Hyperthreading hurts 5.3?

David Kelly dkelly at HiWAAY.net
Tue Jan 11 18:10:02 PST 2005


On Jan 11, 2005, at 6:52 PM, Timothy J. Luoma wrote:

> summary: should I disable hypertheading in the  BIOS when running 5.3?
>
> Background info:
>
> I have a new Dell Dimension 3000 running 5.3.
>
> I noticed some huge pauses when copying a large # of files across the
> network.  Googling around found some information about earlier 
> versions of
> 5.x and Hyperthreading being detrimenatl for performance.
>
> Whether or not it was the source of the network copy problem, I am 
> trying
> to decide if I should disable Hyperthreading.

IMO there are times where 5.3 doesn't schedule the CPU as fairly as one 
would like. Times I've suspected this were during aggressive file 
activity on a few large files. I have HT disabled due to earlier 
problems with the combination of SATA and vinum resulting in a trashed 
fs with a late version of 5.2.1. The benefits of HT are too few for me 
to risk trashing the fs now its full.

If you can reproduce your situation then I suggest disabling HT and see 
what happens. That's the only way anybody would know if HT is part of 
the problem or part of the solution.

> Iif YES, I wasn't clear if people meant "disable in BIOS" or just some
> configuration setting in a *.conf file.

In the BIOS.

> (disabling HT will apparently mean I have to reinstall XP on the other
> drive.

What does XP have to do with it? IIRC on Dell its F2 during the 
power-on diagnostics to reach the built-in BIOS config. That is where 
HT is to be disabled. Works exactly that way on my PowerEdge 400SC 2.8G 
P4. The only question is whether the key is F2 to get there or not. Was 
F2 this afternoon on my ancient Dell Optiplex 450 MHz P2 when I had to 
boot a DOS floppy to remap some bad blocks.

--
David Kelly N4HHE, dkelly at HiWAAY.net
========================================================================
Whom computers would destroy, they must first drive mad.



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