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.
Tag: Performance
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Profiling PHP in production at scale
At Wikipedia, we built an efficient sampling profiler for PHP, and use it to instrument live requests. The trace logs and flame graphs are powered by a simple setup that involves only free open-source software, and runs at low infrastructure cost.
Wikipedia’s JavaScript initialisation on a budget
This week saw the conclusion of a project that I’ve been shepherding on and off since September of last year. The goal was for the initialisation of our asynchronous JavaScript pipeline (at the time, 36 kilobytes in size) to fit within a budget of 28 KB.
Measuring Wikipedia page load times
This post shows how we measure and interpret load times on Wikipedia. It also explains what real-user metrics are, and how percentiles work.