Horton

Re: Detection of hadware feature => please do not use signal

Bastien Roucariès <rouca@debian.org>

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From: Bastien Roucariès <rouca@debian.org>
To: Thomas Munro <thomas.munro@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>, pgsql-bugs@lists.postgresql.org
Date: 2024-11-01T10:20:03Z
Lists: pgsql-bugs 
Le vendredi 1 novembre 2024, 06:16:32 UTC Tom Lane a écrit :
> I wrote:
> > Hmm.  So it seems like we could do this:
> > * Linux, FreeBSD, OpenBSD: do run-time test as recommended
> > * Windows, macOS: assume that supported ARM hardware can do this
> > * anything else: assume no hardware CRC
> 
> Actually, after chewing on that second point awhile longer,
> how about this modest proposal:
> 
> * Drop all code for run-time determination of ARM CRC support.
> Assume it's there unless user builds with a -march option that
> says it definitely isn't.
> 
> Realistically, exactly who is going to be running Postgres 18+
> on ARM hardware that lacks CRC support?  I can think of lots of
> projects that are more worthy of our time than this.
> 
> (Perhaps it's time to apply the same mindset to x86 CRC support
> too?)

arm64 baseline for debian is without CRC so I will prefer to keep crc32

Bastien
> 
> 			regards, tom lane
>

Commits

  1. Update configure probes for CFLAGS needed for ARM CRC instructions.

  2. Support runtime CRC feature probing on NetBSD/ARM using sysctl().

  3. Use auxv to check for CRC32 instructions on ARM.

  4. Improve our method for probing the availability of ARM CRC instructions.