1506435 - On a heavy page, mousing over the different icons on the tab-bar(download arrow, profiler button, library button, hamburger button etc) is janky

Status: RESOLVED DUPLICATE of bug 1441308

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

Description

[Mayank Bansal]

Attachment: Firefox 2018-11-11 15.10 profile.sps(1).7z

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:65.0) Gecko/20100101 Firefox/65.0

Steps to reproduce:

1.enable WR
2. unzip the attachment (a large perf-html profile))
3. Go to https://perf-html.io/
4. Drag and drop the profile there
5. Wait till the profile loads
6. Mouse over the different icons on the tab-bar (download arrow, profiler button, library button, hamburger button etc)


Actual results:

The hover effect on the icons is laggy. CPU use is high (50% of my 2c/4T processor)

https://perfht.ml/2z4HoYa



Expected results:

not so
Heavy page content should not affect the animations of the UI

Comment 1

[Mayank Bansal]

maybe slightly better profile: https://perfht.ml/2OAVaGM

Also STR is a little modified:

Steps 1-5 are same
6. Show only the content process 3
7. Invert the callstack
8. Highlight the topmost function of the content (NTWaitforAlertByThreadID)
8. Mouseover the icons of the tab-bar 
OR
highlight different functions of the inverted stack list. The highlighting is also laggy

Comment 2

[Mayank Bansal]

Actually, this testcase is overly complicated. No need to all of that.
Will close this, and open a new bug with simpler testcase.
Also, this might just be the document splitting work.

Comment 3

[Mayank Bansal]

Simpler STR:

1. Go to Just go to https://ci.chromium.org/p/chromium/g/main/console?limit=500 , 
2. Put mouse cursor over the tab bar/the address bar
3. Let the page settle
4. Move ,ouse over the downloads/extensions/library icons.

Slow movement.