[PlanetCCRMA] planetCCRMA FC1 and 2.80c Hyperthreading

Mark Knecht mknecht@controlnet.com
Fri Sep 3 07:15:02 2004

Louis Lam wrote:
> I'm now running a UP kernel with acpi off because i didn't understand HT at first and was trying
> to get my sound card to use IRQ9. Thinking that i have only 1 (actually yes i have one) processor,
> i disabled acpi in process of getting a better irq priority. So all along i was running UP kernel
> with HT enabled in the bios.

If you are running any form of an APIC/IO-APIC setup then all of the 
descriptions we've given about proper IRQ setup go completely out the 
window. In the hyperthreaded case we do not know if IRQ settings make 
any great difference or how to optimize them. (Or maybe I should say 
that I do not and haven't heard anyone say they do...)

Some people say that IRQ settings in an APIC machine do not matter at 
all. I tend to believe that it's not that simple, but I'm also very sure 
it's not the same rule set as a legacy machine.

Good luck,