Performance Chat Summary: 19 September 2023

Meeting agenda here and the full chat log is available beginning here on Slack.


Priority Projects

Server Response Time

Link to roadmap projects

Contributors: @joemcgill @spacedmonkey @aristath

@swissspidy @thekt12 @mukesh27

Database Optimization

Link to roadmap projects

Contributors: @spacedmonkey @mukesh27

JavaScript & CSS

Link to roadmap project

Contributors: @mukesh27 @10upsimon @westonruter @spacedmonkey


Link to roadmap projects

Contributors: @flixos90 @thekt12 @joemcgill @pereirinha @spacedmonkey


Link to roadmap projects

Contributors: @adamsilverstein @joemcgill @mukesh27 @swissspidy @flixos90

  • @flixos90 Last week I spent some time conducting field analyses to assess the performance impact of the WordPress 6.3 release. Primarily focusing on Web Vitals metric LCP which measures load time performance, and how it’s affected both in general, but also specifically by the two major enhancements that were projected to affect LCP:
    • the emoji loader script optimizations
    • the lazy-loading plus fetchpriority improvements
  • Sharing the most important highlights:
    • Overall, the Largest Contentful Paint (LCP) passing rate has improved by 5.6% for classic theme sites and by 2.7% for block theme sites 
    • The Largest Contentful Paint (LCP) boost for classic theme sites using the emoji loader script is 3.4% to 7% higher than for those that don’t use it, and for block themes it’s 0.7% to 4.5% better as well 
    • When looking at only the sites where that is the case and which were still lazy-loading the LCP image with WordPress 6.2, the LCP performance impact amounts to a massive 16% to 21% improvement for mobile viewports and 6% to 9% on desktop. 
    • Lazy-loading accuracy has notably improved: In WordPress 6.3, only 9-10% of sites still lazy-load their LCP image for classic theme sites (down from 27-28% in 6.2) while for block theme sites it’s 5-8% (down from 17-29% in 6.2) 
  • @flixos90 drafted and published the Analyzing the Core Web Vitals performance impact of WordPress 6.3 in the field post
  • @joemcgill Nothing new from me this week, but we expect to do an initial round of benchmarks against WP 6.4 beta1 after it’s released next week.

Ecosystem Tools

Link to roadmap projects

Contributors: @mukesh27 @swissspidy @westonruter

  • No updates this week

Creating Standalone Plugins

Link to GitHub overview issue

Contributors: @flixos90 @mukesh27 @10upsimon

  • No updates this week

Open Floor

  • @joemcgill I wanted to mention that we should probably prepare some time after beta1 next week for some initial triage of any performance issues we see after the first round of code syncing from the Gutenberg project has occurred.
  • @spacedmonkey I would like to start a tracking ticket for dev notes this team is going to work on
    • Created for tracking 6.4 Trac tickets that require dev notes

Our next chat will be held on Tuesday, September 26, 2023 at 15:00 UTC in the #core-performance channel in Slack.

#core-performance, #performance, #performance-chat, #summary

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