netmap design question - accessing netmap:X-n individual queues on FreeBSD

[Adrian Chadd]

Oh and one other thing - on the cxgbe hardware, the netmap interfaces
(ncxl) have a different MAC. things like broadcast traffic is
duplicated to cxlX AND ncxlX. So, if you're only using netmap and
you're testing promisc/bridging, you should bring /down/ the cxlX
interface and leave ncxlX up - otherwise yeah, the cxbge MAC will
duplicate packets in hardware, which halves the RX bandwidth available
on the NIC /and/ chews CPU in FreeBSD as the normal ethernet input
path drops all of those packets.

(I think the same thing holds with the virtual devices via SR-IOV on
ixgbe hardware, btw..)


-a