Re: Popcount optimization using AVX512

Nathan Bossart <nathandbossart@gmail.com>

From: Nathan Bossart <nathandbossart@gmail.com>

To: Raghuveer Devulapalli <raghuveer.devulapalli@intel.com>

Cc: pgsql-hackers@lists.postgresql.org

Date: 2024-10-30T21:10:10Z

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 →

Fix __attribute__((target(...))) usage.
- 41b98ddb77bf 18.0 landed
Use __attribute__((target(...))) for AVX-512 support.
- f78667bd910e 18.0 landed
Fix code for probing availability of AVX-512.
- 598e0114a3b1 17.0 landed
Optimize visibilitymap_count() with AVX-512 instructions.
- 41c51f0c68b2 17.0 landed
Optimize pg_popcount() with AVX-512 instructions.
- 792752af4eb5 17.0 landed
Inline pg_popcount() for small buffers.
- deb1486c7d36 17.0 landed
Avoid function call overhead of pg_popcount() in syslogger.c.
- 4133c1f45c54 17.0 landed
Refactor code for setting pg_popcount* function pointers.
- 6687430c98f3 17.0 landed
Inline pg_popcount{32,64} into pg_popcount().
- cc4826dd5e52 17.0 landed
Remove MSVC scripts
- 1301c80b2167 17.0 cited
Use ARMv8 CRC instructions where available.
- f044d71e331d 11.0 cited
Use Intel SSE 4.2 CRC instructions where available.
- 3dc2d62d0486 9.5.0 cited

On Wed, Oct 30, 2024 at 08:53:10PM +0000, Raghuveer Devulapalli wrote:
> BTW, I just realized function attributes for xsave and avx512 don't work
> on MSVC (see
> https://developercommunity.visualstudio.com/t/support-function-target-attribute-and-mutiversioning/10130630).
> Not sure if you care about it. Its an easy fix (see
> https://gcc.godbolt.org/z/Pebdj3vMx).

Oh, good catch.  IIUC we only need to check for #ifndef _MSC_VER in the
configure programs for meson.  pg_attribute_target will be empty on MSVC,
and I believe we only support meson builds there.

-- 
nathan