| From: | Nathan Bossart <nathandbossart(at)gmail(dot)com> | 
|---|---|
| To: | John Naylor <johncnaylorls(at)gmail(dot)com> | 
| Cc: | Ants Aasma <ants(at)cybertec(dot)at>, pgsql-hackers(at)postgresql(dot)org | 
| Subject: | Re: add AVX2 support to simd.h | 
| Date: | 2024-03-21 18:38:23 | 
| Message-ID: | 20240321183823.GA1800896@nathanxps13 | 
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| Lists: | pgsql-hackers | 
On Thu, Mar 21, 2024 at 12:09:44PM -0500, Nathan Bossart wrote:
> On Thu, Mar 21, 2024 at 11:30:30AM +0700, John Naylor wrote:
>> Further, now that the algorithm is more SIMD-appropriate, I wonder
>> what doing 4 registers at a time is actually buying us for either SSE2
>> or AVX2. It might just be a matter of scale, but that would be good to
>> understand.
> 
> I'll follow up with these numbers shortly.
It looks like the 4-register code still outperforms the 2-register code,
except for a handful of cases where there aren't many elements.
-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com
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