The following pages should have a more elaborate explanation of the time/total fields of mongotop and top

https://docs.mongodb.com/manual/reference/program/mongotop/
https://docs.mongodb.com/manual/reference/command/top/

My understanding is that it's the sum of latencies per namespace, where the latency is calculated as the time between getting received by the server and the time the request was served, excluding time to acquire locks.

CC ricardo.lorenzo