em0 NIC slow on 8.2-p1 amd64?

[Eduardo Morras]

At 21:16 20/07/2011, Michael W. Lucas wrote:

>It's at gigabit:
>
>em0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
> 
>options=219b<RXCSUM,TXCSUM,VLAN_MTU,VLAN_HWTAGGING,VLAN_HWCSUM,TSO4,WOL_MAGIC>
>         ether 00:15:17:31:c8:fe
>         inet xxxxxxx
>         media: Ethernet autoselect (1000baseT <full-duplex>)
>         status: active

All seems to be ok, try a netstat -I em0 -d  (it's a capital 'i') to 
get statistics. If too much packets are dropped recheck cables.

Other options:

a) 30 MB/s looks very strange, do you have pf or similar with a filter rule?
b) Have you checked your disk i/o performance?
c) If you generate the data dinamically, may be your producer app is 
the problem.

About the em specific problem under 8.2 you cite, others can guide 
better than me.

HTH

>Thanks,
>==ml