GitHub - wikimedia/performance-arc-lamp: 🔥 Flame graphs and trace logs for PHP 7 in production. Mirror from https://gerrit.wikimedia.org/g/performance/arc-lamp. See https://mediawiki.org/wiki/Developer_access for contributing.

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. I'd like to demonstrate that profiling doesn't have