Kernel hooks just to get rid of copy_[to/from]_user() and syscall overhead?

[Mihnea Balta]

Hi,

I have to implement a system which grabs udp packets off a gigabit connection, 
take some basic action based on what they contain, repack their data with a 
custom protocol header and send them through a gigabit ethernet interface on 
broadcast.

I know how to do this in userspace, but I need to know if doing everyting in 
the kernel would show a considerable speed improvement due to removing 
syscall and memory copy overhead. The system will be quite stressed, having 
to deal with around 15-20000 packets/second.

I didn't want to start this e-mail with an excuse, so I delayed it until here 
:). I appologise if this isn't the right place to ask, it seemed that way to 
me. I wasn't able to find sufficient and coherent information about this 
issue on the internet or on this mailing list's archives, so I decided to ask 
you people directly.

Thanks for your time,
Mihnea Balta