kern/94390: poor network performance after promiscuous mode is enabled & disabled

[Stephen Trovato]

>Number:         94390
>Category:       kern
>Synopsis:       poor network performance after promiscuous mode is enabled & disabled
>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:   Sun Mar 12 17:40:50 GMT 2006
>Closed-Date:
>Last-Modified:
>Originator:     Stephen Trovato
>Release:        6.0-RELEASE
>Organization:
Diocese of Columbus Dept for Ed
>Environment:
FreeBSD serenity.localdomain 6.0-RELEASE FreeBSD 6.0-RELEASE #0: Wed Nov  2 19:07:38 UTC 2005     root at rat.samsco.home:/usr/obj/usr/src/sys/GENERIC  amd64
>Description:
Enabling promiscuous mode causes a permanent network performance drop even after it is turned off.  

Hardware description:
K8M800-M7A motherboard
Sempron 2800+ w/amd64
embedded VIA 10/100 (see below)

dmesg output:
vr0: <VIA VT6102 Rhine II 10/100BaseTX> port 0xdc00-0xdcff mem 0xf6001000-0xf60010ff irq 23 at device 18.0 on pci0
miibus0: <MII bus> on vr0
rlphy0: <RTL8201L 10/100 media interface> on miibus0
rlphy0:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
vr0: Ethernet address: 00:14:2a:f5:3a:03

ifconfig output:
vr0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        inet6 fe80::214:2aff:fef5:3a03%vr0 prefixlen 64 scopeid 0x1 
        inet X.X.X.131 netmask 0xffffff00 broadcast X.X.X.255
        ether 00:14:2a:f5:3a:03
        media: Ethernet autoselect (100baseTX <full-duplex>)
        status: active

>How-To-Repeat:
Steps to reproduce:

1) ifconfig vr0 promisc
2) ifconfig vr0 -promisc
3) Network performance is now half of what it was

>Fix:
Bringing the interface down and back up with ifconfig does not resolve the problem, but a reboot does.
>Release-Note:
>Audit-Trail:
>Unformatted: