Improve Website Performance by Checking Logs
Every website relies on logs. You can use logs to troubleshoot problems, improve your performance, and even find out what pages are popular.
Website Performance
New Browser APIs for Detecting Javascript Performance Issues in the Production
To collect performance measurements from end-user sessions, there are various fantastic new APIs and approaches. They're all in varying phases of proposal and implementation in browsers, but all of the ones listed are in the most recent Chromium versions.