Re: [chrony-users] Setting up Chrony with PPS

[Miroslav Lichvar <mlichvar@xxxxxxxxxx>]

On Mon, Apr 11, 2016 at 01:10:30PM -0700, Deven Hickingbotham wrote:
> 
> On 4/10/2016 11:30 PM, Miroslav Lichvar wrote:
> >Hm, did the configuration of the GPS change? Maybe it's giving fewer
> 
> Yes, but I didn't expect that it would affect chrony.  The update rate
> was increased from 1 per second to 10 time per second (since this didn't
> affect the PPS signal, I didn't expect it to impact chrony).
> 
> Changing the update rate back to 1 per second corrected the issue, but I
> need an update rate of at least 5 per second (preferably 10).
> 
> Would it be correct to assume that different update rates require
> different chrony offsets and delays?  And if so, what values should I try?

That probably depends on the FW of the GPS. If with one update per
second the NMEA messages were only 0.1 second late, with 10 updates
per second that delay wouldn't have to change, it would still fit
between updates. But if it's 0.5 second late, that can't work with 10
updates per second.

I think you just need to change the offset of the SHM refclock to 0.1
second. The delay can stay as it was.

-- 
Miroslav Lichvar

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