summaryrefslogtreecommitdiff
path: root/net/mac80211/rc80211_minstrel.h
diff options
context:
space:
mode:
authorFelix Fietkau <nbd@nbd.name>2016-12-14 22:47:00 +0300
committerJohannes Berg <johannes.berg@intel.com>2016-12-15 13:07:52 +0300
commit4f0bc9c61bae9c74ffcf5dbdbd241cbf0ec3a44e (patch)
tree663224eb02449823db0b3ccef21d8deb14867194 /net/mac80211/rc80211_minstrel.h
parent0217eefa64509d63fbe8d1205310bafb2355cf4d (diff)
downloadlinux-4f0bc9c61bae9c74ffcf5dbdbd241cbf0ec3a44e.tar.xz
mac80211: minstrel: store probability variance instead of standard deviation
This avoids the costly int_sqrt calls in the statistics update and moves it to the debugfs code instead. This also fixes an overflow in the previous standard deviation calculation. Signed-off-by: Thomas Huehn <thomas.huehn@evernet-eg.de> Signed-off-by: Felix Fietkau <nbd@nbd.name> Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/mac80211/rc80211_minstrel.h')
-rw-r--r--net/mac80211/rc80211_minstrel.h25
1 files changed, 14 insertions, 11 deletions
diff --git a/net/mac80211/rc80211_minstrel.h b/net/mac80211/rc80211_minstrel.h
index 03716fddaf24..ea86e6784154 100644
--- a/net/mac80211/rc80211_minstrel.h
+++ b/net/mac80211/rc80211_minstrel.h
@@ -36,21 +36,16 @@ minstrel_ewma(int old, int new, int weight)
}
/*
- * Perform EWMSD (Exponentially Weighted Moving Standard Deviation) calculation
+ * Perform EWMV (Exponentially Weighted Moving Variance) calculation
*/
static inline int
-minstrel_ewmsd(int old_ewmsd, int cur_prob, int prob_ewma, int weight)
+minstrel_ewmv(int old_ewmv, int cur_prob, int prob_ewma, int weight)
{
- int diff, incr, tmp_var;
+ int diff, incr;
- /* calculate exponential weighted moving variance */
- diff = MINSTREL_TRUNC((cur_prob - prob_ewma) * 1000000);
+ diff = cur_prob - prob_ewma;
incr = (EWMA_DIV - weight) * diff / EWMA_DIV;
- tmp_var = old_ewmsd * old_ewmsd;
- tmp_var = weight * (tmp_var + diff * incr / 1000000) / EWMA_DIV;
-
- /* return standard deviation */
- return (u16) int_sqrt(tmp_var);
+ return weight * (old_ewmv + MINSTREL_TRUNC(diff * incr)) / EWMA_DIV;
}
struct minstrel_rate_stats {
@@ -65,7 +60,7 @@ struct minstrel_rate_stats {
* prob_ewma - exponential weighted moving average of prob
* prob_ewmsd - exp. weighted moving standard deviation of prob */
unsigned int prob_ewma;
- u16 prob_ewmsd;
+ u16 prob_ewmv;
/* maximum retry counts */
u8 retry_count;
@@ -151,6 +146,14 @@ struct minstrel_debugfs_info {
char buf[];
};
+/* Get EWMSD (Exponentially Weighted Moving Standard Deviation) * 10 */
+static inline int
+minstrel_get_ewmsd10(struct minstrel_rate_stats *mrs)
+{
+ unsigned int ewmv = mrs->prob_ewmv;
+ return int_sqrt(MINSTREL_TRUNC(ewmv * 1000 * 1000));
+}
+
extern const struct rate_control_ops mac80211_minstrel;
void minstrel_add_sta_debugfs(void *priv, void *priv_sta, struct dentry *dir);
void minstrel_remove_sta_debugfs(void *priv, void *priv_sta);