Open Bug 1256133 Opened 6 years ago Updated 3 years ago
Slow, janky scrolling on this support
.mozilla .org thread with e10s enabled
On a new profile, current nightly: 1. Open https://support.mozilla.org/en-US/questions/1111080 2. Scroll to the bottom of the page with Cmd+Down or with the three(?)-finger swipe. 3. Scroll to the top 4. Repeat With e10s scrolling is much slower. When taking the profiles below I did this: scroll down, scroll up, wait a second; repeat. e10s: https://cleopatra.io/#report=fd056b554af26623e0d24467e351a89d799664e5&filter=%5B%7B%22type%22%3A%22RangeSampleFilter%22,%22start%22%3A214795,%22end%22%3A217711%7D,%7B%22type%22%3A%22RangeSampleFilter%22,%22start%22%3A216117,%22end%22%3A216767%7D%5D&selection=0,2662,2663,2664,2665,2359,2666,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,1039,1040,1041,1042,1043,1044,2713,2714,2715,2716,168,169,170,171,183,184,185,186,187,188,189,190,214,215,216,217,218,219,2877,2878,2879,196,197,198,199,2889 no e10s: https://cleopatra.io/#report=f0ac7ed640459a01ac92b87533ab7f23eb1ae32d&filter=%5B%7B%22type%22%3A%22RangeSampleFilter%22,%22start%22%3A15676,%22end%22%3A17733%7D%5D&selection=0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,502,503,504,505,506,507,508,509,510,511,1758,343,344,447,448,449,450,451,453,463,464,465,466,467,468,468,469,470,738,739,740,472,473,474,475 This is likely a duplicate, but I couldn't find a list of known root causes of bad scrolling perf, and a way to confirm that my problem matches a known cause, so I'm filing this anyway.
What do you mean by slow scrolling? Is it jumpy or is there missing content? I expect this might have to do with the horizontal scrolling. Do you see this problem on other support questions that are not horizontally scrollable?
Is this on a retina screen?
The scrolling is jumpy: you can notice the time it takes to paint the next frame, both visually and in the profile. This is a retina screen, yes. > I expect this might have to do with the horizontal scrolling. That was a good guess! I removed the wide <p> from the first post (using the Devtools Inspector) and scrolling became as fast as without e10s.
Bug 1251638 is another bug where we've seen the presence of a horizontally scrollable element have a negative effect on scrolling performance. It's possible these share a root cause.
See Also: → 1251638
Yeah this is next on my to-do list.
6 years ago
See Also: → 1243081
6 years ago
See Also: 1251638 →
I've been using bug 1243081 to investigate since I'm assuming they're the same underlying issue, and it's easier for me to reproduce on that URL. From the APZ side I don't think there's much we can do here without making checkerboarding worse. Doing something like implementing bug 1261166 might help.
Depends on: 1261166
As with bug 1243081, applying the WIP patch on bug 1261166 makes the transaction times here drop to ~0. I specifically tested scrolling up and down on the provided URL using fn+left/right arrow (equivalent to "home"/"end" scrolling on mac) and compared the transaction times with and without bug 1261166.
(In reply to (Back on May31) Kartikaya Gupta (email:firstname.lastname@example.org) from comment #8) > As with bug 1243081, applying the WIP patch on bug 1261166 makes the > transaction times here drop to ~0. Just to make sure I'm understanding this correctly: the slowness here is specific to Mac?
I believe so.
Unassigning since I'm not doing anything here, it is just waiting on the ClientStorage implementation.
Priority: P1 → P2
Sounds like the ClientStorage work is still stalled, so this won't get fixed for 49 or 50 most likely.
Moving to p3 because no activity for at least 1 year(s). See https://github.com/mozilla/bug-handling/blob/master/policy/triage-bugzilla.md#how-do-you-triage for more information
Priority: P2 → P3
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