[CentOS] bond0 performance issues in 5.6

Hi all,

   I've got two gigabit ethernet interfaces bonded in CentOS 5.6. I've 
set "miimode=1000" and I've tried "mode=" 0, 4 and 6. I've not been able 
to get better than 112MB/sec, which is the same as the non-bonded 
interfaces.

   My config files are:

===
cat /etc/sysconfig/network-scripts/ifcfg-{eth1,eth2,bond0}
# SN1
HWADDR=00:30:48:fd:26:71
DEVICE=eth1
BOOTPROTO=none
MASTER=bond0
SLAVE=yes

# SN2
HWADDR=00:1B:21:87:80:CE
DEVICE=eth2
BOOTPROTO=none
MASTER=bond0
SLAVE=yes

# Bonded interfaces for Storage Network
DEVICE=bond0
IPADDR=192.168.21.80
NETMASK=255.255.255.0
ONBOOT=yes
BOOTPROTO=none
USERCTL=no
BONDING_OPTS="miimon=1000 mode=0"
===

I'm running benchmarks using iperf (.90 is the second machine with a 
matching bonded connection):

===
iperf -f M -c 192.168.21.90
------------------------------------------------------------
Client connecting to 192.168.21.90, TCP port 5001
TCP window size: 0.02 MByte (default)
------------------------------------------------------------
[  3] local 192.168.21.80 port 35728 connected with 192.168.21.90 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec  1086 MBytes   109 MBytes/sec
===

This is the speed a non-bonded interface:

===
iperf -f M -c 192.168.22.90
------------------------------------------------------------
Client connecting to 192.168.22.90, TCP port 5001
TCP window size: 0.02 MByte (default)
------------------------------------------------------------
[  3] local 192.168.22.80 port 57475 connected with 192.168.22.90 port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec  1125 MBytes   112 MBytes/sec
===

The switch is a D-Link DGS-3100, which is a managed switch that I 
believe is capable of 801.3ad (for mode=4).

Any advice?

-- 
Digimer
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