[BUG] Serious scheduler starvation

[mru@users.sourceforge.net (Måns Rullgård)]

I'm reposting this, since I got no response last time.

First the machine details.  It's a Pentium4 running at 2 GHz.  Linux
version 2.6.0-test3 + O16int + softrr.

I just experienced something that might be a scheduler problem.  I was
working in XEmacs, when suddenly the machine became very
unresponsive.  The mouse pointer in X moved sporadically.  I could
switch to a text console and log in, though typing lagged tens of
seconds.  Switching between text consoles was fast, though.  I killed
xemacs, and the system was back to normal.  Further investigation
showed that xemacs was stuck in a nasty regexp match.  If I was quick
enough, I could interrupt it with C-g.

With X and the window manager reniced to -10, they seem to be able to
get their job done.  This leads me to believe that maybe xemacs is
considered interactive, and given too high priority when it suddenly
starts burning the cpu.

I'll try it later with other kernel versions, but right now I don't
want to reboot.

What can I do to collect more information about the problem?

-- 
Måns Rullgård
mru@users.sf.net