Re: Hyperthreading

From: James Bourne (
Date: Wed Aug 21 2002 - 08:48:21 EST

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

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).

James Bourne

> Tim

James Bourne, Supervisor Data Centre Operations
Mount Royal College, Calgary, AB, CA

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