[CentOS] problem with machine "freezing" for short periods

Wed Jul 25 14:34:51 UTC 2012
Vanhorn, Mike <michael.vanhorn at wright.edu>

I have two HP dc7800 convertible minitowers that are exhibiting the
following issue: every 5-10 minutes, they will "freeze" for about 30
seconds, and then pick right back up again. During the freeze, it seems
that nothing at all happens on the system; the clock doesn't even advance
(it just picks up again with the next second, and that 30-or-so seconds
are lost).

I've tried both CentOS 5.8 and 5.7, thinking it was a kernel
incompatibility, but the problem happened with both versions. I have tried
different hard drives, different memory, even swapped the entire machine,
and the problem exists everywhere. I have tried adding "pci=nommconf" to
the kernel line, as that was reported as being necessary back with 5.2 on
these machines, but that made no difference (and shouldn't be necessary
now, anyway, as I believe the issue has either been fixed or

I am stuck, and can't figure out where to even suspect the problem might
actually be. There are no errors getting logged anywhere that I can find,
probably because everything just "stops" temporarily, so there's nothing
for the system to log.

Does anyone have any idea where I could look to fix this? I think I am
next going to go back to 5.2, where the pci=nommconf is necessary, because
at least back that far it appears to have been working for other people.
However, I really would like to have this running 5.8.


Mike VanHorn
Senior Computer Systems Administrator
College of Engineering and Computer Science
Wright State University
265 Russ Engineering Center
michael.vanhorn at wright.edu