Input lag in Konsole (karmic)

[Pete Eby]

Binary package hint: konsole

Hi everyone,

I'm seeing some extreme input lag in Konsole (4:4.3.2-0ubuntu3) in Karmic. Other apps are not affected, and input speed is fine in virtual terminals. This does not happen each time you start Konsole, for example after a reboot input speed is fine. However, invariably, after the system is up for a few hours, this input lag shows up. It is not an insignificant amount of lag, and it essentially renders Konsole unusable for input and requires a reboot. This started almost immeadiatly upon this fresh install.

Desktop effects are not enabled. This is running in VIrtualBox ver 3.1.4 (latest)

I have seen similar bugs, such as:
https://bugs.launchpad.net/ubuntu/+source/acpi/+bug/443318

However that bug seems more related to ACPI issues and the acer-wmi kernel module, which are not applicable in my case. I am seeing nothing logged in /var/log/messages at all, and no messages from Konsole. It also never actually crashes, so no crash report is available.

I've also tried starting konsole with:

konsole --notransparency
konsole -graphicssystem raster

I would really appreciate any suggestions as to how to further debug this issue as rebooting this workstation every time Konsole slows down is not that great.

Thank you,
Pete

ProblemType: Bug
Architecture: i386
Date: Sun Mar 21 09:15:39 2010
DistroRelease: Ubuntu 9.10
ExecutablePath: /usr/bin/kdeinit4
InstallationMedia: Kubuntu 9.10 "Karmic Koala" - Release i386 (20091028.5)
Package: kdelibs-bin 4:4.3.2-0ubuntu7.2
ProcEnviron:
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.31-20.58-generic
SourcePackage: kde4libs
Uname: Linux 2.6.31-20-generic i686
XsessionErrors: (polkit-gnome-authentication-agent-1:1485): GLib-CRITICAL **: g_once_init_leave: assertion `initialization_value != 0' failed

[Pete Eby (relative-prime)]

I installed kdelibs5-dbg kdebase-dbg libx11-6-dbg libxrender1-dbg and attached to a running console instance with gdb, but that seems to cause the instance attached to display a blank screen, so you can no then really use it for input or see what is occurring. However, this bug affects all running instances, so if I get anything useful in gdb I'll post it.

[Pete Eby (relative-prime)]

If more information is needed I would be happy to supply it. My attempt to attach to the PID with gdb was not too successful, but if anyone has a suggestion on how to collect further debug info please let me know and I am happy to do so.

[Pete Eby (relative-prime)]

Can I provide any further information to assist in debugging this? This is a new install and from researching this I see it is not isolated to me, but there appears to be no real resolution to this. It almost makes Kubuntu Karmic unusable in Virtual Box if you actually user Konsole, which I certainly do.

This is the first bug report I've filed on Launchpad, so perhaps I am going about this incorrectly, but with no responses it is a bit hard to know.

[Rohan Garg (rohangarg)]

Hi
Thanks for reporting the bug,could you please test this in 10.04 as well just to be sure that its not resolved in the latest packages? This will give us a idea what the problem might be exactly
Thanks for taking the time to report this bug.

[Pete Eby (relative-prime)]

Hi there,
I did a dist upgrade to 10.04, and while this did appear to improve the lag issue a bit, it is still very much there. I'll likely be reinstalling this workstation outside of VirtualBox to eliminate this issue as it is too annoying to continue with, but if there is anything else I can do to provide more information before doing so please let me know - I would like to help get this issue fixed as it would appear from researching it that it certainly does come up for people, but has yet to be tracked down to a specific cause.
Cheers,
Pete

[Pete Eby (relative-prime)]

Hi there,

After some additional updates running 10.04 the issue appears to have been resolved, the horrid lag has disappeared from Konsole.

Thank you,
Pete