[Samba] Samba 4 + Windows XP very slow - especially noticeable with many files

[Bram Matthys]

Hi,

Bram Matthys wrote, on 20-5-2014 15:39:
> After our upgrade from Samba 3.x to 4.1.6 we are having major performance
> issues. Today, I've been able to nail it down to a simple test case.
> What strikes me is that Windows XP takes about 25 seconds for one job, while
> it only costs 3 seconds on Windows 7.
> 
> I have two tests:
> 
> 1000 files of 10k each (total ~10Mb):
> * Linux on localhost or a remote host (1GE or 10GE): 5.5 seconds
> * Windows XP - Machine #1: 24.5 seconds
> * Windows XP - Machine #2: 60 sec
> * Windows 7 - Identical hardware as XP machine #1: 3 seconds
> 
> One 500MB file:
> * Expected result: 4-5 seconds on 1Gbit (100-125Mbyte/s)
> * Linux on localhost: 0.5 sec
> * Other Linux machine with 10GE connect: 0.9 sec
> * Remote Linux machine (1Gbit): 4.6 sec
> * Windows XP - Machine #1: 10.4 sec
> * Windows XP - Machine #2: 11 sec
> * Windows 7 - Identical hardware as XP machine #1: 7 sec 

I also tried the following, on the server-side:
0) Installed a new server
1) Tried version 4.1.7 (was: 4.1.6)
2) Tried latest samba from git (master)
3) As domain member
4) Also, not in a domain: security = user and map to guest = bad user
5) compiling without --enable-debug

These all made no difference. Okay, without --enable-debug it's maybe 20%
faster, but nowhere near the Windows 7 performance (still 6-7 times slower).

On the client-side I reset some TCP/IP settings to Windows default, reboot,
test. Also later tried other 'optimal' values, reboot, test. Made no
difference. Would also be strange when the Samba 3 performance was OK and
when FTP goes at near-full wire speed, see next.

Some more benchmarking / testing:
Although I'm more concerned about the small files case, I also tested
FTP'ing the (same) 500Mb file. This took 4.5 seconds (115Mbyte/sec). In
contrast to 10.4 seconds via Samba (~50Mbyte/sec data transfer, with
protocol overhead I see ~59Mbyte/sec on the LAN). smbd uses 15-20% CPU
during the transfer.

Kinda out of ideas now.

Regards,

Bram.

-- 
Bram Matthys
Software developer/IT consultant        syzop at vulnscan.org
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