1560814 - regression: Firefox occasionally freezes for about 5 seconds after opening a new tab

Status: VERIFIED DUPLICATE of bug 1559690

(Core :: Layout, defect)

Description

[Darkspirit]

Attachment: Screenshot_20190623_215754.png

Debian Testing, KDE, X11, Macbook Pro 1502, WebRender

No clear STR.
I have 10 app tabs and about 5 regular tabs.
When I opened some links by Ctrl+click, new tabs appeared, shrinked the size of the other tabs, and then my Nightly window froze for about 5 seconds.
Sometimes I even get a popup saying a script in scrollbox.xml:761 would not respond.

I remember seeing bugmail mentioning XUL and XHTML on the day of first occurrence, so the regression date should be within the last 2 weeks. I am sorry for not immediately filing a bug. I am not sure if this is related to the XHTML transition, it's just a guess.

Standard8 reported similar on Slack.

Comment 1

[Darkspirit]

I just clicked multiple times on above scrollbox.xml:761 link while pressing Ctrl. Tabs opened, window froze. I tried to scroll within this Bugzilla tab. When the window became responsive again it finally executed all scroll actions like an explosion. (But it was smooth, thanks WebRender! :D)

Comment 2

[Darkspirit]

These steps worked sporadically for me:
mozregression --launch 2019-06-23 -a https://example.com -a https://example.com -a https://example.com -a https://example.com -a https://example.com -a https://example.com -a https://example.com -a https://example.com -a https://example.com -a https://example.com -a https://example.com -a https://bugzilla.mozilla.org/show_bug.cgi?id=1560814#c0

1. Pin all example.com tabs as app tabs.
2. Ctrl+Click some (2 to 7?) times on scrollbox.xml:761 in comment 0. Wait a second.
3. Ctrl+Click some more times fast. Now the window freezes.
4. Scroll up an down a few times. When the window unfreezes these actions will be executed. Some tabs are still loading.
5. Popup appears: scrollbox.xml:761 is not respoding.
6. Tabs resize. Overflow arrows (left, right, down) appear.

Comment 3

[Daniel Holbert [:dholbert]]

This would benefit from a performance profile ( https://profiler.firefox.com/ ).

I think Will Hawkins was partway through to getting one when we looked at this bug during QF triage -- tagging him to follow up, though if you (:darkspirit) can capture one as well, that could be helpful too. Thanks!

Comment 4

[Will Hawkins]

Interesting results, here. I just went back and rebuilt mozilla-central to try to capture the profile. I was able to trigger this behavior last week using mozilla-central and now I can no longer do so. I am going to needinfo :darkspirit and see if s/he is able to run a nightly version of the browser and verify that this behavior no longer exists.

Comment 5

[Darkspirit]

mozregression --find-fix --bad 2019-06-25 --good 2019-06-27 -a https://example.com -a https://example.com -a https://example.com -a https://example.com -a https://example.com -a https://example.com -a https://example.com -a https://example.com -a https://example.com -a https://example.com -a https://example.com -a https://bugzilla.mozilla.org/show_bug.cgi?id=1560814#c0

6:24.43 INFO: First good revision: 91c42888cf7fa67f2b9d08d0e62cb203ad1e6619
6:24.43 INFO: Last bad revision: 3752d5cac66b9f72bfe7252e399349cb0eb3f59f
6:24.43 INFO: Pushlog:
https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=3752d5cac66b9f72bfe7252e399349cb0eb3f59f&tochange=91c42888cf7fa67f2b9d08d0e62cb203ad1e6619

Csoregi Natalia — Backed out 4 changesets (bug 1488953) for causing Bug 1559690. a=backout

(Emilio Cobos Álvarez (:emilio) from bug 1559690 comment 24)

Should be fixed by backout.

:)

Comment 6

[Darkspirit]

I can't explain why I couldn't reproduce it anyhow reliably when I tried to find the regression range... Sorry for that. ^^

Comment 7

[Will Hawkins]

Don't be sorry! I am just glad that it wasn't something that we needed to investigate. I think that we should close this as a dup. I am going to needinfo dholbert just to get his approval. Thanks again!

Comment 8

[Daniel Holbert [:dholbert]]

Makes sense to me. I'm glad it's better now! Thanks for following up.

Marking as "verified" dupe, given that we've got two independent people who could reproduce & can no longer.