1382256 - Typing in etherpad is slow

Status: RESOLVED WORKSFORME

(Core :: Web Painting, enhancement, P2)

Description

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

https://perfht.ml/2uaJSBW

Comment 1

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

Looks like we're painting way too much, and often twice.

Comment 2

[Jonathan Kew [:jfkthame]]

Indeed -- enabling paint flashing shows that we're apparently repainting all the (visible) pad text on every keystroke. :(  I guess something in the etherpad JS must be triggering that, as we don't show the same behavior when typing in a simple <div> with contenteditable, for example.

(FWIW, Chrome seems to manage rather better with etherpad: it only repaints the current paragraph where the keystroke is occurring, plus often the following one, but not the rest of the text in the pad.)

Comment 3

[(no longer active)]

Kan-Ru was explaining some crazy behavior in etherpad upon hitting backspace a while ago IIRC...

Comment 4

[Kan-Ru Chen [:kanru] (UTC+9)]

Yeah, I found this while testing some spellchecker code. It looks like etherpad handles backspace by first remove all nodes then insert them back, so you will find the spellcheckr underline flicks.

Adding texts is less crazy. It removes current line then insert it back.

Comment 5

[Miko Mynttinen]

Cannot reproduce this on Mac with or without WebRender.