Slow network performance (em0 & catalyst 2950)

[Roman Serbski]

Hello list,

I am facing with really slow network performance (nfs/ftp) under
FreeBSD 6.2-PRERELEASE with em0 NIC connected to Cisco Catalyst 2950
switch. The transfer speed is ~150-200kbps for nfs, ftp and httpd.
Here is more information about my setup:

em0: <Intel(R) PRO/1000 Network Connection Version - 6.1.4> port
0xdc00-0xdc3f mem 0xfcfa0000-0xfcfbffff irq 54 at device 4.0 on pci3

%ifconfig
em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
options=b<RXCSUM,TXCSUM,VLAN_MTU>
inet 192.168.1.5 netmask 0xfffffff0 broadcast 192.168.1.15
ether 00:04:23:c7:61:3a
media: Ethernet autoselect (100baseTX <full-duplex>)
status: active

The server is connected to Cisco Catalyst 2950 switch (latest IOS)
with 'auto' set for duplex and speed. 'sh int' shows 100baseTX and
full-duplex.

I googled two threads with the similar symptoms:

http://www.daemonnews.org/mailinglists/FreeBSD/freebsd-performance/msg01732.html

http://unix.derkeiler.com/Mailing-Lists/FreeBSD/performance/2003-06/0014.html

Tried everything mentioned there, but it didn't help. I tried to set
100baseTX and full-duplex both on FreeBSD and Cisco - same slow
throughput. Also tried to play with sysctl - no luck. netstat -i
doesn't show anything suspicious:

Name    Mtu Network       Address              Ipkts Ierrs    Opkts Oerrs  Coll
em0    1500 <Link#1>      00:04:23:c7:61:3a    21401     0    31364     0     0

Anyone with the similar problem? I am ready to provide more detailed
information and I would highly appreciate your assistance!

Thank you in advance.