Re: [Linuxptp-users] clockcheck - need to filter large spurious phase jumps?

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

On Wed, Nov 13, 2013 at 09:07:39AM +0100, Richard Cochran wrote:
> On Tue, Nov 12, 2013 at 02:28:38PM -0500, Rich Schmidt wrote:
> > We use 16s update interval on our NTP servers that are synced to PTP time
> > code using a Spectracom PCIe PTP card, and our system clock jitter is
> > around 700 nanoseconds! Frequency changes due to temperature effects are
> > not rapid in our environment.  If you run adjtime too frequently you may
> > end up chasing your tail.
> 
> That seems like a surprisingly good figure. Do you have a way of
> verifying it, or is this simply what their software tells you?

Okay, I take it back. 700 nanoseconds is perfectly reasonable,
provided your kernel isn't using CONFIG_NO_HZ_IDLE.  Once I reboot
using nohz=off then I get very good results using phc2sys.

Thanks,
Richard