822481 - Loading XDA developers forum in a tab locks up entire Firefox

Status: NEW

(Core :: Layout, defect)

Description

[donrhummy]

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20100101 Firefox/17.0
Build ID: 20121128204232

Steps to reproduce:

Loaded the page: http://forum.xda-developers.com/index.php?tab=all


Actual results:

Firefox became unresponsive and I was unable to go to other tabs.


Expected results:

It should have frozen only that tab as it was loading at worst and at best, only "frozen" the document area and not the ability to hit "stop" or close the tab or switch to other tabs.

Comment 1

[Matthias Versen [:Matti]]

I don't get a freeze with  Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20100101 Firefox/17.0 and a i5 with 2.5Ghz

It froze only during the load - how long ?
Reporting a hang is different from "a hang should not freeze the whole browser".
Firefox is only one single process and if the process is frozen then it's frozen.
We have already a bug open that we should switch to a "one process for each tab" model

Comment 2

[donrhummy]

(In reply to Matthias Versen (Matti) from comment #1)
> I don't get a freeze with  Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0)
> Gecko/20100101 Firefox/17.0 and a i5 with 2.5Ghz
> 
> It froze only during the load - how long ?

for about 11 seconds.

> Reporting a hang is different from "a hang should not freeze the whole
> browser".
> Firefox is only one single process and if the process is frozen then it's
> frozen.
> We have already a bug open that we should switch to a "one process for each
> tab" model

Yes, that would likely fix the problem (although, using a threaded model might do it as well)

Comment 4

[David Bruant]

I'm on Linux 64, FFx Aurora 19, I see a little freeze (more like 1-2 seconds than 11 seconds, but I have a recent machine and it's Aurora)

It might be worth for the Snappy people to take a look at this bug before closing it.
The problem is either:
* a Firefox problem (Snappy folks may dupe it)
* an add-on problem (not sure what can be done about it)
* a website problem (probably a bad DOM patterns like a lot of synchronous append or unnecessary reflows in which case, the website folks are the one who should solve the problem)

Comment 5

[Matthias Versen [:Matti]]

You are right david.

Reporter:
What kind of system are you using ?
Does it make a difference if you run Firefox in the Firefox safemode ?
- http://support.mozilla.org/en-US/kb/Safe+Mode

Comment 6

[Mayank Bansal]

Heres a profile on first time load :

http://people.mozilla.com/~bgirard/cleopatra/#report=31ea21bb10cfe9e14e9f6338fd64a2e7ff33e783

Comment 7

[David Bruant]

(In reply to mayankleoboy1 from comment #6)
> Heres a profile on first time load :
> 
> http://people.mozilla.com/~bgirard/cleopatra/
> #report=31ea21bb10cfe9e14e9f6338fd64a2e7ff33e783
Wow! I want to learn how to do that!
* What should I install?
* How do I publish the result?
* How does it work?

Comment 8

[donrhummy]

(In reply to Matthias Versen (Matti) from comment #5)
> You are right david.
> 
> Reporter:
> What kind of system are you using ?
> Does it make a difference if you run Firefox in the Firefox safemode ?
> - http://support.mozilla.org/en-US/kb/Safe+Mode

David is right. It appears to be Ghostery (an addon). It still locks up with addons disabled but only for 1 second, not 10 or more. I was able to determine the addon causing the issue is Ghostery.

For more info:
I'm using openSUSE 12.1.

Comment 9

[(mostly gone) XtC4UaLL [:xtc4uall]]

(In reply to mayankleoboy1 from comment #6)
> Heres a profile on first time load :
> http://people.mozilla.com/~bgirard/cleopatra/
> #report=31ea21bb10cfe9e14e9f6338fd64a2e7ff33e783

Per that Profile (that was made on Win7) Jank Time is spent mostly in Layout.
I myself did one that confirms this: http://people.mozilla.com/~bgirard/cleopatra/#report=a5eb136f03ef80f9e5cc25610458aff9449f0817

(In reply to David Bruant from comment #7)
> Wow! I want to learn how to do that!
> * What should I install?
> * How do I publish the result?
> * How does it work?

https://developer.mozilla.org/en-US/docs/Performance/Profiling_with_the_Built-in_Profiler#Running%20the%20profiler

Comment 10

[Boris Zbarsky [:bzbarsky]]

Profile from comment 6 shows almost all the jank time under a single style reresolve...  Was that with Ghostery or without?

Comment 11

[Mayank Bansal]

Comment #6 profile is without Ghostery. Though it has AdBlock+ and Do not Track Me.

Comment 12

[Boris Zbarsky [:bzbarsky]]

OK. I'm having a pretty hard time reproducing any sort of jank here, is the problem....  (no addons, though).

Comment 13

[Mayank Bansal]

http://people.mozilla.com/~bgirard/cleopatra/#report=a338d5722635a3df96aa49af48f31938dcec750b

This is with a fresh profile,no addon, with me working in a tab, and the given URL being loaded in the background tab.

Comment 14

[Boris Zbarsky [:bzbarsky]]

Thanks.  That profile shows a single jank instance: 500ms of restyle processing triggered by a Google Analytics script asking for layout info....  Not sure why that takes that long; 500ms is a _huge_ time for a restyle (for context, restyling the entire HTML5 spec takes order of 1000ms).

Comment 15

[Mayank Bansal]

A similar profile can be generated on this page too  :

https://bugzilla.mozilla.org/show_bug.cgi?id=187528

Comment 16

[David Bruant]

Attachment: Original http://forum.xda-developers.com/index.php?tab=all

I've File->Save'd the website and I can reliably observe a ~440-480ms layout::DoReflow call on Linux 64bits Firefox Nightly Dec 16th 2012.
From there, I'll try to reduce the test case