Strange GTK2/Xorg performance problem.

[Richard Mittendorfer <delist gmx net>]

Hi, folks!

Here's one I'm suffering from for quite some time now. As I'm out of
luck and ideas how to isolating what causes it, I hope someone here can
bring some light into it.

Debian testing
2.6.17-rc3 (and earlier) 
Xorg 6.9.0.dfsg.1-6(and earlier)
fluxbox 0.9.14-1.1
libgtk2.0-0 (down a few)
 Source: gtk+2.0
 Version: 2.8.16-1
..missed something?

If I open any gtk2-application (example gtkcookie) on my old 266MHz
notebook, first all seems to be fine. A "ls -l" in an open aterm runs
fluid over the screen. When I then open some list in the application
(gtkcookie - a cookie file, gftp - local/remote filelist, xchat - list
of channels, ..) the list/table get's drawn very slow and Xorg hogs the
cpu. I can clearly see lines getting build slowly from top to bottom and
from left to right. It looks like already written lines get redrawn as
they flicker downward an sometimes even go away again for a second.
Selecting a line and moving up or down shows the same delay.

(Usual X screen-drawing is fast and gtk1-apps as well as other apps work
flawless and comparatively fast for a p266mmx.)

! From the moment such a table gets written, drawing a "ls -l" in the
terminal becomes slow, is jigging and hogs the cpu. Switching off
pseudotransparency only helps a bit. 

! Closing the gtk2 app doesn't change behavior back to normal. So I
assume Xorg might be involved.

I've reinstalled related packages and libs, tried various Xorg versions,
options and dis-/enabled some modules, no success. I'm not sure if
there was such a thing with XFree86, I'll do a downgrade next weekend...

I have a quite similar machine (debian, same versions) with a 866MHz cpu
which hasn't any of these symptoms.

I've already tried valgrind gtkcookie, but it doesn't show anything
unusual. Also there's nothing logged. 

How can I debug this? THX for some help, any ideas welcome..

sl ritch