kwin performance gets worse and worse with every release

Duncan 1i5t5.duncan at
Thu Jun 30 04:28:01 BST 2011

Nikos Chantziaras posted on Wed, 29 Jun 2011 23:22:36 +0300 as excerpted:

> (I'm using a Radeon HD4870 with the open source drivers.)
> I was able to find a tweak that makes kwin usable again though.  I had
> to create a ~/.drirc file and put this in there:
>    <driconf>
>      <device screen="0" driver="dri2">
>          <application name="Default">
>              <option name="vblank_mode" value="0" />
>          </application>
>      </device>
>    </driconf>
> The "driconf" utility doesn't work; the above has to be created by hand.
> Also, the "VSync" option in System Settings must be unchecked.  Both of
> these things must be performed; if only the .drirc file is created, or
> only the VSync checkbox is unchecked, then kwin will keep being slow.
> It should be noted that the desktop is still tear-free after doing the
> above.

Followup here, now that I've had a chance to test this.  As I had hoped 
in the earlier reply elsewhere on-thread, this did finally let glxgears 
run freely, so I could get some idea how much composite and window size 
affect opengl on this thing.

glxgears @ default size:

612-ish Hz (fps) with compositing disabled, or with it enabled but with 
the glxgears window on top at 100% opacity.

580-ish Hz with something else focused so the glxgears window gets 
opacity reduced and composited.  The same when the konsole window's on 
top but the glxgears window is active (so viewing the glxgears window at 
100% opacity thru the konsole window at less than 100% opacity, thus 
triggering compositing of the glxgears window).

AT full maximized across both monitors (save for the the systray and 
superkaramba panels at the top of my top monitor), 1912x1965 client 
window resolution, according to kwin:

80-ish Hz w/o compositing.

70-ish Hz with compositing.

That 70-ish Hz is getting pretty close to the screen-refresh (60 Hz), but 
still remains slightly above it, which is nice.

Since I don't seem to notice any performance issues when refresh-rate 
locked, however, I'll probably eventually switch back to that, after 
playing around with unlocked for awhile longer, just to see what other 
effects it might have.

Meanwhile, I'd be interested in your locked and unlocked glxgears 
framerate stats.  If you're seeing < 60 Hz even maximized (assuming 
you're not running dual 2560x1600 monitors or some such), then there's 
gotta be something wrong with your effects chain, somewhere, because as I 
said, AFAIK, your hd4870/rv780 should in theory be getting better stats 
than my hd4650/rv730.

Next thing to try is OpenGL video playback.  I wonder if the unlocked 
framerate will affect it any...

Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman

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