Kartikaya Gupta (email:kats@mozilla.staktrace.com) Reporter
	Description • 8 years ago

We have some "virtual tiling" code which snaps the displayport to some tile boundaries even when tiling isn't supported/enabled. This is useful on windows for example to avoid extra paints with APZ enabled. However, if you turn on the APZ minimap and scroll down a page on windows, you'll see the displayport moving with the viewport, and not snapping as you'd expect. So the virtual tiling stuff appears to be broken - we should investigate why and fix it if possible.

	Benoit Girard (:BenWa)
	Comment 1 • 8 years ago

This landed in bug 1204136 but it either regressed or perhaps didn't work properly when landed.

	Kartikaya Gupta (email:kats@mozilla.staktrace.com) Reporter
	Comment 2 • 8 years ago

Actually, I think it might be working, it's just that a virtual tile size of 128 rolls over pretty quickly. I bumped it up to 1024 locally and now it behaves more like I would expect. I'm not sure we should increase the default virtual tile size or not - BenWa, thoughts?

	Benoit Girard (:BenWa)
	Comment 3 • 8 years ago

My performance intuition is always wrong so I'll defer to measurements. Might be worth measuring and looking into if we have time.

Since we round out aggressively increasing this will likely regress Talos. I think if we round out less and and increased this we'd be better off overall.

	Kartikaya Gupta (email:kats@mozilla.staktrace.com) Reporter
	Comment 4 • 8 years ago

Ok. This bug at least is WFM, so I'm going to close it.