Re: Time problems...

Riley Williams (
Wed, 2 Dec 1998 12:40:25 +0000 (GMT)

Hi there.

> Whatever it is, it's been consistent across 2.0.33 - 2.0.36 and it
> *didn't* happen on my older system (486DX2/66) with 2.0.33 kernel
> --- but I've only observed it on Red Hat 5 and to date I haven't
> had an RH5 install on the older system (it ran RH4 for over a year
> without showing any such symptom, but the same applies to some
> older ECE systems including some with hardware identical to the
> ones that have severe clock drift).

> The other thing about it is that it's not just lost interrupts:
> the systems are as apt to *gain* time, instead of losing it, again
> enough to make Kerberos upset (I've seen them gain 10 minutes over
> 5 minutes of wall time). Again, I haven't been able to correlate
> gain vs. loss (or amount thereof) to any particular program or
> device/driver.

I don't have kernel sources handy to look through, but the above
sounds suspiciously like something's reprogramming the timer interrupt
frequency from under us, with the result that the system is getting
timer interrupts at the wrong rate - that would explain all of the
above symptoms in one go...

Alan: Can you have a peek through whatever patches RH use in the
relevant RPM's and check whether there's anything in there that may be
causing this sort of effect? I doubt it, but it's something that needs
checking, especially if this is a RH specific problem as is apparently
being reported.

Best wishes from Riley.

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