mac80211: add rate control rewrite and enhance the performance of the minstrel algori...

[openwrt/svn-archive/archive.git] / package / mac80211 / patches / 426-minstrel_performance.patch

diff --git a/package/mac80211/patches/426-minstrel_performance.patch b/package/mac80211/patches/426-minstrel_performance.patch
new file mode 100644 (file)
index 0000000..7b95163
--- /dev/null
+++ b/package/mac80211/patches/426-minstrel_performance.patch
@@ -0,0 +1,100 @@
+This patch enhances minstrel's performance for non-MRR setups,
+by preventing it from sampling slower rates with >95% success
+probability and by putting at least 1 non-sample frame between
+several sample frames.
+
+Signed-off-by: Felix Fietkau <nbd@openwrt.org>
+
+--- a/net/mac80211/rc80211_minstrel.c
++++ b/net/mac80211/rc80211_minstrel.c
+@@ -126,7 +126,9 @@ minstrel_update_stats(struct minstrel_pr
+                       mr->adjusted_retry_count = mr->retry_count >> 1;
+                       if (mr->adjusted_retry_count > 2)
+                               mr->adjusted_retry_count = 2;
++                      mr->sample_limit = 4;
+               } else {
++                      mr->sample_limit = -1;
+                       mr->adjusted_retry_count = mr->retry_count;
+               }
+               if (!mr->adjusted_retry_count)
+@@ -265,7 +267,8 @@ minstrel_get_rate(void *priv, struct iee
+                       (mi->sample_count + mi->sample_deferred / 2);
+ 
+       /* delta > 0: sampling required */
+-      if (delta > 0) {
++      if ((delta > 0) && (mrr || !mi->prev_sample)) {
++              struct minstrel_rate *msr;
+               if (mi->packet_count >= 10000) {
+                       mi->sample_deferred = 0;
+                       mi->sample_count = 0;
+@@ -284,13 +287,20 @@ minstrel_get_rate(void *priv, struct iee
+               }
+ 
+               sample_ndx = minstrel_get_next_sample(mi);
++              msr = &mi->r[sample_ndx];
+               sample = true;
+-              sample_slower = mrr && (mi->r[sample_ndx].perfect_tx_time >
++              sample_slower = mrr && (msr->perfect_tx_time >
+                       mi->r[ndx].perfect_tx_time);
+ 
+               if (!sample_slower) {
+-                      ndx = sample_ndx;
+-                      mi->sample_count++;
++                      if (msr->sample_limit != 0) {
++                              ndx = sample_ndx;
++                              mi->sample_count++;
++                              if (msr->sample_limit > 0)
++                                      msr->sample_limit--;
++                      } else {
++                              sample = false;
++                      }
+               } else {
+                       /* Only use IEEE80211_TX_CTL_RATE_CTRL_PROBE to mark
+                        * packets that have the sampling rate deferred to the
+@@ -302,10 +312,20 @@ minstrel_get_rate(void *priv, struct iee
+                       mi->sample_deferred++;
+               }
+       }
++      mi->prev_sample = sample;
++
++      /* If we're not using MRR and the sampling rate already
++       * has a probability of >95%, we shouldn't be attempting
++       * to use it, as this only wastes precious airtime */
++      if (!mrr && sample && (mi->r[ndx].probability > 17100))
++              ndx = mi->max_tp_rate;
++
+       ar[0].idx = mi->r[ndx].rix;
+       ar[0].count = minstrel_get_retry_count(&mi->r[ndx], info);
+ 
+       if (!mrr) {
++              if (!sample)
++                      ar[0].count = mp->max_retry;
+               ar[1].idx = mi->lowest_rix;
+               ar[1].count = mp->max_retry;
+               return;
+@@ -401,6 +421,7 @@ minstrel_rate_init(void *priv, struct ie
+ 
+               /* calculate maximum number of retransmissions before
+                * fallback (based on maximum segment size) */
++              mr->sample_limit = -1;
+               mr->retry_count = 1;
+               mr->retry_count_cts = 1;
+               mr->retry_count_rtscts = 1;
+--- a/net/mac80211/rc80211_minstrel.h
++++ b/net/mac80211/rc80211_minstrel.h
+@@ -16,6 +16,7 @@ struct minstrel_rate {
+       unsigned int perfect_tx_time;
+       unsigned int ack_time;
+ 
++      int sample_limit;
+       unsigned int retry_count;
+       unsigned int retry_count_cts;
+       unsigned int retry_count_rtscts;
+@@ -57,6 +58,7 @@ struct minstrel_sta_info {
+ 
+       int n_rates;
+       struct minstrel_rate *r;
++      bool prev_sample;
+ 
+       /* sampling table */
+       u8 *sample_table;