1325134 - Far more time spent painting than in Chrome while scrolling on https://www.mydealz.de/

Status: RESOLVED WORKSFORME

(Core :: Web Painting, defect)

Description

[Thomas Wisniewski]

I just compared devtools performance timelines while scrolling around on mydealz.de in Firefox for Android (nightly) and Chrome for Android (stable). Firefox spends a great deal more time "painting" than Chrome, leading to the viewport being obviously checkerboarded/blurred out for seconds at a time on my slower phones.

I don't know if I'll be able to set up an environment for running a Gecko profile anytime soon, but this seems like a fairly simple site to investigate for potentially low-hanging fruit, so I thought it bore reporting. The problem seems easily reproducible, but I can share my devtools performance profile if it helps.

Comment 1

[Kartikaya Gupta (email:[e-mail])]

I got a profile, but sadly it is unsymbolicated: https://cleopatra.io/#report=dd1524aeb15c46d3de1e479d704f4106f740d07e

Still, shows a long time being spent in display list building and other painting things.

Comment 2

[Daniel Holbert [:dholbert]]

Hi Thomas - this came up in QF triage since [qf] was just recently added.

Would you mind confirming whether you can still repro this, and if so, could you capture a profile (fairly straightforward these days via about:debugging on desktop with usb-connected Android phone)?

(The profile from comment 1 is probably not useful anymore, for a handful of reasons.)

Comment 3

[Daniel Holbert [:dholbert]]

For what it's worth: I can rapidly & repeatedly scroll back and forth between the top and bottom of https://www.mydealz.de/ in Firefox Nightly on my Pixel 4a phone, without any obvious checkerboarding or jank. (I'm not sure if this is relevant, if this issue was specific to slow phones; my hardware (Pixel 4a) is fairly fast, and likely a lot faster than the phones that Thomas was testing on when filing this 5 years ago, which he judged to be slow-by-2016-standards.)

Comment 4

[Julien Wajsberg [:julienw]]

Given it's very old and we can't reproduce anymore, let's close it. Please reopen or file a new bug if there's still a problem :-) Thanks for the report in the first place!