Subject: Re: advice/suggestions sought on new configuration
To: None <>
From: Dmitri Nikulin <>
List: current-users
Date: 11/10/2004 18:18:24
Sean Davis wrote:

> My main question is... is there any advantage to be gained by enabling
> the ioapic support in the kernel? It is currently disabled, and the
> box runs just fine... but this is also my first machine to even HAVE
> an APIC, so I know jack about it.
> Any advice is appreciated.
Where ACPI configures devices for you, the APIC routes IRQs and handles 
processor information (vital for SMP, optional for UP). Handy since this 
usually gets the 'optimal' configuration, and means modern standards (no 
static BIOS fetching for device configs) are complied with (people who 
know more than me, please correct this, since I know it's a 
misunderstanding). Linux, Free and NetBSD all do this now if you have 
the support in the kernel.

I'm not sure if it has any real impact on performance, that's something 
only a low-level developer could tell you. I certainly haven't noticed 
any difference. But it does make dmesg look cooler :)

How old were your previous machines? My oldest machine (runs NetBSD :D) 
is a P3 1Ghz laptop (Dell Latitude C800) and it has an APIC. I remember 
having a P3 700 (Precision 410) before that which had an APIC but no 
working ACPI.

-Dmitri Nikulin