i upgraded few computers running arch linux. on all of them kwin effects either stopped working at all or performance reduced significantly

the upgrade is few packages at a time and includes

kde 4.3.2 --> 4.4.2
qt 4.5 --> 4.6.2
xorg 1.7.5 --> 1.7.6
mesa ?
xorg video driver ?
kernel 2.6.30 --> 2.6.32/33

i tried to isolate what causes the problem by upgrading one component at a time (tests below) but did not find out

i tried to disable KMS (as suggested in few sites) but this did not improve performance

what is the issue ?

i am especially interested in restoring good performance with the ati card / open source radeon driver




test #1 : intel 865g integrated graphics / ati radeon 9250 agp (tried each step with both cards) + celeron 2.6 + 1gb ram in dual channel

before upgrade
- all effects work with good performance (wobbly windows and cube near smooth with intel / perfectly smooth with ati)
- small performance difference between opengl and xrender modes (opengl a bit better)

after upgrade xorg+mesa only
- moderate performance drop with opengl - erything still works but slower. bigger performance drop with xrender - everything still works but very slow
- the ati card gets bigger impact than intel - sometimes the intel is better than the ati

after additional upgrade of qt
- no change

after additional upgrade of kde
- some extra performance drop in all modes




test #2 : i cloned the OS on which i did test #1 to another hard drive before doing the test. this test is done on the second copy - with the same starting point as test #1

before upgrade
- see tes #1

after upgrade qt only
- no change

after additional upgrade of kde
- kde broken cause of dependencies on packages that i did not upgrade (all apps have some trouble). kwin won't go to composite mode at all

after additional upgrade of all the other system (incl. kernel and xorg)
- similar perfomance to end of test #1




test #3 : clean install of OS (tried with ati only)

immediately after install
- same perfomance as end of tests 1 / 2

after disabling KMS
- opengl performance = 0. takes few seconds to react to moving windows. takes up to 10 seconds to enter desktop cube (and after 1 frame knocked out by kde performance check)
- xrender transparency works ok but no other effects work at all

I use Arch and noticed kwin effects performance drop as well. However I have Nvidia, therefore it may not be connected with graphic card.

Have you tried adjusting the options in System Settings > Desktop > Desktop Effects > Advanced?

This results in :

before upgrade - xrender and opengl both work well with small performance differences

after upgrade - xrender and opengl are both broken (1 FPS or less). sometimes desktop effects won't switch on at all especially with opengl mode

other settings in the advanced tab dont affect anything




overall desktop performance (with all effects switched off) is impacted too after upgrade with both ati (severely) and intel (slightly)

I'm having the same problem but I believe its not a kde specific issue as neverball is also running very slow and choppy after the upgrade. I think its xorg compositing and ati open source driver related issue specific to arch linux.