On Tue, Apr 29, 2008 at 19:59:37 +0100 (+0100), Hugo Mills wrote:
> On Tue, Apr 29, 2008 at 07:50:36PM +0100, Stephen Davies wrote:
> > I was at a presentation today where the speaker said that one of the
> > differences between SLES & RHEL was that they use a different way to
> > allocate memory.
> > He said that SLES uses a NUMA model whereas RHEL uses a 'flat' model.
> > He indicated that the NUMA model gave a slightly better performance that
> > that used by RHEL. This was observd in a DB Benchmark test. TPC-H
> >
> > Can anyone verify this statement?
> > What do other stock kernels use and can the NUMA model be enable of a
> > RHEL Kernel?
>
> If I recall, it's a compile-time option, so you'd have to rebuild
> your kernel.
>
> I believe that multi-socket Athlon64 machines would benefit from a
> NUMA kernel, because of the memory architecture typically implemented
I remember seeing an Opteron talk a while ago (whilst they were still
emulating it in software....) where they described it as SUMA
(sufficently...) which I think fell somewhere between the two. It
would benefit from NUMA, but it wasn't all that important.
> I'm a little further adrift on the current Intel chips, but I
> believe they're still using a flat memory architecture on the current
> generation, and will be moving to something more NUMA-like fairly
> soon.
I believe the most recent ones are different now, but anything older
is just chips in sockets - however there can be bus-contention between
the cores across the bus.
Only one way to tell for sure - try it and benchmark it for _your_
setup.
Adrian
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