p4 and hyper-threading

[Jamie Guinan]

On Wed, 7 Jan 2004, Castelhano, Dan wrote:

> Hello,
> 
> Please forgive me if any of you feel this post is a little off topic. 
> 
> I have a problem with a Pentium 4 hyper threaded chip running on redhat 7.3
> with all of redhat's errata updates and their latest smp kernel.
...

> The problem is this:
> 
> I seem to be unable to make the hyper-threading functionality of my Pentium
> 4 3.2ghz processor work. I've searched google and redhat/fedora list
> archives and haven't found a similar post to this problem, so I have no idea
> what is wrong.
> 
> *This is an HP system, with the latest BIOS
> *Hyper-threading is enabled in bios
...

I have an HP xw4100 that suffers from the same problem.  The kernel 
doesn't like the size of one the ACPI tables in the BIOS, and gives
up on enabling HT.

More details in the message I posted to acpi-devel,

http://sourceforge.net/mailarchive/forum.php?thread_id=3258219&forum_id=6102

but didn't get a response, and I didn't have time to pursue it further.  

So I tried patching the kernel to ignore the particular check it was 
doing, and HT did in fact work.

-Jamie 

[End of OT thread - reply privately if you want the patch (if I 
 can find it - I didn't get any noticeable improvement from HT
 in my particular load, so I backed it out...)]