Open Bug 100951 Opened 19 years ago Updated 2 years ago

[meta] Slow scrolling bugs


(Core :: General, defect)

Not set





(Reporter: coffeebreaks, Unassigned)


(Depends on 23 open bugs)


(Keywords: meta, perf)


(4 files)

meta bug for teacking slow scrolling bugs

[I took the liberty to create a meta bug. Though it might be helpful as some
bugs have been marked duplicates but sometimes no real testcases have been given]

Here are the bug numbers of slow scrolling bugs that should then be added as

46942 Scrolling is very slow 
60371 slow scrolling of the text field using mouse [Linux]
60986 Scrolling with scrollbar arrows is slow
90198 scrolling very slow 
96088 scrolling on this page is slow 
96959 Very slow scrolling which uses all CPU [duplicate]
97938 Scrolling search results page is painfully slow 
97992 Scrolling on this page is slow 
100799 Mousewheel scrolling very slow

Some may be duplicates.
just added a bug I filed yesterday
Depends on: 100575
Ever confirmed: true
--> Browser General
Component: Layout → Browser-General
forgot to add the bugs mentioned in the bug 
No longer depends on: 97992
over to tracking
Component: Browser-General → Tracking
Blocks: 91351
added meta keyword
Keywords: meta
Blocks: 71668
Depends on: 98252
Target Milestone: --- → Future
Depends on: 111681, 116361
No longer depends on: 111681
Depends on: 111681, 116363
No longer depends on: 116361
No longer depends on: 111681
better add bug 99924 and bug 110113: background rendered images make mozilla
scroll slow.
Depends on: 120417
No longer depends on: 120417
Depends on: 120417
Keywords: perf
*** Bug 121979 has been marked as a duplicate of this bug. ***
Blocks: 74634
Depends on: 52005, 89085, 117376, 117879, 121089
Depends on: 121983
Depends on: 122423
No longer depends on: 122423
Quite a lot of slow scrolling bugs have been fixed with recent builds. So I
think we should try the pages again and report if it was fixed or not.
Depends on: 70156
No longer depends on: 120417
Here are some more:

I still see performance problems with Build 2002020603, but they are not 100%
reproducible. Here is something that does reproduce on Mac OS 9, at least:
1) Open a web page or email, etc. with many lines (more than 150)
2) Drag your mouse down, to select lines, continuing past bottom of window, to
start scrolling.
3) After (at least) 2 seconds, drag mouse back into middle of text area.

Note that scrolling does not stop immediately. It doesn't stop until much more
time later. Images do not play a role. Earlier releases did perform better.
Depends on: 122996
Take a look here please -> Bug 93619  

Also this page is a good testcase...
Depends on: 125892
*** Bug 126645 has been marked as a duplicate of this bug. ***
Depends on: 126645
2002-2-21-03 w2k, probably bug 122996.  not seeing any slow scrolling anymore on
many bugs, please try and confirm the dependency bugs here if they are fixed or
not, Thanks.
Also bug 98252 (in 0.9.8) has contributed to tiling and fixing several problems
with scrolling. 
Still seeing slow scrolling on Bug 126645 on Win2k using 2002022503 nightly build.
For quite some time the page was
scrolling just fine. But now I just tried with Mozilla 2002030803 on Windows XP
and scrolling is terribly slow again.
Depends on: 129942
Depends on: 130228
please see my notes on bug 130228, comment 6, too. the page mentioned in comment
15 is still quite fast compared to for
example. that one is pure pain! (and works smoothly on the 0.9.9 branch)
Depends on: 131194
Depends on: 136356
Depends on: 136447 - very slow scrollin with
build 20020411
Depends on: 138034
Depends on: 139149
Quite slow:  with build 2002041903 on Win2K
Depends on: 140236
Depends on: 140243
Depends on: 141147 seems ok for me, win98 2002043010
Well is veeery slow here. Windows XP, 2002050108.
Are these slow scrolling bugs ever going to be fixed. It would be very bad for
user exprience if they are left in 1.0.0
They're trying to fix every bug :)

Jure: Have you tried completely uninstalling your mozilla (including manually
deleting the stuff that the deinstallation might not get rid of), re-installing
and trying again with a clean profile? 
Well I use zipped mozilla nightlies and also create another clean profiles to
test bugs. When I install another nightly I delete Mozilla bin folder and then
unzip the new nightly. So all gets cleaned.

I know they are working hord on bugs but these scrollung bugs are really
starting to get on my nerves. I just hope they don't forget about them. actually works great for me on win2k 2002050208
Yup I also have 2002050208 on Windows XP and all pages that I found slow are
fine now. Except the page from comment 17 is stil jerky:
Yeah, that's a bit "chunky" for me too.  Has anyone determined if video h/w is a
I think it is not the HW. IE 6, Opera 6.01 and Amaya 6.0 all scroll without a hitch.
Depends on: 144083
Another slow scroll URL:

Anyone want to venture as to shich bug this dupes before I submit?
re comment 27 ; that page works fine for me -- the URL in comment 17 seems like
the only one that is having problems (Linux/2002051507)
I think this may be h/w dependant.  It works on my 266MHz laptop, but not my
1050Mhz nVidia GF3 card.
With Mozilla/5.0 (Windows; U; Win98; en-US; rv:1.0.0+) Gecko/20020531
I saw no further problems at
bug 52005,   bug 60371,  bug 60986,  bug 12417  bug 136356,  bug 140243,  bug
144083,     bug 46942  bug 141786,   bug   bug   bug   bug   bug   

I still see problems at
bug 70156  Page does not work at all 
bug 90198  (but does not wor _so_ bad   

I did not test
bug 89085
Depends on: 133596
*** Bug 135044 has been marked as a duplicate of this bug. ***

This problem does not occur on nightly builds, just official releases.
Confirmed: build 20020607 - no problems with, - performance still unacceptable but better than in
previous builds
Their seems to be some extra programming in the official builds than the nightly
builds. The only difference I see in official builds that I don't see in the
nightly builds, besides the awful performance is the ability to use the Windows
Media plug-in.
Depends on: 148598
Depends on: 147180
build 2002090511 - scrolls awfully, especially when clear
type is enabled (very big difference) (WinXP, 512MB, PIII 600). IE scrolls this
page perfectly.
Depends on: 171597
Depends on: 170928
Depends on: 166691
Depends on: 172419
Depends on: 173453
I now think it is relayted to the way mozilla uses (or probably don't use) the
graphics accelerator.

I am using a IBM laptop (T21) with screen resolution of 1280x1024
When I switch to 1024x800, the performance is OK.

But in high resolution I get all the above performance problems.
Since IE works just fine at this resolution, my guess is that IE uses the
graphics acceleratort through the windows API, and mozilla - since it is cross
platform - does not.
Can you comment on that ?

See the scroll bar in: 
Another testcase URL: is feeding different .css
files based on ie/nonie.  The non-ie one has a "background-attachment: fixed;"
style, the ie one does not.  That url belongs with Bug 90198 is
a reflow/dirtyarea/clipping area problem. For every scroll, Mozilla is dirtying
the whole scrollable table (ID=content1 DIV to be exact) area, which usually
results in a large portion of the page being forced to be redrawn.  What really
should happen is only the ID=clip1 DIV area should be dirtied.
Mozilla 1.3, Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.3)
Gecko/20030312, Windows XP Pro, Build 2600.xpsp1.020828-1920

Dell OPTIPLEX GX50, Celerron 1.2GHz, 256 MB RAM, Intel 82810E Graphics Controller

More CPU/kernel thrashing testcases:

See or
(or any other page, for that matter) for pages that cause intense
CPU/kernel thrashing. 

The hiwaay pages scroll fine in Opera 7.03, IE 6, Amaya 7.2 & even Netscape 2.02(!).

I put these in a few other scroll problem bugs to cover the bases...
earthsound: The reason for the problems you experience on those pages
is probably due to the 9600 pixel background image on every page.

No scrolling problems on any page here (Mozilla 1.4a Windows; U;
Win98; en-US; rv:1.4a) Gecko/20030304
Mark: Shouldn't mozilla handle it better than it does, regardless of the
underlying problem? As you'll note in comment 40, even Netscape 2.02 handles pages better! :\
Attached image performance comparison
This screenshot of XP's Task Manager>Performance tab shows, on the left,
intense scrolling of this bug, and on the right, regular scrolling of Is this
to be expected w/ Mozilla?
Attached image performance comparison
This screenshot of XP's Task Manager>Performance tab shows, on the left,
intense scrolling of this bug, and on the right, regular scrolling of Is this
to be expected w/ Mozilla, even as other browsers (some > 5 yrs old) handle the
same pages quite gracefully?
Mozilla 1.4a, Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.4a)
Gecko/20030401, Windows XP build 2600.xpsp1.020828-1920

update: the pages I posted earlier WFM in 1.4a :) woohoo!
reassign to watching address
Assignee: attinasi → other
Summary: [META] Slow scrolling bugs → Slow scrolling bugs
Depends on: 201307, 203439
Depends on: 216430
Depends on: 100%CPU-bg
Depends on: 163975, 200814
No longer depends on: 200814
No longer depends on: 173453
I am having some very poor scrolling performance with a web site that my company
runs.  The problem seems to be scrolling the 'big' frame in the attached page. 
Opening that frame in its own window yields much better scrolling performance. 
Unpack the zip and open 'results.html'.
I should add that I am running on Mac OS X.3.5, and this has the same behavior
in 1.7, 1.7.2 and 1.8a2.  
Depends on: 249880
Depends on: 271573
No longer depends on: 249880
Depends on: 272801
Depends on: 141710
Depends on: 275618
Depends on: 188208
Depends on: 309464
Depends on: 310500
Blocks: 203448
Depends on: 437178
This website is really slooooooowwwww...
(It worked perfectly well on Firefox 2)
I am also encountering much slower scrolling on some pages in Firefox 3 only. In Firefox 2, it isn't an issue.
900Mhz P3, 320MB RAM
ATI Radeon 9200SE 64MB
Depends on: 426907
Depends on: 441396
Add Bug number 202718 to the list.
Testcase URLs in comment 10 - comment 27 - comment 50 do not exist anymore.

Testcase in comment 47 is WFM.

Testcase in comment 18 is still quite slow.

Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1b4) Gecko/20090427 Shiretoko/3.5b4
Assignee: layout → nobody
QA Contact: chrispetersen → chofmann
Add Bug 266702 to list
Slow scrolling and high CPU usage on this site:

Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv: Gecko/20100401 Firefox/3.6.3
I think Retained Layers should fix a lot of these old slow scrolling bugs.  Many testcases here work fine with latest trunk builds of 1.9.3.  Though bug 266702 is still very slow and probably due to excessive markup.

Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.3a6pre) Gecko/20100621 Minefield/3.7a6pre Firefox/3.6.3
In the site that says RNicoletto, Firefox 7 uses completely one of my 4 CPUs to scroll.
(In reply to Jaroslav Benc from comment #58)
> Created attachment 556680 [details]
> Slow scrollling example showing FPS in the page title when scrolling

With my low-end notebook (specs here ==> I get 24-26 FPS with Firefox 6.0.1 and 20-22 FPS with current nightly. I tested Google Chrome 15 and Opera 11.51 but FPS won't show in page title, however with those browser scrolling is smoother and eats less RAM.
Blocks: 701718
No longer blocks: 701718
Depends on: 701718
Attachment #556680 - Attachment mime type: text/plain → text/html
(In reply to Laurentiu Nicola from comment #60)
> Another example, with an image:
> jpg

Thank you, Laurentiu.
I can't reproduce, could you try with Safe Mode and open a new bug with more informations?
Summary: Slow scrolling bugs → [meta] Slow scrolling bugs
Another site with this problem:

I'm glad I found a place to report it, this makes it hard to browse certain sites. :(
John, you're on the right track, but this isn't the bug to report your issue. This a meta bug for tracking specific bugs. The right thing to do is to file a new bug for the site you mentioned and mark it as blocking this one. Thanks for the report!
Depends on: 785588
Depends on: 791424
Bug 645563 should be on this list, too.
Depends on: 824952
Depends on: 814318
Depends on: 846470
Depends on: 911975
Depends on: 900094
Depends on: 916389
Depends on: 853699
Depends on: 527728
Depends on: 961381
We should re-check dependencies of this bug once 48 hits release - - because e10s - about:config?filter=browser.tabs.remote.autostart (and creating the boolean pref browser.tabs.remote.force-enable if necessary) - *combined with* APZ - about:config?filter=layers.async-pan-zoom.enabled (see prefs for tweaking at ) - was what noticeably improved scrolling according to
(In reply to David.P from comment #67)
> Next try.

These comments are not constructive unfortunately. Please open a new bug explaining
the problem you're seeing, on which website you're seeing it, paste the contents of the
graphics section of your about:support page, collect a profile while you experience
the problem ( and share it in the bug.

Without more information, the problem you're describing is not actionable and is going
to be ignored.
Component: Tracking → General
QA Contact: chofmann
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