package/kernel/mac80211/patches/subsys/343-mac80211-minstrel_ht-fix-max-probability-rate-select.patch

   1 From: Felix Fietkau <nbd@nbd.name>
   2 Date: Sat, 26 Dec 2020 19:09:08 +0100
   3 Subject: [PATCH] mac80211: minstrel_ht: fix max probability rate selection
   4
   5 - do not select rates faster than the max throughput rate if probability is lower
   6 - reset previous rate before sorting again
   7
   8 This ensures that the max prob rate gets set to a more reliable rate
   9
  10 Signed-off-by: Felix Fietkau <nbd@nbd.name>
  11 ---
  12
  13 --- a/net/mac80211/rc80211_minstrel_ht.c
  14 +++ b/net/mac80211/rc80211_minstrel_ht.c
  15 @@ -495,12 +495,13 @@ minstrel_ht_sort_best_tp_rates(struct mi
  16   * Find and set the topmost probability rate per sta and per group
  17   */
  18  static void
  19 -minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u16 index)
  20 +minstrel_ht_set_best_prob_rate(struct minstrel_ht_sta *mi, u16 *dest, u16 index)
  21  {
  22         struct minstrel_mcs_group_data *mg;
  23         struct minstrel_rate_stats *mrs;
  24         int tmp_group, tmp_idx, tmp_tp_avg, tmp_prob;
  25 -       int max_tp_group, cur_tp_avg, cur_group, cur_idx;
  26 +       int max_tp_group, max_tp_idx, max_tp_prob;
  27 +       int cur_tp_avg, cur_group, cur_idx;
  28         int max_gpr_group, max_gpr_idx;
  29         int max_gpr_tp_avg, max_gpr_prob;
  30
  31 @@ -509,18 +510,26 @@ minstrel_ht_set_best_prob_rate(struct mi
  32         mg = &mi->groups[index / MCS_GROUP_RATES];
  33         mrs = &mg->rates[index % MCS_GROUP_RATES];
  34
  35 -       tmp_group = mi->max_prob_rate / MCS_GROUP_RATES;
  36 -       tmp_idx = mi->max_prob_rate % MCS_GROUP_RATES;
  37 +       tmp_group = *dest / MCS_GROUP_RATES;
  38 +       tmp_idx = *dest % MCS_GROUP_RATES;
  39         tmp_prob = mi->groups[tmp_group].rates[tmp_idx].prob_avg;
  40         tmp_tp_avg = minstrel_ht_get_tp_avg(mi, tmp_group, tmp_idx, tmp_prob);
  41
  42         /* if max_tp_rate[0] is from MCS_GROUP max_prob_rate get selected from
  43          * MCS_GROUP as well as CCK_GROUP rates do not allow aggregation */
  44         max_tp_group = mi->max_tp_rate[0] / MCS_GROUP_RATES;
  45 +       max_tp_idx = mi->max_tp_rate[0] % MCS_GROUP_RATES;
  46 +       max_tp_prob = mi->groups[max_tp_group].rates[max_tp_idx].prob_avg;
  47 +
  48         if (minstrel_ht_is_legacy_group(index / MCS_GROUP_RATES) &&
  49             !minstrel_ht_is_legacy_group(max_tp_group))
  50                 return;
  51
  52 +       /* skip rates faster than max tp rate with lower prob */
  53 +       if (minstrel_get_duration(mi->max_tp_rate[0]) > minstrel_get_duration(index) &&
  54 +           mrs->prob_avg < max_tp_prob)
  55 +               return;
  56 +
  57         max_gpr_group = mg->max_group_prob_rate / MCS_GROUP_RATES;
  58         max_gpr_idx = mg->max_group_prob_rate % MCS_GROUP_RATES;
  59         max_gpr_prob = mi->groups[max_gpr_group].rates[max_gpr_idx].prob_avg;
  60 @@ -538,7 +547,7 @@ minstrel_ht_set_best_prob_rate(struct mi
  61                         mg->max_group_prob_rate = index;
  62         } else {
  63                 if (mrs->prob_avg > tmp_prob)
  64 -                       mi->max_prob_rate = index;
  65 +                       *dest = index;
  66                 if (mrs->prob_avg > max_gpr_prob)
  67                         mg->max_group_prob_rate = index;
  68         }
  69 @@ -816,7 +825,8 @@ minstrel_ht_update_stats(struct minstrel
  70         struct minstrel_rate_stats *mrs;
  71         int group, i, j, cur_prob;
  72         u16 tmp_mcs_tp_rate[MAX_THR_RATES], tmp_group_tp_rate[MAX_THR_RATES];
  73 -       u16 tmp_legacy_tp_rate[MAX_THR_RATES], index;
  74 +       u16 tmp_legacy_tp_rate[MAX_THR_RATES], tmp_max_prob_rate;
  75 +       u16 index;
  76         bool ht_supported = mi->sta->ht_cap.ht_supported;
  77
  78         mi->sample_mode = MINSTREL_SAMPLE_IDLE;
  79 @@ -863,6 +873,7 @@ minstrel_ht_update_stats(struct minstrel
  80         else
  81                 index = MINSTREL_OFDM_GROUP * MCS_GROUP_RATES;
  82
  83 +       tmp_max_prob_rate = index;
  84         for (j = 0; j < ARRAY_SIZE(tmp_mcs_tp_rate); j++)
  85                 tmp_mcs_tp_rate[j] = index;
  86
  87 @@ -903,9 +914,6 @@ minstrel_ht_update_stats(struct minstrel
  88                         /* Find max throughput rate set within a group */
  89                         minstrel_ht_sort_best_tp_rates(mi, index,
  90                                                        tmp_group_tp_rate);
  91 -
  92 -                       /* Find max probability rate per group and global */
  93 -                       minstrel_ht_set_best_prob_rate(mi, index);
  94                 }
  95
  96                 memcpy(mg->max_group_tp_rate, tmp_group_tp_rate,
  97 @@ -917,6 +925,27 @@ minstrel_ht_update_stats(struct minstrel
  98                                          tmp_legacy_tp_rate);
  99         memcpy(mi->max_tp_rate, tmp_mcs_tp_rate, sizeof(mi->max_tp_rate));
 100
 101 +       for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
 102 +               if (!mi->supported[group])
 103 +                       continue;
 104 +
 105 +               mg = &mi->groups[group];
 106 +               mg->max_group_prob_rate = MCS_GROUP_RATES * group;
 107 +
 108 +               for (i = 0; i < MCS_GROUP_RATES; i++) {
 109 +                       if (!(mi->supported[group] & BIT(i)))
 110 +                               continue;
 111 +
 112 +                       index = MCS_GROUP_RATES * group + i;
 113 +
 114 +                       /* Find max probability rate per group and global */
 115 +                       minstrel_ht_set_best_prob_rate(mi, &tmp_max_prob_rate,
 116 +                                                      index);
 117 +               }
 118 +       }
 119 +
 120 +       mi->max_prob_rate = tmp_max_prob_rate;
 121 +
 122         /* Try to increase robustness of max_prob_rate*/
 123         minstrel_ht_prob_rate_reduce_streams(mi);
 124