1436056 - Sync painting during tab dragging

Status: NEW

(Core :: Widget: Cocoa, enhancement, P2)

Description

[Jeff Muizelaar [:jrmuizel]]

This doesn't seem necessary.

https://perfht.ml/2Eo31Gs

Comment 1

[Jeff Muizelaar [:jrmuizel]]

This probably only happens on macOS

Comment 2

[Sotaro Ikeda [:sotaro]]

When we address the problem, we need to check if Bug 1380462 does not regress.

Comment 3

[Sotaro Ikeda [:sotaro]]

(In reply to Jeff Muizelaar [:jrmuizel] from comment #1)
> This probably only happens on macOS

Sync painting does not happen on windows with WebRender. It is because nsWindow::OnPaint() is not implemented yet well for WebRender. Then, instead jiggle happened during resizing on Windows. Sync wait is for preventing jiggle during resizing.

Comment 4

[Sotaro Ikeda [:sotaro]]

Then sync wait seems necessary to avoid jiggle. But if there is a situation that we could avoid sync painting, we should avoid it.

Comment 5

[Sotaro Ikeda [:sotaro]]

Sync wait was added by bug 873944.

Comment 6

[Matt Woodrow (:mattwoodrow)]

What do you mean by tab dragging? Is that dragging a tab to a different order within the tab strip? Or dragging it out into a new window?

Can you check to see if it reproduces on Windows? We shouldn't block stage-wr-trains if it doesn't.

Comment 7

[Sotaro Ikeda [:sotaro]]

I saw syn FlushRendering() during dragging a tab to a different order within the tab strip.

Comment 8

[Jeff Muizelaar [:jrmuizel]]

(In reply to Matt Woodrow (:mattwoodrow) from comment #6)
> What do you mean by tab dragging? Is that dragging a tab to a different
> order within the tab strip? Or dragging it out into a new window?

Different order within the tab strip.

> 
> Can you check to see if it reproduces on Windows? We shouldn't block
> stage-wr-trains if it doesn't.

It seems to only happen on mac.

Comment 9

[Markus Stange [:mstange]]

It doesn't seem WebRender specific either. Something calls setNeedsDisplay on our window; it might be us or it might be the system because we use drag&drop APIs or because we have this preview window. I'm actually not sure if the tab dragging preview rectangle is a Gecko window or if it's just a drag image.

Moving to Widget:Cocoa.

Comment 10

[Matt Woodrow (:mattwoodrow)]

We might be able to do something similar to Bug 1486958, where we're trying to make widget paint requests only sync in certain cases (resizing).