Qt Creator provides a QML profiler to collect useful data on your application during the runtime. You can use it on a desktop and also on a remote target such as our Raspberry Pi. Let's check that your debug build configuration allows QML debugging and profiling. Click on Projects | Rpi 2 | Build. Then, you can click on Details of qmake from Build Steps. You should also check it for your desktop kit:
By default, data is only sent from target to host when you stop profiling. You can flush data periodically with Tools | Options | Analyser | QML Profiler.
Keep in mind that flushing data while profiling frees memory ...