[ntp:questions] serialPPS+gpsd+ntpd large offset & jitter
Miroslav Lichvar
mlichvar at redhat.com
Sun Oct 17 15:52:39 UTC 2010
On Sat, Oct 16, 2010 at 08:24:02AM -0700, M Z wrote:
> I have since run ntp on 2 other similar systems, with and without the gps. It
> seems that the problem is not with the gps but with ntp as there is always a
> large offset and jitter. I have tried some things from the ntp.org problems page
> such as setting HZ=100, setting clocksource to tsc, hpet, and acpi_pm. I do not
> know what to do with acpi so i didn't test that. one of my systems has drift of
> < +-10 which is good. one of the systems is not behind my firewall.
> I have snipped all gps info out below as i only want to know what to do with ntp
> now.
Any interesting ntpd messages in syslog?
One additional thing you could try is to disable the kernel discline
by adding "disable kernel" to ntp.conf. If this helps, it's a kernel
bug or possibly a nano/micro mismatch between kernel and ntpd.
--
Miroslav Lichvar
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