Performance Chat Summary: 27 January 2026

The full chat log is available beginning here on Slack.

WordPress Performance TracTrac An open source project by Edgewall Software that serves as a bug tracker and project management tool for WordPress. tickets

• @westonruter shared a Trac query covering performance-related tickets milestoned for WordPress 6.9.1 and 7.0.
• @westonruter shared that for ticketticket Created for both bug reports and feature development on the bug tracker. #61500, some work was done recently as part of the CodeMirror upgrade effort.
  • @westonruter explained that ideally there would be a declarative way to add script modules as dependencies for classic scripts, and noted that a workable approach is to register an empty script module that declares module dependencies, and then enqueue that module whenever the classic script is enqueued. @westonruter shared reference to example diffs demonstrating this workaround and mentioned being glad to find a quick solution.
• @mukesh27 asked whether @westonruter had reviewed the latest comment on #64229, where @wildworks raised a minor point and opened a PR.
  • @westonruter replied that the comment had been seen the night before and initially mentioned not having a patchpatch A special text file that describes changes to code, by identifying the files and lines which are added, removed, and altered. It may also be referred to as a diff. A patch can be applied to a codebase for testing. yet, then noted that a PR already existed and shared PR #10799. @westonruter reviewed the PR, said it looked good, and approved it.
• @westonruter brought up #64066 and shared that @gilbertococchi is actively working on collecting data to support switching to moderate prefetch by default on sites with caching.
  • @westonruter referenced a Slack thread where LCP passing rates for conservative versus moderate prefetch were discussed and noted that additional data is being gathered by flipping a few CrUX-eligible sites from conservative to moderate to compare LCP passing rates and page hit increases over time.
  • @westonruter added that landing #64066 is related to #64370, noting that the latter needs to land to ensure reliable detection.
• @mukesh27 asked about the review status of PR #10606 and mentioned seeing comments from @westonruter.
  • @westonruter replied that the PR had just been closed.

Performance Lab PluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party. (and other performance plugins)

• @westonruter shared being behind on PR reviews.
• @mukesh27 mentioned plans to re-review PR #2321.

Open Floor

• @westonruter shared recent experience using GitHubGitHub GitHub is a website that offers online implementation of git repositories that can easily be shared, copied and modified by other developers. Public repositories are free to host, private repositories require a paid subscription. GitHub introduced the concept of the ‘pull request’ where code changes done in branches by contributors can be reviewed and discussed before being merged by the repository owner. https://github.com/ Copilot together with Gemini CLICLI Command Line Interface. Terminal (Bash) in Mac, Command Prompt in Windows, or WP-CLI for WordPress. locally, describing it as immensely useful both for review and implementation work. @westonruter described Copilot as significantly better than a traditional linter during reviews and noted that it can provide strong first-pass implementations. @westonruter shared PR #10778 as an example of using Gemini CLI during the CodeMirror upgrade and explained that a detailed historical and technical specification was provided to the tool.
  • @westonruter also shared that Copilot was used to draft a Performance Lab fix while on public transit using only a phone, referencing PR #2346.
  • @dmsnell cautioned that Copilot can sometimes reintroduce defects during PR reviews, sharing an anecdote where Copilot repeatedly flagged and reintroduced a PCRE-related bugbug A bug is an error or unexpected result. Performance improvements, code optimization, and are considered enhancements, not defects. After feature freeze, only bugs are dealt with, with regressions (adverse changes from the previous version) being the highest priority. even after it had been fixed.
  • @justlevine added that this behavior can indicate ambiguities in code and suggested that improving self-documentation helps both humans and LLMs.
  • @dmsnell emphasized the need for extra care when LLMs introduce defects, as they can confidently repeat mistakes if the surrounding code does not change enough.
  • @westonruter agreed, noting that while hallucinations occur, the tools still provide good feedback most of the time and help shift focus away from minutiae like coding standards toward higher-level problem solving.
• @dmsnell raised the topic of memoizing wp_normalize_path, noting observed performance improvements of roughly 1ms during WordPress startup in certain environments. @dmsnell explained that while this is a micro-optimization, it can have meaningful impact at scale and shared that @josephscott has been investigating early startup costs using production measurements. @dmsnell mentioned having tested earlier versions without caching and discussed trade-offs between caching and alternative approaches, including replacing PCRE calls and addressing what may be a latent bug.
  • @westonruter asked whether similar performance benefits were observed across different approaches.
  • @dmsnell replied that while direct testing had not yet been done for all variants, prior comparisons suggested the cache provided most of the benefit at a fraction of the cost, and that both approaches could potentially coexist.
  • @westonruter summarized this as a “both/and” situation rather than an either/or choice.

Our next chat will be held on Tuesday, February 10, 2026 at 16:00 UTC in the #core-performance channel in Slack.

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