We should have a good way to know if scrolling is ever not as smooth as it should be and when this happens we should get markers in the profile.

It would be interesting to have the ability to get graphs of scroll position and the difference in scroll position over time.

In bug 1704659 botond made one off graphs of such to debug/visualize another problem.

In bug 1692707 hiro added scroll offset logging to the apz test logging enabled via the pref, it logs the scrollid, the layersid, the scrolloffset and the time since process creation. Shouldn't be too hard to hook up the profiler to get this data to make graphs with.