Re: SMP or UP???

[Helge Hafting]

DervishD wrote:
>     Hi Mikael :)
>
>  * Mikael Pettersson <mikpe@xxxxxxxxx> dixit:
>
> > > kernel: found SMP MP-table at 000fb210
> > >   What, SMP table?
> >
> > You have an anti-problem. The chipset includes an I/O-APIC
> > (good) and your mobo manufacturer was decent enough to include
> > the appropriate BIOS MP tables to describe it to the OS.
>
>
>     Oh, nice. I thought that the mobo was a simple reisuing of a SMP
> mobo from Gigabyte with one socket removed O:)
>
>
> > Other manufacturers skip the MP table, forcing you to enable
> > ACPI and pray it actually works. 
>
>
>     Excuse my ignorance but: why a UP system needs the MP table? Why
> the I/O-APIC needs anything related with multiprocessor in an UP
> system?. I lost my way on hardware back in the 486, I think...
The MP table tells the kernel details about that I/O-APIC.
(Advanced Programmable Interrupt Controller).

This isn't really about SMP, but every SMP board has
one or more APICs.  They have to.  It is optional
on a uniprocessor board, but it is nice to have as it
gives lower interrupt latency.

Helge Hafting

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