Re: HYPERTHREADING on older P4???

From: Dave Jones (davej@codemonkey.org.uk)
Date: Wed Feb 05 2003 - 08:07:07 EST


On Wed, Feb 05, 2003 at 06:02:43AM -0700, b_adlakha@softhome.net wrote:
> hi,
> /proc/cpuinfo reports "ht" in the supported options...I have a p4 2 ghz
> stepping 4, and when I boot with an SMP kernel, it shows another thing :
> siblings 1
>
> I think HT is there in all p4s, so can it be enabled in older P4s? Like
> mine? What does "siblings = 1" mean?
 
It means there is one 'thread'. Ergo, you do not have the possibility
of running this as you would a true HT P4. There are a limited number
of Northwood P4's out there which do support HT and have >1 sibling,
but asides from those, you'll need a Xeon to take advantage of it.

There are countless rumours of being able to enable extra siblings
by poking MSRs, but not one person has to my knowledge achieved this.
Some folks have also allegedly found that snipping pins or wiring extra
bits to them have enabled the 'extra sibling'. Whether this is true or
not, and whether it is 100% equivalent to a real HT part is again,
questionable.

        Dave

-- 
| Dave Jones.        http://www.codemonkey.org.uk
| SuSE Labs
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Fri Feb 07 2003 - 22:00:17 EST