Disabling HyperThreading?

[John Baldwin]

On Monday 26 April 2010 5:59:19 am oklahoma wrote:
> Hubert Tournier wrote:
> >
> > I forgot to specify that the system is a remote dedicated server, for 
which
> > i have no physical access.
> >
> > I could rent a virtual KVM in order to try to access its BIOS settings, 
but
> > i'm not sure this would work.
> >
> > Any other software solution?
> if the server is dedicated entirely to you, ask your colo support to 
> disable it for you.
> other thing i find was
> 
> machdep.hlt_cpus 
> 
> is suppose to tell the scheduler that there is extra cores but not to use 
them.
> try to enable and see with top is there app that use logical cores.

You can manually disable any CPU (except for the boot CPU), via 
'hint.lapic.X.disabled=1' in loader.conf.  You can find the APIC IDs to use in 
place of 'X' in dmesg.

-- 
John Baldwin