package/kernel/mac80211/patches/subsys/301-mac80211-minstrel-remove-divisions-in-tx-status-path.patch

   1 From: Felix Fietkau <nbd@nbd.name>
   2 Date: Sat, 28 Sep 2019 15:44:06 +0200
   3 Subject: [PATCH] mac80211: minstrel: remove divisions in tx status path
   4
   5 Use a slightly different threshold for downgrading spatial streams to
   6 make it easier to calculate without divisions.
   7 Slightly reduces CPU overhead.
   8
   9 Signed-off-by: Felix Fietkau <nbd@nbd.name>
  10 ---
  11
  12 --- a/net/mac80211/rc80211_minstrel.c
  13 +++ b/net/mac80211/rc80211_minstrel.c
  14 @@ -289,8 +289,7 @@ minstrel_tx_status(void *priv, struct ie
  15         if (mi->sample_deferred > 0)
  16                 mi->sample_deferred--;
  17
  18 -       if (time_after(jiffies, mi->last_stats_update +
  19 -                               (mp->update_interval * HZ) / 1000))
  20 +       if (time_after(jiffies, mi->last_stats_update + mp->update_interval))
  21                 minstrel_update_stats(mp, mi);
  22  }
  23
  24 --- a/net/mac80211/rc80211_minstrel_ht.c
  25 +++ b/net/mac80211/rc80211_minstrel_ht.c
  26 @@ -970,23 +970,21 @@ minstrel_ht_tx_status(void *priv, struct
  27                  */
  28                 rate = minstrel_get_ratestats(mi, mi->max_tp_rate[0]);
  29                 if (rate->attempts > 30 &&
  30 -                   MINSTREL_FRAC(rate->success, rate->attempts) <
  31 -                   MINSTREL_FRAC(20, 100)) {
  32 +                   rate->success < rate->attempts / 4) {
  33                         minstrel_downgrade_rate(mi, &mi->max_tp_rate[0], true);
  34                         update = true;
  35                 }
  36
  37                 rate2 = minstrel_get_ratestats(mi, mi->max_tp_rate[1]);
  38                 if (rate2->attempts > 30 &&
  39 -                   MINSTREL_FRAC(rate2->success, rate2->attempts) <
  40 -                   MINSTREL_FRAC(20, 100)) {
  41 +                   rate2->success < rate2->attempts / 4) {
  42                         minstrel_downgrade_rate(mi, &mi->max_tp_rate[1], false);
  43                         update = true;
  44                 }
  45         }
  46
  47         if (time_after(jiffies, mi->last_stats_update +
  48 -                               (mp->update_interval / 2 * HZ) / 1000)) {
  49 +                               mp->update_interval / 2)) {
  50                 update = true;
  51                 minstrel_ht_update_stats(mp, mi, true);
  52         }
  53 @@ -1666,7 +1664,7 @@ minstrel_ht_alloc(struct ieee80211_hw *h
  54                 mp->has_mrr = true;
  55
  56         mp->hw = hw;
  57 -       mp->update_interval = 100;
  58 +       mp->update_interval = HZ / 10;
  59
  60         minstrel_ht_init_cck_rates(mp);
  61