1673070 - Scrolling janky on amp page of Gadgets360 site

Status: UNCONFIRMED

(Core :: Graphics: WebRender, defect, P3)

Description

[bull500]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:84.0) Gecko/20100101 Firefox/84.0

Steps to reproduce:

Use latest Nightly on Android
Visit https://www.google.com/amp/s/gadgets.ndtv.com/tv/reviews/xiaomi-mi-box-4k-review-price-in-india-2233441%3famp=1&akamai-rum=off
Scroll the page

Actual results:

Scrolling is sticky/choppy near the title of the page and its image.

Expected results:

Smooth scrolling should be present

Comment 1

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

This is working fine for me. If you can still reproduce it, can you get a profile using https://profiler.firefox.com/ ? (see this page in the documentation for how to use it on Android). Thanks!

Comment 2

[bull500]

(In reply to Kartikaya Gupta (email:[e-mail]) from comment #1)

This is working fine for me. If you can still reproduce it, can you get a profile using https://profiler.firefox.com/ ? (see this page in the documentation for how to use it on Android). Thanks!

@kats its still happening here's the profile:
https://share.firefox.dev/35c39Wt

Hope it helps

Also this page same issue:
https://gadgets.ndtv.com/social-networking/news/facebook-ankhi-das-quits-steps-down-sunil-abraham-public-policy-director-2316567?amp=1&akamai-rum=off&__twitter_impression=true

Comment 3

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

https://share.firefox.dev/2GJ5GxT shows a long WR composite. If you look at the whole profile the web content paint also seems to take long time on some filter nodes, although that shouldn't result in janking.

Comment 4

[Jeff Muizelaar [:jrmuizel]]

Bull500, what phone is this on?

Jamie, do you see bad performance on this on adreno?

Comment 5

[bull500]

:jrmuizel its a Redmi Note 7S

Comment 6

[Jeff Muizelaar [:jrmuizel]]

That means Adreno 512

Comment 7

[Jamie Nicol [:jnicol]]

I can repro on my Pixel 2. Profile looks much the same, texture upload is the culprit. If it's due to many small uploads my recent change (which should be in the next nightly) should help. But more likely it's due to a single massive upload, which it won't help with.

Interestingly I can't reproduce the slowness on my Mali Samsung S9.

I will find out what exactly is being uploaded.

Comment 8

[Jamie Nicol [:jnicol]]

Another large SVG spritesheet: https://gadgets.ndtv.com/static/v1/images/sprite_20200828.svg

I'm guessing the height of the social media icons changes by plus or minus 1 when scrolling, due to snapping. Causing us to rerasterize and reupload the image every frame.

Deleting the social media icons in the devtools inspector makes scrolling smooth.

Andrew is working on a fix in bug 1673653.

Comment 9

[Jeff Muizelaar [:jrmuizel]]

Attachment: Somewhat reduced test case

4 icons share the sprite sheet, but 2 are scaled to different sizes.