madwifi: put an upper limit on the amount of sampling that minstrel should do when

the link changes its status from very good to slightly bad. the previous version
of the patch could have resulted in erratic rate control behavior when there
was a lot of sampling backlog.

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@10921 3c298f89-4303-0410-b956-a3cf2f4a3e73

diff --git a/package/madwifi/patches/345-minstrel_sampling.patch b/package/madwifi/patches/345-minstrel_sampling.patch
index ea4c25f..3be5a8f 100644 (file)
--- a/package/madwifi/patches/345-minstrel_sampling.patch
+++ b/package/madwifi/patches/345-minstrel_sampling.patch
@@ -1,7 +1,7 @@
 Index: madwifi-trunk-r3314/ath/if_ath.c
 ===================================================================
---- madwifi-trunk-r3314.orig/ath/if_ath.c      2008-04-21 02:44:23.000000000 +0200
-+++ madwifi-trunk-r3314/ath/if_ath.c   2008-04-21 03:33:02.000000000 +0200
+--- madwifi-trunk-r3314.orig/ath/if_ath.c      2008-04-21 09:13:19.000000000 +0200
++++ madwifi-trunk-r3314/ath/if_ath.c   2008-04-23 01:15:49.000000000 +0200
 @@ -8095,6 +8095,7 @@
                ath_hal_setupxtxdesc(sc->sc_ah, ds, mrr.rate1, mrr.retries1,
                                     mrr.rate2, mrr.retries2,
@@ -12,8 +12,8 @@ Index: madwifi-trunk-r3314/ath/if_ath.c
  #ifndef ATH_SUPERG_FF
 Index: madwifi-trunk-r3314/ath/if_athvar.h
 ===================================================================
---- madwifi-trunk-r3314.orig/ath/if_athvar.h   2008-04-21 00:50:13.000000000 +0200
-+++ madwifi-trunk-r3314/ath/if_athvar.h        2008-04-21 03:31:48.000000000 +0200
+--- madwifi-trunk-r3314.orig/ath/if_athvar.h   2008-04-21 09:13:19.000000000 +0200
++++ madwifi-trunk-r3314/ath/if_athvar.h        2008-04-23 01:15:49.000000000 +0200
 @@ -446,6 +446,7 @@
        u_int16_t bf_flags;                             /* tx descriptor flags */
        u_int64_t bf_tsf;
@@ -24,18 +24,30 @@ Index: madwifi-trunk-r3314/ath/if_athvar.h
         *      multiple segments.
 Index: madwifi-trunk-r3314/ath_rate/minstrel/minstrel.c
 ===================================================================
---- madwifi-trunk-r3314.orig/ath_rate/minstrel/minstrel.c      2008-04-21 02:50:31.000000000 +0200
-+++ madwifi-trunk-r3314/ath_rate/minstrel/minstrel.c   2008-04-21 04:08:36.000000000 +0200
-@@ -336,7 +336,7 @@
+--- madwifi-trunk-r3314.orig/ath_rate/minstrel/minstrel.c      2008-04-21 09:13:19.000000000 +0200
++++ madwifi-trunk-r3314/ath_rate/minstrel/minstrel.c   2008-04-23 01:15:50.000000000 +0200
+@@ -333,15 +333,19 @@
+               if (sn->static_rate_ndx >= 0) {
+                           ndx = sn->static_rate_ndx;
+               } else {
++                      int delta;
                        sn->packet_count++;
                        sn->random_n = (sn->a * sn->random_n) + sn->b;
                        offset = sn->random_n & 0xf;
 -                      if ((((100 * sn->sample_count) / (sn->sample_count + sn->packet_count)) < ath_lookaround_rate) && (offset < 2)) {
-+                      if ((((100 * sn->sample_count) / (sn->packet_count ?: 1)) < ath_lookaround_rate) && (offset < 2)) {
++                      delta = (sn->packet_count * ath_lookaround_rate / 100) - sn->sample_count;
++                      if ((delta > 0) && (offset < 2)) {
                                sn->sample_count++;
                                sn->is_sampling = 1;
                                if (sn->packet_count >= 10000) {
-@@ -398,11 +398,14 @@
+                                       sn->sample_count = 0;
+                                       sn->packet_count = 0;
++                              } else if (delta > sn->num_rates * 2) {
++                                      sn->sample_count += ((delta - sn->num_rates * 2) * ath_lookaround_rate) / 100;
+                               }
+ 
+                               /* Don't look for slowest rate (i.e. slowest
+@@ -398,11 +402,14 @@
                if (sn->num_rates <= 0)
                        return;
  
@@ -52,7 +64,7 @@ Index: madwifi-trunk-r3314/ath_rate/minstrel/minstrel.c
                                rc1 = sn->max_tp_rate;
                } else {
                        rc1 = sn->max_tp_rate2;
-@@ -525,6 +528,9 @@
+@@ -525,6 +532,9 @@
                if (tries <= tries1)
                        return;
  
@@ -64,8 +76,8 @@ Index: madwifi-trunk-r3314/ath_rate/minstrel/minstrel.c
                tries = tries - tries1;
 Index: madwifi-trunk-r3314/net80211/ieee80211_rate.h
 ===================================================================
---- madwifi-trunk-r3314.orig/net80211/ieee80211_rate.h 2008-01-31 03:29:42.000000000 +0100
-+++ madwifi-trunk-r3314/net80211/ieee80211_rate.h      2008-04-21 03:30:25.000000000 +0200
+--- madwifi-trunk-r3314.orig/net80211/ieee80211_rate.h 2008-04-21 09:11:19.000000000 +0200
++++ madwifi-trunk-r3314/net80211/ieee80211_rate.h      2008-04-21 09:13:19.000000000 +0200
 @@ -87,6 +87,7 @@
        int retries2;
        int rate3;