Re: ntp problems
From: Jean-Christian de Rivaz
Date: Wed Dec 07 2005 - 18:35:09 EST
Gene Heskett a écrit :
On Wednesday 07 December 2005 16:56, Jean-Christian de Rivaz wrote:
Gene Heskett a écrit :
And, acpi is on, and ntpd is happy with the new bios. Hurrah!
Good news!
I wonder if it would be a good idea to add something into the kernel or
into ntpd to alert the users that ntpd can't run normaly because of a
too fast drift ? Then a BIOS upgrade could be proposed (especially on a
nForce2 system). I don't know if it's even realistc.
Regards,
The drift itself wasn't what I'd call excessive,
something like 6 minutes in a week, which for
mainboard quality crystals is pretty darned good.
ntpd work only on system with a drift of maximum +/-500ppm. This post
summarize a lot of informations about the problem:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113105244509795&w=2
It was found later that an issue into the nForce2 is the root of the
problem and that a BIOS update solve it.
6.0 / (60*24*7) * 1e6 = 595.24
6 minutes per week is near 600ppm, it's enough to trigg the problem you
have seen. Even very cheap crystal are 100ppm at commercial temperature
range. 100ppm is about 1 minute per week. Some crystal manufacturers
propose now 30ppm as the default standard at commercial temperature range.
As your watch prove, good cristal can be just a few ppm (about 3.86ppm
for your watch)
Regards,
--
Jean-Christian de Rivaz
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