Re: only one logical CPU used in Xeon

Oliver Fromme <[email protected]> Tue, 17 Mar 2009 13:30:52 +0100 (CET)
Newsgroups gmane.os.freebsd.devel.smp
Message-ID <[email protected]>
[email protected] wrote:
 > John Baldwin wrote:
 > > in the ULE case (though the sysctl doesn't work).  If
 > > you use 4BSD on 7.1=20
 > > then the tunable and sysctl will work fine.
 > >=20
 >=20
 > I tried this, but I can't see the variable being displayed.

Then your machine doesn't support hyperthreading.

The machdep.hyperthreading_allowed sysctl is only present
if your machine actually has multiple logical CPUs.
If you don't see that sysctl, then your processor doesn't
have multiple hyperthreaded CPUs.

If you're interested how this is done in the source, see the
function cpu_hlt_setup() in src/sys/amd64/amd64/mp_machdep.c
or src/sys/i386/i386/mp_machdep.c, respectively.

Best regards
   Oliver

--=20
Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M.
Handelsregister: Registergericht Muenchen, HRA 74606,  Gesch=E4ftsfuehrun=
g:
secnetix Verwaltungsgesellsch. mbH, Handelsregister: Registergericht M=FC=
n-
chen, HRB 125758,  Gesch=E4ftsf=FChrer: Maik Bachmann, Olaf Erb, Ralf Geb=
hart

FreeBSD-Dienstleistungen, -Produkte und mehr:  http://www.secnetix.de/bsd

C++: "an octopus made by nailing extra legs onto a dog"
        -- Steve Taylor, 1998
_______________________________________________
[email protected] mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-smp
To unsubscribe, send any mail to "[email protected]"