Performance Chat Summary: 4 July 2023

Table of Contents

Announcements

Welcome to our new members of #core-performance
Many folks out today due to US 4 July holiday
Reminder of bug scrub tomorrow for a check on 6.3 issues
Early performance numbers on WP 6.3 beta is out: overall load time performance (represented by the “LCP” metric) sees a boost of a whopping ~26% for block themes and ~19% for classic themes [see Slack post]
For those that missed it, we have a special Performance Improvements for WordPress 6.3 Hallway Hangout scheduled on Thursday July 27 at 3:00pm UTC
Reminder that Beta 4 is next week on July 11 for the 6.3 release cycle

@spacedmonkey Mostly been supporting the beta release. I have also validated the number that Felix got, we are massively in the green for performance improves in WP 6.3
- While profiling, I did find this, https://core.trac.wordpress.org/ticket/58682 wp_trim_excerpt parses and renders blocks twice
- TLDR, excerpts are parsing blocks twice, which is really bad. I will look into that ticket in WP 6.4, as it has been a problem since 5.0. Only noticed now other performance has improved.

@spacedmonkey I did some testing on the lazy loading / fetchpriority changes. I found some places where these were not working:
- https://core.trac.wordpress.org/ticket/58680 Header image does not add fetch priority attribute
- https://core.trac.wordpress.org/ticket/58681 No lazy loading attribute on images in gallery
- https://core.trac.wordpress.org/ticket/58704 Image widget images do not support fetch priority or async
- I would say that header images (used by many core themes) and gallery shortcodes are pretty big issues that I would love to see fix in the WP 6.3 release cycle

@swissspidy I started looking into making the performance testing environment reusable. Nothing concrete to share yet though

@clarkeemily we have received a response from the Plugin Review team on the Dominant Color Images plugin and have some feedback to review. They found an issue that we are unable to replicate, so we are in the process of liaising with the Plugin Review team on this

@spacedmonkey Do we have a list of all the tickets that we want to have dev notes for?
- @clarkeemily I’m not aware of a specific list. We could work on collating one though if folks think it’s helpful
- @clarkeemily I know @10upsimon is working on one for Add support for HTML 5 “async” and “defer” attributes and @flixos90 is working on one for lazy loading and fetchpriority
- @mukesh27 As per report 19 tickets need dev notes
- @spacedmonkey I have 4 dev notes planned
@mukesh27 For the performance aspect, do we have only one developer note or are there multiple developer notes related to it?
- @clarkeemily My understanding is multiple, and there will be blog posts about a holistic review of 6.3 performance
- @spacedmonkey noted that @flixos90 is looking into a retro for WP 6.3. That will cover some of the other ticket that do not need dev notes but had an impact. We don’t normally write a dev note for things we just made faster under the hood.
- @spacedmonkey If anyone else has anything they think we should call out in docs or write dev notes, please reach out on this channel.