From 918fe04b288b3784f4ca90d3dff12fc23dc2751f Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Thu, 3 Mar 2016 22:59:01 +0100 Subject: [PATCH] mac80211: minstrel_ht: set A-MSDU tx limits based on selected max_prob_rate Prevents excessive A-MSDU aggregation at low data rates or bad conditions. Signed-off-by: Felix Fietkau Signed-off-by: Johannes Berg --- net/mac80211/rc80211_minstrel_ht.c | 54 ++++++++++++++++++++++++++++++ 1 file changed, 54 insertions(+) diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c index 46ce08ed70b5..d77a9a842338 100644 --- a/net/mac80211/rc80211_minstrel_ht.c +++ b/net/mac80211/rc80211_minstrel_ht.c @@ -883,6 +883,59 @@ minstrel_ht_set_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi, ratetbl->rate[offset].flags = flags; } +static inline int +minstrel_ht_get_prob_ewma(struct minstrel_ht_sta *mi, int rate) +{ + int group = rate / MCS_GROUP_RATES; + rate %= MCS_GROUP_RATES; + return mi->groups[group].rates[rate].prob_ewma; +} + +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 1600; + + /* + * If the rate is slower than single-stream MCS7, or if the max throughput + * rate success probability is less than 75%, limit A-MSDU to twice the usual + * data packet size + */ + if (g->duration[rate] > MCS_DURATION(1, 0, 260) || + (minstrel_ht_get_prob_ewma(mi, mi->max_tp_rate[0]) < + MINSTREL_FRAC(75, 100))) + return 3200; + + /* + * HT A-MPDU limits maximum MPDU size under BA agreement to 4095 bytes. + * Since aggregation sessions are started/stopped without txq flush, use + * the limit here to avoid the complexity of having to de-aggregate + * packets in the queue. + */ + if (!mi->sta->vht_cap.vht_supported) + return IEEE80211_MAX_MPDU_LEN_HT_BA; + + /* unlimited */ + return 0; +} + static void minstrel_ht_update_rates(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) { @@ -907,6 +960,7 @@ 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); } -- 2.39.5