176150 - Fixed backgrounds cause horribly slow scrolling

Status: RESOLVED DUPLICATE of bug 90198

(SeaMonkey :: General, defect)

Description

[Hrunting Johnson]

Pages with background images, especially fixed background attachments cause
horrible scrolling performance.  In Chimera 0.5 and the latest nightlies, compare:

http://anomaly.hrunting.org/index.html
http://anomaly.hrunting.org/index-nobg.html

This isn't evident in Mozilla 1.2 on Windows (I don't have Mozilla 1.x on the
Mac; that's why I downloaded Chimera).  Furthermore, it appears that if the
background-image is specified and then overruled by a subsequent rule, the
painful lag in scrolling still takes place.

The machine I have is a PowerBook Ti 800MHz with 768MB of RAM and OS X 10.2.1. 
top shows CPU at 100% in Navigator when trying to scroll.

Comment 1

[Niklas Dougherty]

Actually, just doing nothing while having a page with fixed backgrounds open
will cause major CPU drainage in Mozilla on Mac. Have a look at
http://www.student.lu.se/~kin02ndo/ for a good example. I don't have a speedy
machine, so it really slows things down. On newer machines, I imagine QE would
render this off-CPU.

Comment 2

[Greg K.]

Hrunting, it would be worthwhile to test other OS X browsers.

Comment 3

[Hrunting Johnson]

Actually, having tested Windows Mozilla 1.2b today, I see the problem also 
exists in that version in a worse form (99% CPU with no action required by the 
user), so I'm refiling there.  The problem wasn't evident in Mozilla 1.1, so it 
looks like a bug in the newer code rather than specifically Chimera.  See 
Niklas' comments above.

Comment 4

[Niklas Dougherty]

Attachment: Crash report

For what it is worth, reloading the given URL crashed Mozilla 1.2b
2002-10-16/12.

The CPU drainage seems to wear off after a while... dunno, hard to reproduce.
Seems like something is getting into a loop and may escape at a later point. Or
crash. (Didn't see your new filing, so submitting here for now.)

Comment 5

[Greg K.]

Niklas, that crash looks like bug 164893, comment 2. You should mention it on
that bug and update its' Platform and OS setting.

Comment 6

[Stephane Moureau]

With Chimera 1026 under OS X 10.1.5 - iMac 400Mhz 256Mb 1024x768 32bits
and Mozilla 1.2b Mozilla/5.0 Gecko/20021016

None of all the links were slow nor crashing after 10min of tests, scroll,
reload, etc on each of them. WFM.

The only 'special' things I have made to .js file is:
user_pref("browser.quartz.enable", false);

Comment 7

[Hrunting Johnson]

Bah, that's because I did some tests and removed some CSS declarations that 
were causing the problem and didn't put them back in.  If you try it now, 
you'll definitely see it.  I'm using that same build of Chimera and seeing it, 
as well as in Mozilla 1.2b (but not in 1.1).

Comment 8

[Craig]

Mozilla 1.2b 2002101412 under Windoze: the nobg version is fine. The other
version slams the processor to 100% CPU use.

Comment 9

[Hrunting Johnson]

I'm updating the targets on this bug.  It's not a Chimera bug.  It's bug in the 
browser renderer itself.  I've personally confirmed the bug in Mozilla 1.2b, 
Chimera 0.5/0.6, and Phoenix 0.4.  All those use roughly the same codebases.

Comment 10

[Kris Kelvin]

I can confirm very poor scrolling performance with fixed background in Linux
with Mozilla 1.2.1

Mozilla/5.0 (X11; U; Linux i686; de-AT; rv:1.2.1) Gecko/20021130

Comment 11

[Kris Kelvin]

The following 4 bugs seem to be related (or duplicates):

bug 90198  - scrolling very slow (fixed background)
bug 172626 - Very slow scrolling unless the background is commented out
bug 176150 - Fixed backgrounds cause horribly slow scrolling
bug 184556 - style rule for fixed background causes lag when text scrolled

Comment 12

[Sören 'Chucker' Kuklau (gone)]

Thanks Kris!

*** This bug has been marked as a duplicate of 90198 ***