Deploying HTTP/2 support to the Wikimedia CDN significantly changed how browsers negotiate and transfer data during the page load process. We found regressions in performance during the transition and are sharing the lessons we learned.
The story of how we decided to commission the implementation of Paint Timing API, a feature that lets us observe web performance from an end-user perspective. This web browser feature tells us at what point in time content started to appear on the screen for a visitor.
We have been collecting microbenchmark scores for over a year. This lets us see the long-term evolution of our audience as a whole. The information gives us an idea of how fast device/operating system/browser environments improve on their own.
WikimediaDebug is a set of tools for debugging and profiling MediaWiki web requests in a production environment. WikimediaDebug can be used through the accompanying browser extension, or from the command-line. This post highlights changes we made to WikimediaDebug over the past year, and explains more generally how its capabilities work.