hyperthreading CPU and broken scheduling?

[Bill Moran]

In response to Dinesh Nair <dinesh at alphaque.com>:

> On Sun, 18 Nov 2007 12:29:32 +0200, Manolis Kiagias wrote:
> 
> > Wojciech Puchar wrote:
> > > i have machune with intel's CPU with hyperthreading.
> > >
> > > it is detected right, but only first thread is ever used.
> > >
> > > top shows at least 50% idle no matter what i run!
> > >
> > > what's wrong?
> > To enable hyperthreading, try setting the following in /etc/sysctl.conf:
> > 
> > machdep.hyperthreading_allowed=1
> > 
> > and reboot (or execute sysctl machdep.hyperthreading_allowed=1 by hand).
> 
> would an SMP kernel be required to properly use hyperthreading, or would
> just the above sysctl setting be enough ?

The SMP kernel is required as well.

-- 
Bill Moran
http://www.potentialtech.com