Re: Optmize bitmapword macros calc (src/backend/nodes/bitmapset.c) - Mailing list pgsql-hackers

From David Rowley
Subject Re: Optmize bitmapword macros calc (src/backend/nodes/bitmapset.c)
Date
Msg-id CAApHDvqJA9FmiKS5zoRceGFKUY8Y8-pBXVoGVJKyvMPLy=k6SQ@mail.gmail.com
Whole thread Raw
In response to Re: Optmize bitmapword macros calc (src/backend/nodes/bitmapset.c)  (Nathan Bossart <nathandbossart@gmail.com>)
Responses Re: Optmize bitmapword macros calc (src/backend/nodes/bitmapset.c)
List pgsql-hackers
On Tue, 30 Jan 2024 at 08:32, Nathan Bossart <nathandbossart@gmail.com> wrote:
> I'm currently +0.1 for this change.  I don't see any huge problem with
> trimming a few instructions, but I'm dubious there's any measurable impact.
> However, a cycle saved is a cycle earned...

FWIW, In [1] and subsequent replies, there are several examples of
benchmarks where various bitmapset functions are sitting high in the
profiles. So I wouldn't be too surprised if such a small change to the
WORDNUM and BITNUM macros made a noticeable difference.

A benchmark speaks a thousand words, however.

David

[1] https://postgr.es/m/CAApHDvq9eq0W_aFUGrb6ba28ieuQN4zM5Uwqxy7+LMZjJc+VGg@mail.gmail.com



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