Re: is CONFIG_PACKET_MMAP always a win?

[Jamie Lokier]

Alan Cox wrote:
> > >    Overhead: kernel does a full memcpy of the packet body to get it
> > >    into the ring buffer, and my program does another to get it out.
> > 
> > I had a look at this about a year ago, and it seems there is no method
> > provided to read the packets without copying them, if you need them in
> > user space.
> 
> You can process them in the ring buffer. If you can't keep up then you
> are screwed any way you look at it 8)

That still doesn't avoid copying: af_packet copies the whole packet (if
you want the whole packet) from the original skbuff to the ring buffer.

-- Jamie