1489184 - Performance regression during scrolling

Status: REOPENED

(Core :: Web Painting, defect, P2)

Description

[[:philipp]]

we have a german user report at https://www.camp-firefox.de/forum/viewtopic.php?f=7&t=125985 about a noticeable perf regression/lag while scrolling long pages in recent nightly builds on older graphics hardware.

he came up with this mozregression pushlog: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=bade35bc346f3bc1f5e8b59d3d49c7a1ba28166c&tochange=c3734e0f634e10ad994112e49d1849817c1688ff
toggling layout.display-list.retain.chrome to false alleviated the problem, so it's looking related to the changes in bug 1413546.

Comment 1

[Jason Duell]

Matt, does the bug pointed to in comment 0 seem right?  Is this something we're likely to get to before 64 ships?

Comment 2

[Jason Duell]

Philipp: are there any useful test URIs or other info in the original German bug report?

Comment 3

[Miko Mynttinen]

(In reply to Jason Duell [:jduell] (Regression Engineering Owner for 64; needinfo me) from comment #1)
> Matt, does the bug pointed to in comment 0 seem right?  Is this something
> we're likely to get to before 64 ships?

It is likely that this problem will get fixed by bug 1494124. I hope that the original reporter can try flipping the pref back to verify the fix after bug 1494124 lands.

Comment 4

[Miko Mynttinen]

Closing this as a duplicate since this should be fixed by bug 1494124, and the feature that caused this will be disabled for 64.

Comment 5

[[:philipp]]

i tried to reach out to the affected user two weeks ago to see if the issue was fixed with bug 1494124.
in case i receive a reply i will follow up here.

Comment 6

[[:philipp]]

i was in contact with the affected user - his feedback was that he can still reproduce the lags/slow performance while scrolling through long pages in recent nightly builds when setting layout.display-list.retain.chrome to true (that setting got disabled by default again by bug 1496491 in the meantime).

Comment 7

[Miko Mynttinen]

(In reply to [:philipp] from comment #6)
> i was in contact with the affected user - his feedback was that he can still
> reproduce the lags/slow performance while scrolling through long pages in
> recent nightly builds when setting layout.display-list.retain.chrome to true
> (that setting got disabled by default again by bug 1496491 in the meantime).

Thank you for the update, philipp.
I'll be sure to look into this before the pref flag is flipped again.