FreeBSD on dual core Opterons - stupid buildworld test

Astrodog astrodog at gmail.com
Wed May 18 11:44:18 PDT 2005


On 5/18/05, Jung-uk Kim <jkim at niksun.com> wrote:
> On Wednesday 18 May 2005 02:05 pm, Brooks Davis wrote:
> > On Wed, May 18, 2005 at 07:29:00PM +0200, Pav Lucistnik wrote:
> > > Attila Nagy pí?e v st 18. 05. 2005 v 18:39 +0200:
> > > > Hello,
> > > >
> > > > I did some buildworld tests on an HP BL45p with 4 2,2 GHz
> > > > Opterons.
> > > >
> > > > Sequential time make buildworld -jX times (if there is a
> > > > missing iteration, then the build has failed):
> > > >
> > > > http://people.fsn.hu/~bra/bl45p/dmesg.boot
> > > >
> > > >  Hyperthreading: 2 logical CPUs
> > >
> > > So dual-core Opterons report into system as Hyperthreading?
> > > Uncool.
> >
> > What the AMD reps said at a session I attended last year is that
> > they report as supporting hyper threading, but set another bit to
> > say that they are actually real cores.  We probably need to find
> > out what that bit is.
> 
> FYI, Linux says:
> 
> http://lxr.linux.no/source/include/asm-x86_64/cpufeature.h#L78
> http://lxr.linux.no/source/arch/x86_64/kernel/setup.c#L834
> 
> Jung-uk Kim
> 

Opteron reports Hyperthreading, because it tries to take advantage of
the licencing benifit. Keep in mind, HT P4s are counted as a single
CPU for the most part, in a licence. Opteron may not. By acting as
though its a HT processor, it gets that same benifit.


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