1426357 - buildFontList causes jank soon after displaying about:preferences

Status: RESOLVED FIXED

(Firefox :: Settings UI, defect, P2)

Description

[Florian Quèze [:florian]]

Bug 1375978 changed the font enumeration code to avoid main thread I/O, but this still does inefficient DOM manipulations. See https://perfht.ml/2Bpmkyz from the profile in bug 1425398.

buildFontList (https://searchfox.org/mozilla-central/rev/ff462a7f6b4dd3c3fdc53c9bc0b328f42a5b3d2b/toolkit/mozapps/preferences/fontbuilder.js#19) causes jank by repeatedly calling appendChild (for each font found on the system). It should use a document fragment instead.

See https://developer.mozilla.org/en-US/Firefox/Performance_best_practices_for_Firefox_fe_engineers#Adding_nodes_using_DocumentFragments

Comment 1

[Javi Rueda :javirid]

https://share.firefox.dev/49YjxIW

(for my own records)

Comment 2

[Javi Rueda :javirid]

Attachment: WIP: Bug 1426357 - Use DocumentFragment on buildFontList()

Comment 3

[Javi Rueda :javirid]

Attachment: Bug 1426357 - Use DocumentFragment on buildFontList(). r?jfkthame

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/c8923cbbfd5a
Use DocumentFragment on buildFontList(). r=jfkthame,mconley

Comment 5

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/c8923cbbfd5a