HTT and SMP question

[Rumen Telbizov]

Hello, 

On Mon, Apr 19, 2004 at 02:35:23AM -0700, Kris Kennaway wrote:
> On Mon, Apr 19, 2004 at 11:20:52AM +0200, Morten A. Middelthon wrote:
> > sysctl -w machdep.hlt_logical_cpus=0
> > 
> > that did the trick. I added it to loader.conf as well.
> > 
> > regards,
> 
> Note that HTT causes worse performance in many workloads, which is why
> that sysctl defaults to off.

Would you please point out some cases when HTT with machdep.hlt_logical_cpus=0
causes worse performance than machdep.hlt_logical_cpus=1?
I am using an HTT Xeon since recently and in my tests it showed that
machdep.hlt_logical_cpus=0 is better!
A simple ubench (spawning 2 processes) gives better results in 0 mode!


Thank you in advance!

Rumen Telbizov