mac80211: avoid sampling rates that are too slow, improves throughput

Signed-off-by: Felix Fietkau <nbd@nbd.name>
This commit is contained in:
Felix Fietkau 2018-03-03 18:51:49 +01:00
parent e72b2464b1
commit 11d70f0600

View file

@ -0,0 +1,40 @@
From: Felix Fietkau <nbd@nbd.name>
Date: Sat, 3 Mar 2018 18:48:58 +0100
Subject: [PATCH] mac80211: minstrel: do not sample rates 3 times slower than
max_prob_rate
These rates are highly unlikely to be used quickly, even if the link
deteriorates rapidly. This improves throughput in cases where CCK rates
are not reliable enough to be skipped entirely during sampling.
Sampling these rates regularly can cost a lot of airtime.
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -1004,10 +1004,13 @@ minstrel_get_sample_rate(struct minstrel
return -1;
/*
- * Do not sample if the probability is already higher than 95%
- * to avoid wasting airtime.
+ * Do not sample if the probability is already higher than 95%,
+ * or if the rate is 3 times slower than the current max probability
+ * rate, to avoid wasting airtime.
*/
- if (mrs->prob_ewma > MINSTREL_FRAC(95, 100))
+ sample_dur = minstrel_get_duration(sample_idx);
+ if (mrs->prob_ewma > MINSTREL_FRAC(95, 100) ||
+ minstrel_get_duration(mi->max_prob_rate) * 3 < sample_dur)
return -1;
/*
@@ -1017,7 +1020,6 @@ minstrel_get_sample_rate(struct minstrel
cur_max_tp_streams = minstrel_mcs_groups[tp_rate1 /
MCS_GROUP_RATES].streams;
- sample_dur = minstrel_get_duration(sample_idx);
if (sample_dur >= minstrel_get_duration(tp_rate2) &&
(cur_max_tp_streams - 1 <
minstrel_mcs_groups[sample_group].streams ||