package/kernel/mac80211/patches/subsys/348-mac80211-minstrel_ht-reduce-the-need-to-sample-slowe.patch

   1 From: Felix Fietkau <nbd@nbd.name>
   2 Date: Fri, 22 Jan 2021 19:24:59 +0100
   3 Subject: [PATCH] mac80211: minstrel_ht: reduce the need to sample slower
   4  rates
   5
   6 In order to more gracefully be able to fall back to lower rates without too
   7 much throughput fluctuations, initialize all untested rates below tested ones
   8 to the maximum probabilty of higher rates.
   9 Usually this leads to untested lower rates getting initialized with a
  10 probability value of 100%, making them better candidates for fallback without
  11 having to rely on random probing
  12
  13 Signed-off-by: Felix Fietkau <nbd@nbd.name>
  14 ---
  15
  16 --- a/net/mac80211/rc80211_minstrel_ht.c
  17 +++ b/net/mac80211/rc80211_minstrel_ht.c
  18 @@ -791,14 +791,11 @@ minstrel_ht_calc_rate_stats(struct minst
  19         unsigned int cur_prob;
  20
  21         if (unlikely(mrs->attempts > 0)) {
  22 -               mrs->sample_skipped = 0;
  23                 cur_prob = MINSTREL_FRAC(mrs->success, mrs->attempts);
  24                 minstrel_filter_avg_add(&mrs->prob_avg,
  25                                         &mrs->prob_avg_1, cur_prob);
  26                 mrs->att_hist += mrs->attempts;
  27                 mrs->succ_hist += mrs->success;
  28 -       } else {
  29 -               mrs->sample_skipped++;
  30         }
  31
  32         mrs->last_success = mrs->success;
  33 @@ -851,7 +848,6 @@ minstrel_ht_update_stats(struct minstrel
  34                 mi->ampdu_packets = 0;
  35         }
  36
  37 -       mi->sample_slow = 0;
  38         mi->sample_count = 0;
  39
  40         if (mi->supported[MINSTREL_CCK_GROUP])
  41 @@ -882,6 +878,7 @@ minstrel_ht_update_stats(struct minstrel
  42         /* Find best rate sets within all MCS groups*/
  43         for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
  44                 u16 *tp_rate = tmp_mcs_tp_rate;
  45 +               u16 last_prob = 0;
  46
  47                 mg = &mi->groups[group];
  48                 if (!mi->supported[group])
  49 @@ -896,7 +893,7 @@ minstrel_ht_update_stats(struct minstrel
  50                 if (group == MINSTREL_CCK_GROUP && ht_supported)
  51                         tp_rate = tmp_legacy_tp_rate;
  52
  53 -               for (i = 0; i < MCS_GROUP_RATES; i++) {
  54 +               for (i = MCS_GROUP_RATES - 1; i >= 0; i--) {
  55                         if (!(mi->supported[group] & BIT(i)))
  56                                 continue;
  57
  58 @@ -905,6 +902,11 @@ minstrel_ht_update_stats(struct minstrel
  59                         mrs = &mg->rates[i];
  60                         mrs->retry_updated = false;
  61                         minstrel_ht_calc_rate_stats(mp, mrs);
  62 +
  63 +                       if (mrs->att_hist)
  64 +                               last_prob = max(last_prob, mrs->prob_avg);
  65 +                       else
  66 +                               mrs->prob_avg = max(last_prob, mrs->prob_avg);
  67                         cur_prob = mrs->prob_avg;
  68
  69                         if (minstrel_ht_get_tp_avg(mi, group, i, cur_prob) == 0)
  70 @@ -1469,13 +1471,9 @@ minstrel_get_sample_rate(struct minstrel
  71         if (sample_dur >= minstrel_get_duration(tp_rate2) &&
  72             (cur_max_tp_streams - 1 <
  73              minstrel_mcs_groups[sample_group].streams ||
  74 -            sample_dur >= minstrel_get_duration(mi->max_prob_rate))) {
  75 -               if (mrs->sample_skipped < 20)
  76 +            sample_dur >= minstrel_get_duration(mi->max_prob_rate)))
  77                         return -1;
  78
  79 -               if (mi->sample_slow++ > 2)
  80 -                       return -1;
  81 -       }
  82         mi->sample_tries--;
  83
  84         return sample_idx;
  85 --- a/net/mac80211/rc80211_minstrel_ht.h
  86 +++ b/net/mac80211/rc80211_minstrel_ht.h
  87 @@ -123,7 +123,6 @@ struct minstrel_rate_stats {
  88         u8 retry_count;
  89         u8 retry_count_rtscts;
  90
  91 -       u8 sample_skipped;
  92         bool retry_updated;
  93  };
  94
  95 @@ -179,7 +178,6 @@ struct minstrel_ht_sta {
  96         u8 sample_wait;
  97         u8 sample_tries;
  98         u8 sample_count;
  99 -       u8 sample_slow;
 100
 101         enum minstrel_sample_mode sample_mode;
 102         u16 sample_rate;