Solving rendering delay in timeline

I compiled activity watch with watcher-input myself and everything works just fine, but after a whole day the timeline rendering takes ages. That's because of the rendering of all keypresses and mouseevents.
The activity tab loads instant and the aggregated data is shown instantly. On the timeline tab the "Events shown" are very fast too, only the bars indicating the activity take long for the watcher input bucket.

Which of these strategies would be the best?
- Exclude the watcher-input from the timeline visualisation
- Load the watcher-input data in larger chunks instead of every event for the timeline
- aggregate data and commit only every 5 seconds
- ...