package/kernel/mac80211/patches/subsys/305-mac80211-improve-AQL-tx-airtime-estimation.patch

   1 From: Felix Fietkau <nbd@nbd.name>
   2 Date: Fri, 24 Jul 2020 20:25:07 +0200
   3 Subject: [PATCH] mac80211: improve AQL tx airtime estimation
   4
   5 AQL does not take into account that most HT/VHT/HE traffic is A-MPDU aggregated.
   6 Because of that, the per-packet airtime overhead is vastly overestimated.
   7 Improve it by assuming an average aggregation length of 16 for non-legacy
   8 traffic if not using the VO AC queue.
   9 This should improve performance with high data rates, especially with multiple
  10 stations
  11
  12 Signed-off-by: Felix Fietkau <nbd@nbd.name>
  13 ---
  14
  15 --- a/net/mac80211/airtime.c
  16 +++ b/net/mac80211/airtime.c
  17 @@ -551,7 +551,7 @@ EXPORT_SYMBOL_GPL(ieee80211_calc_tx_airt
  18  u32 ieee80211_calc_expected_tx_airtime(struct ieee80211_hw *hw,
  19                                        struct ieee80211_vif *vif,
  20                                        struct ieee80211_sta *pubsta,
  21 -                                      int len)
  22 +                                      int len, bool ampdu)
  23  {
  24         struct ieee80211_supported_band *sband;
  25         struct ieee80211_chanctx_conf *conf;
  26 @@ -572,10 +572,26 @@ u32 ieee80211_calc_expected_tx_airtime(s
  27         if (pubsta) {
  28                 struct sta_info *sta = container_of(pubsta, struct sta_info,
  29                                                     sta);
  30 +               struct ieee80211_tx_rate *rate = &sta->tx_stats.last_rate;
  31 +               u32 airtime;
  32
  33 -               return ieee80211_calc_tx_airtime_rate(hw,
  34 -                                                     &sta->tx_stats.last_rate,
  35 -                                                     band, len);
  36 +               if (!(rate->flags & (IEEE80211_TX_RC_VHT_MCS |
  37 +                                    IEEE80211_TX_RC_MCS)))
  38 +                       ampdu = false;
  39 +
  40 +               /*
  41 +                * Assume that HT/VHT transmission on any AC except VO will
  42 +                * use aggregation. Since we don't have reliable reporting
  43 +                * of aggregation length, assume an average of 16.
  44 +                * This will not be very accurate, but much better than simply
  45 +                * assuming un-aggregated tx.
  46 +                */
  47 +               airtime = ieee80211_calc_tx_airtime_rate(hw, rate, band,
  48 +                                                        ampdu ? len * 16 : len);
  49 +               if (ampdu)
  50 +                       airtime /= 16;
  51 +
  52 +               return airtime;
  53         }
  54
  55         if (!conf)
  56 --- a/net/mac80211/ieee80211_i.h
  57 +++ b/net/mac80211/ieee80211_i.h
  58 @@ -2294,7 +2294,7 @@ extern const struct ethtool_ops ieee8021
  59  u32 ieee80211_calc_expected_tx_airtime(struct ieee80211_hw *hw,
  60                                        struct ieee80211_vif *vif,
  61                                        struct ieee80211_sta *pubsta,
  62 -                                      int len);
  63 +                                      int len, bool ampdu);
  64  #ifdef CPTCFG_MAC80211_NOINLINE
  65  #define debug_noinline noinline
  66  #else
  67 --- a/net/mac80211/tx.c
  68 +++ b/net/mac80211/tx.c
  69 @@ -3707,10 +3707,11 @@ encap_out:
  70
  71         if (vif &&
  72             wiphy_ext_feature_isset(local->hw.wiphy, NL80211_EXT_FEATURE_AQL)) {
  73 +               bool ampdu = txq->ac != IEEE80211_AC_VO;
  74                 u32 airtime;
  75
  76                 airtime = ieee80211_calc_expected_tx_airtime(hw, vif, txq->sta,
  77 -                                                            skb->len);
  78 +                                                            skb->len, ampdu);
  79                 if (airtime) {
  80                         airtime = ieee80211_info_set_tx_time_est(info, airtime);
  81                         ieee80211_sta_update_pending_airtime(local, tx.sta,