performance.wikimedia.org is a site maintained by the Performance Team.
Currently hosted on webperf003.
MediaWiki collects stack traces using php-excimer and sends them to the Arc Lamp service, which then stores them as log files and also generates interactive SVG flame graphs using the FlameGraph tool. The perf site exposes these files from the Arc Lamp server via an Apache proxy.
The XHGui web service is exposed via an Apache proxy.