[linux-cifs-client] Slow Folder Traversal on One system, Fast on Another

[Tanthrix]

Jeff Layton wrote:
> Ok, good to check. Other than the change to server inode numbers, I'm
> not sure of any huge changes to the readdir code recently. You could
> try mounting with '-o nounix' to disable unix extensions. I'm not sure
> what the state of those was around 2.6.21.
>
> The more you can do to narrow it down, the better. If you can rule out
> hw changes, then you might get some wire captures while doing this on
> the old and new kernels and look for the differences there.
>
>   
So here's what I did:

I created a new share called "Test" on my Windows7 machine. This 
directory contains 10 subdirectories, each with some 800+ blank text 
files in it. The total number of folders is 10, and the total number of 
files is 8,270. I figured this would help exaggerate the differences in 
speed, making it a bit easier to see what was going on.

I then mounted this share on my Ubuntu 2.6.31-17 machine and my older 
Arch Linux 2.6.21 machine using the exact command "mount -t cifs -o 
username=q,password=q //192.168.0.2/test /Test". I then performed an "ls 
-R" on the /Test directory on both machines while running a wire capture.

Here are the results with links to SMB-filtered tcpdump summaries as 
well as the captures with full packets:

Ubuntu 2.6.31-17
------------------
Time to complete: ~18 seconds
Capture Summary - 4.95mb: http://novae-res.org/sambatest/Ubuntu.txt
Full dumpfile  - 9.15mb: http://novae-res.org/sambatest/UbuntuTcpdump

Arch Linux 2.6.21
------------------
Time to complete: ~2 seconds
Capture Summary - 416kb: http://novae-res.org/sambatest/Arch.txt
Full dumpfile - 470kb: http://novae-res.org/sambatest/ArchTcpdump

Clearly, the Ubuntu machine is doing a whole heck of a lot more, but I 
must admit that I'm in over my head here, so I can't draw any useful 
conclusions or solutions from the above data.

Any thoughts you have will of course be appreciated, and again I thank 
you kindly for taking the time to help me with this.