[Beowulf] Forwarded from a long time reader having trouble posting

[Tom Elken]

Toon wrote:  "Any idea why it gives better performance? Was it on memory bw intensive apps? Could it be due to changes in the kernel that take into account the Numa architecture (affinity)"

This is very likely it.  Dredging thru old e-mails, I see that, in Jan-09, the application of a then-current 2.6.28 kernel to a RHEL 5.2 system provided about a 2x improvement in 8-thread OpenMP STREAM performance.  Subsequently, moving to RHEL 5.3 and its default kernel provided the same good STREAM performance.

-Tom


From: Toon Knapen [mailto:toon.knapen at gmail.com]
Sent: Tuesday, December 01, 2009 12:53 PM
To: Tom Elken
Cc: gerry.creager at tamu.edu; landman at scalableinformatics.com; beowulf
Subject: Re: [Beowulf] Forwarded from a long time reader having trouble posting

Any idea why it gives better performance? Was it on memory bw intensive apps? Could it be due to changes in the kernel that take into account the Numa architecture (affinity) or ...
On Tue, Dec 1, 2009 at 8:57 PM, Tom Elken <tom.elken at qlogic.com<mailto:tom.elken at qlogic.com>> wrote:
> On Behalf Of Gerald Creager
> I've been quite happy with CentOS 5.3 and we're experimenting with
> CentOS 5.4 now.  I see good stability in 5.[34]
I have to second the recommendation of 5.3 or 5.4.

Some time ago, we saw significant performance improvements on Nehalem (Xeon X5570) in moving from RHEL 5.2 to 5.3.  So I expect that moving from 5.1 to 5.[34] would also be a significant improvement in performance.

Cheers,
-Tom

> and the incorporation
> of
> a couple of tools worth having in a distribution for 'Wulf use.  I'd
> not
> recommend sticking with the old version, but of course, once you're
> established, not carelessly upgrading, either.
>
> gerry
>
> Joe Landman wrote:
> > My apologies if this is bad form, I know Toon from his past
> > participation on this list, and he asked me to forward.
> >
> > -------- Original Message --------
> >
> > Dear all,
> >
> > I've been working on hpux-itanium for the last 2 years (and even
> > unsubscribed to beowulf-ml during most of that time, my bad) but soon
> > will turn back to a beowulf cluster (HP DL380G6's with Xeon X5570,
> > amcc/3ware 9690SA-8i with 4 x 600GB Cheetah 15krpm). Now I have a few
> > questions on the config.
> >
> > 1) our company is standardised on RHEL 5.1. Would sticking with rhel
> 5.1
> > instead of going to the latest make a difference.
> > 2) What are the advantages of the hpc version of rhel. I browsed the
> doc
> > but unless having to compile mpi myself I do not see a difference or
> did
> > I miss soth.
> > 3) which filesystem is advisable knowing that we're calculating on
> large
> > berkeley db databases
> >
> > thanks in advance,
> >
> > toon
> >
> > Toon Knapen toon.knapen at gmail.com<mailto:toon.knapen at gmail.com>
> >
> > -----------------------------------
> >
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