Public bug reported: Since upgrading from Kubuntu 11.04 (KDE 4.6.2, Xorg 1.10.1, xserver-xorg v7.6 kernel 2.6.38-11) to Kubuntu 11.10 (KDE 4.7.1, Xorg 1.10.4, xserver-xorg v7.6, kernel 3.0.0-12), I have noticed a severe drop in kwin performance when drawing changes to the window decorations. The slowness can be observed when new windows are created (the decorations are slow to be created) and when windows become active or inactive (the decorations are slow to change between active/inactive state).
Since I have been able to reproduce this problem on systems with both Intel and NVIDIA graphics cards, I don't believe this bug to be graphics driver-related. The issue does not seem tied to any particular Kwin theme either. Please see the following YouTube video for a demonstration: http://www.youtube.com/watch?v=MUSRzUyjXY0 The slowness goes away when kwin is switched to "native" rendering instead of the default "raster". According to the related KDE bug report (https://bugs.kde.org/show_bug.cgi?id=284291), this will be fixed in KDE 4.8. However, the question for Kubuntu is whether or not kwin should be set to "raster" or "native" rendering by default. Steps to Reproduce: This test can be reproduced easily using the Kubuntu 11.04 and 11.10 live CDs. For best results, use a slower PC to do these tests: 1) Open Dolphin. 2) Click the desktop to make Dolphin an inactive window. Click on Dolphin to make it the active window. You will observe a delay under Kubuntu 11.10 when performing this step. To see this effect easier, you may want to disable animations and enable "outline active window title" in the Oxygen decoration settings. 3) From Dolphin's "Help" menu, select "About Dolphin". When the about window appears, you will see the window decoration sluggish to appear around the newly-created window contents. Workaround: Those affected by this bug can run the following command: kwin --replace --graphicssystem=native If the kwin performance improves, you can make the setting permanent by creating the following script as /usr/local/bin/kwin-native: #!/bin/bash kwin --graphicssystem=native Then, add the following to /etc/profile: export KDEWM="kwin-native" ** Affects: kde-workspace (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Kubuntu Bugs, which is subscribed to kde-workspace in Ubuntu. https://bugs.launchpad.net/bugs/877538 Title: kwin is slow with raster rendering & compositing disabled To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/kde-workspace/+bug/877538/+subscriptions -- kubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/kubuntu-bugs
