DPDK and HW offloads

[Stephen Hemminger <stephen@networkplumber.org>]

As I look at how the ethernet device interface in DPDK has exploded in complexity;
it makes life very hard for end users.  The goal has been to enable all the cool hardware
features, but it has put blinders on the driver devlopers; they are ignoring the fact
that real applications can't just work on one kind of hardware.

The DPDK is doing a terrible job at providing abstractions.  There needs to be a
real generic set of operations, and every hardware offload feature must:
  * have a clear well defined API
  * if feature is not available in software, then the DPDK must provide
    a software equivalent feature.
  * any difference in API must be hidden from application.
  * no compile config options about offload.
  * tests and documentation must work for both hw and sw version

Right now, all those offload features are pretty much unusable in a real product
without lots and lots of extra codes and huge bug surface. It bothers me enough
that I would recommend removing much of the filter/offload/ptype stuff from DPDK!