[PATCH 2/2] mac80211: minstrel_ht: set A-MSDU tx limits based on selected max_prob_rate
From: Felix Fietkau <hidden>
Date: 2016-02-18 20:13:33
Subsystem:
mac80211, the rest · Maintainers:
Johannes Berg, Linus Torvalds
Prevents excessive A-MSDU aggregation at low data rates or bad conditions. Signed-off-by: Felix Fietkau <redacted> --- net/mac80211/rc80211_minstrel_ht.c | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+)
diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c
index 3928dbd..ad8859c 100644
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c@@ -882,6 +882,39 @@ minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, ratetbl->rate[offset].flags = flags; } +static int +minstrel_ht_get_max_amsdu_len(struct minstrel_ht_sta *mi) +{ + int group = mi->max_prob_rate / MCS_GROUP_RATES; + const struct mcs_group *g = &minstrel_mcs_groups[group]; + int rate = mi->max_prob_rate % MCS_GROUP_RATES; + + /* Disable A-MSDU if max_prob_rate is bad */ + if (mi->groups[group].rates[rate].prob_ewma < MINSTREL_FRAC(50, 100)) + return 1; + + /* If the rate is slower than single-stream MCS1, make A-MSDU limit small */ + if (g->duration[rate] > MCS_DURATION(1, 0, 52)) + return 500; + + /* + * If the rate is slower than single-stream MCS4, limit A-MSDU to usual + * data packet size + */ + if (g->duration[rate] > MCS_DURATION(1, 0, 104)) + return 1500; + + /* + * If the rate is slower than single-stream MCS7, limit A-MSDU to twice + * the usual data packet size + */ + if (g->duration[rate] > MCS_DURATION(1, 0, 260)) + return 3000; + + /* unlimited */ + return 0; +} + static void minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) {
@@ -906,6 +939,7 @@ minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) minstrel_ht_set_rate(mp, mi, rates, i++, mi->max_prob_rate); } + mi->sta->max_rc_amsdu_len = minstrel_ht_get_max_amsdu_len(mi); rates->rate[i].idx = -1; rate_control_set_rates(mp->hw, mi->sta, rates); }
--
2.2.2