1645620 - C-C TB Performance regression? Please do not use mouseenter/leave events in chrome. They are slower than mouseover/out!: '!nsContentUtils::IsChromeDoc(d)', file .../mozilla/dom/events/EventListenerManager.cpp, line 337

Status: RESOLVED FIXED

(Thunderbird :: Testing Infrastructure, defect)

Description

[ISHIKAWA, Chiaki]

I suddenly began seeing the following warnings in my local mochitest log (C-C TB FULL DEBUG version.)

32: Main Thread] WARNING: Please do not use mouseenter/leave events in chrome. They are slower than mouseover/out!: '!nsContentUtils::IsChromeDoc(d)', file /NEW-SSD/NREF-COMM-CENTRAL/mozilla/dom/events/EventListenerManager.cpp, line 337

32 at the beginning of the line is the number of occurrences.

I did not see the perf regression warning in a log of mochitest run on May 30.
But I found them in a log file from June 6th.
So this regression is rather new.

I also see the warnings on tryserver jobs.:
For example, benc's job:
https://treeherder.mozilla.org/#/jobs?repo=try-comm-central&revision=b36d20f09a11e8a3af3076d85ba00c5da913613b
See
https://firefoxci.taskcluster-artifacts.net/bFrLNNFEQy26gjrJxSFYjg/0/public/logs/live_backing.log

Someone who is familar with Calendar code needs to check them since the perf regression warning messages are all from calendar tests.
(I attach a listing that shows the name of the test files created by the following command:

egrep "(TEST_START|TEST_END|Entering test|Leaving test|do not use mouseenter/leave)" /FF-NEW/log1236-older-mochitest.txt

Since the perf warning started appear very recently, I think the change that introduced it is relatively easily to catch, I suppose.

Related bugzilla entries that may offer hints about how to fix the CSS/HTML page used for Calendar.:
Bug 1138787 Lots of "Please do not use mouseenter/leave events in chrome. They are slower than mouseover/out!" warnings during mochitest-dt runs
Bug 854075 WARNING: Please do not use mouseenter/leave events in chrome. They are slower than mouseover/out!: '!nsContentUtils::IsChromeDoc(d)', file content/events/src/nsEventListenerManager.cpp, line 337

Comment 1

[ISHIKAWA, Chiaki]

Attachment: Tests that produced the errors (excerpt from the log).

Oops. I forgot to attach the excerpt form the log.
This was produced by

egrep "(TEST_START|TEST_END|Entering test|Leaving test|do not use mouseenter/leave)" /FF-NEW/log1236-older-mochitest.txt

Comment 2

[Wayne Mery (:wsmwk)]

Someone who is familar with Calendar code needs to check them since the perf regression warning messages are all from calendar tests.

Comment 3

[Geoff Lankow (:darktrojan)]

Attachment: Bug 1645620 - Stop using mouseenter/mouseleave events. r?pmorris

Comment 4

[Geoff Lankow (:darktrojan)]

This is so minor it's almost not worth fixing, but I shouldn't have made the mistake in the first place.

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/comm-central/rev/d0ad66c21385
Stop using mouseenter/mouseleave events. r=pmorris