Open MPI logo

Hardware Locality Development Mailing List Archives

  |   Home   |   Support   |   FAQ   |   all Hardware Locality Development mailing list

Subject: Re: [hwloc-devel] hwloc powerpc rhel5 and power7 patch
From: Samuel Thibault (samuel.thibault_at_[hidden])
Date: 2010-09-16 04:49:51


Alexey Kardashevskiy, le Thu 16 Sep 2010 15:57:47 +1000, a écrit :
> >Is the device tree linux-specific ? If so, it can stay in linux file as
> >long as it's not 30k lines :) We already have both sysfs and
> >/proc/cpuinfo code there anyway.
>
> It is powerpc-specific. It is mapped from the system firmware (aka bios)
> by the powerpc kernel. However it is just a folder within /proc so it is
> usual linux folder. But PowerPC might be not the only architecture which
> uses the same pathname for the same thing.

Apparently microblaze uses it too, but it doesn't provide the cpus/
subdirectory.

> >>- may be there is a better way to detect that no cache info was
> >>fetched from sysfs
> >>
> >That's something that's not clear to me yet. There will likely be other
> >cases in the future where we will fetch some info from different
> >backends, and merging them may not be easy. Do you think the device tree
> >generally contains more information than sysfs? If so, we could start by
> >disabling cache info from sysfs when a device-tree is found, and maybe
> >have a way to change that default (we already have a hidden en variable
> >to use cpuinfo when sysfs is available).
>
> See my note above about the system firmware :) Almost every powerpc
> system has device-tree no matter which OS you run on it (sony ps3 is
> probably the only exception). /proc/device-tree is the only source for
> sysfs on powerpc linux.

Do you perhaps happen to know where it might be on AIX?

Samuel