Re: [Linuxptp-users] Building a PTP grandmaster with disciplined oscillator

[Richard C. <ric...@gm...>]

On Tue, Mar 15, 2022 at 04:06:31PM +0100, Marco Davids (SIDN) via Linuxptp-users wrote:
> I have a setup with an interface being a PTP client (HW timestamping, a nice
> Meinberg GM and such) and phc2sys supplying time from it to another
> interface's PHC in the same server.
> 
> Is there anything to be said about the accuracy/precision on the second
> interface's PHC with this approach?

The answer is, "it depends".

The timestamps used by phc2sys are SW, and a busy system might
preempt phc2sys a just the wrong times, causing time error.  You a
can mitigate by using a preempt_rt kernel and giving phc2sys
sched_fifo priority.

You can force artificial system load using `hackbench` `stress` and
friends.

You can characterize your performance by measuring end to end, like
from a PPS from a client on the second port back to the Meinberg's PPS.

HTH,
Richard