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Date: Thu, 14 Sep 2006 09:40:27 -0400
To: Danny Braniss <danny@cs.huji.ac.il>
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From: Mike Meyer <mwm-keyword-freebsdhackers2.e313df@mired.org>
Cc: freebsd-hackers@freebsd.org, Kris Kennaway <kris@obsecurity.org>
Subject: Re: numbers don't lie ... 
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In <E1GNoDy-0004CF-5k@cs1.cs.huji.ac.il>, Danny Braniss <danny@cs.huji.ac.il> typed:
> > In <E1GNOLq-000DC2-1Q@cs1.cs.huji.ac.il>, Danny Braniss <danny@cs.huji.ac.il> typed:
> > What's the CPU configuration? The AMD is dual core - is that it? Could
> > the Xeon be dual-core and hyperthreaded, so it's got that many more
> > CPUs to contribute towards user time?
> > 
> > To illustrate, I have numbers for "make -j4" for a P4 with and without
> > hyperthreading enabled:
> > 
> > machdep.hyperthreading_allowed: 1 -> 0
> >      50m55.99s real      35m28s.19 user       8m20s.02 sys
> > machdep.hyperthreading_allowed: 0 -> 1
> >      38m48s.85 real      55m2s.43 user       12m27s.90 sys
> > 
> > Note the effect of the second CPU on the user time.
> >
> i did the tests with hyperbluffing disabled in the bios.
> now, since you asked i tried:
> sysctl machdep.cpu_idle_hlt=0
> machdep.cpu_idle_hlt: 1 -> 0
> dell-2950 : make -j8 TARGET_ARCH=amd64 buildworld : 23m55.03s real 1h2m54.84s 
> user 16m48.79s sys
> and no difference, by the way, i did this also changing the bios setting
> (called logical cpus :-), but again, no difference.

Um - what version of FreeBSD are you running? I don't change
machdep.cpu_idle_hlt on mine; I chang machdep.hyperthreading_allowed
(as indicated in the tests). Did you check to see if the system
actually saw more cpus when you changed it?

	<mike
-- 
Mike Meyer <mwm@mired.org>		http://www.mired.org/consulting.html
Independent Network/Unix/Perforce consultant, email for more information.