Horton

Re: AIX support

Heikki Linnakangas <hlinnaka@iki.fi>

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From: Heikki Linnakangas <hlinnaka@iki.fi>
To: Srirama Kucherlapati <sriram.rk@in.ibm.com>, Heikki Linnakangas <hlinnaka@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>
Cc: Peter Eisentraut <peter@eisentraut.org>, Alvaro Herrera <alvherre@alvh.no-ip.org>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>, Laurenz Albe <laurenz.albe@cybertec.at>, Noah Misch <noah@leadboat.com>, Michael Paquier <michael@paquier.xyz>, Andres Freund <andres@anarazel.de>, Thomas Munro <thomas.munro@gmail.com>, "tvk1271@gmail.com" <tvk1271@gmail.com>, "postgres-ibm-aix@wwpdl.vnet.ibm.com" <postgres-ibm-aix@wwpdl.vnet.ibm.com>, Bruce Momjian <bruce@momjian.us>
Date: 2024-09-11T21:57:33Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Restore AIX support.

  2. pg_createsubscriber: Improve error messages.

  3. Use <stdint.h> and <inttypes.h> for c.h integers.

  4. Stabilize jsonb_path_query test case.

  5. Fix C23 compiler warning

  6. pg_stat_statements: Add tests for nested queries with level tracking

  7. Add missing newline at the end of index_including.sql

  8. Remove AIX support

  9. Fix s_lock.h PPC assembly code to be compatible with native AIX assembler.

  10. Use a non-locking initial test in TAS_SPIN on PPC.

  11. Use LWSYNC in place of SYNC/ISYNC in PPC spinlocks, where possible.

  12. Use mutex hint bit in PPC LWARX instructions, where possible.

  13. Adjust TAS assembly as per recent discussions: use "+m"(*lock) everywhere

  14. Apple's assembler likes the inlined TAS syntax too, so no reason to

  15. Tighten up register usage for inline PPC version of tas().

  16. Put the isync where it's supposed to be.

  17. > > I'll re-check that with the ppc architecture guy here.

  18. Fix PPC s_lock operations to work correctly on multi-CPU machines.

  19. I tried to build PostgreSQL with the following step to see backends hung

  20. Complete merge of all old man page information.

  21. s_lock aix patch.

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)