netmap custom RSS and custom packet info

[Slawa Olhovchenkov]

On Mon, Jun 29, 2015 at 10:41:39AM -0700, Adrian Chadd wrote:

> Hi,
> 
> PPPoE will not be hashed according to RSS on the 1g/10g (igb, ixgbe)
> intel hardware. you're going to have to figure out some other method
> for traffic redistribution.

I propose ephemeral but permanent NETMAP RX pipe with redistribution
function from user-loadable kernel module.

Hardware RxRing(i) => loadable hash => user-visible RxRing(j).

As I perceive overhead is packet-parsing and hash computation +
swaping of slot indexes (zero-copying between hardware ring and
user-visible ring).

In other (Tx) direction user-visible direct mapped to hardware ring.

> If it's inside GRE, then it's IPv4/IPv6 and thus yes, you can do
> symmetric hashing. But if it's raw pppoe coming in, you're SoL.

This is will be only hashed tunnel IPs, yes?
Not sessions inside tunnel.