On Wed, May 31, 2023 at 06:03:01PM +1200, David Rowley wrote:
> I don't think this should go under "E.1.3.11. Source Code". The patch
> was entirely aimed to increase performance, not just of allocations
> themselves, but of any operations which uses palloc'd memory. This is
> due to the patch increasing the density of memory allocation on blocks
> malloc'd by our memory context code so that fewer CPU cache lines need
> to be touched in the entire backend process for *all* memory that's
> allocated with palloc. The performance increase here can be fairly
> significant for small-sized palloc requests when CPU cache pressure is
> high. Since CPU caches aren't that big, it does not take much of a
> query to put the cache pressure up. Hashing or sorting a few million
> rows is going to do that.
>
> The patch here was born out of the regression report I made in [1],
> which I mention in [2] about the prototype patch Andres wrote to fix
> the performance regression.
>
> I think "E.1.3.1.2. General Performance" might be a better location.
> Having it under "Source Code" makes it sound like it was some
> refactoring work. That's certainly not the case.
Okay, moved.
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EDB https://enterprisedb.com
Only you can decide what is important to you.