516969 - Handling onfoo event listener is heavy

Status: RESOLVED WORKSFORME

(Core :: DOM: Events, defect, P5)

Description

[Olli Pettay [:smaug][[e-mail]]]

Attachment: a profile

Compiling the attribute value and then calling it is heavy.
Nearly 80% of *event dispatch time* in a testcase is spent in nsEventListenerManager::CompileEventHandlerInternal and
nsJSEventListener::HandleEvent
(Includes the time, 11.6%, which is spent to really call the JS function.)

Slow-looking things are for example
nsScriptSecurityManager::CheckFunctionAccess
and often used JS context stack push/pop.
JS_CompileUCFunctionForPrincipals (17%) could be optimized too, I hope.

Comment 1

[Boris Zbarsky [:bzbarsky]]

Olli, do you want to either mail me the .mshark file for that or put it somewhere where I can get at it?  I assume it's too big to attach to this bug?

Comment 2

[Brendan Eich [:brendan]]

We cache compiled event handlers, IIRC, so this is first-click (just checking)?

It would be great to see the hierarchical profile data.

/be

Comment 3

[Olli Pettay [:smaug][[e-mail]]]

We do cache compiled event handlers, but the first case the handler is called/compiled, we spend lots of time compiling/binding it.

Comment 4

[:Ms2ger (he/him; ⌚ UTC+1/+2)]

How about now?

Comment 5

[Olli Pettay [:smaug][[e-mail]]]

Need to reprofile compilation.

Comment 6

[Olli Pettay [:smaug][[e-mail]]]

Situation isn't any better. Compilation seems to be still slow. Bug 517385 has a testcase.

Comment 7

[Olli Pettay [:smaug][[e-mail]]]

Actually, since event dispatch itself is faster, compilation takes even more % from the total time.

Comment 8

[Firefox Bug Husbandry Bot]

https://bugzilla.mozilla.org/show_bug.cgi?id=1472046

Move all DOM bugs that haven’t been updated in more than 3 years and has no one currently assigned to P5.

If you have questions, please contact :mdaly.

Comment 9

[Jens Stutte [:jstutte]]

Hi Olli, I assume this is obsolete and/or covered elsewhere?

Comment 10

[Olli Pettay [:smaug][[e-mail]]]

I guess this is good enough, when comparing to others (better than in Chrome)