Jan Kiszka wrote:
> > > > - it does not work on SMP because the kgdb patch uses
> > > > smp_processor_id(), which does not work on SMP over Xenomai domain.
> > > >
> > >
> > > Ok, but probably fixable. If simple search&replace in the kgdb patch is
> > > not enough, a similar workaround could be applied for now: disallow kgdb
> > > usage over SMP.
> >
> > Since we are going to have this problem over and over again for each
> > patch that we want to adapt to xenomai (ltt comes to my mind), maybe we
> > could make smp_processor_id() in adeos patch safe to be called over non
> > root domain by using ipipe_processor_id() when called over non-root
> > domains.
> >
> > I think there is currently no code that take advantage of the fact that
> > the fast smp_processor_id() may safely be called over shadow threads, so
> > the performance penalty of using ipipe_processor_id() will be minimal.
> >
>
> What about the potential penalty for normal Linux callers of
> smp_processor_id()? Would this degrade the overall performance
> noticeably even if there is now kgdb or ltt? Or should we make this
> "ipipe-safe" smp_processor_id() optional for such users?
ipipe_current_domain uses ipipe_processor_id, so that replacing
smp_processor_id with :
if (ipipe_current_domain() == ipipe_root_domain)
return raw_smp_processor_id()
is really stupid...
--
Gilles Chanteperdrix.
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