Re: Hyperthreading

James Bourne (jbourne@mtroyal.ab.ca)
Wed, 21 Aug 2002 07:48:21 -0600 (MDT)


On Wed, 21 Aug 2002, Reed, Timothy A wrote:

> Anyone,
>
> Can anyone lead me to a good source of information on what options should be
> in the kernel for hyperthreading?? I am still fighting with a
> sub-contractor over kernel options.

As long as you have a P4 and use the P4 support you will get
hyperthreading with 2.4.19 (CONFIG_MPENTIUM4=y). 2.4.18 you have to also
turn it on with a lilo option of acpismp=force on the kernel command line.

You might want to balance IRQs across the cpus. Ingo Molnar has created
patches for this, which I've put on my website
at http://www.hardrock.org/kernel/.

hyperthreading will give you some performance boostes, but *only*
if you have many runable processes a majority of the time, or very heavily
threaded applications running on the system. (an example would
be running 4 setiathome clients on a dual processor system).

regards
James Bourne

> Tim
>
> timothy.a.reed@lmco.com

-- 
James Bourne, Supervisor Data Centre Operations
Mount Royal College, Calgary, AB, CA
www.mtroyal.ab.ca

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