1479201 - HTML page full of emojis scrolls poorly

Status: RESOLVED FIXED

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

Description

[Mayank Bansal]

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:63.0) Gecko/20100101 Firefox/63.0
Build ID: 20180728101501

Steps to reproduce:

create new profile. Enable WR

Open https://bugzilla.mozilla.org/attachment.cgi?id=8995714

scroll with the mouse



Actual results:

poor janky scrolling
https://perfht.ml/2NSsPvP


Expected results:

not so
non-WR is pretty smooth

Comment 1

[Mayank Bansal]

see also: bug 1479196

Comment 2

[Alice0775 White]

confirmed

Comment 3

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

From the profile it looks like the renderer thread is swamped. So bug 1480317 would help.

Comment 4

[Aria Beingessner [:Gankra]]

I don't think this needs to block release

Comment 5

[Mayank Bansal]

the testcase has started to act a bit weird. Now it takes 2GB memory to display with tons of CPU

Comment 6

[Mayank Bansal]

It now scrolls better than what I remember it used to : https://perfht.ml/2L7Knnb

Comment 7

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

The new profile in comment 6 shows better behaviour than before, but still shows long composites (upwards of 60ms). 3% of time on the renderer thread is in NtQueryLicenseValue much like your other profiles. But this time 7% is in draw_elements_instanced so there might be something we can improve here.

Comment 8

[Mayank Bansal]

(In reply to Kartikaya Gupta (email:[e-mail]) from comment #7)

>3% of time on the renderer thread is in NtQueryLicenseValue much like your other profiles. But this time >7% is in draw_elements_instanced so there might be something we can improve here.

Anecdotally, the last round of reducing mem_cpy work on the WR side reduced the time spent in NtQueryLicenseValue in general on all pages.

Comment 9

[Mayank Bansal]

Attachment: emoji_working.html

This is a UTF encoded emoji page, that will show actual emojis in proper rows and columns.
This still scrolls with jank and checkerboard with the latest patch from bug 1493353 applied. Bug 1493353 did fix the original testcase from #comment 0

Comment 10

[Jeff Muizelaar [:jrmuizel]]

Mayank, can you post of a profile?

Comment 11

[Mayank Bansal]

https://perfht.ml/2Cgyadd

Comment 12

[Mayank Bansal]

of course, feel free to WONTFIX this, as its terribly artificail.

Comment 13

[Mayank Bansal]

heres a profile I took on a slow network. Which means the page took over 20 seconds to load on the network.

https://perfht.ml/2FueSTP

Comment 14

[Mayank Bansal]

Marking this as resolved fixed. as the testcase doesnt jank at all while scrolling. It does turn white, but that is the general "make painting fast" bug.