Re: add AVX2 support to simd.h

Nathan Bossart <nathandbossart@gmail.com>

From: Nathan Bossart <nathandbossart@gmail.com>

To: John Naylor <johncnaylorls@gmail.com>

Cc: Ants Aasma <ants@cybertec.at>, pgsql-hackers@postgresql.org

Date: 2024-03-25T15:21:21Z

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 →

Improve style of pg_lfind32().
- 7188a7806d20 17.0 landed
Fix compiler warning for pg_lfind32().
- 1f42337be535 17.0 landed
Micro-optimize pg_lfind32().
- 7644a7340c8a 17.0 landed
Introduce helper SIMD functions for small byte arrays
- 9f225e992bed 17.0 cited
Optimize xid/subxid searches in XidInMVCCSnapshot().
- 37a6e5df3713 16.0 cited

On Mon, Mar 25, 2024 at 10:03:27AM +0700, John Naylor wrote:
> Seems pretty good. It'd be good to see the results of 2- vs.
> 4-register before committing, because that might lead to some
> restructuring, but maybe it won't, and v8 is already an improvement
> over HEAD.

I tested this the other day [0] (only for x86).  The results seemed to
indicate that the 4-register approach was still quite a bit better.

> /* Process the remaining elements one at a time. */
> 
> This now does all of them if that path is taken, so "remaining" can be removed.

Right, will do.

[0] https://postgr.es/m/20240321183823.GA1800896%40nathanxps13

-- 
Nathan Bossart
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