Re: 2.6.18-mm2

Ingo Molnar
2006-09-29T20:40:39Z

* Andi Kleen <ak@suse.de> wrote:

> On Friday 29 September 2006 22:14, Ingo Molnar wrote:
> >
> > * Andi Kleen <ak@suse.de> wrote:
> >
> > > BTW I was planning to make LOCAL_APIC unconditional on i386 too like
> > > on x86-64.
> >
> > please dont - embedded doesnt need it most of the time.
>
> What do you mean with not need? Local APIC is an infinitely better
> interface than PIC and faster. On embedded too this makes a lot of
> sense.

it's just not present or hardware-disabled.

> And a lot of modern systems don't even work anymore without APIC
> enabled because Windows uses it and the BIOS haven't been tested
> without it (e.g. you often find totally broken code paths in the AML
> for PIC mode)
>
> The code size also isn't a good argument because the delta
> isn't that big:
>
> text data bss dec hex filename
> 3303894 694980 436420 4435294 43ad5e obj32-up/vmlinux
> 3266532 665732 402372 4334636 42242c obj32-up-noapic/vmlinux
>
> ~63K.

63K???? You've got to be kidding. That's huge. That's ~10% of the
minconfig kernel. Even 1K would be bad. We did config hacks for half a K
win. Please ... dont cripple the i686 kernel.

Ingo