[compiz] Wobbly jerkyness

[David Reveman]

On Sun, 2007-04-29 at 17:54 +0800, Sam Spilsbury wrote:
> About a month ago, David made a commit to wobbly to the spring engine
> which has introduced some bugs. They are hard to explain so bear with
> me.
> 
> In a sense, the wobbly plugin does not seem as smooth as it used to be
> and the windows jerk all over the place. For example, I sometimes
> notice that when I move a large window (around 2/3 of the size of the
> desktop window), If I moved it down, the top of the window would jerk
> up then come down quickly. If you want me to explain further then let
> me know 

I didn't change anything in the wobbly plugin, I changed how the move
plugin works.

The jerkyness and high CPU load is actually expected behavior. The high
CPU load is caused by the move plugin changing the server-side window
attributes to reflect the current position of the window in real-time.
The move plugin doesn't have to do this but it's important that things
don't break when it does. I've already been able to fix a number of
performance issues after making this change and I think there's some
more low hanging fruit that can be taken care of quickly.

Eventually, I'll make it possible to not have the move plugin update the
window attributes in real-time and I can guarantee that performance will
be at least as good as before I did these changes to the move plugin.
However, before I can make this possible we need to improve the way
window animations are performed. What the move plugin was doing before
was wrong and I'm not going to change back to that.

You're very welcome to help out with testing, profiling and fixing
issues related to how the move plugin currently works. If you're not
interested in that and if you can't live with the issues and performance
of the current move plugin, you're welcome to use an older version of
the move plugin with the bad but better performing behavior.

- David