Buggy network connection causes very low system responsiveness

[David Mansfield]

On Tue, 2008-04-01 at 14:00 -0800, Jeff Spaleta wrote:
> 
> 
> 2008/4/1 Martin Sourada <martin.sourada at gmail.com>:
>         So, I restored the /etc/hosts and the problem didn't went away
>         (even
>         after computer restart). Also it didn't get emptied again.
>         However,
>         recently I switched over to rawhide and have yet to see if the
>         problem
>         still persists.
> 
> 
> I have a reproducible situation on F8 that you might find interesting.
> 
> 1) boot up into a NetworkManager enabled desktop, 
> 2) connect to a wireless network that has dhcp
> 3) gnome-terminal behaves normally
> 4) disable NM
> 5) connect a wired network cable for eth0
> 6) enable the network service configured to start eth0 using dhcp to a
> different network segment than the NM wireless connected to.
> 7) watch gnome-terminal take +30 seconds to spawn a window.
> 
> My /etc/hosts file never changes during these operations, and the
> environment variable $HOSTNAME continues to be localhost.localdomain,
> which is defined in /etc/hosts
> 
> I am able to consistently reproduce the slow application problem, and
> doing an strace it appears to be related to socket file access
> in /tmp/.ICE-unix
> 
> Forcibly restarting the X server fixes the problem, and on relogin
> things work.

I've always suspected that some apps cache values read
from /etc/resolv.conf (for example, I KNOW that postfix does) so if you
start the app (or perhaps a bonobo activation server....) and then later
when network configs change, the app keeps using the old values.  It
would be interesting to me to see the 'tcpdump' on the wired eth0
interface over the 30 seconds, maybe.

David