Bug 427823 - RFE: Build PPC970 tuned addon
RFE: Build PPC970 tuned addon
Product: Fedora
Classification: Fedora
Component: glibc (Show other bugs)
powerpc Linux
low Severity low
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Assigned To: Jakub Jelinek
Fedora Extras Quality Assurance
Depends On:
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Reported: 2008-01-07 13:15 EST by Josh Boyer
Modified: 2008-01-07 18:02 EST (History)
1 user (show)

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Doc Type: Bug Fix
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Last Closed: 2008-01-07 17:48:08 EST
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Description Josh Boyer 2008-01-07 13:15:37 EST
Description of problem:

Glibc includes the power6/power6x cpu-addon libraries, which are tuned for
power6 processors.  That is great.  However, most of Fedora's PPC64 userbase
would be based on the PPC970 processor.  That is used in all of the G5 based
Apple machines, as well as JS20/JS21 IBM blades.

Would it be possible to build the ppc970 tuned libraries in addition to
power6/power6x?  I believe this would benefit the majority of Fedora PowerPC users.
Comment 1 Josh Boyer 2008-01-07 17:33:45 EST
As a side note, it seems when building for power6 you build some kind of
emulation library if you aren't running on a power6 machine.  Couldn't you avoid
that by using cross-compiling=yes?
Comment 2 Jakub Jelinek 2008-01-07 17:48:08 EST
No, already the power6 optimized ones double the build and testing time, adding
some other variant is just not a good idea.
cross-compiling=yes is a bad idea, glibc with the few small hacks to avoid using
the newly built ld.so during building builds just fine for power6 even on
pre-power6 CPUs.  The emul hack is there just so that it can be somewhat tested
with make check even on earlier CPUs (though that works only on Altivec capable
CPUs, unfortunately koji build boxes don't have even that and I really don't
want to write altivec emulator).
Comment 3 Josh Boyer 2008-01-07 18:02:30 EST
Hm.  I understand the reluctance to extending build and test time for official
releases.  It's unfortunate that we can't build for the majority of the desktop
machines out there though.

Would you take a patch that adds conditional building (similar to power6) for
970 with the default being disabled?

Also, the koji builders should be switching to ppc970 blades soon as the
bladecenter is phased in.

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