High CPU usage slows system down after upgrade to 10.04 final release

[mymiasma]

After about a day and a half of trying to upgrade I just finished the upgrade from 9.10 to 10.04 and am having big problems.

My biggest issue is with high CPU usage under the KDE4 desktop slowing my system to an unusable state. The problem with slowness is only evident when using the KDE desktop. Fortunately I also had the XFCE4 desktop installed on the same installation and it seems to be working just fine after fixing a relatively minor problem with Xfwm not getting started along with the XFCE4 desktop. If I didn't have XFCE4 installed I wouldn't have a usable system.

Everything seems to start normally with KDE but it slows down to a crawl after a minute or so, even if I don't start any new programs and close down those that are. It starts out OK but after a minute or two one CPU starts running at or near 100% and the other starts doing the same not long after that. Oddly when using the top command from a terminal it doesn't report the same level of usage.

Here is some info on my system:

AMD Athlon(tm) 64 X2 Dual Core Processor 4800+
2008 MiB RAM
9640 MiB swap
Ubuntu 10.04 (lucid)
2.6.32-22-generic (#33-Ubuntu SMP Wed Apr 28 13:28:05 UTC 2010)
GeForce 9400 GT PCI-E 16x 512MB Video RAM w/nvidia-glx-185 driver

I'd appreciate if anyone knows how to fix this or to at least have my experience serve as a warning to anyone expecting an easy upgrade.

[rfakhrai]

Re: High CPU usage slows system down after upgrade to 10.04 final release

do you know what is sucking the CPU? the easiest way to find out is Alt+F2 and click on the box on the left side of the input line.

[Snowhog]

Re: High CPU usage slows system down after upgrade to 10.04 final release

Or just press Ctrl+Esc

[mymiasma]

Re: High CPU usage slows system down after upgrade to 10.04 final release

I had used the top command from the command line which basically reports the same information as the System Activity GUI app you get with Alt+F2 or Ctrl+Esc. Nothing reported higher than 12% CPU usage.

However, I found the culprit for my high CPU slowdown. Even though top only reported all the processes as using less than 30% of the CPU my CPU monitoring widget showed at or near 100% of both CPUs. Out of desperation I started Googling for info on all the processes at the top of the list. The virtuoso-t process was reported as using more than the other processes at 12%. I found it was part of Nepomuk and that Nepomuk had long been identified as a potential CPU hog.

I disabled Nepomuk in [System Settings], [Advanced], [Desktop Search] by unchecking the [Enable Nepomuk Semantic Desktop] option under [Basic Settings]. Apparently there have been ongoing problems with Nepomuk hogging the CPU(s) ever since Nepomuk had be included with KDE.

I'm not sure why the top command only reported nepomukservices and virtuoso-t as taking from 0% to 12% of the CPU and 0% to 3% of memory. I'm also unsure why I had the problem now and not before but maybe it felt the need to index all the changes from the upgrade. But, whatever the reason my system is so much improved after disabling Nepomuk I'm back in business using KDE4.4.2

[doctordruidphd]

Re: High CPU usage slows system down after upgrade to 10.04 final release

The problem with nepomuk may just be that it is trying to do what it is supposed to do -- index your whole file system. Should you want to use its search capabilities, you can configure it to search only those directories you want searched, which may cut its indexing time down drastically. I am running it here with no problems, but I set it up to search only my document file tree.

SystemSettings > Advanced > Desktop Search > File Indexing

[Marlin]

Re: High CPU usage slows system down after upgrade to 10.04 final release

I am having similar symptoms, but TOP is showing that XORG is taking 75-90% of my CPU.

[TheStatsMan]

Re: High CPU usage slows system down after upgrade to 10.04 final release

I am having a problem with High CPU usage on my desktop, my laptop works fine. virtuoso-t is using up over 100% according to top (it is using both cores). This seems to happen for quite some time (several minutes) after I turn my desktop on. Then it drops down. Yesterday I was getting regular spikes in CPU usage continually after that, but this does not seem to be the case today. This does not occur on my laptop which works perfectly. Both cases I upgraded to Lucid.

[rfakhrai]

Re: High CPU usage slows system down after upgrade to 10.04 final release

disabling nepomuk in system settings seems to take care of the virtuoso-t problem.

[TheStatsMan]

Re: High CPU usage slows system down after upgrade to 10.04 final release

Thanks, nepomuk is disabled.