em driver input errors

[alexpalias-bsdnet at yahoo.com]

--- On Wed, 8/19/09, H.Fazaeli <fazaeli at sepehrs.com> wrote:

> From: H.Fazaeli <fazaeli at sepehrs.com>
> Subject: Re: em driver input errors
> To: alexpalias-bsdnet at yahoo.com
> Cc: freebsd-net at freebsd.org
> Date: Wednesday, August 19, 2009, 6:09 PM
> Have you tries fixed speed/duplex?

Hello.  Flow control is already disabled in the switch, and now I have configured fixed speed and duplex both on the switch and the network card.

# ifconfig em0
em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
        options=9b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM>
        ether 00:xx:xx:xx:xx:xx
        media: Ethernet 1000baseTX <full-duplex>
        status: active


I will let you know if this fixes the problem; however, I seem to remember that speed/duplex problems usually result in lots of collisions and CRC errors, but I get very little of those (no collisions in fact):

# netstat -nI em0
Name    Mtu Network       Address              Ipkts Ierrs    Opkts Oerrs  Coll
em0    1500 <Link#1>      00:xx:xx:xx:xx:xx 10448059238 2746221 12382379424     0     0

Also:
r# sysctl dev.em.0.stats=1 ; dmesg | tail -21
dev.em.0.stats: -1 -> -1
em0: Excessive collisions = 0
em0: Sequence errors = 0
em0: Defer count = 0
em0: Missed Packets = 2746217
em0: Receive No Buffers = 4996579
em0: Receive Length Errors = 0
em0: Receive errors = 2
em0: Crc errors = 2
em0: Alignment errors = 0
em0: Collision/Carrier extension errors = 0
em0: RX overruns = 1134
em0: watchdog timeouts = 0
em0: RX MSIX IRQ = 0 TX MSIX IRQ = 0 LINK MSIX IRQ = 0
em0: XON Rcvd = 0
em0: XON Xmtd = 0
em0: XOFF Rcvd = 0
em0: XOFF Xmtd = 0
em0: Good Packets Rcvd = 10443504721
em0: Good Packets Xmtd = 12377389802
em0: TSO Contexts Xmtd = 0
em0: TSO Contexts Failed = 0

This seems to suggest that the number of errors seen in ifconfig is linked to the "missed packets" statistic that's produced by the sysctl.  Note that there are only 2 CRC errors and 2 other errors; I can't see anything that corresponds to the "Receive no buffers" figure; are those packets dropped by the NIC itself?

Alex