Re: only one logical CPU used in Xeon

Won De Erick <[email protected]> Tue, 17 Mar 2009 07:14:02 -0700 (PDT)
Newsgroups gmane.os.freebsd.devel.smp
Message-ID <[email protected]>
--- On Tue, 3/17/09, Oliver Fromme <[email protected]> wrote:=0A> won.=
[email protected] wrote:=0A>  > John Baldwin wrote:=0A>  > > in the ULE case=
 (though the sysctl doesn't work).=A0 If=0A>  > > you use 4BSD on 7.1 =0A> =
 > > then the tunable and sysctl will work fine.=0A>  > > =0A>  > =0A>  > I=
 tried this, but I can't see the variable being=0A>  > displayed.=0A> =0A> =
Then your machine doesn't support hyperthreading.=0A> =0A> The machdep.hype=
rthreading_allowed sysctl is only present=0A> if your machine actually has =
multiple logical CPUs.=0A> If you don't see that sysctl, then your processo=
r doesn't=0A> have multiple hyperthreaded CPUs.=0A> =0A=0AThanks for that f=
urther clarification. The dmesg has also justified this.=0A=0A#dmesg=0A...=
=0ACores per package: 4=0A...=0AFreeBSD/SMP: Multiprocessor System Detected=
: 4 CPUs=0A...=0A=0A> If you're interested how this is done in the source, =
see=0A> the=0A> function cpu_hlt_setup() in=0A> src/sys/amd64/amd64/mp_mach=
dep.c=0A> or src/sys/i386/i386/mp_machdep.c, respectively.=0A> =0A=0A=0A=0A=
=0A=0A=0A      

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