Open Bug 1361427 Opened 8 years ago Updated 3 years ago

Scrolling fps drops heavily on rbc.ru

Categories

(Core :: Panning and Zooming, defect, P3)

Product:
Core
Component:
Panning and Zooming
Version:
55 Branch
Type:
defect

Tracking

()

Status:
UNCONFIRMED

People

(Reporter: ajfhajf, Unassigned)

Details

(Whiteboard: [gfx-noted])

User Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:55.0) Gecko/20100101 Firefox/55.0 Build ID: 20170502030211 Steps to reproduce: Create new profile, launch it Start recording performance profile using Shift-F2 Go to http://www.rbc.ru/rbcfreenews/59084d579a7947bdf49eab74?from=newsfeed Start scrolling the page down. Once you reach the bottom of the first article, the next article will be loaded automatically. Make sure you scroll through at least 3-4 articles Actual results: The problem is that scrolling fps drops heavily when articles are changing. I guess that shouldn't happen. Screenshot of my performance profiles: http://i.imgur.com/YhpeV8p.png http://i.imgur.com/W8hYzws.png Minimum frame rate = 3 fps Expected results: I think scrolling frame rate should stay at 60 fps. But I might be wrong.
Product: Firefox → Core
https://perfht.ml/2pUxXr2 There is some jank when the new articles "slides" up.
Component: Untriaged → Panning and Zooming
Priority: -- → P3
Whiteboard: [gfx-noted]
At first glance it looks like the animation is mostly driven by the main thread, which is running some fairly heavy scripts and incurring repaints. This is evident from the second profile screenshot (http://i.imgur.com/W8hYzws.png) which shows long-running scripts and paints. The profile linked in comment 1 shows ~24% of time spent inside the scroll event handler. The inverted callstack on the content thread doesn't show any one particular thing taking up a lot of time (SelectorMatches is #1 at less than 2% of time). I'm sure there's things to optimize in gecko here, but most likely the bigger wins will come from tuning the website to do things more efficiently. Not really sure what that would look like though.
Same problem on https://forum.kingdomcomerpg.com/t/npc-routines-are-a-waste-of-resources/32429/c Scrolling fps drops heavily. It looks like Shift-F5 doesn't work in Nightly because it is stuck on "Loading" after I click "Stop recording" so the only screenshot I can upload is this: http://i.imgur.com/euz2OfB.png Min fps=6.40, not good. STR are simple: create new profile, load the link above and start scrolling the page down until you reach ~25th post (the number of the current post on screen is in the upper right corner of the web page). Should I file a separate bug for this?
Sorry, the link in the post above is broken: https://forum.kingdomcomerpg.com/t/npc-routines-are-a-waste-of-resources/32429/
Severity: normal → S3
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