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Subject: Re: [hwloc-devel] hwloc-distrib: how to start at lower hiearchy level?
From: Jirka Hladky (jhladky_at_[hidden])
Date: 2010-07-07 10:05:33


On Monday, July 05, 2010 07:12:58 am Brice Goglin wrote:
> Le 05/07/2010 02:41, Jirka Hladky a écrit :
> > Hi all,
> >
> > I'm using hwloc-distrib quite often to distribute jobs optimally on NUMA
> > boxes. I use it to test linux kernel task - scheduler by comparing
> > runtime of jobs bound to best possible CPU configuration (keeping CPU
> > cache in mind) with runs without CPU affinity set.
> >
> > I just run into strange issue on box with newest Intel's Nehalem CPUs.
> > There are 4 Sockets, each with 8 physical cores and hyper-threading
> > enabled, which gives you 64 OS processors.
> >
> > The box has strange NUMA layout - I will need to check why it is so.
> > Basically, there are 3 NUMA nodes - one includes 2 Sockets, other 2 have
> > one Socket associated to each of it.
>
> Seems strange to me, likely a BIOS bug. Nehalem-EX should always have
> one NUMA node per socket from what I understand.

Confirmed to be BIOS bug. Asked Intel to get fixed BIOS.
Thanks!
Jirka