From f793c7eedd94fa41e8b969b18c4907335065a376 Mon Sep 17 00:00:00 2001 From: Felix Fietkau Date: Tue, 20 Aug 2019 11:54:47 +0200 Subject: [PATCH] mac80211: minstrel_ht: reduce unnecessary rate probing attempts On hardware with static fallback tables (e.g. mt76x2), rate probing attempts can be very expensive. On such devices, avoid sampling rates slower than the per-group max throughput rate, based on the assumption that the fallback table will take care of probing lower rates within that group if the higher rates fail. To further reduce unnecessary probing attempts, skip duplicate attempts on rates slower than the max throughput rate. Signed-off-by: Felix Fietkau Link: https://lore.kernel.org/r/20190820095449.45255-2-nbd@nbd.name Signed-off-by: Johannes Berg --- net/mac80211/rc80211_minstrel_ht.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c index ba230b037257..ad5da9a71da0 100644 --- a/net/mac80211/rc80211_minstrel_ht.c +++ b/net/mac80211/rc80211_minstrel_ht.c @@ -1059,6 +1059,21 @@ minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi) minstrel_get_duration(mi->max_prob_rate) * 3 < sample_dur) return -1; + + /* + * For devices with no configurable multi-rate retry, skip sampling + * below the per-group max throughput rate, and only use one sampling + * attempt per rate + */ + if (mp->hw->max_rates == 1 && + (minstrel_get_duration(mg->max_group_tp_rate[0]) < sample_dur || + mrs->attempts)) + return -1; + + /* Skip already sampled slow rates */ + if (sample_dur >= minstrel_get_duration(tp_rate1) && mrs->attempts) + return -1; + /* * Make sure that lower rates get sampled only occasionally, * if the link is working perfectly. -- 2.45.2