...Hermione can run tests in parallel sessions in different browsers out of the box. Running of too many tests in parallel can lead to the overloading of the main process CPU usage which causes degradation in test passing time, so Hermione runs all tests in subprocesses in order to solve this problem.
Clinic.js diagnoses your Node.js performance issues
Node Clinic is a suite of diagnostic tools for Node.js applications, designed to help developers identify and resolve performance issues, memory leaks, and other common problems in their code.