Re[3]: Assymetric NIC performance problem

[Konstantin Kuzvesov]

I've got a FreeBSD file server running Samba, file upload speeds are okay, but downloads are too slow.
First, I decided it is Samba's fault, but then I ran iperf tests...

On a windows machine with gigabit NIC:
Z:\iperf>iperf -c 192.168.0.1
------------------------------------------------------------
Client connecting to 192.168.0.1, TCP port 5001
TCP window size: 64.0 KByte (default)
------------------------------------------------------------
[  3] local 192.168.0.2 port 1064 connected with 192.168.0.1 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.2 sec  12.4 MBytes  10.2 Mbits/sec

Z:\iperf>iperf -s
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 64.0 KByte (default)
------------------------------------------------------------
[  4] local 192.168.0.2 port 5001 connected with 192.168.0.1 port 41220
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0-10.0 sec   716 MBytes   600 Mbits/sec

And on a another with FastEthernet NIC:
C:\iperf>iperf.exe -c 192.168.0.1
------------------------------------------------------------
Client connecting to 192.168.0.1, TCP port 5001
TCP window size: 64.0 KByte (default)
------------------------------------------------------------
[  3] local 192.168.0.5 port 4756 connected with 192.168.0.1 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.1 sec  11.4 MBytes  9.42 Mbits/sec

C:\iperf>iperf.exe -s
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 64.0 KByte (default)
------------------------------------------------------------
[  4] local 192.168.0.5 port 5001 connected with 192.168.0.1 port 18558
[ ID] Interval       Transfer     Bandwidth
[  4]  0.0-10.0 sec   106 MBytes  88.5 Mbits/sec

Both tests show server's NIC performance degradation to around 10Mbit/s when traffic goes from server to client. And everything works fine in other direction.

I verified the cables and hub by simply connecting server and a test machine with a new short patch cord. I tried to change server's NIC from D-Link DGE-528T to Planet ENW-9604. And it became even worse -
 using Planet NIC
 speeds slowed down to around 500Mbit/s to server and the same 10Mbit/s to client. I tried to change NIC's media to 100BaseTX, it didn't help too. What else should I try to fix the problem? Maybe my system requires is just misconfigured?

System configuration:
OS: FreeBSD 9.2-release
Kernel: generic
Firewall: none
/boot/loader.conf - load zfs modules only
/etc/sysctl.conf - empty
NIC: D-Link DGE-528T / Planet ENW-9604

> Hello,
>
>    I have a problem with NIC performance. Is this the right place to ask for help?
>
 Probably, if you are able to provide some more detailed information :)

-- 
Konstantin Kuzvesov