Re: [Linuxptp-users] Want to reduce offset (which is distance dependant) between boundary clocks.

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

On Tue, Jan 19, 2016 at 05:30:10PM +0530, Aniket Hendre wrote:
> *phc2sys -s CLOCK_REALTIME -c eth1 -m -O -35 *

FYI, you should be aware that this method reads time stamps over the
PCIe interface.  Because of the delay and uncertainty in reading
single values over PCIe, this introduces a time error on the order of
microseconds.

You can avoid this error by directly feeding the 1-PPS into PTP card
that supports external time stamps (like the Intel i210).  Then you
can write a little servo to discipline the PTP card to the GPS clock.

> I mean to say that I am observing offset at slave side and noticed that the
> offset from master is large for large distance between master and slave.

Not sure what you mean.  Can you post the client side ptp4l logs for
both cases?

Thanks,
Richard