Re: Popcount optimization using AVX512

On 2024-Jan-25, Alvaro Herrera wrote:

> Finally, the matter of using ifunc as proposed by Noah seems to be still
> in the air, with no patches offered for the popcount family.

Oh, I just realized that the patch as currently proposed is placing the
optimized popcount code in the path that does not require going through
a function pointer.  So the performance increase is probably coming from
both avoiding jumping through the pointer as well as from the improved
instruction.

This suggests that finding a way to make the ifunc stuff work (with good
performance) is critical to this work.

-- 
Álvaro Herrera        Breisgau, Deutschland  —  https://www.EnterpriseDB.com/
"The ability of users to misuse tools is, of course, legendary" (David Steele)
https://postgr.es/m/11b38a96-6ded-4668-b772-40f992132797@pgmasters.net