1332100 - Intersection observers run too often

Status: RESOLVED FIXED

(Core :: Layout, defect)

Description

[Bill McCloskey [inactive unless it's an emergency] (:billm)]

Attachment: patch

Every 100ms or so, we notify intersection observers from the refresh driver. For each document managed by the refresh driver, we dispatch a runnable to do the notification. When a document has lots of frames, this ends up dispatching tons of runnables that never do anything.

Since intersection observers are currently rare, I think the easiest fix is to avoid dispatching if there isn't anything to do. Hopefully this still satisfies the spec.

Comment 1

[Ben Kelly [:bkelly, not reviewing]]

And if the spec requires this we should file a spec issue to try to fix it.

Comment 2

[Markus Stange [:mstange]]

Comment on attachment 8828127 [details] [diff] [review]
patch

Review of attachment 8828127 [details] [diff] [review]:
-----------------------------------------------------------------

Seems reasonable. IIRC the spec doesn't require a certain notification latency, so even if this patch made us delay intersection observer notifications in some cases, we'd still be compliant.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/46a9096745e7
Check for intersection observers before posting runnable (r=mstange)

Comment 4

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

This got backed out along with bug 1331804.

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/96837f017b83
Check for intersection observers before posting runnable (r=mstange)

Comment 6

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/96837f017b83