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>

1 files changed, 19 insertions, 8 deletions

diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c
index 0b5cdd94d4f0..6c735e0d66a3 100644
--- 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;
 }