Instruments
1: iPhone (iPad), Settings - Developer - Logging
Open Energy, then click Start Recording
Then start using your own app (of course you can also analyze other apps), after a period of time, connect the phone to the computer
Open Instruments, create a new Energy Log
Import Logged data on your phone
Now you can see the detailed resource usage, the power part 1-20, 20 means the consumption of resources is very high
There are other specific usage of cpu, network, bluetooth, positioning and other functions.