Re: maximum number of CPUs

[Mindaugas Rasiukevicius <rmind%netbsd.org@localhost>]

Manuel Bouyer <bouyer%antioche.eu.org@localhost> wrote:
> > I have a preliminary patch to support up to 255 CPUs on amd64 (not worth
> > on i386), however there is still some bug in the early initialisation
> > code, when TLBs are not being flushed.  I have not had time yet to
> > debug it out.
> > 
> > http://www.netbsd.org/~rmind/x86_256_cpus_v4.diff
> > 
> > Apart from that bug, it should be mostly complete.
> 
> It looks like the patch need to be updated for the latest Xen pmap :)

Right.  Patch synced with HEAD changes, if somebody enjoys debugging:

http://www.netbsd.org/~rmind/x86_256_cpus_v5.diff

> Please make as little assumption as possible about the number of
> CPUs Xen supports. I need to do a bit more reverse-ingeenering on
> the interface, but I guess hypercalls like MMUEXT_INVLPG_MULTI takes
> an array of uint32_t, so we can use more than 32 cpus here as well.

I just did mechanical update for Xen to use kcpuset(9) interface.  Xen can
be updated to support more CPUs later (if hypercalls allow suport that).

-- 
Mindaugas