Interactivity issue in 2.6.25-rc3

["Carlos R. Mafra" <crmafra2@gmail.com>]

I want to report a bad interactivity which happened in my 
desktop running the latest kernel (2.6.25-rc3-00081-g7704a8b).

I tried to play 'flightgear' and the desktop became _very_
slow while flightgear was "loading scenery objects" (a task
which never finished and I could not play it).

The desktop is a P4 @ 3.0 GHz, 512MB, with the nv graphics 
driver. 

I ran 'fgfs' firstly as a regular user (mafra) and tried to execute
Ingo's cfs-debug script as root in a terminal (mrxvt) which had 3 open
tabs. It took minutes to switch tabs and run cfs-debug-info.sh, which
completed its job only after I managed to kill flightgear (after more
than a couple minutes). The result is here:

http://www.ift.unesp.br/users/crmafra/cfs-debug-info-2008.02.28-14.04.59

[ I want to emphasize that I started the script while the system
was slow, waited a few minutes, killed flightgear, and then
the script finished its job. ]

As I have the group scheduler enabled, I tried to run flightgear as
root to see what happens. I could not even start to run the debug
script, because each letter I typed took many seconds to appear.

The mouse pointer however was responsive, but Window Maker wasn't.
I tried to switch desktops, and after a few minutes the pressing
of "Alt+5" took effect and the desktop 5 appeared ok in the screen.

Then I tried to go back to desktop 1 with "Alt+1" and after exactly
12 minutes I gave up and hit "Ctrl-Alt-Backspace". After 5 or
10 seconds X was killed and everything was normal 
again (no need to reboot).

Is this experience normal? I know that trying to play a game without
3D is a crazy thing, but it didn't feel _fair_ to wait minutes to
see the result of a key press.