via make.wordpress.org => original post link
Gathering performance metrics automatically is a way to track performance over time and ensure that WordPress continues to improve. Automated performance tooling will also help the core team identify issues and resolve them with less effort.
Why add automated performance testing?
Adding automated performance testing will help us monitor performance changes in WordPress core continuously. It gives us a track record to capture how core performance is being enhanced over time, and it allows us to catch regressions early and accurately identify underlying causes. Similar to our unit test suite, automated performance testing would help protect core from introducing large performance regressions by catching problems immediately and tracking performance over time. Automating testing also means saving contributor effort by replacing a time consuming manual process.