1815422 - Slow performance on https://compat-table.github.io/compat-table/es6/ compared to Chrome

Status: NEW

(Core :: Web Painting, defect)

Description

[Bas Schouten (:bas.schouten)]

Hovering on the page is significantly slower in Firefox when compared to Chrome.

See the profile: https://share.firefox.dev/3YsDPnN

Emilio noted some of this is caused by querySelectorAll. There is also an unexplained reflow here. And DisplayList building also shows up.

Comment 1

[Mayank Bansal]

FWIW, the difference becomes even more stark if you first expand the whole table by clicking on the arrow on the "Feature NAme" cell on the table.
Example profile: https://share.firefox.dev/3HFdZWN

Chrome is visually smoother.

Comment 2

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1815422 - Deal with table cells in the abspos cb change optimization code-path. r=dholbert,#layout

Comment 3

[Phabricator Automation]

Comment on attachment 9316431 [details]
Bug 1815422 - Deal with table cells in the abspos cb change optimization code-path. r=dholbert,#layout

Revision D169127 was moved to bug 1815552. Setting attachment 9316431 [details] to obsolete.

Comment 4

[Emilio Cobos Álvarez (:emilio)]

Bug 1815552 makes it quite noticeably faster, removing all the reflow. The rest is display list building.

Comment 5

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:jwatt, could you have a look please?

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Comment 6

[Emilio Cobos Álvarez (:emilio)]

(After bug 1815552 this should be much better as per comment 4)

Comment 7

[Mayank Bansal]

(In reply to Mayank Bansal from comment #1)

FWIW, the difference becomes even more stark if you first expand the whole table by clicking on the arrow on the "Feature NAme" cell on the table.
Example profile: https://share.firefox.dev/3HFdZWN

Chrome is visually smoother.

Profile with patches from bug 1815552 : https://share.firefox.dev/3EOktCj
Visually, we are comparable (and maybe slightly faster) than Chrome

Comment 8

[BugBot [:suhaib / :marco/ :calixte]]

The severity field is not set for this bug.
:tnikkel, could you have a look please?

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Comment 9

[Timothy Nikkel (:tnikkel)]

If we are on par or slightly better than Chrome -> S3.