snorp/fennec-profiler-addon

Fennec Profiler Addon

Instructions

• Locally build and install Fennec. https://developer.mozilla.org/en-US/docs/Mozilla/Developer_guide/Build_Instructions/Simple_Firefox_for_Android_build
• Start Fennec on your device and go to about:config. Change xpinstall.signatures.required to false.
• Clone this repo
• Run npm install in the checkout
• Run ./build. This will install the addon into your local build of Fennec on the device. You will need to approve some on-screen prompts.
• You should now have a "Start Profiler" entry in the three-dot menu. Selecting it once will start the profiler, and selecting it again will stop it. When the profiler stops, it writes the JSON output into /sdcard/gecko_profile.json on the device. Make sure you have the storage permission enabled for Fennec.
• You can use the symbolicate tool in the repo to pull the profile from the device and symbolicate it using your object directory. First pull the libraries off the device with ./symbolicate pull-libs. You only need to do this once for each device you are using. Once this is complete, pull the profile and symbolicate it with ./symbolicate pull-profile --objdir ~/objdir-android. Substitute the correct path for your Gecko object directory.
• Finally, you can open the profile in https://perf-html.io and analyze the profile.