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Plasma unresponsive under heavy I/O load?

User avatar soumyadeep
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I have had huge lag issues while doing i/o operations(sometimes the desktop would come to a halt when copying files to a usb pendrive) until i upgraded my archbox to kernel 2.6.36. If u can try updating your kernel.
User avatar the_mouse
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I'll be moving to Kubuntu 10.10 soon and see if anything's different ;). In the meantime I'll check to see if my kernel does memory swapping too often ;).
User avatar the_mouse
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As for the over-swapping suggestion:
I was doing a 3MB/s download with uTorrent on a separate partition and was experiencing the plasma unresponsiveness. I decided to turn off swap with the swapoff -a command and to see if there's any difference. No, Plasma still had hiccups. Interestingly I decided to turn on compositing (Xrender, because works faster for me for some reason), and voala the desktop experience just got smoother :).

So why is Plasma without compositing much more unresponsive, than with it turned on?

PS. I'm updating to a newer version of Kubuntu soon and will see if there's any difference there, but I doubt it, since I was experiencing this issue ever since KDE 4.2 (or maybe KDE 4, but I started using KDE after 4.2).
User avatar bcooksley
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Very interesting, this indicates possible issues with Plasma in other areas. With swap disabled and compositing also disabled, can you please monitor the disk activity of Plasma using iotop/strace and the CPU usage of Plasma?


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User avatar the_mouse
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Well, I ran some tests and the interesting thing was that when copying large files, I had 100% CPU usage (kio_file), but I was told it's ok. Plasma's CPU usage weren't high (only 1-2%), but was having regular requests to the HDD (I'm not sure if it's necessary) - tomorrow I can show it in a video.
User avatar bcooksley
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Plasma's regular requests to the HD are the likely cause of these responsiveness issues. Please use a program such as strace to determine which file(s) are being altered, then file a bug report at bugs.kde.org containing that information.


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User avatar the_mouse
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Thank you for your advice. I'll read strace's manual and try to determine wich files are being accessed :).
User avatar denysonique
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I am experiencing the same problem.
Arch Linux, KDE 4.8.1, BTRFS

Intel Core duo 2x2GHz and 2GB of RAM.
User avatar bcooksley
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Have you been able to determine which files Plasma is accessing that cause this to occur?


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User avatar DrHouse123
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I'm experiencing the same problem too.
Gentoo Linux AMD64, KDE 4.9.1, EXT4
It happen during building anything (-j3) in chroot after 2-3 hours. Also I noticed often starting few kio- processes in another time.

My machine:
Intel DualCore 2.93GHz and 4GB of RAM.
I will try to to determine which files Plasma is accessing that cause when it appeared again.
User avatar bcooksley
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Just a note - lsof and strace may be helpful in determining which files are being interacted with by Plasma Desktop. The results of your investigation will be quite interesting.


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