On 01/20/2016 12:16 PM, Dan HorĂ¡k 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_Architectu...
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.)
Actually POWER7 does not work just fine for ppc64le. Unaligned
load/stores take a big performance hit for micro-code in LE mode.
POWER7LE require special firmware and was only intended as a lab/disro
bring up platform for LE development. IBM does not support POWER7LE for
production use.
POWER8 was designed from the ground up for LE and is the first
officially supported LE platform for general availability.