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
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.
Notes:
Apps must now work in bursts, as up to 8 are given to a worker at a time
For performance in matching, Flow ID's are 15-bits
If 32 bits Flow IDs are required, use the packet-at-a-time (SINGLE)
mode.
Performance Gains
2.2GHz Intel(R) Xeon(R) CPU E5-2699 v4 @ 2.20GHz
2 x XL710 40GbE NICS to 2 x 40Gbps traffic generator channels 64b packets
separate cores for rx, tx, distributor
1 worker - 4.8x
4 workers - 2.9x
8 workers - 1.8x
12 workers - 2.1x
16 workers - 1.8x
[01/17] lib: rename legacy distributor lib files
[02/17] lib: symbol versioning of functions in distributor
[03/17] lib: create rte_distributor_private.h
[04/17] lib: add new burst oriented distributor structs
[05/17] lib: add new distributor code
[06/17] lib: add SIMD flow matching to distributor
[07/17] lib: apply symbol versioning to distibutor lib
[08/17] test: change params to distributor autotest
[09/17] test: switch distributor test over to burst API
[10/17] test: test single and burst distributor API
[11/17] test: add perf test for distributor burst mode
[12/17] example: add extra stats to distributor sample
[13/17] sample: distributor: wait for ports to come up
[14/17] sample: switch to new distributor API
[15/17] lib: make v20 header file private
[16/17] doc: distributor library changes for new burst api
[17/17] maintainers: add to distributor lib maintainers
