mac80211/minstrel_ht: improve max_prob_rate selection

max_prob_rate should be selected to be very reliable, however limiting
it to single-stream on 3-stream devices is a bit much.
Allow max_prob_rate to use one stream less than the max_tp_rate.

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

diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c
index 0b5cdd94d4f08b60e3e43f62e014a85d12ab2ea4..6c735e0d66a31e7d83bb1cb75a8deb6b51964dd5 100644 (file)
--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -246,6 +246,7 @@ minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
        struct minstrel_rate_stats *mr;
        int cur_prob, cur_prob_tp, cur_tp, cur_tp2;
        int group, i, index;
+       int prob_max_streams = 1;
 
        if (mi->ampdu_packets > 0) {
                mi->avg_ampdu_len = minstrel_ewma(mi->avg_ampdu_len,
@@ -323,20 +324,13 @@ minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
                if (!mg->supported)
                        continue;
 
-               mr = minstrel_get_ratestats(mi, mg->max_prob_rate);
-               if (cur_prob_tp < mr->cur_tp &&
-                   minstrel_mcs_groups[group].streams == 1) {
-                       mi->max_prob_rate = mg->max_prob_rate;
-                       cur_prob = mr->cur_prob;
-                       cur_prob_tp = mr->cur_tp;
-               }
-
                mr = minstrel_get_ratestats(mi, mg->max_tp_rate);
                if (cur_tp < mr->cur_tp) {
                        mi->max_tp_rate2 = mi->max_tp_rate;
                        cur_tp2 = cur_tp;
                        mi->max_tp_rate = mg->max_tp_rate;
                        cur_tp = mr->cur_tp;
+                       prob_max_streams = minstrel_mcs_groups[group].streams - 1;
                }
 
                mr = minstrel_get_ratestats(mi, mg->max_tp_rate2);
@@ -346,6 +340,23 @@ minstrel_ht_update_stats(struct minstrel_priv *mp, struct minstrel_ht_sta *mi)
                }
        }
 
+       if (prob_max_streams < 1)
+               prob_max_streams = 1;
+
+       for (group = 0; group < ARRAY_SIZE(minstrel_mcs_groups); group++) {
+               mg = &mi->groups[group];
+               if (!mg->supported)
+                       continue;
+               mr = minstrel_get_ratestats(mi, mg->max_prob_rate);
+               if (cur_prob_tp < mr->cur_tp &&
+                   minstrel_mcs_groups[group].streams <= prob_max_streams) {
+                       mi->max_prob_rate = mg->max_prob_rate;
+                       cur_prob = mr->cur_prob;
+                       cur_prob_tp = mr->cur_tp;
+               }
+       }
+
+
        mi->stats_update = jiffies;
 }