1423367 - We spend a lot of time during TextDrawing in nsIFrame::IsSelected

Status: RESOLVED DUPLICATE of bug 1503581

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

Description

[Jeff Muizelaar [:jrmuizel]]

About 27% of the time from a profile of Gmail

Comment 1

[Aria Beingessner [:Gankra]]

Is this still an issue?

I took a quick look at the code, and it seems like the only non-trivial work (e.g. not checking flags) is 

https://searchfox.org/mozilla-central/source/dom/base/nsRange.cpp#198-281

which is doing a bunch of hashtable/linkedlist walking

Comment 2

[Jeff Muizelaar [:jrmuizel]]

Another profile: https://perfht.ml/2LUufnT

You can reproduce this pretty easily on https://github.com/mozilla/gecko-dev/blob/master/layout/painting/FrameLayerBuilder.cpp by selecting a lot of test.

Comment 3

[Jeff Muizelaar [:jrmuizel]]

This is really bad with regular Gecko too https://perfht.ml/2LYjK30.

We can probably postpone.

Comment 4

[Emilio Cobos Álvarez (:emilio)]

Looking at the profile it's likely that it became worse with bug 651120. Olli has improvements to CompareDocumentPosition / ComputeIndexOf IIRC... Though maybe something smarter can be done to this selection code.

This is particularly bad because tables, which is what GitHub uses for the view source stuff, create a bunch of different ranges.

Comment 5

[Aria Beingessner [:Gankra]]

hopefully fixed by Bug 1488278

Comment 6

[Olli Pettay [:smaug][[e-mail]]]

Nope, how would that fix this. This was filed when we still had childarray with faster indexof(childnode). Bug 1488278 may help a bit with this in Nightly.

Comment 7

[Olli Pettay [:smaug][[e-mail]]]

yeah, doesn't help much.

Comment 8

[Olli Pettay [:smaug][[e-mail]]]

FWIW, that case somehow manages to break the indexof cache. Both the old and new version of that.

Comment 9

[Mayank Bansal]

Is this a dupe of bug 1464632 , and bug 1503581 for the remaining work ?

Comment 10

[Aria Beingessner [:Gankra]]

Yep! Totally forgot this bug existed.