I just found this blog post written by Mario from the libgdx dev team which details how to discover how much CPU your app is using in real time.

This is a great help when trying to cut the battery drain of an app or just generally improving performance.

the command window/terminal command to show the top ten battery users on your connected android phone is as follows:

adb shell top -m 10

Picking out just your application can be performed using grep (linux) or FINDSTR (windows). Just search for a section of your apps name, eg.

adb shell top -m 10 | grep isys