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 ea4c25f3ada0dfc5fb18614bb14580b74508b7d6..3be5a8fee3fb22ddf44a315d3ebe0476a012ee12 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;