PPC/PPC64 disabled in Koji for dist-f13

Kevin Kofler kevin.kofler at chello.at
Thu Oct 1 00:58:15 UTC 2009


Jeff Garzik wrote:
> I would rather the problem be approached in a logical, scalable fashion:
> by distributing the workload across the package maintainers who have
> firsthand knowledge.  ie. how things worked before.
> 
> But you're dodging the larger point -- Fedora has, de facto, demoted big
> endian support in its entirety to a second-hand effort, rather than
> distributed the workload much more widely.  Given M package maintainers
> and N secondary-platform volunteers, it is clear M > N by orders of
> magnitude.

I think it is only fair that the people who actually care get to do the 
work. Package maintainers can still fix their packages for PPC, they'll even 
get e-mail reports from the secondary arch Koji if the builds fail. (It 
already happens for the other secondary architectures.) They just won't be 
required to do it anymore. You can't force volunteers (and many Fedora 
developers are volunteers; even those paid by RH are paid primarily to work 
on RHEL, not Fedora, and often do Fedora work in their own free time) to 
work on something they're not interested in.

> Was ppc really such a burden?

Yes. It slowed down builds, and it often triggered bizarre build failures 
which were NOT bugs in the program, but in the toolchain or in some core 
library like glibc, which in turn delayed important updates to the affected 
packages.

In fact, my "favorite" ppc64 issue was a problem with OpenBabel hitting a 
limitation in the ppc64 toolchain: there's a "table of contents" which can 
grow only to a small fixed size, so large compilation units just don't 
compile on ppc64, while being perfectly valid C/C++ and compiling fine on 
all other architectures. (And that's already with the "minimal TOC". Without 
it, the limit is for the whole executable!) OpenBabel's SWIG-generated 
bindings exceeded that limit. We were the only ones hitting it as no other 
distribution is insane enough to build their packages for ppc64. (The 
binaries don't even get actually used as ppc32 is the preferred multilib on 
64-bit PowerPC!) I played around with both compiler and SWIG flags to reduce 
the amount of TOC entries, which worked for 2 beta releases (requiring 
additional tweaking for the second one), but then it overflowed again. This 
was a big annoyance because the new OpenBabel betas were required for new 
kdeedu betas in Rawhide, so this stalled our KDE work. In the end, upstream 
removed some things from their bindings to get them to build, a quite 
suboptimal solution. IMHO the ppc64 ABI is just completely broken and needs 
to be redesigned from scratch.

        Kevin Kofler




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