Subject: Re: Hyperthreading?
To: Nathan J. Williams <nathanw@wasabisystems.com>
From: Jaromir Dolecek <jdolecek@NetBSD.org>
List: port-i386
Date: 09/20/2003 11:13:50
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.
Jaromir
--
Jaromir Dolecek <jdolecek@NetBSD.org> http://www.NetBSD.cz/
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