Horton

Re: Popcount optimization using AVX512

Nathan Bossart <nathandbossart@gmail.com>

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From: Nathan Bossart <nathandbossart@gmail.com>
To: Raghuveer Devulapalli <raghuveer.devulapalli@intel.com>
Cc: pgsql-hackers@lists.postgresql.org
Date: 2024-10-31T19:21:24Z
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. Fix __attribute__((target(...))) usage.

  2. Use __attribute__((target(...))) for AVX-512 support.

  3. Fix code for probing availability of AVX-512.

  4. Optimize visibilitymap_count() with AVX-512 instructions.

  5. Optimize pg_popcount() with AVX-512 instructions.

  6. Inline pg_popcount() for small buffers.

  7. Avoid function call overhead of pg_popcount() in syslogger.c.

  8. Refactor code for setting pg_popcount* function pointers.

  9. Inline pg_popcount{32,64} into pg_popcount().

  10. Remove MSVC scripts

  11. Use ARMv8 CRC instructions where available.

  12. Use Intel SSE 4.2 CRC instructions where available.

Attachments

On Wed, Oct 30, 2024 at 04:10:10PM -0500, Nathan Bossart wrote:
> 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.

Here is an updated patch with this change.

-- 
nathan