1640545 - make attribute substring selectors a little faster

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, enhancement, P1)

Description

[Cameron McCormack (:heycam)]

I use uBlock Origin. That inserts a style sheet with around 700 [href^=...] selectors and 100 [href*=...]. I accidentally took a Gecko profile with uBlock Origin enabled, and I noticed that on pages with many links, this can add a substantial amount of processing time. For example, on the HTML single page spec on my fast machine, we spend a total of 1.1 seconds under Gecko_AttrHasPrefix during page load. It looks like a lot of that is refcount traffic on the string buffer that the nsAttrValue holds. Adding functions to nsAttrValue to do the substring matches so that we don't need to take a new reference to the string buffer saves 520 ms.

Comment 1

[Cameron McCormack (:heycam)]

Attachment: Bug 1640545 - Make attribute substring selectors a little faster.

Comment 2

[Cameron McCormack (:heycam)]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=d73a69e0fe60cdc797eb5a82b7a5e26e83a66069

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/1a207307e72c
Make attribute substring selectors a little faster. r=emilio

Comment 4

[Natalia Csoregi [:nataliaCs]]

https://hg.mozilla.org/mozilla-central/rev/1a207307e72c

Comment 5

[Cameron McCormack (:heycam)]

Attachment: Bug 1640545 - Add perf-reftest-singleton for bug 1640545 changes.

Comment 6

[Phabricator Automation]

Comment on attachment 9151942 [details]
Bug 1640545 - Add perf-reftest-singleton for bug 1640545 changes.

Revision D76966 was moved to bug 1641108. Setting attachment 9151942 [details] to obsolete.