[Linux-cluster] Ls and globbing taking ridiculously long on GFS

["Dylan Vanderhoof" <DylanV semaphore com>]

I understand that a df, or ls -l that requires statting files should be
slow.  However, I'm seeing ridiculous performance of just an ls, or
anything doing file globbing in directory reads.

For example:

dylanv iscsi0 /srv/rancid/logs $ time ls
[snip]

real    0m4.434s
user    0m0.000s
sys     0m0.000s
dylanv iscsi0 /srv/rancid/logs $ ls | wc -l
412
dylanv iscsi0 /srv/rancid/logs $


I consider 400 files a fairly small directory.  4.5 seconds to do an ls
is pretty bad.  Its worse in a large directory, although not
porportionally to the amount of files:

dylanv iscsi0 /srv/flows/9/13 $ time ls
[snip]

real    0m31.693s
user    0m0.070s
sys     0m0.430s
dylanv iscsi0 /srv/flows/9/13 $ ls | wc -l
14274
dylanv iscsi0 /srv/flows/9/13 $

And an even larger dir:

dylanv iscsi0 /srv/flows/6/7 $ time ls
[snip]

real    1m31.849s
user    0m0.520s
sys     0m1.450s
dylanv iscsi0 /srv/flows/6/7 $ ls | wc -l
42462
dylanv iscsi0 /srv/flows/6/7 $


Any ideas for why this might be?  Its clearly blocking on IO somewhere,
but I'm not sure where.  Both kernel and userland are 32-bit for now.
Caching doesn't really appear to make a whole lot of difference.  (A
subsequent ls on the large directory above takes 1m24.274s)  What
concerns me even more is that I'm not even using DLM yet!  This is with
lock_nolock.  

Any suggestions or ideas are much appreciated.  =)

Thanks,
Dylan