[wp-trac] [WordPress Trac] #58360: Measure additional performance metrics on each commit

[WordPress Trac]

#58360: Measure additional performance metrics on each commit
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 Reporter:  joemcgill         |       Owner:  (none)
     Type:  task (blessed)    |      Status:  new
 Priority:  normal            |   Milestone:  Awaiting Review
Component:  Build/Test Tools  |     Version:
 Severity:  normal            |  Resolution:
 Keywords:  needs-patch       |     Focuses:  performance
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Comment (by flixos90):

 I would say, given that load time performance is where WordPress struggles
 the most (LCP passing rate of WordPress sites is far lower than CLS, INP,
 or FID passing rates, see https://cwvtech.report) we should focus on
 additional load time metrics first.

 I would suggest using LCP like you are saying, but also TTFB. While that
 should give us similar values like the `wp-total` Server-Timing metric, it
 is measured in a more holistic way also encompassing the request so it
 provides another reference point which IMO is useful to have alongside
 `wp-total`: Effectively TTFB is server response time as seen from the
 client, while `wp-total` is ''just'' the WordPress-specific response time
 as seen from the server.

 Regarding the implementation: While Gutenberg uses the implementation you
 mentioned, I think it would be worth considering using
 https://github.com/GoogleChrome/web-vitals instead, as that is a library
 specifically to measure those metrics. Rather than manually implementing
 it and having to ensure our implementation remains up to date with Web
 Vitals changes, using that library would simplify things by avoiding that.
 [https://github.com/GoogleChromeLabs/wpp-research/blob/main/cli/commands
 /benchmark-web-vitals.mjs This command] is an example of using that
 library in a headless browser, and I think we could follow a similar
 approach in our CI workflow.

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Ticket URL: <https://core.trac.wordpress.org/ticket/58360#comment:1>
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