277123 - Chews up lots of CPU on a page with a big form.

Status: NEW

(Core :: Layout: Form Controls, defect)

Description

[Steven Augart]

This is on the latest nightly build (Build ID: 2005010405), Linux/i686.

Pentium 4, 1.8 GHz, 1.5 GiB RAM, unloaded.



Problem: Mozilla chews up huge amounts of CPU when displaying the page.
It chews up more CPU time when shutting down.

How to reproduce:

## First, I timed starting up mozilla with a blank homepage, then
## immediately shutting it down (with control-Q, File=>Quit):

~/JikesRVM/Lists $ time mozilla

real    0m4.200s
user    0m1.540s
sys     0m0.070s

## Next, I timed starting up mozilla with my sample page (I'll attach
## a copy of this sample page).  Then I immediately exited with Control-Q.
## (When I submit the form, it chews up even more CPU time.)



~/JikesRVM/Lists $ time mozilla $PWD/jc3.html

real    0m42.866s
user    0m29.090s
sys     0m0.660s

Comment 1

[Steven Augart]

Attachment: Sample page that shows the bug, plus aux. files

Extract it to a directory, CD there, and try:
time mozilla $PWD/jc3.html

Comment 2

[Martijn Wargers (dead)]

Looks to me related/a duplicate of bug 148636.

Comment 3

[Gervase Markham [:gerv]]

This is an automated message, with ID "auto-resolve01".

This bug has had no comments for a long time. Statistically, we have found that
bug reports that have not been confirmed by a second user after three months are
highly unlikely to be the source of a fix to the code.

While your input is very important to us, our resources are limited and so we
are asking for your help in focussing our efforts. If you can still reproduce
this problem in the latest version of the product (see below for how to obtain a
copy) or, for feature requests, if it's not present in the latest version and
you still believe we should implement it, please visit the URL of this bug
(given at the top of this mail) and add a comment to that effect, giving more
reproduction information if you have it.

If it is not a problem any longer, you need take no action. If this bug is not
changed in any way in the next two weeks, it will be automatically resolved.
Thank you for your help in this matter.

The latest beta releases can be obtained from:
Firefox:     http://www.mozilla.org/projects/firefox/
Thunderbird: http://www.mozilla.org/products/thunderbird/releases/1.5beta1.html
Seamonkey:   http://www.mozilla.org/projects/seamonkey/

Comment 4

[Boris Zbarsky [:bzbarsky]]

I can't reproduce this problem.  On my p3-733, the page loads in 20 seconds and the browser is responsive throughout...

Comment 5

[Wayne Mery (:wsmwk)]

(In reply to comment #4)
> I can't reproduce this problem.  On my p3-733, the page loads in 20 seconds and
> the browser is responsive throughout...

agree WFM FF & SM (on windows, don't have linux) - responsive and 10-20sec, thinkpad T40
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.0.6) Gecko/20060728 Firefox/1.5.0.6

reporter, Steven Augart, is not reachable

Comment 6

[Boris Zbarsky [:bzbarsky]]

I profiled the testcase; unfortunately the profile is too big to conveniently upload.

About 10% of the time is spent setting up text inputs.  Marking this dependent on the bug about that.  We should retest once they're fixed.

Comment 7

[Jonas Sicking (:sicking) No longer reading bugmail consistently]

Are we still not lazy with starting up the editors for the text inputs? So that we only fire up an editor once the user focuses the textfield (and possibly once the value is changed from javascript). That seems like an obvious place to start otherwise.

It'd be cool if all we did was to have a few normal frames that made up the textbox until we really need editor to kick in. Though maybe that is hard to do while making sure that the textbox looks exactly the same once editor is there?

Of course, an alternative is to make editor not suck :)

Comment 8

[Boris Zbarsky [:bzbarsky]]

> Are we still not lazy with starting up the editors for the text inputs?

Yes.  See bug 221820 (which this bug depends on) for my attempts to make it lazy, and the editor brokenness that ran into.

> It'd be cool if all we did was to have a few normal frames 

That's exactly what I tried to do.

> Though maybe that is hard to do while making sure that the textbox looks
> exactly the same once editor is there?

The look was fine.  But the editor blew away and recreated the DOM, which confused drag/drop, clicks, etc.  The solution is to have editor edit the existing DOM and nuke the <br> crap in plaintext editor.  See the dep chain for this bug.  ;)

Comment 9

[(no longer active)]

I benchmarked the testcase here using a stupid (new Date()).getTime() comparison.  Without bug 221820, this test loaded on average in 2014ms, and with bug 221820, it loaded on average in 1094ms.