Intel 82580 lagg(4) problem

[Andriy Kopystyansky]

Greetings!
We've got a strange problem with lagg(4) interfaces built on Intel's  
82580 chipset igb (dual port 1Gb card).
We cannot send over lagg interface more than ~1Gb/s, yet receiving  
~2GB over it.
Looks like something indicating the problem can be seen here:

anri at host:[8:13]~#ifstat -i lagg0 -i igb1 -i igb3 1
       lagg0                igb1                igb3
  KB/s in  KB/s out   KB/s in  KB/s out   KB/s in  KB/s out
  9116.50  26515.16   4147.70  28871.43   5004.86  23683.31
  8423.08  26544.62   3853.22  28980.60   4594.21  23520.97
  8796.48  26395.28   4248.46  28344.00   4567.42  23978.17

Note (IN) traffic - everything's ok, about 50% on each igb interfaces  
and total summary on lagg0.
But (OUT) traffic looks weird - there is more traffic on the single  
igb1 than on lagg0!
Tried with default driver came with the system, also the new one  
igb-2.3.10 from Intel site - no luck.

Testing lagg interface built on other cards (em, bce) on the same  
machine shows expected normal behavior for both directions.
---------------------------------------
anri at host:[9:02]~#uname -a
FreeBSD host 9.1-RELEASE-p4 FreeBSD 9.1-RELEASE-p4 #5: Fri Sep 20  
14:52:18 EEST 2013     anri at host:/usr/obj/usr/src/sys/NODEONE  amd64
--------------------------------------
Interfaces:
lagg0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
          
options=401bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,VLAN_HWTSO>
         ether 90:e2:ba:36:95:1d
         inet 172.16.0.1 netmask 0xffffffc0 broadcast 172.16.0.63
         media: Ethernet autoselect
         status: active
         laggproto lacp lagghash l2,l3,l4
         laggport: igb3 flags=1c<ACTIVE,COLLECTING,DISTRIBUTING>
         laggport: igb1 flags=1c<ACTIVE,COLLECTING,DISTRIBUTING>

igb1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
          
options=401bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,VLAN_HWTSO>
         ether 90:e2:ba:36:95:1d
         media: Ethernet autoselect (1000baseT <full-duplex>)
         status: active

igb3: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
          
options=401bb<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,JUMBO_MTU,VLAN_HWCSUM,TSO4,VLAN_HWTSO>
         ether 90:e2:ba:36:95:1d
         media: Ethernet autoselect (1000baseT <full-duplex>)
         status: active

---------------------------------------
Hardware: IBM 3550 with 2x Intel(R) Xeon(R) CPU  E5430  @ 2.66GHz (amd64)
pciconf -lv:
igb1 at pci0:19:0:1:       class=0x020000 card=0x12b28086 chip=0x15168086  
rev=0x01 hdr=0x00
     vendor     = 'Intel Corporation'
     device     = '82580 Gigabit Network Connection'
     class      = network
     subclass   = ethernet

---------------------------------------
/boot/loader.conf:
hw.igb.rxd=4096
hw.igb.txd=4096
hw.igb.max_interrupt_rate=32000
hw.igb.num_queues=2
net.isr.maxthreads=8
net.isr.dispatch=direct
net.isr.bindthreads=1
net.link.ifqmaxlen=10240

/etc/sysctl.conf: (relevant part)

dev.igb.1.rx_processing_limit=-1
dev.igb.3.rx_processing_limit=-1
net.inet.ip.intr_queue_maxlen=512
net.route.netisr_maxqlen=4096
net.inet.ip.redirect=0
net.inet.ip.fastforwarding=1
kern.maxfiles=204800
kern.maxfilesperproc=200000
kern.ipc.nmbclusters=204800
kern.ipc.maxsockets=204800

Any tips, advices?

thanks in advance, with best regards,
Andriy Kopystyansky