To enable remote profiling, first thing you’ll need to do is open
devtools.debugger.remote-enabled variable to
true and restart your browser:
After you’ve done that, go to Tools -> Web Developer -> Connect and connect to your remote device:
Once you’re successfully connected you’ll see a list of available tabs. Clicking on any of them will open a separate Developer Tools window with a profiler attached to that remote instance. That’s it!
So if you’re a B2G or Firefox for Android developer, give our profiler a try and share your feedback! Because everytime you share your feedback with us somewhere in the world two Mozillians high five each other and hug a kitten.
 — Here are a couple of links on how to setup your device for remote debugging and profiling: Setting up to debug on Firefox OS using Firefox developer tools, Remote debugging.