[dpdk-dev] [RFC PATCHv2 0/2] pktdev as wrapper type

[Bruce Richardson]

Hi all,

after a small amount of offline discussion with Marc Sune, here is an
alternative proposal for a higher-level interface - aka pktdev - to allow a
common Rx/Tx API across device types handling mbufs [for now, ethdev, ring
and KNI]. The key code is in the first patch fo the set - the second is an
example of a trivial usecase.

What is different about this to previously:
* wrapper class, so no changes to any existing ring, ethdev implementations
* use of function pointers for RX/TX with an API that maps to ethdev
  - this means there is little/no additional overhead for ethdev calls
  - inline special case for rings, to accelerate that. Since we are at a 
    higher level, we can special case process some things if appropriate. This
    means the impact to ring ops is one (predictable) branch per burst
* elimination of the queue abstraction. For the ring and KNI, there is no
  concept of queues, so we just wrap the functions directly (no need even for
  wrapper functions, the api's match so we can call directly). This also
  means:
  - adding in features per-queue, is far easier as we don't need to worry about
    having arrays of multiple queues. For example:
  - adding in buffering on TX (or RX) is easier since again we only have a 
    single queue.
* thread safety is made easier using a wrapper. For a MP ring, we can create
  multiple pktdevs around it, and each thread will then be able to use their
  own copy, with their own buffering etc.

However, at this point, I'm just looking for general feedback on this as an
approach. I think it's quite flexible - even more so than the earlier proposal
we had. It's less proscriptive and doesn't make any demands on any other libs.

Comments/thoughts welcome.

Bruce Richardson (2):
  Add example pktdev implementation
  example app showing pktdevs used in a chain

 config/common_bsdapp           |   5 +
 config/common_linuxapp         |   5 +
 examples/pktdev/Makefile       |  57 +++++++++++
 examples/pktdev/basicfwd.c     | 221 +++++++++++++++++++++++++++++++++++++++++
 lib/Makefile                   |   1 +
 lib/librte_pktdev/Makefile     |  53 ++++++++++
 lib/librte_pktdev/rte_pktdev.h | 200 +++++++++++++++++++++++++++++++++++++
 7 files changed, 542 insertions(+)
 create mode 100644 examples/pktdev/Makefile
 create mode 100644 examples/pktdev/basicfwd.c
 create mode 100644 lib/librte_pktdev/Makefile
 create mode 100644 lib/librte_pktdev/rte_pktdev.h

-- 
2.1.0