Fwd: netmap-ipfw on em0 em1

[ulric at siag.nu]

2015-05-04 17:29 skrev Barney Cordoba via freebsd-net:
> It's not faster than "wedging" into the if_input()s. It simply can't
> be. Your getting packets at interrupt time as soon as their processed
> and  you there's no network stack involved, and your able to receive
> and transmit without a process switch. At worst it's the same, without
> the extra plumbing. It's not rocket science to "bypass the network
> stack".
> The only advantage of bringing it into user space would be that it's
> easier to write threaded handlers for complex uses; but not as a
> firewall (which is the limit of the context of my comment). You can do
> anything in the kernel that you can do in user space. The reason a
> kernel module with if_input() hooks is better is that you can use the
> standard kernel without all of the netmap hacks. You can just pop it
> into any kernel and it works.

If my little application is N*1000 lines, the part that needs fast raw 
network access is N*100 lines and can get that at wirespeed with N*10 
lines interfacing with Netmap, then that is IMHO an excellent 
proposition. I don't see how popping it into the kernel makes any sense.

Ulric