> + if (unlikely(first_sample)) {
> + first_sample = false;
> +
> glob_stats->min_latency = latency;
> - else if (latency > glob_stats->max_latency)
> glob_stats->max_latency = latency;
> - /*
> - * The average latency is measured using exponential moving
> - * average, i.e. using EWMA
> - * https://en.wikipedia.org/wiki/Moving_average
> - */
> - glob_stats->avg_latency +=
> - alpha * (latency - glob_stats->avg_latency);
> + glob_stats->avg_latency = latency;
> + glob_stats->jitter = latency / 2;
Setting jitter at first sample as latency / 2 is wrong.
Jitter should remain zero at first sample.
> + } else {
> + /*
> + * The jitter is calculated as statistical mean of
> interpacket
> + * delay variation. The "jitter estimate" is computed
> by taking
> + * the absolute values of the ipdv sequence and
> applying an
> + * exponential filter with parameter 1/16 to generate
> the
> + * estimate. i.e J=J+(|D(i-1,i)|-J)/16. Where J is
> jitter,
> + * D(i-1,i) is difference in latency of two
> consecutive packets
> + * i-1 and i.
> + * Reference: Calculated as per RFC 5481, sec 4.1,
> + * RFC 3393 sec 4.5, RFC 1889 sec.
> + */
> + glob_stats->jitter += ((prev_latency - latency)
> + - glob_stats->jitter) / 16;
With jitter remaining zero at first sample,
Acked-by: Morten Brørup <m...@smartsharesystems.com>
