svn commit: r267935 - head/sys/dev/e1000 (with work around?)

[Mike Tancsa]

On 9/12/2014 10:09 AM, Mike Tancsa wrote:
>
> FYI, I just ran into this bug on another box, with an onboard em nic, so
> I dont think its a one off hardware issue. AMD64,  FreeBSD 10.0-STABLE
> #4 r270560:
> This is on an Intel MB S1200BTL ( S1200BT.86B.02.00.0035.030220120927)
>
> Unfortunately, this is also a production box so its difficult to test. I
> am going to see if I can find a similar MB to test against.


I found another board I can test with. It takes a bit of random traffic 
to wedge, but I can lock up the NIC to the point where I have to down 
and up it

When the NIC is wedged, sending sysctl -w em.1.debug=1 shows


Sep 12 11:05:05 backup3 kernel: Interface is RUNNING and ACTIVE
Sep 12 11:05:05 backup3 kernel: em1: hw tdh = 414, hw tdt = 980
Sep 12 11:05:05 backup3 kernel: em1: hw rdh = 768, hw rdt = 767
Sep 12 11:05:05 backup3 kernel: em1: Tx Queue Status = 1
Sep 12 11:05:05 backup3 kernel: em1: TX descriptors avail = 449
Sep 12 11:05:05 backup3 kernel: em1: Tx Descriptors avail failure = 3
Sep 12 11:05:05 backup3 kernel: em1: RX discarded packets = 0
Sep 12 11:05:05 backup3 kernel: em1: RX Next to Check = 768
Sep 12 11:05:05 backup3 kernel: em1: RX Next to Refresh = 767

em1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
 
options=4219b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,TSO4,WOL_MAGIC,VLAN_HWTSO>
         ether 00:15:17:ed:68:a4
         inet 1.1.1.2 netmask 0xffffff00 broadcast 1.1.1.255
         nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
         media: Ethernet autoselect (1000baseT <full-duplex>)
         status: active

The network traffic involves sending a lot of traffic via NFS.  I found 
that if I disable TSO on the nic, it seems to fix the problem, or at 
least makes its hard to reproduce. With tso enabled, it took perhaps 
30-120 seconds for the problem to manifest.  Both on my test and 
production box, I have not run into the problem in the past 45min.

	---Mike




-- 
-------------------
Mike Tancsa, tel +1 519 651 3400
Sentex Communications, mike at sentex.net
Providing Internet services since 1994 www.sentex.net
Cambridge, Ontario Canada   http://www.tancsa.com/