samba - Feb 2006 - smbd write performance depending on windows operating system?

Hello list,

using samba 3.0.9-2.3 on SuSE/Novell Linux 9.2 I have reasonable
performance when reading from the samba shares. I have tried this with
windows-95, 98, NT, 2000 and XP. I get up to 5 MBytes/s.

My problem: when copying files from the windows systems to the samba
shares, I find good performance with windows-95, 98 and NT (comparable
to reading performance). Using windows-2000 and windows-XP professional
(SP1 and SP2) systems, however, I am stuck with around 300 to 500
kBytes/s which is 10 times lower.

I have already tried adding "IPTOS_LOWDELAY" in addition to
"TCP_NODELAY" in the socket options, but there was no difference.

First I thought that there might be a hardware problem. One of the
windows XP system hardware I could also boot as Linux system. Then I
used smbmount to mount the same samba share as before under windows-XP.
Now I got a good write performance, using the same hardware as before.

I am using a 100 MB switch between server and clients. The lights tell
me that the connection is 100 MB. I have even forced windows-XP to only
negotiate 100 MB connections but this did not make any difference.

Does anyone have an idea what could be the reason for my terribly low
write performance when using windows-XP? It can't be my server hardware
since write performance is good when using different windows operating
systems...


Thanks
Martin Rosenbauer