kern/182917: strange out traffic with igb interfaces

[sh1970]

>Number:         182917
>Category:       kern
>Synopsis:       strange out traffic with igb interfaces
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sat Oct 12 02:20:00 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator:     sh1970
>Release:        freebsd 8.4 stable
>Organization:
>Environment:
FreeBSD  8.4-STABLE FreeBSD 8.4-STABLE #0: Sun Aug 26 18:06:21 UTC 2012     root@:/usr/obj/usr/src/sys/GENERIC  i386
>Description:
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.

Set net.link.lagg.0.use_flowid=0 not solve the problem.


Testing lagg interface built on other cards (em, bce) on the same  
machine shows expected normal behavior for both directions.
>How-To-Repeat:

>Fix:
My system is freebsd 8.4, use the e1000 driver from freebsd 8.3 , the result is OK .

>Release-Note:
>Audit-Trail:
>Unformatted: