[nSLUG] no networking

Dop Ganger nslug at fop.ns.ca
Tue Jan 6 16:42:49 AST 2004


On Tue, 6 Jan 2004, Peter Cordes wrote:

>  For anything other than a number-crunching machine, HT is probably a good
> thing.

HT's also a good thing for (some) number crunching apps. We did a test on
the cluster I installed at Dal and found that one processor with HT
enabled gave 80% of the performance of two processors without HT enabled.
If you're running different apps instead of one I suspect you won't get
the performance due to cache issues.

> Maybe there's an HT interface that the
> kernel can use to interrogate the hardware, but laptop CPUs support it but
> only have one logical CPU?

I think that's the situation. It's probably cheaper for Intel to have a
mask that has everything enabled and picks out parts that are "good" for
different apps, but any chip that doesn't cut the mustard as (say) a P4
with HT can be reused as a P4 without HT. I remember that's what they did
with 486 SX and DX, and it wouldn't surprise me if that were still the
case...

Cheers... Dop.




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