Subject: Re: Hyperthreading?
To: Jaromir Dolecek <jdolecek@NetBSD.org>
From: Frederick Bruckman <fredb@immanent.net>
List: port-i386
Date: 09/20/2003 08:09:24
On Sat, 20 Sep 2003, Jaromir Dolecek wrote:
> Nathan J. Williams wrote:
> > seebs@plethora.net (Peter Seebach) writes:
> >
> > > In message <mtullsmm5f9.fsf@contents-vnder-pressvre.mit.edu>, "Nathan J. Willia
> > > ms" writes:
> > > >Under -current, P4s with hyperthreading show up as multiple CPUs. My
> > > >Dell PWS 650 (dual P4 Xeon) shows up as:
> > >
> > > Huh.  Maybe my CPU doesn't *really* have HT.
> >
> > It does need to be enabled by the BIOS. I've heard rumors that some
> > BIOSes foul that up for the newer Xeons with 512k L2 cache... they
> > don't expect to see HT on processors slower than 2.4GHz, but HT Xeons
> > with 512K L2 also exist at 1.8, 2.0, and 2.2GHz.
>
> Yeah, I've played once with one such a Compaq box, with (IIRC) 1.8
> HT Xeon. Even through the CPU did support HTT, there was no
> way to enable it in BIOS and (surely enough) only one CPU
> was seen by NetBSD.

I have a Compaq W8000, 2.2GHz, which does have an option in the CMOS
utility to enable hyperthreading, but no matter -- NetBSD 1.6ZC as of
yesterday still sees only one processor (feature list shows HTT, BIOS
has been upgraded to the latest, 1.27).

Frederick