On 11/09/2024 15:38, Srirama Kucherlapati wrote:
I still don't understand. We have Linux powerpc systems running
happily in the buildfarm. They are happy with the current spinlock
implementation. Why is this needed? What happens without it?
Not sure, by the time the below commits were made if there was a
consideration to use the gcc routines.
The PPC asm code was originally written in 2002, and the first use of
__sync_lock_test_and_set(), for ARM, appeared in 2012. The commit that
made __sync_lock_test_and_set() be chosen automatically for platforms
that don't specify anything else was added in 2022.
I tried to replace the AIX asm (under__ppc__ macro) with the gcc
routine __sync_lock_test_and_set(), and all the buildfarm tests
passed. Attached patch and the buildfarm output. Please let me know
your feedback.
Ok, if we don't need the assembler code at all, that's good. A patch to
introduce AIX support should not change it for non-AIX powerpc systems
though. That might be a good change, but would need to be justified
separately, e.g. by some performance testing, and should be a separate
patch.
If you make no changes to s_lock.h at all, will it work? Why not?
You said earlier:
I mean this part of the code is needed as this is specific to AIX kernel memory
operation which is different from __sync_lock_test_and_set().
I would like to mention that the changes made in src/include/storage/s_lock.h
are pretty much required and need to be operated in assemble specific to IBM
Power architecture.
Was that earlier statement incorrect? Is the manual wrong or outdated or
not applicable to us?
Moving on..
Do you still need mkldexport.sh? Surely there's a better way to do that
in year 2024. Some quick googling says there's a '-bexpall' option to
'ld', which kind of sounds like what we want. Will that work? How do
other programs do this?
--
Heikki Linnakangas
Neon (https://neon.tech)
