2 * Copyright (C) 2010-2013 Felix Fietkau <nbd@openwrt.org>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
8 #include <linux/netdevice.h>
9 #include <linux/types.h>
10 #include <linux/skbuff.h>
11 #include <linux/debugfs.h>
12 #include <linux/random.h>
13 #include <linux/ieee80211.h>
14 #include <net/mac80211.h>
16 #include "rc80211_minstrel.h"
17 #include "rc80211_minstrel_ht.h"
19 #define AVG_PKT_SIZE 1200
21 /* Number of bits for an average sized packet */
22 #define MCS_NBITS (AVG_PKT_SIZE << 3)
24 /* Number of symbols for a packet with (bps) bits per symbol */
25 #define MCS_NSYMS(bps) DIV_ROUND_UP(MCS_NBITS, (bps))
27 /* Transmission time (nanoseconds) for a packet containing (syms) symbols */
28 #define MCS_SYMBOL_TIME(sgi, syms) \
30 ((syms) * 18000 + 4000) / 5 : /* syms * 3.6 us */ \
31 ((syms) * 1000) << 2 /* syms * 4 us */ \
34 /* Transmit duration for the raw data part of an average sized packet */
35 #define MCS_DURATION(streams, sgi, bps) MCS_SYMBOL_TIME(sgi, MCS_NSYMS((streams) * (bps)))
38 * Define group sort order: HT40 -> SGI -> #streams
40 #define GROUP_IDX(_streams, _sgi, _ht40) \
41 MINSTREL_MAX_STREAMS * 2 * _ht40 + \
42 MINSTREL_MAX_STREAMS * _sgi + \
45 /* MCS rate information for an MCS group */
46 #define MCS_GROUP(_streams, _sgi, _ht40) \
47 [GROUP_IDX(_streams, _sgi, _ht40)] = { \
48 .streams = _streams, \
50 (_sgi ? IEEE80211_TX_RC_SHORT_GI : 0) | \
51 (_ht40 ? IEEE80211_TX_RC_40_MHZ_WIDTH : 0), \
53 MCS_DURATION(_streams, _sgi, _ht40 ? 54 : 26), \
54 MCS_DURATION(_streams, _sgi, _ht40 ? 108 : 52), \
55 MCS_DURATION(_streams, _sgi, _ht40 ? 162 : 78), \
56 MCS_DURATION(_streams, _sgi, _ht40 ? 216 : 104), \
57 MCS_DURATION(_streams, _sgi, _ht40 ? 324 : 156), \
58 MCS_DURATION(_streams, _sgi, _ht40 ? 432 : 208), \
59 MCS_DURATION(_streams, _sgi, _ht40 ? 486 : 234), \
60 MCS_DURATION(_streams, _sgi, _ht40 ? 540 : 260) \
64 #define CCK_DURATION(_bitrate, _short, _len) \
65 (1000 * (10 /* SIFS */ + \
66 (_short ? 72 + 24 : 144 + 48) + \
67 (8 * (_len + 4) * 10) / (_bitrate)))
69 #define CCK_ACK_DURATION(_bitrate, _short) \
70 (CCK_DURATION((_bitrate > 10 ? 20 : 10), false, 60) + \
71 CCK_DURATION(_bitrate, _short, AVG_PKT_SIZE))
73 #define CCK_DURATION_LIST(_short) \
74 CCK_ACK_DURATION(10, _short), \
75 CCK_ACK_DURATION(20, _short), \
76 CCK_ACK_DURATION(55, _short), \
77 CCK_ACK_DURATION(110, _short)
80 [MINSTREL_MAX_STREAMS * MINSTREL_STREAM_GROUPS] = { \
83 CCK_DURATION_LIST(false), \
84 CCK_DURATION_LIST(true) \
89 * To enable sufficiently targeted rate sampling, MCS rates are divided into
90 * groups, based on the number of streams and flags (HT40, SGI) that they
93 * Sortorder has to be fixed for GROUP_IDX macro to be applicable:
94 * HT40 -> SGI -> #streams
96 const struct mcs_group minstrel_mcs_groups
[] = {
99 #if MINSTREL_MAX_STREAMS >= 3
105 #if MINSTREL_MAX_STREAMS >= 3
111 #if MINSTREL_MAX_STREAMS >= 3
117 #if MINSTREL_MAX_STREAMS >= 3
125 #define MINSTREL_CCK_GROUP (ARRAY_SIZE(minstrel_mcs_groups) - 1)
127 static u8 sample_table
[SAMPLE_COLUMNS
][MCS_GROUP_RATES
] __read_mostly
;
130 minstrel_ht_update_rates(struct minstrel_priv
*mp
, struct minstrel_ht_sta
*mi
);
133 * Look up an MCS group index based on mac80211 rate information
136 minstrel_ht_get_group_idx(struct ieee80211_tx_rate
*rate
)
138 return GROUP_IDX((rate
->idx
/ MCS_GROUP_RATES
) + 1,
139 !!(rate
->flags
& IEEE80211_TX_RC_SHORT_GI
),
140 !!(rate
->flags
& IEEE80211_TX_RC_40_MHZ_WIDTH
));
143 static struct minstrel_rate_stats
*
144 minstrel_ht_get_stats(struct minstrel_priv
*mp
, struct minstrel_ht_sta
*mi
,
145 struct ieee80211_tx_rate
*rate
)
149 if (rate
->flags
& IEEE80211_TX_RC_MCS
) {
150 group
= minstrel_ht_get_group_idx(rate
);
153 group
= MINSTREL_CCK_GROUP
;
155 for (idx
= 0; idx
< ARRAY_SIZE(mp
->cck_rates
); idx
++)
156 if (rate
->idx
== mp
->cck_rates
[idx
])
160 if (!(mi
->groups
[group
].supported
& BIT(idx
)))
163 return &mi
->groups
[group
].rates
[idx
];
166 static inline struct minstrel_rate_stats
*
167 minstrel_get_ratestats(struct minstrel_ht_sta
*mi
, int index
)
169 return &mi
->groups
[index
/ MCS_GROUP_RATES
].rates
[index
% MCS_GROUP_RATES
];
174 * Recalculate success probabilities and counters for a rate using EWMA
177 minstrel_calc_rate_ewma(struct minstrel_rate_stats
*mr
)
179 if (unlikely(mr
->attempts
> 0)) {
180 mr
->sample_skipped
= 0;
181 mr
->cur_prob
= MINSTREL_FRAC(mr
->success
, mr
->attempts
);
183 mr
->probability
= mr
->cur_prob
;
185 mr
->probability
= minstrel_ewma(mr
->probability
,
186 mr
->cur_prob
, EWMA_LEVEL
);
187 mr
->att_hist
+= mr
->attempts
;
188 mr
->succ_hist
+= mr
->success
;
190 mr
->sample_skipped
++;
192 mr
->last_success
= mr
->success
;
193 mr
->last_attempts
= mr
->attempts
;
199 * Calculate throughput based on the average A-MPDU length, taking into account
200 * the expected number of retransmissions and their expected length
203 minstrel_ht_calc_tp(struct minstrel_ht_sta
*mi
, int group
, int rate
)
205 struct minstrel_rate_stats
*mr
;
206 unsigned int nsecs
= 0;
210 mr
= &mi
->groups
[group
].rates
[rate
];
211 prob
= mr
->probability
;
213 if (prob
< MINSTREL_FRAC(1, 10)) {
219 * For the throughput calculation, limit the probability value to 90% to
220 * account for collision related packet error rate fluctuation
222 if (prob
> MINSTREL_FRAC(9, 10))
223 prob
= MINSTREL_FRAC(9, 10);
225 if (group
!= MINSTREL_CCK_GROUP
)
226 nsecs
= 1000 * mi
->overhead
/ MINSTREL_TRUNC(mi
->avg_ampdu_len
);
228 nsecs
+= minstrel_mcs_groups
[group
].duration
[rate
];
230 /* prob is scaled - see MINSTREL_FRAC above */
231 tp
= 1000000 * ((prob
* 1000) / nsecs
);
232 mr
->cur_tp
= MINSTREL_TRUNC(tp
);
236 * Find & sort topmost throughput rates
238 * If multiple rates provide equal throughput the sorting is based on their
239 * current success probability. Higher success probability is preferred among
240 * MCS groups, CCK rates do not provide aggregation and are therefore at last.
243 minstrel_ht_sort_best_tp_rates(struct minstrel_ht_sta
*mi
, u8 index
,
246 int cur_group
, cur_idx
, cur_thr
, cur_prob
;
247 int tmp_group
, tmp_idx
, tmp_thr
, tmp_prob
;
248 int j
= MAX_THR_RATES
;
250 cur_group
= index
/ MCS_GROUP_RATES
;
251 cur_idx
= index
% MCS_GROUP_RATES
;
252 cur_thr
= mi
->groups
[cur_group
].rates
[cur_idx
].cur_tp
;
253 cur_prob
= mi
->groups
[cur_group
].rates
[cur_idx
].probability
;
255 tmp_group
= tp_list
[j
- 1] / MCS_GROUP_RATES
;
256 tmp_idx
= tp_list
[j
- 1] % MCS_GROUP_RATES
;
257 tmp_thr
= mi
->groups
[tmp_group
].rates
[tmp_idx
].cur_tp
;
258 tmp_prob
= mi
->groups
[tmp_group
].rates
[tmp_idx
].probability
;
260 while (j
> 0 && (cur_thr
> tmp_thr
||
261 (cur_thr
== tmp_thr
&& cur_prob
> tmp_prob
))) {
263 tmp_group
= tp_list
[j
- 1] / MCS_GROUP_RATES
;
264 tmp_idx
= tp_list
[j
- 1] % MCS_GROUP_RATES
;
265 tmp_thr
= mi
->groups
[tmp_group
].rates
[tmp_idx
].cur_tp
;
266 tmp_prob
= mi
->groups
[tmp_group
].rates
[tmp_idx
].probability
;
269 if (j
< MAX_THR_RATES
- 1) {
270 memmove(&tp_list
[j
+ 1], &tp_list
[j
], (sizeof(*tp_list
) *
271 (MAX_THR_RATES
- (j
+ 1))));
273 if (j
< MAX_THR_RATES
)
278 * Find and set the topmost probability rate per sta and per group
281 minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta
*mi
, u8 index
)
283 struct minstrel_mcs_group_data
*mg
;
284 struct minstrel_rate_stats
*mr
;
285 int tmp_group
, tmp_idx
, tmp_tp
, tmp_prob
, max_tp_group
;
287 mg
= &mi
->groups
[index
/ MCS_GROUP_RATES
];
288 mr
= &mg
->rates
[index
% MCS_GROUP_RATES
];
290 tmp_group
= mi
->max_prob_rate
/ MCS_GROUP_RATES
;
291 tmp_idx
= mi
->max_prob_rate
% MCS_GROUP_RATES
;
292 tmp_tp
= mi
->groups
[tmp_group
].rates
[tmp_idx
].cur_tp
;
293 tmp_prob
= mi
->groups
[tmp_group
].rates
[tmp_idx
].probability
;
295 /* if max_tp_rate[0] is from MCS_GROUP max_prob_rate get selected from
296 * MCS_GROUP as well as CCK_GROUP rates do not allow aggregation */
297 max_tp_group
= mi
->max_tp_rate
[0] / MCS_GROUP_RATES
;
298 if((index
/ MCS_GROUP_RATES
== MINSTREL_CCK_GROUP
) &&
299 (max_tp_group
!= MINSTREL_CCK_GROUP
))
302 if (mr
->probability
> MINSTREL_FRAC(75, 100)) {
303 if (mr
->cur_tp
> tmp_tp
)
304 mi
->max_prob_rate
= index
;
305 if (mr
->cur_tp
> mg
->rates
[mg
->max_group_prob_rate
].cur_tp
)
306 mg
->max_group_prob_rate
= index
;
308 if (mr
->probability
> tmp_prob
)
309 mi
->max_prob_rate
= index
;
310 if (mr
->probability
> mg
->rates
[mg
->max_group_prob_rate
].probability
)
311 mg
->max_group_prob_rate
= index
;
317 * Assign new rate set per sta and use CCK rates only if the fastest
318 * rate (max_tp_rate[0]) is from CCK group. This prohibits such sorted
319 * rate sets where MCS and CCK rates are mixed, because CCK rates can
320 * not use aggregation.
323 minstrel_ht_assign_best_tp_rates(struct minstrel_ht_sta
*mi
,
324 u8 tmp_mcs_tp_rate
[MAX_THR_RATES
],
325 u8 tmp_cck_tp_rate
[MAX_THR_RATES
])
327 unsigned int tmp_group
, tmp_idx
, tmp_cck_tp
, tmp_mcs_tp
;
330 tmp_group
= tmp_cck_tp_rate
[0] / MCS_GROUP_RATES
;
331 tmp_idx
= tmp_cck_tp_rate
[0] % MCS_GROUP_RATES
;
332 tmp_cck_tp
= mi
->groups
[tmp_group
].rates
[tmp_idx
].cur_tp
;
334 tmp_group
= tmp_mcs_tp_rate
[0] / MCS_GROUP_RATES
;
335 tmp_idx
= tmp_mcs_tp_rate
[0] % MCS_GROUP_RATES
;
336 tmp_mcs_tp
= mi
->groups
[tmp_group
].rates
[tmp_idx
].cur_tp
;
338 if (tmp_cck_tp
> tmp_mcs_tp
) {
339 for(i
= 0; i
< MAX_THR_RATES
; i
++) {
340 minstrel_ht_sort_best_tp_rates(mi
, tmp_cck_tp_rate
[i
],
348 * Try to increase robustness of max_prob rate by decrease number of
349 * streams if possible.
352 minstrel_ht_prob_rate_reduce_streams(struct minstrel_ht_sta
*mi
)
354 struct minstrel_mcs_group_data
*mg
;
355 struct minstrel_rate_stats
*mr
;
356 int tmp_max_streams
, group
;
359 tmp_max_streams
= minstrel_mcs_groups
[mi
->max_tp_rate
[0] /
360 MCS_GROUP_RATES
].streams
;
361 for (group
= 0; group
< ARRAY_SIZE(minstrel_mcs_groups
); group
++) {
362 mg
= &mi
->groups
[group
];
363 if (!mg
->supported
|| group
== MINSTREL_CCK_GROUP
)
365 mr
= minstrel_get_ratestats(mi
, mg
->max_group_prob_rate
);
366 if (tmp_tp
< mr
->cur_tp
&&
367 (minstrel_mcs_groups
[group
].streams
< tmp_max_streams
)) {
368 mi
->max_prob_rate
= mg
->max_group_prob_rate
;
375 * Update rate statistics and select new primary rates
377 * Rules for rate selection:
378 * - max_prob_rate must use only one stream, as a tradeoff between delivery
379 * probability and throughput during strong fluctuations
380 * - as long as the max prob rate has a probability of more than 75%, pick
381 * higher throughput rates, even if the probablity is a bit lower
384 minstrel_ht_update_stats(struct minstrel_priv
*mp
, struct minstrel_ht_sta
*mi
)
386 struct minstrel_mcs_group_data
*mg
;
387 struct minstrel_rate_stats
*mr
;
389 u8 tmp_mcs_tp_rate
[MAX_THR_RATES
], tmp_group_tp_rate
[MAX_THR_RATES
];
390 u8 tmp_cck_tp_rate
[MAX_THR_RATES
], index
;
392 if (mi
->ampdu_packets
> 0) {
393 mi
->avg_ampdu_len
= minstrel_ewma(mi
->avg_ampdu_len
,
394 MINSTREL_FRAC(mi
->ampdu_len
, mi
->ampdu_packets
), EWMA_LEVEL
);
396 mi
->ampdu_packets
= 0;
400 mi
->sample_count
= 0;
402 /* Initialize global rate indexes */
403 for(j
= 0; j
< MAX_THR_RATES
; j
++){
404 tmp_mcs_tp_rate
[j
] = 0;
405 tmp_cck_tp_rate
[j
] = 0;
408 /* Find best rate sets within all MCS groups*/
409 for (group
= 0; group
< ARRAY_SIZE(minstrel_mcs_groups
); group
++) {
411 mg
= &mi
->groups
[group
];
417 /* (re)Initialize group rate indexes */
418 for(j
= 0; j
< MAX_THR_RATES
; j
++)
419 tmp_group_tp_rate
[j
] = group
;
421 for (i
= 0; i
< MCS_GROUP_RATES
; i
++) {
422 if (!(mg
->supported
& BIT(i
)))
425 index
= MCS_GROUP_RATES
* group
+ i
;
428 mr
->retry_updated
= false;
429 minstrel_calc_rate_ewma(mr
);
430 minstrel_ht_calc_tp(mi
, group
, i
);
435 /* Find max throughput rate set */
436 if (group
!= MINSTREL_CCK_GROUP
) {
437 minstrel_ht_sort_best_tp_rates(mi
, index
,
439 } else if (group
== MINSTREL_CCK_GROUP
) {
440 minstrel_ht_sort_best_tp_rates(mi
, index
,
444 /* Find max throughput rate set within a group */
445 minstrel_ht_sort_best_tp_rates(mi
, index
,
448 /* Find max probability rate per group and global */
449 minstrel_ht_set_best_prob_rate(mi
, index
);
452 memcpy(mg
->max_group_tp_rate
, tmp_group_tp_rate
,
453 sizeof(mg
->max_group_tp_rate
));
456 /* Assign new rate set per sta */
457 minstrel_ht_assign_best_tp_rates(mi
, tmp_mcs_tp_rate
, tmp_cck_tp_rate
);
458 memcpy(mi
->max_tp_rate
, tmp_mcs_tp_rate
, sizeof(mi
->max_tp_rate
));
460 /* Try to increase robustness of max_prob_rate*/
461 minstrel_ht_prob_rate_reduce_streams(mi
);
463 /* try to sample all available rates during each interval */
464 mi
->sample_count
*= 8;
466 #ifdef CONFIG_MAC80211_DEBUGFS
467 /* use fixed index if set */
468 if (mp
->fixed_rate_idx
!= -1) {
469 for (i
= 0; i
< 4; i
++)
470 mi
->max_tp_rate
[i
] = mp
->fixed_rate_idx
;
471 mi
->max_prob_rate
= mp
->fixed_rate_idx
;
475 /* Reset update timer */
476 mi
->stats_update
= jiffies
;
480 minstrel_ht_txstat_valid(struct minstrel_priv
*mp
, struct ieee80211_tx_rate
*rate
)
488 if (rate
->flags
& IEEE80211_TX_RC_MCS
)
491 return rate
->idx
== mp
->cck_rates
[0] ||
492 rate
->idx
== mp
->cck_rates
[1] ||
493 rate
->idx
== mp
->cck_rates
[2] ||
494 rate
->idx
== mp
->cck_rates
[3];
498 minstrel_next_sample_idx(struct minstrel_ht_sta
*mi
)
500 struct minstrel_mcs_group_data
*mg
;
504 mi
->sample_group
%= ARRAY_SIZE(minstrel_mcs_groups
);
505 mg
= &mi
->groups
[mi
->sample_group
];
510 if (++mg
->index
>= MCS_GROUP_RATES
) {
512 if (++mg
->column
>= ARRAY_SIZE(sample_table
))
520 minstrel_downgrade_rate(struct minstrel_ht_sta
*mi
, u8
*idx
, bool primary
)
522 int group
, orig_group
;
524 orig_group
= group
= *idx
/ MCS_GROUP_RATES
;
528 if (!mi
->groups
[group
].supported
)
531 if (minstrel_mcs_groups
[group
].streams
>
532 minstrel_mcs_groups
[orig_group
].streams
)
536 *idx
= mi
->groups
[group
].max_group_tp_rate
[0];
538 *idx
= mi
->groups
[group
].max_group_tp_rate
[1];
544 minstrel_aggr_check(struct ieee80211_sta
*pubsta
, struct sk_buff
*skb
)
546 struct ieee80211_hdr
*hdr
= (struct ieee80211_hdr
*) skb
->data
;
547 struct sta_info
*sta
= container_of(pubsta
, struct sta_info
, sta
);
550 if (unlikely(!ieee80211_is_data_qos(hdr
->frame_control
)))
553 if (unlikely(skb
->protocol
== cpu_to_be16(ETH_P_PAE
)))
556 tid
= *ieee80211_get_qos_ctl(hdr
) & IEEE80211_QOS_CTL_TID_MASK
;
557 if (likely(sta
->ampdu_mlme
.tid_tx
[tid
]))
560 if (skb_get_queue_mapping(skb
) == IEEE80211_AC_VO
)
563 ieee80211_start_tx_ba_session(pubsta
, tid
, 5000);
567 minstrel_ht_tx_status(void *priv
, struct ieee80211_supported_band
*sband
,
568 struct ieee80211_sta
*sta
, void *priv_sta
,
571 struct minstrel_ht_sta_priv
*msp
= priv_sta
;
572 struct minstrel_ht_sta
*mi
= &msp
->ht
;
573 struct ieee80211_tx_info
*info
= IEEE80211_SKB_CB(skb
);
574 struct ieee80211_tx_rate
*ar
= info
->status
.rates
;
575 struct minstrel_rate_stats
*rate
, *rate2
;
576 struct minstrel_priv
*mp
= priv
;
577 bool last
, update
= false;
581 return mac80211_minstrel
.tx_status(priv
, sband
, sta
, &msp
->legacy
, skb
);
583 /* This packet was aggregated but doesn't carry status info */
584 if ((info
->flags
& IEEE80211_TX_CTL_AMPDU
) &&
585 !(info
->flags
& IEEE80211_TX_STAT_AMPDU
))
588 if (!(info
->flags
& IEEE80211_TX_STAT_AMPDU
)) {
589 info
->status
.ampdu_ack_len
=
590 (info
->flags
& IEEE80211_TX_STAT_ACK
? 1 : 0);
591 info
->status
.ampdu_len
= 1;
595 mi
->ampdu_len
+= info
->status
.ampdu_len
;
597 if (!mi
->sample_wait
&& !mi
->sample_tries
&& mi
->sample_count
> 0) {
598 mi
->sample_wait
= 16 + 2 * MINSTREL_TRUNC(mi
->avg_ampdu_len
);
599 mi
->sample_tries
= 1;
603 if (info
->flags
& IEEE80211_TX_CTL_RATE_CTRL_PROBE
)
604 mi
->sample_packets
+= info
->status
.ampdu_len
;
606 last
= !minstrel_ht_txstat_valid(mp
, &ar
[0]);
607 for (i
= 0; !last
; i
++) {
608 last
= (i
== IEEE80211_TX_MAX_RATES
- 1) ||
609 !minstrel_ht_txstat_valid(mp
, &ar
[i
+ 1]);
611 rate
= minstrel_ht_get_stats(mp
, mi
, &ar
[i
]);
614 rate
->success
+= info
->status
.ampdu_ack_len
;
616 rate
->attempts
+= ar
[i
].count
* info
->status
.ampdu_len
;
620 * check for sudden death of spatial multiplexing,
621 * downgrade to a lower number of streams if necessary.
623 rate
= minstrel_get_ratestats(mi
, mi
->max_tp_rate
[0]);
624 if (rate
->attempts
> 30 &&
625 MINSTREL_FRAC(rate
->success
, rate
->attempts
) <
626 MINSTREL_FRAC(20, 100)) {
627 minstrel_downgrade_rate(mi
, &mi
->max_tp_rate
[0], true);
631 rate2
= minstrel_get_ratestats(mi
, mi
->max_tp_rate
[1]);
632 if (rate2
->attempts
> 30 &&
633 MINSTREL_FRAC(rate2
->success
, rate2
->attempts
) <
634 MINSTREL_FRAC(20, 100)) {
635 minstrel_downgrade_rate(mi
, &mi
->max_tp_rate
[1], false);
639 if (time_after(jiffies
, mi
->stats_update
+ (mp
->update_interval
/ 2 * HZ
) / 1000)) {
641 minstrel_ht_update_stats(mp
, mi
);
642 if (!(info
->flags
& IEEE80211_TX_CTL_AMPDU
) &&
643 mi
->max_prob_rate
/ MCS_GROUP_RATES
!= MINSTREL_CCK_GROUP
)
644 minstrel_aggr_check(sta
, skb
);
648 minstrel_ht_update_rates(mp
, mi
);
652 minstrel_calc_retransmit(struct minstrel_priv
*mp
, struct minstrel_ht_sta
*mi
,
655 struct minstrel_rate_stats
*mr
;
656 const struct mcs_group
*group
;
657 unsigned int tx_time
, tx_time_rtscts
, tx_time_data
;
658 unsigned int cw
= mp
->cw_min
;
659 unsigned int ctime
= 0;
660 unsigned int t_slot
= 9; /* FIXME */
661 unsigned int ampdu_len
= MINSTREL_TRUNC(mi
->avg_ampdu_len
);
662 unsigned int overhead
= 0, overhead_rtscts
= 0;
664 mr
= minstrel_get_ratestats(mi
, index
);
665 if (mr
->probability
< MINSTREL_FRAC(1, 10)) {
667 mr
->retry_count_rtscts
= 1;
672 mr
->retry_count_rtscts
= 2;
673 mr
->retry_updated
= true;
675 group
= &minstrel_mcs_groups
[index
/ MCS_GROUP_RATES
];
676 tx_time_data
= group
->duration
[index
% MCS_GROUP_RATES
] * ampdu_len
/ 1000;
678 /* Contention time for first 2 tries */
679 ctime
= (t_slot
* cw
) >> 1;
680 cw
= min((cw
<< 1) | 1, mp
->cw_max
);
681 ctime
+= (t_slot
* cw
) >> 1;
682 cw
= min((cw
<< 1) | 1, mp
->cw_max
);
684 if (index
/ MCS_GROUP_RATES
!= MINSTREL_CCK_GROUP
) {
685 overhead
= mi
->overhead
;
686 overhead_rtscts
= mi
->overhead_rtscts
;
689 /* Total TX time for data and Contention after first 2 tries */
690 tx_time
= ctime
+ 2 * (overhead
+ tx_time_data
);
691 tx_time_rtscts
= ctime
+ 2 * (overhead_rtscts
+ tx_time_data
);
693 /* See how many more tries we can fit inside segment size */
695 /* Contention time for this try */
696 ctime
= (t_slot
* cw
) >> 1;
697 cw
= min((cw
<< 1) | 1, mp
->cw_max
);
699 /* Total TX time after this try */
700 tx_time
+= ctime
+ overhead
+ tx_time_data
;
701 tx_time_rtscts
+= ctime
+ overhead_rtscts
+ tx_time_data
;
703 if (tx_time_rtscts
< mp
->segment_size
)
704 mr
->retry_count_rtscts
++;
705 } while ((tx_time
< mp
->segment_size
) &&
706 (++mr
->retry_count
< mp
->max_retry
));
711 minstrel_ht_set_rate(struct minstrel_priv
*mp
, struct minstrel_ht_sta
*mi
,
712 struct ieee80211_sta_rates
*ratetbl
, int offset
, int index
)
714 const struct mcs_group
*group
= &minstrel_mcs_groups
[index
/ MCS_GROUP_RATES
];
715 struct minstrel_rate_stats
*mr
;
719 mr
= minstrel_get_ratestats(mi
, index
);
720 if (!mr
->retry_updated
)
721 minstrel_calc_retransmit(mp
, mi
, index
);
723 if (mr
->probability
< MINSTREL_FRAC(20, 100) || !mr
->retry_count
) {
724 ratetbl
->rate
[offset
].count
= 2;
725 ratetbl
->rate
[offset
].count_rts
= 2;
726 ratetbl
->rate
[offset
].count_cts
= 2;
728 ratetbl
->rate
[offset
].count
= mr
->retry_count
;
729 ratetbl
->rate
[offset
].count_cts
= mr
->retry_count
;
730 ratetbl
->rate
[offset
].count_rts
= mr
->retry_count_rtscts
;
733 if (index
/ MCS_GROUP_RATES
== MINSTREL_CCK_GROUP
) {
734 idx
= mp
->cck_rates
[index
% ARRAY_SIZE(mp
->cck_rates
)];
737 idx
= index
% MCS_GROUP_RATES
+ (group
->streams
- 1) * 8;
738 flags
= IEEE80211_TX_RC_MCS
| group
->flags
;
742 ratetbl
->rate
[offset
].count
= ratetbl
->rate
[offset
].count_rts
;
743 flags
|= IEEE80211_TX_RC_USE_RTS_CTS
;
746 ratetbl
->rate
[offset
].idx
= idx
;
747 ratetbl
->rate
[offset
].flags
= flags
;
751 minstrel_ht_update_rates(struct minstrel_priv
*mp
, struct minstrel_ht_sta
*mi
)
753 struct ieee80211_sta_rates
*rates
;
756 rates
= kzalloc(sizeof(*rates
), GFP_ATOMIC
);
760 /* Start with max_tp_rate[0] */
761 minstrel_ht_set_rate(mp
, mi
, rates
, i
++, mi
->max_tp_rate
[0]);
763 if (mp
->hw
->max_rates
>= 3) {
764 /* At least 3 tx rates supported, use max_tp_rate[1] next */
765 minstrel_ht_set_rate(mp
, mi
, rates
, i
++, mi
->max_tp_rate
[1]);
768 if (mp
->hw
->max_rates
>= 2) {
770 * At least 2 tx rates supported, use max_prob_rate next */
771 minstrel_ht_set_rate(mp
, mi
, rates
, i
++, mi
->max_prob_rate
);
774 rates
->rate
[i
].idx
= -1;
775 rate_control_set_rates(mp
->hw
, mi
->sta
, rates
);
779 minstrel_get_duration(int index
)
781 const struct mcs_group
*group
= &minstrel_mcs_groups
[index
/ MCS_GROUP_RATES
];
782 return group
->duration
[index
% MCS_GROUP_RATES
];
786 minstrel_get_sample_rate(struct minstrel_priv
*mp
, struct minstrel_ht_sta
*mi
)
788 struct minstrel_rate_stats
*mr
;
789 struct minstrel_mcs_group_data
*mg
;
790 unsigned int sample_dur
, sample_group
, cur_max_tp_streams
;
793 if (mi
->sample_wait
> 0) {
798 if (!mi
->sample_tries
)
801 sample_group
= mi
->sample_group
;
802 mg
= &mi
->groups
[sample_group
];
803 sample_idx
= sample_table
[mg
->column
][mg
->index
];
804 minstrel_next_sample_idx(mi
);
806 if (!(mg
->supported
& BIT(sample_idx
)))
809 mr
= &mg
->rates
[sample_idx
];
810 sample_idx
+= sample_group
* MCS_GROUP_RATES
;
813 * Sampling might add some overhead (RTS, no aggregation)
814 * to the frame. Hence, don't use sampling for the currently
817 if (sample_idx
== mi
->max_tp_rate
[0] ||
818 sample_idx
== mi
->max_tp_rate
[1] ||
819 sample_idx
== mi
->max_prob_rate
)
823 * Do not sample if the probability is already higher than 95%
824 * to avoid wasting airtime.
826 if (mr
->probability
> MINSTREL_FRAC(95, 100))
830 * Make sure that lower rates get sampled only occasionally,
831 * if the link is working perfectly.
834 cur_max_tp_streams
= minstrel_mcs_groups
[mi
->max_tp_rate
[0] /
835 MCS_GROUP_RATES
].streams
;
836 sample_dur
= minstrel_get_duration(sample_idx
);
837 if (sample_dur
>= minstrel_get_duration(mi
->max_tp_rate
[1]) &&
838 (cur_max_tp_streams
- 1 <
839 minstrel_mcs_groups
[sample_group
].streams
||
840 sample_dur
>= minstrel_get_duration(mi
->max_prob_rate
))) {
841 if (mr
->sample_skipped
< 20)
844 if (mi
->sample_slow
++ > 2)
853 minstrel_ht_check_cck_shortpreamble(struct minstrel_priv
*mp
,
854 struct minstrel_ht_sta
*mi
, bool val
)
856 u8 supported
= mi
->groups
[MINSTREL_CCK_GROUP
].supported
;
858 if (!supported
|| !mi
->cck_supported_short
)
861 if (supported
& (mi
->cck_supported_short
<< (val
* 4)))
864 supported
^= mi
->cck_supported_short
| (mi
->cck_supported_short
<< 4);
865 mi
->groups
[MINSTREL_CCK_GROUP
].supported
= supported
;
869 minstrel_ht_get_rate(void *priv
, struct ieee80211_sta
*sta
, void *priv_sta
,
870 struct ieee80211_tx_rate_control
*txrc
)
872 const struct mcs_group
*sample_group
;
873 struct ieee80211_tx_info
*info
= IEEE80211_SKB_CB(txrc
->skb
);
874 struct ieee80211_tx_rate
*rate
= &info
->status
.rates
[0];
875 struct minstrel_ht_sta_priv
*msp
= priv_sta
;
876 struct minstrel_ht_sta
*mi
= &msp
->ht
;
877 struct minstrel_priv
*mp
= priv
;
880 if (rate_control_send_low(sta
, priv_sta
, txrc
))
884 return mac80211_minstrel
.get_rate(priv
, sta
, &msp
->legacy
, txrc
);
886 info
->flags
|= mi
->tx_flags
;
887 minstrel_ht_check_cck_shortpreamble(mp
, mi
, txrc
->short_preamble
);
889 #ifdef CONFIG_MAC80211_DEBUGFS
890 if (mp
->fixed_rate_idx
!= -1)
894 /* Don't use EAPOL frames for sampling on non-mrr hw */
895 if (mp
->hw
->max_rates
== 1 &&
896 (info
->control
.flags
& IEEE80211_TX_CTRL_PORT_CTRL_PROTO
))
899 sample_idx
= minstrel_get_sample_rate(mp
, mi
);
904 if (mi
->total_packets
== ~0) {
905 mi
->total_packets
= 0;
906 mi
->sample_packets
= 0;
912 sample_group
= &minstrel_mcs_groups
[sample_idx
/ MCS_GROUP_RATES
];
913 info
->flags
|= IEEE80211_TX_CTL_RATE_CTRL_PROBE
;
916 if (sample_idx
/ MCS_GROUP_RATES
== MINSTREL_CCK_GROUP
) {
917 int idx
= sample_idx
% ARRAY_SIZE(mp
->cck_rates
);
918 rate
->idx
= mp
->cck_rates
[idx
];
923 rate
->idx
= sample_idx
% MCS_GROUP_RATES
+
924 (sample_group
->streams
- 1) * 8;
925 rate
->flags
= IEEE80211_TX_RC_MCS
| sample_group
->flags
;
929 minstrel_ht_update_cck(struct minstrel_priv
*mp
, struct minstrel_ht_sta
*mi
,
930 struct ieee80211_supported_band
*sband
,
931 struct ieee80211_sta
*sta
)
935 if (sband
->band
!= IEEE80211_BAND_2GHZ
)
938 if (!(mp
->hw
->flags
& IEEE80211_HW_SUPPORTS_HT_CCK_RATES
))
941 mi
->cck_supported
= 0;
942 mi
->cck_supported_short
= 0;
943 for (i
= 0; i
< 4; i
++) {
944 if (!rate_supported(sta
, sband
->band
, mp
->cck_rates
[i
]))
947 mi
->cck_supported
|= BIT(i
);
948 if (sband
->bitrates
[i
].flags
& IEEE80211_RATE_SHORT_PREAMBLE
)
949 mi
->cck_supported_short
|= BIT(i
);
952 mi
->groups
[MINSTREL_CCK_GROUP
].supported
= mi
->cck_supported
;
956 minstrel_ht_update_caps(void *priv
, struct ieee80211_supported_band
*sband
,
957 struct cfg80211_chan_def
*chandef
,
958 struct ieee80211_sta
*sta
, void *priv_sta
)
960 struct minstrel_priv
*mp
= priv
;
961 struct minstrel_ht_sta_priv
*msp
= priv_sta
;
962 struct minstrel_ht_sta
*mi
= &msp
->ht
;
963 struct ieee80211_mcs_info
*mcs
= &sta
->ht_cap
.mcs
;
964 u16 sta_cap
= sta
->ht_cap
.cap
;
970 /* fall back to the old minstrel for legacy stations */
971 if (!sta
->ht_cap
.ht_supported
)
974 BUILD_BUG_ON(ARRAY_SIZE(minstrel_mcs_groups
) !=
975 MINSTREL_MAX_STREAMS
* MINSTREL_STREAM_GROUPS
+ 1);
978 memset(mi
, 0, sizeof(*mi
));
981 mi
->stats_update
= jiffies
;
983 ack_dur
= ieee80211_frame_duration(sband
->band
, 10, 60, 1, 1, 0);
984 mi
->overhead
= ieee80211_frame_duration(sband
->band
, 0, 60, 1, 1, 0);
985 mi
->overhead
+= ack_dur
;
986 mi
->overhead_rtscts
= mi
->overhead
+ 2 * ack_dur
;
988 mi
->avg_ampdu_len
= MINSTREL_FRAC(1, 1);
990 /* When using MRR, sample more on the first attempt, without delay */
992 mi
->sample_count
= 16;
995 mi
->sample_count
= 8;
998 mi
->sample_tries
= 4;
1000 stbc
= (sta_cap
& IEEE80211_HT_CAP_RX_STBC
) >>
1001 IEEE80211_HT_CAP_RX_STBC_SHIFT
;
1002 mi
->tx_flags
|= stbc
<< IEEE80211_TX_CTL_STBC_SHIFT
;
1004 if (sta_cap
& IEEE80211_HT_CAP_LDPC_CODING
)
1005 mi
->tx_flags
|= IEEE80211_TX_CTL_LDPC
;
1007 for (i
= 0; i
< ARRAY_SIZE(mi
->groups
); i
++) {
1008 mi
->groups
[i
].supported
= 0;
1009 if (i
== MINSTREL_CCK_GROUP
) {
1010 minstrel_ht_update_cck(mp
, mi
, sband
, sta
);
1014 if (minstrel_mcs_groups
[i
].flags
& IEEE80211_TX_RC_SHORT_GI
) {
1015 if (minstrel_mcs_groups
[i
].flags
& IEEE80211_TX_RC_40_MHZ_WIDTH
) {
1016 if (!(sta_cap
& IEEE80211_HT_CAP_SGI_40
))
1019 if (!(sta_cap
& IEEE80211_HT_CAP_SGI_20
))
1024 if (minstrel_mcs_groups
[i
].flags
& IEEE80211_TX_RC_40_MHZ_WIDTH
&&
1025 sta
->bandwidth
< IEEE80211_STA_RX_BW_40
)
1028 /* Mark MCS > 7 as unsupported if STA is in static SMPS mode */
1029 if (sta
->smps_mode
== IEEE80211_SMPS_STATIC
&&
1030 minstrel_mcs_groups
[i
].streams
> 1)
1033 mi
->groups
[i
].supported
=
1034 mcs
->rx_mask
[minstrel_mcs_groups
[i
].streams
- 1];
1036 if (mi
->groups
[i
].supported
)
1043 /* create an initial rate table with the lowest supported rates */
1044 minstrel_ht_update_stats(mp
, mi
);
1045 minstrel_ht_update_rates(mp
, mi
);
1051 memset(&msp
->legacy
, 0, sizeof(msp
->legacy
));
1052 msp
->legacy
.r
= msp
->ratelist
;
1053 msp
->legacy
.sample_table
= msp
->sample_table
;
1054 return mac80211_minstrel
.rate_init(priv
, sband
, chandef
, sta
,
1059 minstrel_ht_rate_init(void *priv
, struct ieee80211_supported_band
*sband
,
1060 struct cfg80211_chan_def
*chandef
,
1061 struct ieee80211_sta
*sta
, void *priv_sta
)
1063 minstrel_ht_update_caps(priv
, sband
, chandef
, sta
, priv_sta
);
1067 minstrel_ht_rate_update(void *priv
, struct ieee80211_supported_band
*sband
,
1068 struct cfg80211_chan_def
*chandef
,
1069 struct ieee80211_sta
*sta
, void *priv_sta
,
1072 minstrel_ht_update_caps(priv
, sband
, chandef
, sta
, priv_sta
);
1076 minstrel_ht_alloc_sta(void *priv
, struct ieee80211_sta
*sta
, gfp_t gfp
)
1078 struct ieee80211_supported_band
*sband
;
1079 struct minstrel_ht_sta_priv
*msp
;
1080 struct minstrel_priv
*mp
= priv
;
1081 struct ieee80211_hw
*hw
= mp
->hw
;
1085 for (i
= 0; i
< IEEE80211_NUM_BANDS
; i
++) {
1086 sband
= hw
->wiphy
->bands
[i
];
1087 if (sband
&& sband
->n_bitrates
> max_rates
)
1088 max_rates
= sband
->n_bitrates
;
1091 msp
= kzalloc(sizeof(*msp
), gfp
);
1095 msp
->ratelist
= kzalloc(sizeof(struct minstrel_rate
) * max_rates
, gfp
);
1099 msp
->sample_table
= kmalloc(SAMPLE_COLUMNS
* max_rates
, gfp
);
1100 if (!msp
->sample_table
)
1106 kfree(msp
->ratelist
);
1113 minstrel_ht_free_sta(void *priv
, struct ieee80211_sta
*sta
, void *priv_sta
)
1115 struct minstrel_ht_sta_priv
*msp
= priv_sta
;
1117 kfree(msp
->sample_table
);
1118 kfree(msp
->ratelist
);
1123 minstrel_ht_alloc(struct ieee80211_hw
*hw
, struct dentry
*debugfsdir
)
1125 return mac80211_minstrel
.alloc(hw
, debugfsdir
);
1129 minstrel_ht_free(void *priv
)
1131 mac80211_minstrel
.free(priv
);
1134 static u32
minstrel_ht_get_expected_throughput(void *priv_sta
)
1136 struct minstrel_ht_sta_priv
*msp
= priv_sta
;
1137 struct minstrel_ht_sta
*mi
= &msp
->ht
;
1141 return mac80211_minstrel
.get_expected_throughput(priv_sta
);
1143 i
= mi
->max_tp_rate
[0] / MCS_GROUP_RATES
;
1144 j
= mi
->max_tp_rate
[0] % MCS_GROUP_RATES
;
1146 /* convert cur_tp from pkt per second in kbps */
1147 return mi
->groups
[i
].rates
[j
].cur_tp
* AVG_PKT_SIZE
* 8 / 1024;
1150 static const struct rate_control_ops mac80211_minstrel_ht
= {
1151 .name
= "minstrel_ht",
1152 .tx_status
= minstrel_ht_tx_status
,
1153 .get_rate
= minstrel_ht_get_rate
,
1154 .rate_init
= minstrel_ht_rate_init
,
1155 .rate_update
= minstrel_ht_rate_update
,
1156 .alloc_sta
= minstrel_ht_alloc_sta
,
1157 .free_sta
= minstrel_ht_free_sta
,
1158 .alloc
= minstrel_ht_alloc
,
1159 .free
= minstrel_ht_free
,
1160 #ifdef CONFIG_MAC80211_DEBUGFS
1161 .add_sta_debugfs
= minstrel_ht_add_sta_debugfs
,
1162 .remove_sta_debugfs
= minstrel_ht_remove_sta_debugfs
,
1164 .get_expected_throughput
= minstrel_ht_get_expected_throughput
,
1168 static void __init
init_sample_table(void)
1170 int col
, i
, new_idx
;
1171 u8 rnd
[MCS_GROUP_RATES
];
1173 memset(sample_table
, 0xff, sizeof(sample_table
));
1174 for (col
= 0; col
< SAMPLE_COLUMNS
; col
++) {
1175 prandom_bytes(rnd
, sizeof(rnd
));
1176 for (i
= 0; i
< MCS_GROUP_RATES
; i
++) {
1177 new_idx
= (i
+ rnd
[i
]) % MCS_GROUP_RATES
;
1178 while (sample_table
[col
][new_idx
] != 0xff)
1179 new_idx
= (new_idx
+ 1) % MCS_GROUP_RATES
;
1181 sample_table
[col
][new_idx
] = i
;
1187 rc80211_minstrel_ht_init(void)
1189 init_sample_table();
1190 return ieee80211_rate_control_register(&mac80211_minstrel_ht
);
1194 rc80211_minstrel_ht_exit(void)
1196 ieee80211_rate_control_unregister(&mac80211_minstrel_ht
);