From owner-freebsd-stable  Fri Jun 28 18: 2:35 2002
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From: Aaron Seelye <aseelye@urx.com>
To: John David Duncan <jdd@greatschools.net>,
	freebsd-smp@freebsd.org, <freebsd-stable@freebsd.org>
Subject: Re: 2 xeons = 4 CPUs?
Date: Fri, 28 Jun 2002 18:03:45 -0700
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Yes, that's hyperthreading (as two others before me have said), but one thing 
to keep in mind is that you may want to disable it, as on some benchmarks it 
actually /slows down/ the system.  YMMV.

Aaron

On Friday 28 June 2002 02:52 pm, John David Duncan wrote:
> Hey,
>
> I just installed 4.6-RELEASE on a dual 1.8Mhz Xeon + Tyan S2720
> motherboard (a Relion 140 server from Penguin Computing, actually).
> When I reboot with an SMP kernel, I see:
>
> CPU: Pentium 4 (2199.76-Mhz 686-class CPU)
> CPU: Pentium 4 (2199.76-Mhz 686-class CPU)
> CPU: Pentium 4 (2199.76-Mhz 686-class CPU)
> CPU: Pentium 4 (2199.76-Mhz 686-class CPU)
> SMP: AP CPU #1 Launched!
> SMP: AP CPU #2 Launched!
> SMP: AP CPU #3 Launched!
>
> That's twice as many CPUs as I think I have, each going 400Mhz faster.  Is
> this safe?  Correct?  Is it that hyperthreading stuff?  Should I disable
> it?
>
> Thanks
>
> - JD
>
>
>
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