Gustavo Luiz Duarte <gustavold@linux.vnet.ibm.com> wrote on 01/20/2016 08:51:06 AM:

> From: Gustavo Luiz Duarte <gustavold@linux.vnet.ibm.com>

> To: Florian Weimer <fweimer@redhat.com>
> Cc: ppc@lists.fedoraproject.org, Dan Horák <dan@danny.cz>, carlos@redhat.com
> Date: 01/20/2016 08:57 AM
> Subject: Re: revisiting the architecture support on Power
>
>
> On 01/20/2016 10:13 AM, Florian Weimer wrote:
> > On 01/20/2016 12:16 PM, Dan Horák wrote:
> >
> > > The Fedora infrastructure is currently using Power8 HW for the main Koji
> > > build system [1] to produce the binary rpms for the distrobution and we
> > > have planned to reuse the previous Power7+ builders for COPR [2] and
> > > Fedora Cloud.
> > >
> > > Carlos, Florian, could you please comment on the situation?
> >
> > Dan,
> >
> > I think there is a fundamental misunderstanding here.  As long as their
> > is active upstream support, the glibc team will provide whatever
> > architectures you request, and make a best-effort attempt at isolating
> > issues.  (Personally, I lack ppc64 assembly knowledge, so it's rare that
> > I can fix architecture-specific bugs.)
> >
> > We declined to fix bug 1295797 because the Fedora POWER wiki page
> >
> > <https://fedoraproject.org/wiki/Architectures/
> PowerPC#Supported_Architectures>
> >
> > clearly says that on ppc64le, the minimum architecture requirement is
> > POWER8.  If this is not what you want, please update the wiki page, make
> > sure that both gcc, redhat-rpm-config, and binutils have been configured
> > in the appropriate way, and rebuild glibc to see if the problematic
> > instructions are still there.  If you have trouble getting the toolchain
> > side sorted out, please let me know.  Bug 1295797 appears to be a
> > toolchain configuration issue because the offending file is not compiled
> > with -mcpu=power8 or anything like that (assuming that the debugging
> > information can be trusted, which says that it's not the POWER8 memcpy
> > which triggers the crash, but the C implementation).
> >
> > But the key task for you is that you need to decide what you want and
> > document that.  On the glibc side, we do not have a strong preference
> > for POWER8.  POWER7 should just work fine for ppc64le with a
> > properly-configured toolchain.  (Earlier architecture versions may be
> > more difficult, I have not checked that.)
>
> I understand that there are benefits to moving up to POWER8, and
> that includes performance gain and we will be safer in a completely
> supported setup (supported by IBM and upstream communities).
>
> On the other hand, the fact that POWER7 is able to run little endian
> has helped Fedora a lot (we built the whole ppc64le distro solely
> based on POWER7). Moving to POWER8 as a requirement now would have a
> great impact on those people who are in the same situation we were
> not long ago, relying on POWER7 hardware to run little endian.
>
> I vote for updating the wiki and keep the POWER7 support on ppc64le
> for now. We can always re-evaluate this decision in the future if we like.


The wiki page is correct.  IBM will not be supporting LE on the P7+ architecture.
There are no customers using that setup, it requires a special version of FW in
order to run as well.  So from an IBM point of view LE is support on Power 8 and
newer systems only.  

As far as I know Power7 LE is only in the labs for build machines etc.  I will work
with the Fedora release and infrastructure folks to see what P8 only will mean to them.

thanks
Mike Wolf
>
> []'s
> Gustavo
>
> >
> > Florian
> > _______________________________________________
> > ppc mailing list
> > ppc@lists.fedoraproject.org
> > http://lists.fedoraproject.org/admin/lists/ppc@lists.fedoraproject.org
> >
> _______________________________________________
> ppc mailing list
> ppc@lists.fedoraproject.org
> http://lists.fedoraproject.org/admin/lists/ppc@lists.fedoraproject.org