mac80211/minstrel_ht: avoid useless sampling of high-probability slower rates

Slow rates that have >95% success probability do not need to be
monitored continuously. When the channel conditions change rapidly, the
slow sampling results are useless anyway. When conditions change slowly,
they will be monitored by gradual downgrading of the actively used
rates. This patch slightly improves throughput under good conditions.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/rc80211_minstrel_ht.c

@@ -653,10 +653,10 @@ minstrel_get_sample_rate(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
 	if (sample_idx == mi->max_tp_rate)
 		return -1;
 	/*
-	 * When not using MRR, do not sample if the probability is already
+	 * Do not sample if the probability is already higher than 95%
-	 * higher than 95% to avoid wasting airtime
+	 * to avoid wasting airtime.
 	 */
-	if (!mp->has_mrr && (mr->probability > MINSTREL_FRAC(95, 100)))
+	if (mr->probability > MINSTREL_FRAC(95, 100))
 		return -1;
 
 	/*