Re: ntp sanity limit kills ntp daily

From: Douglas Mayne (doug_at_slackware-3.localnet)
Date: 05/23/05 

Date: Mon, 23 May 2005 10:05:50 -0600

On Fri, 20 May 2005 11:55:10 -0700, Michael Ward wrote:

> Hello All,
>
> I've configured my FC3 system to run ntp successfully at boot time and
> ntp seems to run successfully for about a day. However, every night the
> clock looses some 1200 seconds while the system is busy making backups.
> When ntp figures this out, it refuses to update the clock because this
> is classified as insane, and terminates.
>
> I happen to agree that the clock loosing about 1200 seconds (for any
> reason) seems insane. However, given that this sort of behavior seems
> common enough to be found via google (search for: ntp exceeds sanity
> limit), I'm hopeful that there is a way to coax ntp (or some other
> automated program) to trudge on and do the deed anyway.
>
> Default rules can make is seem like a crazy world, can't they?
>
> I'm running a self compiled linux kernel 2.6.9 with FC3 linux as
> installed from Negus' "Red Hat Fedora Linux 3". Anyoune out there know
> how to make this sort of thing work in a rational manner?
>
> Thanks.
>
> - Mike
>
Caveat: I am not running FCx (or Red Hat). I do know the database for
the locate command is rebuilt at some time interval and I have
noticed high CPU utilization when this occurs. If your backup operation is
on the same schedule as this database refresh, then the system may be
pushing its limits. This is especially true for older CPUs on 2.6.x. What
is the speed of your CPU?

Does the clock lose time when using a "stock" Red Hat kernel?

Relevant Pages

  • Re: Power-saving patch to NTP
    ... The ntpd does not require a tickle ... And, please, don't consider the power used by NTP itself, but rather ... the power used by the CPU idling in a higher power state than before ... deep C-state in order to run NTP for microseconds and then it remains ...
    (comp.protocols.time.ntp)
  • Re: Dual-core systems - AMD - Windows Vista
    ... but I recall that NTP on Windows uses some interpolation technique ... and that the interpolation used a CPU ... I didn't think that a 64-bit version of NTP was included in the Meinberg ... When I looked briefly at the Windows port in: ...
    (comp.protocols.time.ntp)
  • Re: Power-saving patch to NTP
    ... As I have said several times, if you expect ntpd to discipline the frequency, the CPU needs to nudge the time on a regular basis, like once per second. ... And, please, don't consider the power used by NTP itself, but rather ... deep C-state in order to run NTP for microseconds and then it remains ...
    (comp.protocols.time.ntp)
  • Re: Dual-core systems - AMD - Windows Vista
    ... The multiple-CPU nanokernel code that left here and is in the Alpha kernel assumes each CPU has an individual cycle counter and the timer interupts are vectored to a designated CPU. ... I do have a dual-core system, so I was wondering how NTP handled dual-core. ...
    (comp.protocols.time.ntp)
  • Re: Power-saving patch to NTP
    ... The cpu is in sleep mode. ... ntp is NOT running. ... ntp cannot wake up the cpu because ntp is not ... Only external events can wake up the cpu, ...
    (comp.protocols.time.ntp)