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authorThomas Huehn <thomas@net.t-labs.tu-berlin.de>2013-03-05 02:30:05 +0400
committerJohannes Berg <johannes.berg@intel.com>2013-03-06 19:36:09 +0400
commitf744bf81f7501d03f45ba23f9cf947abc3b422c9 (patch)
tree365aa54da77095cc1e31fdf63a6d51669633f0c0 /net/mac80211/rc80211_minstrel.c
parent1e9c27df7b4a59f2269b9c88a5cef1e9018e77f6 (diff)
downloadlinux-f744bf81f7501d03f45ba23f9cf947abc3b422c9.tar.xz
mac80211: add lowest rate into minstrel's random rate sampling table
While minstrel bootstraps and fills the success probabilities of each rate the lowest rate has typically a very high success probability (often 100% in our tests). Its statistics are never updated but considered to setup the mrr chain. In our tests we see that especially the 3rd mrr stage (which is that rate providing highest success probability) is filled with the lowest rate because its initial high sucess probability is never updated. By design the 4th mrr stage is filled with the lowest rate so often 3rd and 4th mrr stage are equal. This patch follows minstrels general approach of assuming as little as possible about rate dependencies. Consequently we include the lowest rate into the random sampling table to get balanced up-to-date statistics of all rates and therefore balanced decisions. Acked-by: Felix Fietkau <nbd@openwrt.org> Signed-off-by: Thomas Huehn <thomas@net.t-labs.tu-berlin.de> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/mac80211/rc80211_minstrel.c')
-rw-r--r--net/mac80211/rc80211_minstrel.c20
1 files changed, 7 insertions, 13 deletions
diff --git a/net/mac80211/rc80211_minstrel.c b/net/mac80211/rc80211_minstrel.c
index aa59f2962c38..5c0f5327c77f 100644
--- a/net/mac80211/rc80211_minstrel.c
+++ b/net/mac80211/rc80211_minstrel.c
@@ -55,7 +55,6 @@
#include "rate.h"
#include "rc80211_minstrel.h"
-#define SAMPLE_COLUMNS 10
#define SAMPLE_TBL(_mi, _idx, _col) \
_mi->sample_table[(_idx * SAMPLE_COLUMNS) + _col]
@@ -210,7 +209,7 @@ minstrel_get_next_sample(struct minstrel_sta_info *mi)
unsigned int sample_ndx;
sample_ndx = SAMPLE_TBL(mi, mi->sample_row, mi->sample_column);
mi->sample_row++;
- if ((int) mi->sample_row > (mi->n_rates - 2)) {
+ if ((int) mi->sample_row >= mi->n_rates) {
mi->sample_row = 0;
mi->sample_column++;
if (mi->sample_column >= SAMPLE_COLUMNS)
@@ -370,26 +369,21 @@ static void
init_sample_table(struct minstrel_sta_info *mi)
{
unsigned int i, col, new_idx;
- unsigned int n_srates = mi->n_rates - 1;
u8 rnd[8];
mi->sample_column = 0;
mi->sample_row = 0;
- memset(mi->sample_table, 0, SAMPLE_COLUMNS * mi->n_rates);
+ memset(mi->sample_table, 0xff, SAMPLE_COLUMNS * mi->n_rates);
for (col = 0; col < SAMPLE_COLUMNS; col++) {
- for (i = 0; i < n_srates; i++) {
+ for (i = 0; i < mi->n_rates; i++) {
get_random_bytes(rnd, sizeof(rnd));
- new_idx = (i + rnd[i & 7]) % n_srates;
+ new_idx = (i + rnd[i & 7]) % mi->n_rates;
- while (SAMPLE_TBL(mi, new_idx, col) != 0)
- new_idx = (new_idx + 1) % n_srates;
+ while (SAMPLE_TBL(mi, new_idx, col) != 0xff)
+ new_idx = (new_idx + 1) % mi->n_rates;
- /* Don't sample the slowest rate (i.e. slowest base
- * rate). We must presume that the slowest rate works
- * fine, or else other management frames will also be
- * failing and the link will break */
- SAMPLE_TBL(mi, new_idx, col) = i + 1;
+ SAMPLE_TBL(mi, new_idx, col) = i;
}
}
}