System gets unresponsive under moderate load

After further testing it turns out that I get the same problem with all kernels starting from 2.6.22-6.13. I could not test with earlier kernels, because I don't have them anymore...

So either it's an old problem (but I think I would have noticed earlier then). Or the problem is caused by something else besides the kernel. And ideas?

The problem goes away when I disable desktop effects. Reassigning...

What video card and driver do you use?

I'm using an onboard nVidia chip:
00:05.0 VGA compatible controller: nVidia Corporation C51G [GeForce 6100] (rev a2)

And I'm using the proprietary driver from nVidia:
Section "Device"
        Identifier "Generic Video Card"
        Driver "nvidia"
        BusID "PCI:0:5:0"
        Option "NoLogo" "true"
        Option "AddARGBGLXVisuals" "true"
        Option "FlatPanelProperties" "Scaling = aspect-scaled"
EndSection

Actually this seems to be something bigger...

When I watch a movie using kaffeine (no compiz or similar running) and I start Firefox (generating disk I/O) the video skips like crazy and becomes unwatchable until Firefox has finished starting.

So I think this is a problem with the I/O scheduler or the CPU scheduler.

I'm no expert on these things so I would appreciate if you could tell me ways how I can find out if this claim is actually true...

Thanks a lot for helping me figure this out.

Thank you for taking the time to report this bug and helping to make Ubuntu better. Unfortunately we can't fix it, because your description doesn't yet have enough information.
Please include as attachments the following additional information, if you have not already done so (please pay attention to lspci's additional options), as required by the Ubuntu Kernel Team:
1. Please include the output of the command 'uname -a' in your next response. It should be one, long line of text which includes the exact kernel version you're running, as well as the CPU architecture.
2. Please run the command 'dmesg > dmesg.log' after reproducing the issue and attach the resulting file 'dmesg.log' to this bug report.
3. Please run the command 'sudo lspci -vvnn > lspci-vvnn.log' and attach the resulting file 'lspci-vvnn.log' to this bug report.
For your reference, the full description of procedures for kernel-related bug reports is available at https://wiki.ubuntu.com/KernelTeamBugPolicies . Thanks in advance!

I've done a fresh install of tribe5 and basically have the same problems here. Even the desktop effects sometimes cause the mouse pointer to freeze for up to two seconds or so.

Again, I'll probably need a way to measure this, so if you know of any way to do this, please tell.

Here's the requested info:
mika@mika-pc:~$ uname -a
Linux mika-pc 2.6.22-10-generic #1 SMP Wed Aug 22 08:11:52 GMT 2007 i686 GNU/Linux

Thanks a lot for your help!

I am seeing these symptoms also on an old Dell Inspiron laptop, which has no 3D acceleration. A good example was when copying the Kubuntu gutsy RC CD image to another system over the network (using fish:// KIO slave). During this the mouse periodically stopped responding for a couple of seconds or more. I have never noticed this on Feisty, but it has persisted on Gutsy-development for some months. Current kernel:
Linux ubuntu 2.6.22-14-generic #1 SMP Wed Oct 10 06:00:47 GMT 2007 i686 GNU/Linux

Same problem on a Toshiba Satellite A135 with Gutsy (didn't have the problem in Feisty).

Linux karg-laptop1 2.6.22-14-generic #1 SMP Sun Oct 14 23:05:12 GMT 2007 i686 GNU/Linux

Hi everyone, I just found out that in my case the problem is way too slow SATA performance, see bug #119730. I measured reading time with `cat Some350MBFile>/dev/null' and got 97 seconds, which leads to 3.5MB/s. It seems to be way too slow. I wonder if others have same roots?

try mounting ext3 paritions with "barrier=0"
this could be meta-bug with many things cousing performance loss.
it is fruther discussed here: http://forums.gentoo.org/viewtopic-t-482731-postdays-0-postorder-asc-highlight-fast-start-575.html

Beginning with the Hardy Heron 8.04 development cycle, all open Ubuntu kernel bugs need to be reported against the "linux" kernel package. We are automatically migrating this bug to the new "linux" package. However, development has already began for the upcoming Intrepid Ibex 8.10 release. It would be helpful if you could test the upcoming release and verify if this is still an issue - http://www.ubuntu.com/testing . If the issue still exists, please update this report by changing the Status of the "linux" task from "Incomplete" to "New". We appreciate your patience and understanding as we make this transition. Thanks!

The Ubuntu Kernel Team is planning to move to the 2.6.27 kernel for the upcoming Intrepid Ibex 8.10 release. As a result, the kernel team would appreciate it if you could please test this newer 2.6.27 Ubuntu kernel. There are one of two ways you should be able to test:

1) If you are comfortable installing packages on your own, the linux-image-2.6.27-* package is currently available for you to install and test.

--or--

2) The upcoming Alpha5 for Intrepid Ibex 8.10 will contain this newer 2.6.27 Ubuntu kernel. Alpha5 is set to be released Thursday Sept 4. Please watch http://www.ubuntu.com/testing for Alpha5 to be announced. You should then be able to test via a LiveCD.

Please let us know immediately if this newer 2.6.27 kernel resolves the bug reported here or if the issue remains. More importantly, please open a new bug report for each new bug/regression introduced by the 2.6.27 kernel and tag the bug report with 'linux-2.6.27'. Also, please specifically note if the issue does or does not appear in the 2.6.26 kernel. Thanks again, we really appreicate your help and feedback.

Per a decision made by the Ubuntu Kernel Team, bugs will longer be assigned to the ubuntu-kernel-team in Launchpad as part of the bug triage process. The ubuntu-kernel-team is being unassigned from this bug report. Refer to https://wiki.ubuntu.com/KernelTeamBugPolicies for more information. Thanks.

This bug report is being closed because we received no response to the previous inquiry for information. Please reopen if this is still an issue in the current Ubuntu release, Jaunty Jackalope 9.04 - http://www.ubuntu.com/getubuntu/download. To reopen the bug, click on the current status under the Status column and change the status back to "New". Thanks.