Bugzilla – Bug 411587
radeon[RV280/RV370] Very slow to switch desktops with Composite extension enabled
Last modified: 2010-11-27 16:16:42 UTC
Under some circumstances it's very slow to switch virtual desktops. I'm not sure what the exact conditions are, but here is one way to reproduce it: 1) Open five nedit (www.nedit.org) windows. 2) Switch to another virtual desktop 3) Switch back to the desktop where the nedit windows are 4) Experience a big delay. You can watch the window decorations being painted for something like two seconds before the desktop becomes responsive again.
I can reproduce this using Metacity too, and Sysprof shows majority of CPU time spent in Xorg.
Please attach /etc/X11/xorg.conf and /var/log/Xorg.0.log.
Created attachment 230040 [details] X config
Created attachment 230041 [details] X log
Reassigning.
The problem is reproducible. I use the exact same nedit package as on 10.3, where the problem doesn't occur, so I doubt it's a general problem of Motif apps. It certainly was triggered by a change in the X server (or some other component of 11.0). The problem even occurs when all nedit windows are hidden by other windows. If it helps, I can trace the x-traffic. How do I do that?
Any news? What can I do to help to find and fix the problem?
How often do we circumstances where this is 'slowness' is observed? If these circumstances are rare maybe we should lower the prio.
Cornelius, nedit isn't even part of 11.1. I will therefore lower the prio of this bug.
Egbert, Cornelius was asking how he can help to debug this issue. I'm not sure how lowlevel this would be and if it's more effort to explain how to do this than to do the investigation yourself.
I've talked to Cornelius about this myself a while ago. I explained to him that I will put this on the back burner. The only thing I've done so far is to add time stamps to my X protocol tracker so that I can compare runs of different server versions. One needs to plug this between nedit and the server and collect all traffic from the point the desktop with nedit running gets exposed until all window content is drawn. This will show which events and requess were sent and how much lag there was between them.
FWIW, I am affected by this issue as well. I am a big user of nedit and this hurts me a lot. That being said, I do not think the problem is limited to nedit, even though this may be the application which exposes it most prominently. Running Xfce, I can also reproduce the problem by opening several terminals (/usr/bin/Terminal). While switching to desktops with other applications (firefox, claws-mail, konversation) is very fast, switching back to the desktop with the terminals is not so fast (although not as slow as with nedit.) The more terminals, the slower. Having many open windows isn't the problem though - I can open two dozens file managers or mousepad editors and it doesn't hurt desktop switching at all Bumping severity accordingly - this is _very_ annoying for daily work. Please let me know if I can do anything to help solve this issue.
Problem is still present in openSUSE 11.1.
I have found a workaround to this issue. Edit /etc/X11/xorg.conf and add: Section "Extensions" Option "Composite" "Disable" EndSection Restart X, desktop switching will be fast again. This strongly suggests that the slowdown if caused by the compositing extension.
I can confirm that. Disabling composite fixes the problem. Thanks a ton for the workaround. It made my desktop with nedit usable again.
FWIW, I have this problem on a RV280, not RV370.
Is this still an issue with openSUSE 11.3?
No openSUSE 11.3 installed yet (and no immediate plan.) When I have it installed, I'll test and report, unless Cornelius beats me on it.
In case you're trying with openSUSE 11.3. What are the results on 11.3 with radeon driver instead (without boot option 'nomodeset').
(In reply to comment #22) > In case you're trying with openSUSE 11.3. What are the results on 11.3 with > radeon driver instead (without boot option 'nomodeset'). Sorry, this comment was nonsense.
As I have no immediate plan to install openSUSE 11.3 on that hardware, I booted an openSUSE 11.3 GNOME Live CD on it for testing. After downloading nedit and opening 4 nedit windows on one virtual desktop, I can reproduce the slow desktop switching problem. So as far as I can see, this is still an issue with openSUSE 11.3. Cornelius, anything to add?
Well, on 11.3 LiveCD radeon driver is still not using KMS, whereas on a real installation on HD radeon/KMS is used. So the result with a LiveCD might be different ...
Cornelius, we're waiting for a response for 4 weeks now. Please reopen once you can provide the requested feedback. Please note that testing a LiveCD is unfortunately not sufficient (we plan to address that issue for openSUSE 11.4). Thanks.
I finally found the time to install openSUSE 11.3 on the affected system. X.org uses the radeon driver by default, the composite extension is enabled and I do not witness the slugish desktop switching I was seeing with openSUSE 11.1. I still find it slow to switch but it's probably reasonable considering the large number of applications I started for the purpose of testing and the fact that my new screen has a much higher resolution than the one I was using before (1920x1080 vs. 1280x1024). 1920x1080 is probably too demanding for such old graphics adapter and CPU. So I come to the conclusion that the bug is solved in openSUSE 11.3.
Thanks for confirmation, Jean!