SMP ia32 support with Pistachio

[Daniel Waddington]

Hi Stefan,
We did finally manage to get it working!  The problem was the Pistachio
kernel's support for IO Flex pages doesn't work - and non-virtual TCB are
needed atleast with SMP enabled.  New mapping seems OK.  My next step is to
try to build the rest of the Genode demo.

> Do you plan to extend Genode's cpu-session interface to support an
> explicit cpu-migration of threads, or do you want to do load-balance
> somehow implicitly?

As far as this, I am currently not sure.  We are really just surveying the
landscape and seeing what we can get to work, as well as gaining a better
understanding of where things are.  We are actually looking at extending
Pistachio to a multikernel for multicore processors - ultimately.  

Thanks for the help,
Daniel

> -----Original Message-----
> From: Stefan Kalkowski [mailto:stefan.kalkowski at ...1...]
> Sent: Friday, January 14, 2011 7:57 AM
> To: genode-main at lists.sourceforge.net
> Subject: Re: SMP ia32 support with Pistachio
> 
> Hello Daniel,
> 
> On 01/14/2011 12:52 AM, Daniel Waddington - SISA wrote:
> > Hi,
> >
> >
> >
> > Has anyone managed to get Pistachio+Genode with SMP+ia32 running?  We
> > have managed to get Pistachio+Genode+ia32 without SMP working fine.
> 
> that's nice to hear!
> 
> > As soon as we compile SMP it goes into an endless loop.
> >
> >
> >
> > Any ideas?
> 
> Well, I'm not sure what you exactly mean by 'it goes into an endless
> loop'. Do you mean the kernel or Genode's core? Do you have some serial
> output, or can you even enter the kernel-debugger?
> 
> In fact we normally only use the single-processor version of pistachio.
> Nevertheless, we've tested SMP support today, and there seems to be a
> general problem with SMP in the current version of pistachio. We got
> different races sometimes even before 'core' (Genode's roottask) got
> started.
> 
> In older versions of pistachio, SMP support seems to work, but there we
> got minor problems with the old mapping-database. Possibly the SMP
> version doesn't use the new mapping database implementation, at least
> in
> the version we've tested (from 08.01.2010). Probably, Genode can easily
> be reworked to use the old mapping semantic, but it has known stability
> problems.
> 
> I think a better way is to solve the presumptive, current SMP support
> problem in pistachio directly. You might ask the pistachio developers
> for help[1]. Maybe you can reproduce the SMP problems with a tiny
> example application?
> 
> Once, the pistachio port of Genode (formerly known as Bastei) was done
> by Julian Stecklina[2] as study work, he successfully implemented
> rudimentary SMP support into the cpu-session interface of Genode. So at
> least at that point SMP worked with the predecessor of Genode together,
> but that experimental code isn't part of Genode today.
> 
> Do you plan to extend Genode's cpu-session interface to support an
> explicit cpu-migration of threads, or do you want to do load-balance
> somehow implicitly?
> 
> >
> > Thanks
> > Daniel Waddington
> >
> 
> You're welcome.
> 
> regards
> Stefan Kalkowski
> 
> [1] http://l4ka.org/maillist.php
> [2] http://os.inf.tu-dresden.de/papers_ps/jstecklina-beleg.pdf
> 
> --
> Stefan Kalkowski
> Genode Labs
> 
> http://www.genode-labs.com/ · http://genode.org/
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