749075 - Improve performance of display list construction, ComputeVisibility and layer construction

Status: RESOLVED FIXED

(Core :: Layout, defect)

Description

[Robert O'Callahan (:roc) (email my personal email if necessary)]

We do this a lot and it shows up on mobile profiles. I'm using the test patch here:
https://bugzilla.mozilla.org/show_bug.cgi?id=735898#c1
and profiling a saved version of cnn.com.

Comment 1

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Attachment: Part 1: Refactor the nsDisplayItem API for testing whether the item needs to be rendered to a transparent surface

Comment 2

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Attachment: Part 2: Skip the guts of Accumulate if we're adding a display item in an area of the layer that's already opaque and visible

In my test this improves perf from around 25s to around 22s.

Comment 3

[Matt Woodrow (:mattwoodrow)]

Comment on attachment 618565 [details] [diff] [review]
Part 1: Refactor the nsDisplayItem API for testing whether the item needs to be rendered to a transparent surface

Review of attachment 618565 [details] [diff] [review]:
-----------------------------------------------------------------

::: layout/base/nsDisplayList.h
@@ +501,5 @@
> +      // Web pages or extensions could trigger this by using
> +      // -moz-appearance:win-borderless-glass etc on their own elements.
> +      // Keep the first one, since that will be the background of the root
> +      // window
> +      NS_WARNING("Multiple glass backgrounds found?");

Does this need to be a warning if it can be hit by website code?

Comment 4

[Robert O'Callahan (:roc) (email my personal email if necessary)]

(In reply to Matt Woodrow (:mattwoodrow) from comment #3)
> ::: layout/base/nsDisplayList.h
> @@ +501,5 @@
> > +      // Web pages or extensions could trigger this by using
> > +      // -moz-appearance:win-borderless-glass etc on their own elements.
> > +      // Keep the first one, since that will be the background of the root
> > +      // window
> > +      NS_WARNING("Multiple glass backgrounds found?");
> 
> Does this need to be a warning if it can be hit by website code?

Yes. Warnings can be hit by website code.

Comment 5

[Robert O'Callahan (:roc) (email my personal email if necessary)]

http://hg.mozilla.org/integration/mozilla-inbound/rev/ec2bba7d11b4

Comment 6

[Robert O'Callahan (:roc) (email my personal email if necessary)]

http://hg.mozilla.org/integration/mozilla-inbound/rev/82531cc259b3

Comment 7

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/ec2bba7d11b4
https://hg.mozilla.org/mozilla-central/rev/82531cc259b3