== What ==
Flamegraphs provide insight to where and how your MediaWiki component or extension spends its time. We instrument real web requests on the MediaWiki app servers at WMF (using php-excimer, a low-overhead sampling profiler) and continually publish interactive SVG visuals by entrypoint (e.g. index.php, JobQueue, ResourceLoader load.php, or rest.php API). [1] [2]
Read more about the Arc Lamp pipeline, introduced by Ori during the 2014 HHVM migration [3], through our blog post:
== What's New ==
- Date: You can now choose any date in the last 2+ years. Previously, this was limited to 2-3 weeks. In the dropdown menu, choose "Other", and select any date using the native datepicker. Existing URLs remain compatible.
- Source: Real-time performance data from the MediaWiki-on-Kubernetes deployment is now available through here (excimer-k8s and excimer-k8s-wall). While web traffic remains largely on bare metal (except for test2wiki), internal MediaWiki API traffic is already partly on Kubernetes. Refer to T333120 for work by SRE ServiceOps (e.g. CXServer uses MediaWiki-on-Kubernetes).
- Entrypoint: JobQueue (RunSingleJob) is now included in the selector, plus the new detailed breakdowns for EditAction, PreSend, and PostSend are now promoted here. These were previously available via the file browser only.
== How ==
The new interface is an HTML form with vanilla JavaScript to navigate you to the right SVG.
As before, we promote "good" defaults. You don't have to make any choices to start exploring the data. Press the big blue button to instantly view the most recent index.php flamegraph with the default settings.
--
Timo Tijhof,
Performance Team,
Wikimedia Foundation.