1367505 - Set and clear pseudo-class locks all at once to avoid restyle thrashing when sending select options to parent process

Status: RESOLVED FIXED

(Core :: Layout: Form Controls, enhancement)

Description

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

This removes nearly half of the time spent in the child process pause in
bug 1118086.  (On my laptop, it cuts the child process pause from about
1560ms to 860ms; the parent process pause is still just over 5 seconds.)

Using querySelectorAll to find only the options that need to be locked
is much faster than iterating over them and locking all of them both
because the iteration is slow and the locking is somewhat slow even when
it's a no-op.

MozReview-Commit-ID: 17h3WIt9c2O

Comment 1

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

Attachment: Set and clear pseudo-class locks all at once to avoid restyle thrashing when sending select options to parent process

Comment 2

[Jared Wein [:jaws] (please needinfo? me)]

Comment on attachment 8870932 [details] [diff] [review]
Set and clear pseudo-class locks all at once to avoid restyle thrashing when sending select options to parent process

Review of attachment 8870932 [details] [diff] [review]:
-----------------------------------------------------------------

Thanks!

Comment 3

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=6cdc1b5ab20ce1e6e4654da3d850a193c5f7d874&group_state=expanded

Comment 4

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/6f30a5d2fa33cc7dc51a8714bee4d83165c825a9
Bug 1367505 - Set and clear pseudo-class locks all at once to avoid restyle thrashing when sending select options to parent process.  r=jaws

Comment 5

[Sebastian Hengst [:aryx] (needinfo me if it's about an intermittent or backout)]

https://hg.mozilla.org/mozilla-central/rev/6f30a5d2fa33