Re: only one logical CPU used in Xeon

Oliver Fromme <[email protected]> Wed, 11 Mar 2009 09:03:28 +0100 (CET)
Newsgroups gmane.os.freebsd.devel.smp
Message-ID <[email protected]>
Robert Heron wrote:
 > Oliver Fromme wrote:
 > > No need for benchmarks here, because Robert's processors
 > > don't do hyperthreading at all.  FreeBSD 6.2 recognized
 > > the *cores* as logical HT processors, so he needs to
 > > set hyperthreading_allowed in order to enable the cores.
 > >=20
 > > Of course, the better solution is to update to a more
 > > recent release, such as 6.4 or even 7.1.  His 6.2 is
 > > more than 2 years old and contains lots of known bugs,
 > > of which the wrong recognition of cores is a relatively
 > > harmless one.
 >=20
 > I also tried 6.4 with exactly the same wrong results as 6.2.

That's suprising.  Actually I think that all fixes to the
CPU detection code have been backported to 6-stable.

 > 7.1 is OK, but is has hyperthreading_allowed=3D1 by default.

What happens if you set hyperthreading_allowed=3D0 on 7.1?

Are you 100% sure that your processor are really multi-core
and not just hyperthreaded?  Please post the relevant lines
from /var/run/dmesg.boot or output from the `dmesg` command
(as Adrian already suggested), preferably on a recent
FreeBSD system (i.e. 7.1).  The top 25 lines should be
sufficient.

Best regards
   Oliver

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