Re: Enable SMP support

[James Clarke]

On 8 Jun 2018, at 18:06, Joshua Branson <jbranso@fastmail.com> wrote:
> 
> Almudena Garcia <liberamenso10000@gmail.com> writes:
> 
>> Hi all:
>> 
>> Reading this post in Hurd FAQ, I read that Mach has SMP support, but It was 
>> disabled because the Linux device drivers glue code isn't thread-safe.
>> 
>> https://www.gnu.org/software/hurd/faq/smp.html
>> 
>> Then, I ask . Are there any form to enable this SMP support in GNU Mach? (At 
>> my own risk).
>> 
>> I would like to test it.
>> 
>> P.D.: It's only a curiosity, not an urgency
> 
> That actually sounds like really fun!  haha.  I bet it would involve
> diving into the mach code...I believe that the Hurd currently uses
> drivers from linux via DDE.  A lot of that code was shoved into
> GNU/Mach.  You'd have to pull it out, or find the commandline option to
> not compile it in...but I don't know how to do it.

From gnumach's configfrag.ac:

> # Multiprocessor support is still broken.
> AH_TEMPLATE([MULTIPROCESSOR], [set things up for a uniprocessor])
> mach_ncpus=1
> AC_DEFINE_UNQUOTED([NCPUS], [$mach_ncpus], [number of CPUs])
> [if [ $mach_ncpus -gt 1 ]; then]
>   AC_DEFINE([MULTIPROCESSOR], [1], [set things up for a multiprocessor])
> [fi]

So enabling it is just a case of tweaking that constant or making it a
configurable option.

James