Quoting folkert <folk...@vanheusden.com>:
Not sure if it is interesting for you guys but I wrote a simple program
for e.g. Linux (or any other system with the pps api implemented) that
listens on a pps source waiting for a pulse and then toggles a gpio
pin. That way you can measure the latency introduced by the the kernel
when listening from userspace. Note that there's a little extra latency
due to the gpio-pin handling.
You can also use it e.g. blink a led :-)
It is on github: https://github.com/flok99/pps2gpio
What sort of latency have you seen?
This is a histogram (200ns bins) of interrupt latencies I've seen on
the BeagleBone Black:
http://blog.dan.drown.org/content/images/2014/Dec/interrupt-latency.png
Over 6.5 days worth of samples, 99% were under 8.62us, and 1% were
under 6.04us. The mean was 6.92us and the stddev was 1.72us.
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