[NTLUG:Discuss] 2 Xeons look like 4

[kbrannen@gte.net]

Thomas Cameron wrote:
> ----- Original Message ----- 
> From: "Bishop, Cass" <cbishop at atxna.com>
> To: "'NTLUG Discussion List'" <discuss at ntlug.org>
> Sent: Tuesday, December 23, 2003 1:02 PM
> Subject: [NTLUG:Discuss] 2 Xeons look like 4
> 
> 
> 
>>I have 2 Intel Xeon processors in my server.  When I run top it says there
>>are 4 cpu's.  Any idea why?  I see this in RedHat 7.3 and RedHat
> 
> Enterprise
> 
>>Server 3.

> 
> Welcome to the world of HyperThreading.  Basically each physical processor
> runs two virtual instances of itself, in theory giving the computer more
> oomf.  We use only HT procs at my job, and I love them.  It seems to work
> pretty darned well.

Hmm, you're having better luck than I then.  We tried it on RH9.0 on a Compaq 
DL380 (G3 model w/ dual Xeons) and I found weird stability problems.  The 
problems all went away when I turned off hyperthreading in the BIOS.

Kevin