[Rtai] maxcpus kernel parameter

[mantegazza at aero.polimi.it]

>
>
> On Sun, 28 Sep 2008 mantegazza at aero.polimi.it wrote:
>
>> >
>> > Hi everybody,
>> >
>> > I tried using maxcpus=1 kernel parameter hoping that would magically
>> fix
>> > things. This parameter tells kernel to boot one CPU only and leave the
>> > three others alone.
>> >
>> > My code however did not start, it printed the following error message:
>> >
>> > APIC error on CPU0: 00(04)
>> >
>> > Still I have high hopes for this method. Since the kernel is
>> completely
>> > oblivious of the other CPUs (they do not show up in top, nor in
>> > /proc/interrupts) this might work well for us if we can find a way to
>> run
>> > the code on one of the "missing" CPUs.
>> >
>>
>> But then you must be able to boot them up.
>
>
> Which brings up a question, is there a way to boot them up? :)

Yes, reading specs and suggestions of the CPU manifacturer, possibly just
to understand well what Linux does already and then copying it in the
appropriate way. Once upon a time I was able to prepare my boostrapping,
but only up to 286 CPUs. Looking at Linux now and remebering how missing
the least thing took days to fix I'm glad to have to do it nomore. Clearly
once it is done and working it is for ever. Notice it is just my small
experience.

Paolo.