kwin-4.7.1-0ubuntu2~ppa1 needs testing

[Harald Sitter]

On Tue, Sep 13, 2011 at 1:47 PM, Dan Chen <seven.steps at gmail.com> wrote:
>
> On Sep 12, 2011 11:31 PM, "Clay Weber" <claydoh at midmaine.com> wrote:
>>
>> What sort of things should we be looking for,  positive or negative?
>
> Ditto. I normally have several dozen app/windows open, and the performance
> hitches I noticed before seem resolved. It would be nice to know which
> parameters to test, however.

>From Martin's top secret mail:
> During working for an optimization in 4.8 we noticed that we do deep non-const vector copies where a const
> at() operation was expected. This means that we have in each frame:
> 4x+5xy unneeded copy operations
> (x == number of loaded effects)
> (y == number of windows).

So on a stock kubuntu desktop we have something like 15 effects
activated, additionally say you have a browser, a music player and a
chat window (mind you, plasma is also a window ;)) that means per
frame you get 4*15+5*4=80 copies of effects, if you get 15 frames per
second (which would be mostly enough to perceive the desktop as
responsive) that means 15*80=1200 copies. You probably do not have 15
but >40 frames per second that means 3200 copies. Now I actually
forgot what I wanted to write about...
Ah right, so, if you turn on *all* kwin effects (or at least those
that load on your system) and open as many windows a possible, kwin
should not feel overly sluggish (movement of windows, resizing etc.).
Also all effects that worked with the old package should still work
with the new one.

http://blog.fishsoup.net/2011/06/13/benchmarking-compositor-performance/