[ntp:questions] Re: NTP client on Windows platform provides lessaccurate results then on the UNIX or Linux. Why?

David J Taylor david-taylor at blueyonder.co.not-this-bit.nor-this-part.uk
Thu Mar 30 16:38:18 UTC 2006


Karel Sandler wrote:
> "David J Taylor"
> <david-taylor at blueyonder.co.not-this-bit.nor-this-part.uk> wrote
>
>> Karel Sandler wrote:
>>> I'm using  ntp-4.2.0b at 1.1436mbg-xmas-o-win32 from Meinberg on a W2k3
>>> system. Some stats an offset distribution for this system you can
>>> see at http://lx.ujf.cas.cz/mrtg/ntp/. My early experience with
>>> ntpd on a windows systems was rather bad but this version of ntpd I
>>> consider good.
>>> Karel Sandler
>>
>> Karel,
>>
>>  http://lx.ujf.cas.cz/ntp-lx/lx-off.html
>>
>> shows a series of one millisecond steps at about roughly 1 hour
>> intervals. Any idea why?
>>
>> (My systems may do this as well, but my plots are only one tenth of
>> the resolution of yours, I allow for +/- 100ms which was perhaps more
>> appropriate when I relied on Internet ntp sources).
>
> I don't know the cause of this behaviour. The ntpd obviously uses a
> brute force approach to steer this Linux system. Maybe the hardware
> is not good enough. I have already shifted the original 155 ppm value
> to 55 ppm but without any impact. Another possible cause may be
> clock-hopping between two sets of peers but any subsequent change in
> the number of peers between four to seven has no effect as well and
> none of my peers allows me to simly prefer it. Hope the situation
> will improve after setting up one's own stratum 1. I think there are
> at least two other fields to play with namely ACPI and ntpd tos
> directive but it remains to be seen. There isn't much room to
> experiment with this public timeserver and our webserver. Any advice
> would be appreciated.
> Karel

Oh, that's with Internet sources!  Very good, then.  I had assumed it was 
with a GPS source!  I hope someone else can comment on the "steps".

David 





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