Example of bad long JS tasks which don't block scrolling

3 views

Skip to first unread message

Tim Dresser

unread,

Apr 20, 2016, 2:21:42 PM4/20/16

to scheduler-dev, input-dev

eero.com has a 3 second long JS method called during page load, but doesn't have blocking touch event listeners, so it doesn't block scrolling.

However, it does prevent the page from updating the style on their header, which results in user experience issues.

Any thoughts on how we could mitigate this other than "don't run 3 seconds of JS" or "use compositor worker once it's available"?

I think we'll start noticing these cases a lot more once we have a good story for the scroll start intervention. Currently janky scrolling during page load is the primary problem, but even once we've solved the scrolling problem, other performance issues will show up.