Median filter has an advantage over moving average that it is much less
sensitive to outliers.
For instance, it allows much faster recovery from an external clock
time step which happened between receiving sync message and sending
delay_req message. The measured delay includes a large error, but the
median is still a good estimate of the delay and the first step
correction applied by the servo is right.
In this implementation the median update has linear time complexity.
Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>
Miroslav Lichvar