only one logical CPU used in Xeon

Oliver Fromme olli at
Wed Mar 11 01:03:46 PDT 2009

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.
 > > 
 > > 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.
 > 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=1 by default.

What happens if you set hyperthreading_allowed=0 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

Best regards

Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M.
Handelsregister: Registergericht Muenchen, HRA 74606,  Geschäftsfuehrung:
secnetix Verwaltungsgesellsch. mbH, Handelsregister: Registergericht Mün-
chen, HRB 125758,  Geschäftsführer: Maik Bachmann, Olaf Erb, Ralf Gebhart

FreeBSD-Dienstleistungen, -Produkte und mehr:

"Documentation is like sex; when it's good, it's very, very good,
and when it's bad, it's better than nothing."
        -- Dick Brandon

More information about the freebsd-smp mailing list