amd64/154236: High Collision count on "re" network interface

[Alex]

>Number:         154236
>Category:       amd64
>Synopsis:       High Collision count on "re" network interface
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-amd64
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Jan 23 07:50:10 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator:     Alex
>Release:        8.2 RC2
>Organization:
>Environment:
FreeBSD srv.mydomain.net 8.2-RC2 FreeBSD 8.2-RC2 #1: Sun Jan 23 12:49:35 EST 2011     alex at nospam.nospam.nospam:/usr/obj/usr/src/sys/custom-server  amd64
>Description:
I can report this issue is also present in 8.1/amd64 (and also occurs with the stock GENERIC kernels in both releases)

I am running FreeBSD on my VPS. The host is using XEN HVM.

There is an unusually high collision rate being reported on the network interface:

Name    Mtu Network       Address              Ipkts Ierrs Idrop    Opkts Oerrs  Coll
re0    1500 <Link#1>      00:16:3e:f0:8b:6c   136929     0     0   104042     0 104036

So, out of 104042 packets transmitted, collisions were detected on 104036 of them.

I thought that perhaps this may just be a XEN related issue until I ran into this article on the web:

http://blather.michaelwlucas.com/?p=268&cpage=1

This seems to be the same issue, but when running FreeBSD under KVM. Same network interface (re). Is this likely to be an issue with the "re" driver under virtualized environments?



>How-To-Repeat:
Run FreeBSD 8.1/amd64 in a XEN HVM environment
>Fix:


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