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

1 files changed, 24 insertions, 12 deletions

diff --git a/package/madwifi/patches/345-minstrel_sampling.patch b/package/madwifi/patches/345-minstrel_sampling.patch
index ea4c25f3ad..3be5a8fee3 100644
--- 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;