The Profiles panel lets you profile the execution time and memory usage of a web app or page. The Profiles panel includes two profilers: a CPU profiler and a Heap profiler. These help you to understand where resources are being spent, and so help you to optimize your code:
- The CSS Selector Profiler records the aggregate time spent matching selectors to elements in the DOM tree. This time is also captured within "Style Recalculation" Timeline events.