kern/72293: de(4) NIC performance degradation with debug.mpsafenet=1

[Philip Murray]

>Number:         72293
>Category:       kern
>Synopsis:       de(4) NIC performance degradation with debug.mpsafenet=1
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Oct 04 04:50:23 GMT 2004
>Closed-Date:
>Last-Modified:
>Originator:     Philip Murray
>Release:        FreeBSD 5.3-BETA6 i386
>Organization:
>Environment:
System: FreeBSD mirage.office.open2view.com 5.3-BETA6 FreeBSD 5.3-BETA6 #5: Fri Oct 1 21:10:13 NZST 2004 root at mirage.office.open2view.com:/usr/obj/usr/src/sys/MIRAGE i386

    de0: <Digital 21140A Fast Ethernet> port 0xc400-0xc47f mem 0xdd021000-0xdd02107f irq 11 at device 3.0 on pci2
    de0: [GIANT-LOCKED]
    de0: 21140A [10-100Mb/s] pass 2.2
    de0: Ethernet address: 00:80:c8:64:dd:3d

    de0 at pci2:3:0:   class=0x020000 card=0x11001186 chip=0x00091011 rev=0x22 hdr=0x00
    vendor   = 'Digital Equipment Corporation'
    device   = 'DecChip 21140 Fast Ethernet Adapter'
    class    = network
    subclass = ethernet

I can provide more information on request (not sure what else is needed atm)

>Description:
    After booting the interface will work for a short time, as traffic passes through it, it suddenly gets very slow and unuseable.
    Unable to SSH over 100Mbit to it and doesn't respond to pings.

    Booting with debug.mpsafenet=0 in /boot/loader.conf resolves it.
>How-To-Repeat:
    Boot with debug.mpsafenet=1 with a de(4) NIC

>Fix:

    Boot with debug.mpsafenet=0

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