How to diagnose what loads the processor on Ubuntu, MeteorJS?

Question

ubuntu

Hello everyone, I'm developing an application on Meteor.Js, but for some reason the processor is heavily clogged, and the average load is generally crazy. The poke method did not help, I tried to disable parts of the code that were potentially gluttonous, but this did not help.
Through htopI see that the main load is due to mongoDB, but I really can’t find the culprit.
Tell me how you can diagnose and calculate which operation causes such a load?