Why does Cygwin slow down after it has been running for a while?

Question

If I leave a cygwin shell (usually putty-cyg, but also true with xterm or the normal Cygwin bash shell) running for a while I tend to find that after a certain amount of time, it goes really really slowly. I assume this is some sort of interaction with another process, but I've been unable to identify which process is causing the problem.

According to the task manager, the "system idle process" is up at about 94%, so there's very little that's actually doing anything. However, when it's going quickly I get:

$ time ls
_viminfo test.txt

real    0m0.026s
user    0m0.030s
sys     0m0.015s

When it's going slowly I get:

$ time ls
_viminfo test.txt

real    0m25.989s
user    0m0.030s
sys     0m0.061s

This makes cygwin close to unusable! Can anyone suggest how I might identify what is going on to cause cygwin to go so slowly?

I'm using Windows XP in case that's relevant.

Answer 1

Process Monitor revealed that whenever Cygwin was doing something, it was trying to open every directory of the PATH variable. There were a couple of directories on a network drive on the path and I'm not on the network at the moment. It seems the problem has happened in the past when the network has gone down. Removing the network drives from the path seems to have cured the problem.