kern/189234: [em] Big lag with Ethernet Connection I217-V

[Cedric]

>Number:         189234
>Category:       kern
>Synopsis:       [em] Big lag with Ethernet Connection I217-V
>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:   Fri May 02 13:30:00 UTC 2014
>Closed-Date:
>Last-Modified:
>Originator:     Cedric
>Release:        10.0-STABLE
>Organization:
Kreiz IT
>Environment:
FreeBSD Test.RP614v4 10.0-STABLE FreeBSD 10.0-STABLE #0: Thu May  1 06:25:14 CEST 2014     root at Test.RP614v4:/usr/obj/usr/src/sys/GENERIC  amd64
>Description:
Pciconf : 
em0 at pci0:0:25:0:        class=0x020000 card=0xe0001458 chip=0x153b8086 rev=0x04 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = 'Ethernet Connection I217-V'
    class      = network
    subclass   = ethernet

Network lag when using this interface with ssh. SMB share are unusable on this nic.
Quick network trace reveal a lot of DUP ack and retransmit.

With a re0 nic, system go well.


>How-To-Repeat:
Use a I217-V chipset as nic and do some ssh keying or use samba.
>Fix:


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