Horton

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

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>, Bastien Roucariès <rouca@debian.org>, pgsql-bugs@lists.postgresql.org
Date: 2024-11-01T06:16:32Z
Lists: pgsql-bugs 
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?)

			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.