Performance Metric Improvements July 22

Hi all!

Does anyone know of any updates in WPT that were deployed around July 22nd?

I’ve been tracking performance metrics via the WPT API for the past few months. I noticed a sudden improvement (about ~60% improvement) on all perf metrics for all URLs I’m tracking on July 22nd.

There were no changes to the URLs I’m testing, in addition the captured asset sizes for tests after July 22nd have stayed static. so I’m not sure

This wasn’t a fluke, because the metrics have stayed at this improved level on all tests since July 22nd (so there’s a weeks worth of data now).

I’m testing with the following connection ec2-eu-west-3:Chrome.4G on an emulated MotoG4 phone.



Most likely this change:

The agents were changed from using OS-level CPU throttling to Chrome-based throttling when emulating mobile CPU’s (to match Lighthouse and because there were reports of the OS throttling having unexpected overhead).

^ that explains it. Thanks for getting back to me so quickly!