[PATCH] powerpc: update ibm,client-architecture
Michael Neuling
mikey at neuling.org
Tue Dec 22 08:12:15 EST 2009
> >> Subject: Re: [PATCH] powerpc: update ibm,client-architecture
> >>
> >
> > Please give this a more appropriate name.
> >
> Any suggestions?
Something that's more descriptive of what the patch does. Say "Add
max CPU nodes field to ibm,client-architecture call"
> >
> >> In order to boot with more than 64 cores on machines that support the
> >> ibm,client-architecture RTAS call a new field has been added to the
> >> structure. This patch updates that field and adds a few others in the
> >> process.
> >>
> >
> > Please detail what these are here.
> >
> OK.
> >> + W(NR_CPUS/4), /* max cores supported */
FYI reading the PAPR, this comment should technically be "max 'cpu'
nodes presented".
> >>
> >
> > 4?
> >
> >
> 4 is the new 2.
I'd still be asking what 2 is. It's needs a #define to make clearer
what you are doing.
> Since you don't know the actual threads per core at
> this point in boot you have to be conservative and go with the maximum
> number of any processor. See page 4 of these charts:
> http://www.power.org/events/powercon09/taiwan09/IBM_Overview_POWER7.pdf
I don't think hard wiring 4 in here is right. If we are booting a
machine with SMT2, we will put only half the number of cores that we can
handle in this field. This is going to break a lot of machines where
people have compiled with NR_CPUS = thread number.
I think you just want to put NR_CPUS here.
Mikey
> >
> >
> > Can we do this now or remove the comment. Maybe UTS_RELEASE or
> > something like that.
> >
> I'll just remove the comment for now.
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