On Tue, Feb 21, 2017 at 03:17:36AM +0000, David Hunt wrote:

This patch aims to improve the throughput of the distributor library.

It uses a similar handshake mechanism to the previous version of
the library, in that bits are used to indicate when packets are ready
to be sent to a worker and ready to be returned from a worker. One main
difference is that instead of sending one packet in a cache line, it makes
use of the 7 free spaces in the same cache line in order to send up to
8 packets at a time to/from a worker.

The flow matching algorithm has had significant re-work, and now keeps an
array of inflight flows and an array of backlog flows, and matches incoming
flows to the inflight/backlog flows of all workers so that flow pinning to
workers can be maintained.

The Flow Match algorithm has both scalar and a vector versions, and a
function pointer is used to select the post appropriate function at run time,
depending on the presence of the SSE2 cpu flag. On non-x86 platforms, the
the scalar match function is selected, which should still gives a good boost
in performance over the non-burst API.

v2 changes:
  * Created a common distributor_priv.h header file with common
    definitions and structures.
  * Added a scalar version so it can be built and used on machines without
    sse2 instruction set
  * Added unit autotests
  * Added perf autotest

For future reference, I think it's better to put the list of deltas from
each version in reverse order, so that the latest changes are on top,
and save scrolling for those of us who have been tracking the set.

v3 changes:
  * Addressed mailing list review comments
  * Test code removal
  * Split out SSE match into separate file to facilitate NEON addition
  * Cleaned up conditional compilation flags for SSE2
  * Addressed c99 style compilation errors
  * rebased on latest head (Jan 2 2017, Happy New Year to all)

v4 changes:
   * fixed issue building shared libraries

v5 changes:
   * Removed some un-needed code around retries in worker API calls
   * Cleanup due to review comments on mailing list
   * Cleanup of non-x86 platform compilation, fallback to scalar match

v6 changes:
   * Fixed intermittent segfault where num pkts not divisible
     by BURST_SIZE
   * Cleanup due to review comments on mailing list
   * Renamed _priv.h to _private.h.

v7 changes:
   * Reorganised patch so there's a more natural progression in the
     changes, and divided them down into easier to review chunks.
   * Previous versions of this patch set were effectively two APIs.
     We now have a single API. Legacy functionality can
     be used by by using the rte_distributor_create API call with the
     RTE_DISTRIBUTOR_SINGLE flag when creating a distributor instance.
   * Added symbol versioning for old API so that ABI is preserved.

The merging to a single API is great to see, making it so much easier
for app developers. Thanks for that.

/Bruce