RE: Popcount optimization using AVX512

> -----Original Message-----
> From: Amonson, Paul D <paul.d.amonson@intel.com>
> Sent: Friday, March 15, 2024 8:31 AM
> To: Nathan Bossart <nathandbossart@gmail.com>
...
> When I tested the code outside postgres in a micro benchmark I got 200-
> 300% improvements. Your results are interesting, as it implies more than
> 300% improvement. Let me do some research on the benchmark you
> referenced. However, in all cases it seems that there is no regression so should
> we move forward on merging while I run some more local tests?

When running quick test with small buffers (1 to 32K) I see up to about a 740% improvement. This was using my
stand-alonemicro benchmark outside of PG. My original 200-300% numbers were averaged including sizes up to 512MB which
seemsto not run as well on large buffers.  I will try the referenced micro benchmark on Monday. None of my benchmark
testingused the command line "time" command. For Postgres is set "\timing" before the run and for the stand-alone
benchmarkis took timestamps in the code. In all cases I used -O2 for optimization. 

Thanks,
Paul