xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

mac80211: rc80211_minstrel: remove variance / stddev calculation

Browse Source 
When there are few packets (e.g. for sampling attempts), the exponentially
weighted variance is usually vastly overestimated, making the resulting data
essentially useless. As far as I know, there has not been any practical use
for this, so let's not waste any cycles on it.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Felix Fietkau
2018-10-06 19:35:07 +02:00
committed by Johannes Berg
parent f4ec7cb0f9
commit 506dbf90c1
4 changed files with 9 additions and 51 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
net/mac80211/rc80211_minstrel.h
View File

@@ -35,19 +35,6 @@ minstrel_ewma(int old, int new, int weight)
return old + incr;
}
/*
* Perform EWMV (Exponentially Weighted Moving Variance) calculation
*/
static inline int
minstrel_ewmv(int old_ewmv, int cur_prob, int prob_ewma, int weight)
{
int diff, incr;
diff = cur_prob - prob_ewma;
incr = (EWMA_DIV - weight) * diff / EWMA_DIV;
return weight * (old_ewmv + MINSTREL_TRUNC(diff * incr)) / EWMA_DIV;
}
struct minstrel_rate_stats {
/* current / last sampling period attempts/success counters */
u16 attempts, last_attempts;
@@ -56,11 +43,8 @@ struct minstrel_rate_stats {
/* total attempts/success counters */
u32 att_hist, succ_hist;
/* statistis of packet delivery probability
* prob_ewma - exponential weighted moving average of prob
* prob_ewmsd - exp. weighted moving standard deviation of prob */
/* prob_ewma - exponential weighted moving average of prob */
u16 prob_ewma;
u16 prob_ewmv;
/* maximum retry counts */
u8 retry_count;
@@ -140,14 +124,6 @@ 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);