Periodic long pause before applications starting, key shortcuts working, etc.

[chconnor]

Hello - my knowledge of underlying KDE/Ubuntu architecture is scant, but occasionally (maybe once a day, or a few times a week) i'll hit one of the khotkeys i've configured to start an application, e.g. a terminal, or I'll Alt-F2 and try to run kate or whatever, and nothing happens (sometimes application mini-icon appears next to mouse cursor, but app doesn't start, no disk activity, etc.)

Mouse moves around, things seem essentially normal. I'll hit the key combo again, try to launch again, etc, and still nothing. Then, maybe 10 to 20 seconds later, it becomes clear that all my keystrokes and app launches were buffered and just hung up on something, and I'll get five terminal screens and three instances of kate all appear at once. Thereafter, things are back to normal (meaning apps launch normally).

Doesn't correlate in any way to the particular application I'm trying to launch. Doesn't seem to happen at the same time in the day. Doesn't seem to be related to high CPU usage. Doesn't seem to be related to any hardware changes or network or disk usage, etc etc etc. I mean, something is happening, clearly, but it's not obvious. I can't bring up a task manager to see what's up because it doesn't appear until the bottleneck resolves. Never saw it until 11.10 I believe (11.04 at the earliest, definitely not before that).

I don't know what subsystem is hung up and thus what log to check out... would this be a "dbus" thing?

Next time I'll see if a ctrl-alt-F1 gets me to a term before or after the logjam period (i assume it will work before).

Thanks for any ideas,
-Casey
(Kubuntu 11.10, Dell Insprion 6000 laptop, radeon video driver)

[ronw]

Shot in the dark: if you have desktop effects enabled, have you tried disabling it?

[chconnor]

Thanks for the brainstorm ronw - I have no effects or compositing or anything fancy whatsoever on, though.

If anyone knows what KDE (or Ubuntu?) subsystem handles the queue of "things to launch" or "actions requested by the user that need attending to" or whatever it is, that's what I'd like to investigate... something seems to be intermittently clogging up that queue...

-c

[Snowhog]

Do you by chance have Nepomuk (Desktop Search) enabled?

[chconnor]

Thanks - Nope, no Nepomuk (disabled in autostart and service manager), akonadi, deja, zeitgeist... all off. All the services and autoload stuff I don't use are disabled in the various autostart directories as well... (i seem to remember that disabling nepomuk still left a "nepomukserver.desktop" active that i disabled.)

Not sure if it's what you were guessing, but: I'm not seeing "system is loaded down with some other task" behavior -- there's no disk activity and no apparent CPU drag when this is happening. And in general use of the computer, even when the CPU is pegged (say I'm launching 3 big apps at once or something) I can still pull up a terminal in less than 20 seconds... this seems like something else...

It happens rarely enough that it's hard to get info on, but often enough that it's really annoying. :-)

[Snowhog]

Well, you can keep a console open with top running, so when it does happen, you can maybe see something in the listing that might be informative. Just a thought.

[chconnor]

Thanks, yeah, I'm doing that now... have htop and some log tails going in tty1... I'm a little concerned that it won't turn anything up, but who knows.

I'm guessing that a khotkey action goes through D-Bus? Does the Alt-F2 launcher do so as well?

[chconnor]

An update: this is still happening... I'm pretty convinced at this point that it's the dbus flow being clogged.

I have a process in the background that takes "top" snapshots and does a diff, about once a second, so I can see what processes have started and stopped from moment to moment.

Everytime this happens, when the hotkeys finally go through, I see that the "apper-sentinel" process has just exited. So that's my lead at this point... I'll report more if I discover it, but feel free to throw out suggestions.

When I run that process manually (/usr/lib/kde4/libexec/apper-sentinel) it just returns, no hold up on the dbus.

-c

[ManGo]

Hi,

if you still have this issue, can you poste:
1) which version of KDE are u using
2) which graph card/ chip are u using and
3) which graph-driver for this device...

[chconnor]

Bug filed at: https://bugs.launchpad.net/ubuntu/+source/apper/+bug/929862

Thanks ManGo -

KDE 4.7.4
ATI Technologies Inc M22 [Mobility Radeon X300]
radeon driver being used
(Dell Inspiron 6000 laptop)

[ManGo]

Hi,
I experiënced "somewhat similar" effects as you describe. Although I'm on an desktop (with nvidia).
The first thing I would recommend is update to KDE 4.8. Did improve a lot in my situation.