Closed Bug 1468739 Opened 6 years ago Closed 6 years ago

forwarding slides on a page spends a lot of time in querySelector.

Categories

(Core :: DOM: CSS Object Model, defect, P3)

defect

Tracking

()

RESOLVED DUPLICATE of bug 1497389

People

(Reporter: mayankleoboy1, Unassigned)

References

Details

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:62.0) Gecko/20100101 Firefox/62.0
Build ID: 20180614100146

Steps to reproduce:

1. Go to https://slidewiki.org/presentation/584-14/semantic-data-web-lecture/2038-5/15160-2/#/slide-15160-2

2. keep the forward arrow key pressed, so that the slides move quickly


Actual results:

transitions are slow
Profile shows large time spent in stylo


Expected results:

not so

https://perfht.ml/2t7qRyD  with stylo
https://perfht.ml/2t9Q7Em with stylo+sequential styling
here is a profile with "Style" added to the profiler : https://perfht.ml/2JKe1NQ
Flags: needinfo?(emilio)
This is not styling, this is all querySelector stuff.

Still worth looking if there's something to optimize there.
Summary: forwarding slides on a page is slow due to styling → forwarding slides on a page spends a lot of time in querySelector.
Component: CSS Parsing and Computation → DOM: CSS Object Model
Priority: -- → P3
Is there anything further actionable here? If not, I would be happy with closing this
Bug 1497389 will help quite a bit here. But no, looking at the selectors, nothing else immediately actionable, all of them should peek the fast path with that optimization except "p, pre", but that's less than 0.1% of the time in a profile I just took.

I'll dup to that one. Thanks a lot for reporting it! And sorry for not getting to all the ni?s, I wish I had more time :)
Status: UNCONFIRMED → RESOLVED
Closed: 6 years ago
Flags: needinfo?(emilio)
Resolution: --- → DUPLICATE
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