Re: add AVX2 support to simd.h

Nathan Bossart <nathandbossart@gmail.com>

From: Nathan Bossart <nathandbossart@gmail.com>

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

Cc: John Naylor <johncnaylorls@gmail.com>, Ants Aasma <ants@cybertec.at>, pgsql-hackers@postgresql.org

Date: 2024-03-27T18:57:16Z

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

Attachments

v1-0001-improve-style-of-pg_lfind32.patch (text/x-diff)

On Tue, Mar 26, 2024 at 09:48:57PM -0400, Tom Lane wrote:
> Nathan Bossart <nathandbossart@gmail.com> writes:
>> I just did the minimal fix for now, i.e., I moved the new label into the
>> SIMD section of the function.  I think it would be better stylistically to
>> move the one-by-one logic to an inline helper function, but I didn't do
>> that just in case it might negatively impact performance.  I'll look into
>> this and will follow up with another patch if it looks good.
> 
> Sounds like a plan.

Here's what I had in mind.  My usual benchmark seems to indicate that this
shouldn't impact performance.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com