Tool for running SPS profiler on Fennec
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frof is a convenience script to make generating Gecko SPS profile traces easier with the Fennec mobile browser. It automates much of the grunt work you'd normally have to do manually.

For more information on the Gecko Profiler, see:


  • Make arm-eabi-addr2line from the Android NDK visible in your path. In my case, I just created a symbolic link from its location in the NDK to a file in my home's bin directory:

    ln -s /home/wlach/opt/android-ndk-r6/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/arm-linux-androideabi-addr2line $HOME/bin/arm-eabi-addr2line

  • Then, simply run the '' script from the toplevel directory.


  • Shut down the running instance of fennec on your phone (if there is one).

  • From toplevel, activate the virtualenv from the console:

    source bin/activate

  • Run with arguments corresponding to appname, url, and profile file. For example:

    frof org.mozilla.fennec

Interact with the application as normal, then press enter when you're ready to stop profiling. You will need to wait a while the profile is taken off the device and processed.

  • When the above process is finished, unzip the symbolicated profile from the archive:


  • Open up an instance of the SPS profiler (e.g. and upload the unpacked symbolicated_profile.txt file.