On Wed, Jan 20, 2016 at 05:00:33PM +0100, Daniel Lezcano wrote: > + variance = stats_variance(&w->stats, mean); > + /* > + * We want to check the last interval is: > + * > + * mean - stddev < interval < mean + stddev > + * > + * That simplifies to: > + * > + * -stddev < interval - mean < stddev > + * > + * abs(interval - mean) < stddev > + * > + * The standard deviation is the sqrt of the variance: > + * > + * abs(interval - mean) < sqrt(variance) > + * > + * and we want to prevent to do an sqrt, so we square > + * the equation: > + * > + * (interval - mean)^2 < variance > + * > + * So if the latest value of the stats complies with > + * this condition, then the wakeup source is > + * considered predictable and can be used to predict > + * the next event. > + */ > + interval = w->stats.values[w->stats.w_ptr]; > + if ((u64)((interval - mean) * (interval - mean)) > variance) > + continue; > +
Cute :-) You could consider putting a simple 3 point median filter in front of stat_add() to get rid of the worst input noise. (I know, improving all this was a point for later)
