[Beowulf] CentOS plus Fedora kernel?

Michael H. Frese Michael.Frese at NumerEx-LLC.com
Wed Nov 25 16:31:41 PST 2009

At 01:14 PM 11/25/2009, Andrew Shewmaker wrote:
>On Wed, Nov 25, 2009 at 12:34 PM, Greg Lindahl <lindahl at pbm.com> wrote:
> > On Wed, Nov 25, 2009 at 12:37:01PM +0100, Bogdan Costescu wrote:
> >
> >> A much newer kernel from Fedora usually requires newer utils as well
> >
> > Yeah, last time I did this I didn't rpm-ize the kernel, and that saved
> > me quite a bit of work. I snagged the .config file out of Fedora, but
> > didn't grab any patches.
> >
> > Since you guys seem determined to speculate about what feature I need,
> > it's the new scheduler, CFS, which appeared in 2.6.23.
>In case you were considering the 2.6.25 kernel that shipped with Fedora 9,
>I recommend against it.  I know there have been studies showing that it is
>a nice kernel with regard to low interrupt noise, but I have regularly seen it
>lock up while running MPI apps.  2.6.27 hasn't had the same issue, but we
>have seen 10-20% regression in IP network performance.

I think I'm seeing 2.6.23 lockup with a big MPI app, but I wouldn't 
have guessed the connection without Andrew's message.

We've been moving away from Fedora toward CentOS 5.4, and thus, back 
to 2.6.18, but apparently not fast enough.


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