1869505 - Screen transition (CSS transition) performance on Puzzowl game has regressed badly in Firefox for Android

Status: RESOLVED INVALID

(Core :: Graphics, defect)

Description

[Chris Lord [:cwiiis]]

Not sure of the specific component to file against because I've not worked on Gecko for a long time (I'd guess WebRender?), but it would appear that CSS animation performance in this specific case has regressed very badly. This used to run at a solid 60Hz on low spec phones (think FirefoxOS...) and now drops frames badly on my Fairphone 4 (a relatively mid-spec, modern phone). This continues to perform great on Chrome and presumably on much older versions of Firefox for Android.

My best guess is that over-invalidation is happening or some animated CSS property that should be accelerated is falling back to rendering on every frame, but I can't for the life of me find the paint flashing option in dev tools to check this. Does it even still work like that with WebRender? I'm very much out of the loop...

To reproduce, go to the given URL and choose any option (perhaps easiest to pick the 'How to Play' as the change is visually larger than any of the other options). Observe that the frame-rate is terrible.

Comment 1

[Mayank Bansal]

1. Can you capture and share a performance profile ( steps are here : https://profiler.firefox.com/docs/#/./guide-profiling-android-directly-on-device?id=profiling-firefox-for-android-directly-on-device)

2. Attach the contents of about:support to this bug

FWIW, my andrpid phone is probably much more fast and I couldnt repro this.

Comment 2

[Robert Longson [:longsonr]]

Or use https://mozilla.github.io/mozregression/ to find a regression range.

Comment 3

[Jamie Nicol [:jnicol]]

Hey Chris! Hope you're well!

If you mean it sliding between eg "How to Play" and back to the main menu, then it looks really smooth on the few devices I tested. Could perhaps be a GPU-specific issue. If you could capture a performance profile or find a regression range that'd be super helpful!

Comment 4

[Chris Lord [:cwiiis]]

Attachment: FP4 about support.txt

Hey Jamie, I'm good thanks :)

Absolutely typical, now what was very obvious bad performance seems mostly fine... Not Chrome-smooth, but not bad at all... I've attached about:support and done a profile, but if there isn't anything obvious, please close this as invalid and if I ever find a proper reproducable case I'll come back with it.

Profile: https://profiler.firefox.com/public/wajzw1p2k5js83m2r4q2janpamvjpdswt7mbd68

Comment 5

[Jamie Nicol [:jnicol]]

Thanks. Yeah can't see anything wrong in the profile. I'm going to close as invalid, but please reopen if it reappears!