| From: Felix Fietkau <nbd@nbd.name> |
| Date: Sat, 6 Feb 2021 16:08:01 +0100 |
| Subject: [PATCH] mac80211: minstrel_ht: reduce fluctuations in rate |
| probability stats |
| |
| In some scenarios when there is a lot of fluctuation in packet error rates, |
| rate switching can be amplified when the statistics get skewed by time slots |
| with very few tries. |
| Make the input data to the moving average more smooth by adding the |
| success/attempts count from the last stats window as well. This has the |
| advantage of smoothing the data without introducing any extra lag to sampling |
| rates. |
| This significantly improves rate stability on a strong test link subjected to |
| periodic noise bursts generated with a SDR |
| |
| Signed-off-by: Felix Fietkau <nbd@nbd.name> |
| --- |
| |
| --- a/net/mac80211/rc80211_minstrel_ht.c |
| +++ b/net/mac80211/rc80211_minstrel_ht.c |
| @@ -769,7 +769,8 @@ minstrel_ht_calc_rate_stats(struct minst |
| unsigned int cur_prob; |
| |
| if (unlikely(mrs->attempts > 0)) { |
| - cur_prob = MINSTREL_FRAC(mrs->success, mrs->attempts); |
| + cur_prob = MINSTREL_FRAC(mrs->success + mrs->last_success, |
| + mrs->attempts + mrs->last_attempts); |
| minstrel_filter_avg_add(&mrs->prob_avg, |
| &mrs->prob_avg_1, cur_prob); |
| mrs->att_hist += mrs->attempts; |