package/kernel/mac80211/patches/subsys/351-mac80211-minstrel_ht-remove-sample-rate-switching-co.patch

   1 From: Felix Fietkau <nbd@nbd.name>
   2 Date: Sat, 23 Jan 2021 07:18:26 +0100
   3 Subject: [PATCH] mac80211: minstrel_ht: remove sample rate switching code for
   4  constrained devices
   5
   6 This was added to mitigate the effects of too much sampling on devices that
   7 use a static global fallback table instead of configurable multi-rate retry.
   8 Now that the sampling algorithm is improved, this code path no longer performs
   9 any better than the standard probing on affected devices.
  10
  11 Signed-off-by: Felix Fietkau <nbd@nbd.name>
  12 ---
  13
  14 --- a/net/mac80211/rc80211_minstrel_ht.c
  15 +++ b/net/mac80211/rc80211_minstrel_ht.c
  16 @@ -648,27 +648,6 @@ __minstrel_ht_get_sample_rate(struct min
  17         return 0;
  18  }
  19
  20 -static void
  21 -minstrel_ht_rate_sample_switch(struct minstrel_priv *mp,
  22 -                              struct minstrel_ht_sta *mi)
  23 -{
  24 -       u16 rate;
  25 -
  26 -       /*
  27 -        * Use rate switching instead of probing packets for devices with
  28 -        * little control over retry fallback behavior
  29 -        */
  30 -       if (mp->hw->max_rates > 1)
  31 -               return;
  32 -
  33 -       rate = __minstrel_ht_get_sample_rate(mi, MINSTREL_SAMPLE_TYPE_INC);
  34 -       if (!rate)
  35 -               return;
  36 -
  37 -       mi->sample_rate = rate;
  38 -       mi->sample_mode = MINSTREL_SAMPLE_ACTIVE;
  39 -}
  40 -
  41  static inline int
  42  minstrel_ewma(int old, int new, int weight)
  43  {
  44 @@ -1012,8 +991,7 @@ minstrel_ht_refill_sample_rates(struct m
  45   *    higher throughput rates, even if the probablity is a bit lower
  46   */
  47  static void
  48 -minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi,
  49 -                        bool sample)
  50 +minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
  51  {
  52         struct minstrel_mcs_group_data *mg;
  53         struct minstrel_rate_stats *mrs;
  54 @@ -1023,18 +1001,6 @@ minstrel_ht_update_stats(struct minstrel
  55         u16 index;
  56         bool ht_supported = mi->sta->ht_cap.ht_supported;
  57
  58 -       mi->sample_mode = MINSTREL_SAMPLE_IDLE;
  59 -
  60 -       if (sample) {
  61 -               mi->total_packets_cur = mi->total_packets -
  62 -                                       mi->total_packets_last;
  63 -               mi->total_packets_last = mi->total_packets;
  64 -       }
  65 -       if (!mp->sample_switch)
  66 -               sample = false;
  67 -       if (mi->total_packets_cur < SAMPLE_SWITCH_THR && mp->sample_switch != 1)
  68 -           sample = false;
  69 -
  70         if (mi->ampdu_packets > 0) {
  71                 if (!ieee80211_hw_check(mp->hw, TX_STATUS_NO_AMPDU_LEN))
  72                         mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
  73 @@ -1148,16 +1114,12 @@ minstrel_ht_update_stats(struct minstrel
  74         minstrel_ht_prob_rate_reduce_streams(mi);
  75         minstrel_ht_refill_sample_rates(mi);
  76
  77 -       if (sample)
  78 -               minstrel_ht_rate_sample_switch(mp, mi);
  79 -
  80  #ifdef CPTCFG_MAC80211_DEBUGFS
  81         /* use fixed index if set */
  82         if (mp->fixed_rate_idx != -1) {
  83                 for (i = 0; i < 4; i++)
  84                         mi->max_tp_rate[i] = mp->fixed_rate_idx;
  85                 mi->max_prob_rate = mp->fixed_rate_idx;
  86 -               mi->sample_mode = MINSTREL_SAMPLE_IDLE;
  87         }
  88  #endif
  89
  90 @@ -1247,11 +1209,10 @@ minstrel_ht_tx_status(void *priv, struct
  91         struct ieee80211_tx_info *info = st->info;
  92         struct minstrel_ht_sta *mi = priv_sta;
  93         struct ieee80211_tx_rate *ar = info->status.rates;
  94 -       struct minstrel_rate_stats *rate, *rate2, *rate_sample = NULL;
  95 +       struct minstrel_rate_stats *rate, *rate2;
  96         struct minstrel_priv *mp = priv;
  97         u32 update_interval = mp->update_interval;
  98         bool last, update = false;
  99 -       bool sample_status = false;
 100         int i;
 101
 102         /* This packet was aggregated but doesn't carry status info */
 103 @@ -1278,49 +1239,18 @@ minstrel_ht_tx_status(void *priv, struct
 104         mi->ampdu_packets++;
 105         mi->ampdu_len += info->status.ampdu_len;
 106
 107 -       if (mi->sample_mode != MINSTREL_SAMPLE_IDLE)
 108 -               rate_sample = minstrel_get_ratestats(mi, mi->sample_rate);
 109 -
 110         last = !minstrel_ht_txstat_valid(mp, mi, &ar[0]);
 111         for (i = 0; !last; i++) {
 112                 last = (i == IEEE80211_TX_MAX_RATES - 1) ||
 113                        !minstrel_ht_txstat_valid(mp, mi, &ar[i + 1]);
 114
 115                 rate = minstrel_ht_get_stats(mp, mi, &ar[i]);
 116 -               if (rate == rate_sample)
 117 -                       sample_status = true;
 118 -
 119                 if (last)
 120                         rate->success += info->status.ampdu_ack_len;
 121
 122                 rate->attempts += ar[i].count * info->status.ampdu_len;
 123         }
 124
 125 -       switch (mi->sample_mode) {
 126 -       case MINSTREL_SAMPLE_IDLE:
 127 -               if (mp->hw->max_rates > 1 ||
 128 -                    mi->total_packets_cur < SAMPLE_SWITCH_THR)
 129 -                       update_interval /= 2;
 130 -               break;
 131 -
 132 -       case MINSTREL_SAMPLE_ACTIVE:
 133 -               if (!sample_status)
 134 -                       break;
 135 -
 136 -               mi->sample_mode = MINSTREL_SAMPLE_PENDING;
 137 -               update = true;
 138 -               break;
 139 -
 140 -       case MINSTREL_SAMPLE_PENDING:
 141 -               if (sample_status)
 142 -                       break;
 143 -
 144 -               update = true;
 145 -               minstrel_ht_update_stats(mp, mi, false);
 146 -               break;
 147 -       }
 148 -
 149 -
 150         if (mp->hw->max_rates > 1) {
 151                 /*
 152                  * check for sudden death of spatial multiplexing,
 153 @@ -1343,7 +1273,7 @@ minstrel_ht_tx_status(void *priv, struct
 154
 155         if (time_after(jiffies, mi->last_stats_update + update_interval)) {
 156                 update = true;
 157 -               minstrel_ht_update_stats(mp, mi, true);
 158 +               minstrel_ht_update_stats(mp, mi);
 159         }
 160
 161         if (update)
 162 @@ -1522,18 +1452,14 @@ static void
 163  minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
 164  {
 165         struct ieee80211_sta_rates *rates;
 166 -       u16 first_rate = mi->max_tp_rate[0];
 167         int i = 0;
 168
 169 -       if (mi->sample_mode == MINSTREL_SAMPLE_ACTIVE)
 170 -               first_rate = mi->sample_rate;
 171 -
 172         rates = kzalloc(sizeof(*rates), GFP_ATOMIC);
 173         if (!rates)
 174                 return;
 175
 176         /* Start with max_tp_rate[0] */
 177 -       minstrel_ht_set_rate(mp, mi, rates, i++, first_rate);
 178 +       minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_tp_rate[0]);
 179
 180         if (mp->hw->max_rates >= 3) {
 181                 /* At least 3 tx rates supported, use max_tp_rate[1] next */
 182 @@ -1592,11 +1518,6 @@ minstrel_ht_get_rate(void *priv, struct
 183             (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
 184                 return;
 185
 186 -       if (mp->hw->max_rates == 1 && mp->sample_switch &&
 187 -           (mi->total_packets_cur >= SAMPLE_SWITCH_THR ||
 188 -            mp->sample_switch == 1))
 189 -               return;
 190 -
 191         if (time_is_before_jiffies(mi->sample_time))
 192                 return;
 193
 194 @@ -1810,7 +1731,7 @@ minstrel_ht_update_caps(void *priv, stru
 195         minstrel_ht_update_ofdm(mp, mi, sband, sta);
 196
 197         /* create an initial rate table with the lowest supported rates */
 198 -       minstrel_ht_update_stats(mp, mi, true);
 199 +       minstrel_ht_update_stats(mp, mi);
 200         minstrel_ht_update_rates(mp, mi);
 201  }
 202
 203 @@ -1926,8 +1847,6 @@ minstrel_ht_alloc(struct ieee80211_hw *h
 204         if (!mp)
 205                 return NULL;
 206
 207 -       mp->sample_switch = -1;
 208 -
 209         /* contention window settings
 210          * Just an approximation. Using the per-queue values would complicate
 211          * the calculations and is probably unnecessary */
 212 @@ -1947,7 +1866,7 @@ minstrel_ht_alloc(struct ieee80211_hw *h
 213                 mp->has_mrr = true;
 214
 215         mp->hw = hw;
 216 -       mp->update_interval = HZ / 10;
 217 +       mp->update_interval = HZ / 20;
 218
 219         minstrel_ht_init_cck_rates(mp);
 220         for (i = 0; i < ARRAY_SIZE(mp->hw->wiphy->bands); i++)
 221 @@ -1965,8 +1884,6 @@ static void minstrel_ht_add_debugfs(stru
 222         mp->fixed_rate_idx = (u32) -1;
 223         debugfs_create_u32("fixed_rate_idx", S_IRUGO | S_IWUGO, debugfsdir,
 224                            &mp->fixed_rate_idx);
 225 -       debugfs_create_u32("sample_switch", S_IRUGO | S_IWUSR, debugfsdir,
 226 -                          &mp->sample_switch);
 227  }
 228  #endif
 229
 230 --- a/net/mac80211/rc80211_minstrel_ht.h
 231 +++ b/net/mac80211/rc80211_minstrel_ht.h
 232 @@ -75,7 +75,6 @@
 233  struct minstrel_priv {
 234         struct ieee80211_hw *hw;
 235         bool has_mrr;
 236 -       u32 sample_switch;
 237         unsigned int cw_min;
 238         unsigned int cw_max;
 239         unsigned int max_retry;
 240 @@ -147,12 +146,6 @@ struct minstrel_mcs_group_data {
 241         struct minstrel_rate_stats rates[MCS_GROUP_RATES];
 242  };
 243
 244 -enum minstrel_sample_mode {
 245 -       MINSTREL_SAMPLE_IDLE,
 246 -       MINSTREL_SAMPLE_ACTIVE,
 247 -       MINSTREL_SAMPLE_PENDING,
 248 -};
 249 -
 250  struct minstrel_sample_category {
 251         u8 sample_group;
 252         u16 sample_rates[MINSTREL_SAMPLE_RATES];
 253 @@ -182,23 +175,19 @@ struct minstrel_ht_sta {
 254         unsigned int overhead_legacy;
 255         unsigned int overhead_legacy_rtscts;
 256
 257 -       unsigned int total_packets_last;
 258 -       unsigned int total_packets_cur;
 259         unsigned int total_packets;
 260         unsigned int sample_packets;
 261
 262         /* tx flags to add for frames for this sta */
 263         u32 tx_flags;
 264
 265 -       unsigned long sample_time;
 266 -       struct minstrel_sample_category sample[__MINSTREL_SAMPLE_TYPE_MAX];
 267 +       u8 band;
 268
 269         u8 sample_seq;
 270 -
 271 -       enum minstrel_sample_mode sample_mode;
 272         u16 sample_rate;
 273
 274 -       u8 band;
 275 +       unsigned long sample_time;
 276 +       struct minstrel_sample_category sample[__MINSTREL_SAMPLE_TYPE_MAX];
 277
 278         /* Bitfield of supported MCS rates of all groups */
 279         u16 supported[MINSTREL_GROUPS_NB];