Re: [Emc-users] latency calculation

[Jeff E. <je...@un...>]

The latency-test runs the following realtime component:
http://git.linuxcnc.org/gitweb?p=emc2.git;a=blob;f=src/hal/components/timedelta.comp

Each time a realtime thread runs, the time interval del=(now-last) is computed.
The minimum and maximum del ever seen are computed in min_ and max_.
The jitter is the bigger of max_-period or period-min_.

period is the promised realtime interval in nanoseconds, and
rtapi_get_time() is the measured wall time also in nanoseconds.

The timedelta component also measures long term error in 'err' and
'avg_err'.  These values are not shown in the latency-test GUI but can
be used to determine if there are long-term differences between expected
and actual intervals.

Jeff