1803643 - Various querySelector micro-optimizations

Status: RESOLVED FIXED

(Core :: DOM: CSS Object Model, defect)

Description

[Emilio Cobos Álvarez (:emilio)]

This helps a bit with bug 1803464, but unfortunately doesn't have the magnitude I would've hoped...

Comment 1

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1803643 - Speed up selector matching with already-lowercase local name selectors. r=dholbert

This makes relatively simple changes so that we check lowercase-ness of
local-name selectors first. If so, we don't need to check whether we're
an HTML element in an HTML document, which requires a fair bit of
pointer-chasing.

Comment 2

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1803643 - Speed up dom iteration in querySelector. r=dholbert

This removes a few branches and null-checks that I found in profiles.

Depends on D163627

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/7a8e8890780f
Speed up selector matching with already-lowercase local name selectors. r=dholbert
https://hg.mozilla.org/integration/autoland/rev/63b85eeb214b
Speed up dom iteration in querySelector. r=dholbert

Comment 4

[Atila Butkovits]

https://hg.mozilla.org/mozilla-central/rev/7a8e8890780f
https://hg.mozilla.org/mozilla-central/rev/63b85eeb214b

Comment 5

[Andrej (:aglavic)]

== Change summary for alert #36318 (as of Tue, 06 Dec 2022 05:33:57 GMT) ==

Improvements:

Ratio	Test	Platform	Options	Absolute values (old vs new)
6%	perf_reftest_singletons parent-basic-singleton.html	linux1804-64-shippable-qr	e10s fission stylo webrender	87.97 -> 82.40

For up to date results, see: https://treeherder.mozilla.org/perfherder/alerts?id=36318