, rix), dot11rate_label(rt, rix),
1363 			    calc_usecs_unicast_packet(sc, 1600, rix, 0,0,
1364 			        (ni->ni_chw == 40)));
1365 		}
1366 		printf("\n");
1367 	}
1368 #endif
1369 	for (y = 0; y < NUM_PACKET_SIZE_BINS; y++) {
1370 		int size = bin_to_size(y);
1371 		uint64_t mask;
1372 
1373 		sn->packets_sent[y] = 0;
1374 		sn->current_sample_rix[y] = -1;
1375 		sn->last_sample_rix[y] = 0;
1376 		/* XXX start with first valid rate */
1377 		sn->current_rix[y] = ffs(sn->ratemask)-1;
1378 
1379 		/*
1380 		 * Initialize the statistics buckets; these are
1381 		 * indexed by the rate code index.
1382 		 */
1383 		for (rix = 0, mask = sn->ratemask; mask != 0; rix++, mask >>= 1) {
1384 			if ((mask & 1) == 0)		/* not a valid rate */
1385 				continue;
1386 			sn->stats[y][rix].successive_failures = 0;
1387 			sn->stats[y][rix].tries = 0;
1388 			sn->stats[y][rix].total_packets = 0;
1389 			sn->stats[y][rix].packets_acked = 0;
1390 			sn->stats[y][rix].last_tx = 0;
1391 			sn->stats[y][rix].ewma_pct = 0;
1392 
1393 			sn->stats[y][rix].perfect_tx_time =
1394 			    calc_usecs_unicast_packet(sc, size, rix, 0, 0,
1395 			    (ni->ni_chw == 40));
1396 			sn->stats[y][rix].average_tx_time =
1397 			    sn->stats[y][rix].perfect_tx_time;
1398 		}
1399 	}
1400 #if 0
1401 	/* XXX 0, num_rates-1 are wrong */
1402 	IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
1403 	    "%s: %d rates %d%sMbps (%dus)- %d%sMbps (%dus)", __func__,
1404 	    sn->num_rates,
1405 	    DOT11RATE(0)/2, DOT11RATE(0) % 1 ? ".5" : "",
1406 	    sn->stats[1][0].perfect_tx_time,
1407 	    DOT11RATE(sn->num_rates-1)/2, DOT11RATE(sn->num_rates-1) % 1 ? ".5" : "",
1408 	    sn->stats[1][sn->num_rates-1].perfect_tx_time
1409 	);
1410 #endif
1411 	/* set the visible bit-rate */
1412 	if (sn->static_rix != -1)
1413 		ni->ni_txrate = DOT11RATE(sn->static_rix);
1414 	else
1415 		ni->ni_txrate = RATE(0);
1416 #undef RATE
1417 #undef DOT11RATE
1418 }
1419 
1420 /*
1421  * Fetch the statistics for the given node.
1422  *
1423  * The ieee80211 node must be referenced and unlocked, however the ath_node
1424  * must be locked.
1425  *
1426  * The main difference here is that we convert the rate indexes
1427  * to 802.11 rates, or the userland output won't make much sense
1428  * as it has no access to the rix table.
1429  */
1430 int
1431 ath_rate_fetch_node_stats(struct ath_softc *sc, struct ath_node *an,
1432     struct ath_rateioctl *rs)
1433 {
1434 	struct sample_node *sn = ATH_NODE_SAMPLE(an);
1435 	const HAL_RATE_TABLE *rt = sc->sc_currates;
1436 	struct ath_rateioctl_tlv av;
1437 	struct ath_rateioctl_rt *tv;
1438 	int y;
1439 	int o = 0;
1440 
1441 	ATH_NODE_LOCK_ASSERT(an);
1442 
1443 	/*
1444 	 * Ensure there's enough space for the statistics.
1445 	 */
1446 	if (rs->len <
1447 	    sizeof(struct ath_rateioctl_tlv) +
1448 	    sizeof(struct ath_rateioctl_rt) +
1449 	    sizeof(struct ath_rateioctl_tlv) +
1450 	    sizeof(struct sample_node)) {
1451 		device_printf(sc->sc_dev, "%s: len=%d, too short\n",
1452 		    __func__,
1453 		    rs->len);
1454 		return (EINVAL);
1455 	}
1456 
1457 	/*
1458 	 * Take a temporary copy of the sample node state so we can
1459 	 * modify it before we copy it.
1460 	 */
1461 	tv = malloc(sizeof(struct ath_rateioctl_rt), M_TEMP,
1462 	    M_NOWAIT | M_ZERO);
1463 	if (tv == NULL) {
1464 		return (ENOMEM);
1465 	}
1466 
1467 	/*
1468 	 * Populate the rate table mapping TLV.
1469 	 */
1470 	tv->nentries = rt->rateCount;
1471 	for (y = 0; y < rt->rateCount; y++) {
1472 		tv->ratecode[y] = rt->info[y].dot11Rate & IEEE80211_RATE_VAL;
1473 		if (rt->info[y].phy == IEEE80211_T_HT)
1474 			tv->ratecode[y] |= IEEE80211_RATE_MCS;
1475 	}
1476 
1477 	o = 0;
1478 	/*
1479 	 * First TLV - rate code mapping
1480 	 */
1481 	av.tlv_id = ATH_RATE_TLV_RATETABLE;
1482 	av.tlv_len = sizeof(struct ath_rateioctl_rt);
1483 	copyout(&av, rs->buf + o, sizeof(struct ath_rateioctl_tlv));
1484 	o += sizeof(struct ath_rateioctl_tlv);
1485 	copyout(tv, rs->buf + o, sizeof(struct ath_rateioctl_rt));
1486 	o += sizeof(struct ath_rateioctl_rt);
1487 
1488 	/*
1489 	 * Second TLV - sample node statistics
1490 	 */
1491 	av.tlv_id = ATH_RATE_TLV_SAMPLENODE;
1492 	av.tlv_len = sizeof(struct sample_node);
1493 	copyout(&av, rs->buf + o, sizeof(struct ath_rateioctl_tlv));
1494 	o += sizeof(struct ath_rateioctl_tlv);
1495 
1496 	/*
1497 	 * Copy the statistics over to the provided buffer.
1498 	 */
1499 	copyout(sn, rs->buf + o, sizeof(struct sample_node));
1500 	o += sizeof(struct sample_node);
1501 
1502 	free(tv, M_TEMP);
1503 
1504 	return (0);
1505 }
1506 
1507 static void
1508 sample_stats(void *arg, struct ieee80211_node *ni)
1509 {
1510 	struct ath_softc *sc = arg;
1511 	const HAL_RATE_TABLE *rt = sc->sc_currates;
1512 	struct sample_node *sn = ATH_NODE_SAMPLE(ATH_NODE(ni));
1513 	uint64_t mask;
1514 	int rix, y;
1515 
1516 	printf("\n[%s] refcnt %d static_rix (%d %s) ratemask 0x%jx\n",
1517 	    ether_sprintf(ni->ni_macaddr), ieee80211_node_refcnt(ni),
1518 	    dot11rate(rt, sn->static_rix),
1519 	    dot11rate_label(rt, sn->static_rix),
1520 	    (uintmax_t)sn->ratemask);
1521 	for (y = 0; y < NUM_PACKET_SIZE_BINS; y++) {
1522 		printf("[%4u] cur rix %d (%d %s) since switch: packets %d ticks %u\n",
1523 		    bin_to_size(y), sn->current_rix[y],
1524 		    dot11rate(rt, sn->current_rix[y]),
1525 		    dot11rate_label(rt, sn->current_rix[y]),
1526 		    sn->packets_since_switch[y], sn->ticks_since_switch[y]);
1527 		printf("[%4u] last sample (%d %s) cur sample (%d %s) packets sent %d\n",
1528 		    bin_to_size(y),
1529 		    dot11rate(rt, sn->last_sample_rix[y]),
1530 		    dot11rate_label(rt, sn->last_sample_rix[y]),
1531 		    dot11rate(rt, sn->current_sample_rix[y]),
1532 		    dot11rate_label(rt, sn->current_sample_rix[y]),
1533 		    sn->packets_sent[y]);
1534 		printf("[%4u] packets since sample %d sample tt %u\n",
1535 		    bin_to_size(y), sn->packets_since_sample[y],
1536 		    sn->sample_tt[y]);
1537 	}
1538 	for (mask = sn->ratemask, rix = 0; mask != 0; mask >>= 1, rix++) {
1539 		if ((mask & 1) == 0)
1540 				continue;
1541 		for (y = 0; y < NUM_PACKET_SIZE_BINS; y++) {
1542 			if (sn->stats[y][rix].total_packets == 0)
1543 				continue;
1544 			printf("[%2u %s:%4u] %8ju:%-8ju (%3d%%) (EWMA %3d.%1d%%) T %8ju F %4d avg %5u last %u\n",
1545 			    dot11rate(rt, rix), dot11rate_label(rt, rix),
1546 			    bin_to_size(y),
1547 			    (uintmax_t) sn->stats[y][rix].total_packets,
1548 			    (uintmax_t) sn->stats[y][rix].packets_acked,
1549 			    (int) ((sn->stats[y][rix].packets_acked * 100ULL) /
1550 			     sn->stats[y][rix].total_packets),
1551 			    sn->stats[y][rix].ewma_pct / 10,
1552 			    sn->stats[y][rix].ewma_pct % 10,
1553 			    (uintmax_t) sn->stats[y][rix].tries,
1554 			    sn->stats[y][rix].successive_failures,
1555 			    sn->stats[y][rix].average_tx_time,
1556 			    ticks - sn->stats[y][rix].last_tx);
1557 		}
1558 	}
1559 }
1560 
1561 static int
1562 ath_rate_sysctl_stats(SYSCTL_HANDLER_ARGS)
1563 {
1564 	struct ath_softc *sc = arg1;
1565 	struct ieee80211com *ic = &sc->sc_ic;
1566 	int error, v;
1567 
1568 	v = 0;
1569 	error = sysctl_handle_int(oidp, &v, 0, req);
1570 	if (error || !req->newptr)
1571 		return error;
1572 	ieee80211_iterate_nodes(&ic->ic_sta, sample_stats, sc);
1573 	return 0;
1574 }
1575 
1576 static int
1577 ath_rate_sysctl_smoothing_rate(SYSCTL_HANDLER_ARGS)
1578 {
1579 	struct sample_softc *ssc = arg1;
1580 	int rate, error;
1581 
1582 	rate = ssc->smoothing_rate;
1583 	error = sysctl_handle_int(oidp, &rate, 0, req);
1584 	if (error || !req->newptr)
1585 		return error;
1586 	if (!(0 <= rate && rate < 100))
1587 		return EINVAL;
1588 	ssc->smoothing_rate = rate;
1589 	ssc->smoothing_minpackets = 100 / (100 - rate);
1590 	return 0;
1591 }
1592 
1593 static int
1594 ath_rate_sysctl_sample_rate(SYSCTL_HANDLER_ARGS)
1595 {
1596 	struct sample_softc *ssc = arg1;
1597 	int rate, error;
1598 
1599 	rate = ssc->sample_rate;
1600 	error = sysctl_handle_int(oidp, &rate, 0, req);
1601 	if (error || !req->newptr)
1602 		return error;
1603 	if (!(2 <= rate && rate <= 100))
1604 		return EINVAL;
1605 	ssc->sample_rate = rate;
1606 	return 0;
1607 }
1608 
1609 static void
1610 ath_rate_sysctlattach(struct ath_softc *sc, struct sample_softc *ssc)
1611 {
1612 	struct sysctl_ctx_list *ctx = device_get_sysctl_ctx(sc->sc_dev);
1613 	struct sysctl_oid *tree = device_get_sysctl_tree(sc->sc_dev);
1614 
1615 	SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
1616 	    "smoothing_rate", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
1617 	    ssc, 0, ath_rate_sysctl_smoothing_rate, "I",
1618 	    "sample: smoothing rate for avg tx time (%%)");
1619 	SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
1620 	    "sample_rate", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
1621 	    ssc, 0, ath_rate_sysctl_sample_rate, "I",
1622 	    "sample: percent air time devoted to sampling new rates (%%)");
1623 	/* XXX max_successive_failures, stale_failure_timeout, min_switch */
1624 	SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
1625 	    "sample_stats", CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
1626 	    sc, 0, ath_rate_sysctl_stats, "I", "sample: print statistics");
1627 }
1628 
1629 struct ath_ratectrl *
1630 ath_rate_attach(struct ath_softc *sc)
1631 {
1632 	struct sample_softc *ssc;
1633 
1634 	ssc = malloc(sizeof(struct sample_softc), M_DEVBUF, M_NOWAIT|M_ZERO);
1635 	if (ssc == NULL)
1636 		return NULL;
1637 	ssc->arc.arc_space = sizeof(struct sample_node);
1638 	ssc->smoothing_rate = 75;		/* ewma percentage ([0..99]) */
1639 	ssc->smoothing_minpackets = 100 / (100 - ssc->smoothing_rate);
1640 	ssc->sample_rate = 10;			/* %time to try diff tx rates */
1641 	ssc->max_successive_failures = 3;	/* threshold for rate sampling*/
1642 	ssc->stale_failure_timeout = 10 * hz;	/* 10 seconds */
1643 	ssc->min_switch = hz;			/* 1 second */
1644 	ath_rate_sysctlattach(sc, ssc);
1645 	return &ssc->arc;
1646 }
1647 
1648 void
1649 ath_rate_detach(struct ath_ratectrl *arc)
1650 {
1651 	struct sample_softc *ssc = (struct sample_softc *) arc;
1652 
1653 	free(ssc, M_DEVBUF);
1654 }
1655