Re: Comments about SMP

[Damien Zammit]

Hi Almudena,

> El dom., 10 mar. 2019 a las 18:35, Samuel Thibault
> (<samuel.thibault@gnu.org <mailto:samuel.thibault@gnu.org>>) escribió:
>     Adam Van Ymeren, le dim. 10 mars 2019 13:08:23 -0400, a ecrit:
>     > I don't think that's necessary.  The process doesn't have to
>     initiated from gnumach.  Hurd could have an SMP server that is
>     started at boot, parses acpi tables and calls in to Mach to
>     initialize the additional cores and start scheduling on them.
> 
>     That's the idea.

I'm not sure if it is required to send IPI etc, doesn't the BIOS set up
the extra cores?  I've seen code in coreboot that sets up the extra
cores.  I thought you only need the ACPI tables to know how many cores
to use and pass this value somehow to Mach (?)

See
https://github.com/AlmuHS/GNUMach_SMP/blob/5bceb7fc20176b75ed3284ca3fc9856dfe2cd158/configfrag.ac#L33

It appears mach_ncpus is hardcoded at compile time, maybe you just need
to detect this value via ACPI (?) Maybe someone else can comment on how
"broken" is multiprocessor support as specified in that inline comment.

Damien