[dpdk-dev] [PATCH v8 0/6] Elastic Flow Distributor

Pablo de Lara pablo.de.lara.guarch at intel.com
Tue Jan 17 23:23:50 CET 2017


EFD is a distributor library that uses perfect hashing to determine a
target/value for a given incoming flow key. It has the following advantages:
first, because it uses perfect hashing it does not store the key itself and
hence lookup performance is not dependent on the key size. Second, the
target/value can be any arbitrary value hence the system designer and/or
operator can better optimize service rates and inter-cluster network traffic
locating.  Third, since the storage requirement is much smaller than a
hash-based flow table (i.e. better fit for CPU cache), EFD can scale to millions
of flow keys. Finally, with current optimized library implementation performance
is fully scalable with number of CPU cores.

The basic idea of EFD is when a given key is to be inserted, a family of hash
functions is searched until the correct hash function that maps the input key to
the correct value is found. However, rather than explicitly storing all keys and
their associated values, EFD stores only indices of hash functions that map keys
to values, and thereby consumes much less space than conventional  flow-based
tables. The lookup operation is very simple, similar to computational-based
scheme, given an input key the lookup operation is reduced to hashing that key
with the correct hash function.

Intuitively, finding a hash function that maps each of a large number (millions)
of input keys to the correct output value is effectively impossible, as a result
EFD, breaks the problem into smaller pieces (divide and conquer). EFD divides
the entire input key set into many small groups. Each group consists of
approximately 20-28 keys (a configurable parameter for the library), then, for
each small group, a brute force search to find a hash function that produces the
correct outputs for each key in the group.
It should be mentioned that since in the online lookup table for EFD doesn’t
store the key itself, the size of the EFD table is independent of the key size
and hence EFD lookup performance which is almost constant irrespective of the
length of the key which is a highly desirable feature especially for longer
keys.

Library code is included in the patch, plus an sample application that shows
how the library can be used.

RFC for this library was already sent:
http://dpdk.org/ml/archives/dev/2016-October/049238.html

Changes in v8:

- Removed .rej file added in v7 by mistake

Changes in v7:

- Fixed figure reference in documentation
- Removed unnecessary library dependencies
- Separated x86 SIMD code in different patch
- Added extra comments
- Fixed ARM compilation issue

Changes in v6:

- Separated x86 SIMD code in different file
- Fixed shared library compilation
- Fixed figure reference in documentation
- Added missing parameter documentation

Changes in v5:

- Removed trailing whitespace in doc

Changes in v4:

- Added References section

Changes in v3:

- Fixed SVG files
- Fixed copyright dates
- Reformatted parts of documentation

Changes in v2:

- Added documentation for library and sample app
- Fixed checkpatch errors/warnings
- Added functional and performance tests
- Made key size variable at runtime
- Made code multi-architecture compatible at runtime


Pablo de Lara (6):
  efd: new Elastic Flow Distributor library
  efd: add AVX2 vect lookup function
  app/test: add EFD functional and perf tests
  examples/flow_distributor: sample app to demonstrate EFD usage
  doc: add EFD library section in Programmers guide
  doc: add flow distributor guide

 MAINTAINERS                                       |    9 +
 app/test/Makefile                                 |    5 +-
 app/test/test_efd.c                               |  494 ++++++++
 app/test/test_efd_perf.c                          |  407 +++++++
 config/common_base                                |    5 +
 doc/api/doxy-api-index.md                         |    3 +-
 doc/api/doxy-api.conf                             |    1 +
 doc/api/examples.dox                              |    4 +
 doc/guides/prog_guide/efd_lib.rst                 |  440 +++++++
 doc/guides/prog_guide/img/efd_i1.svg              |  130 ++
 doc/guides/prog_guide/img/efd_i10.svg             |  384 ++++++
 doc/guides/prog_guide/img/efd_i11.svg             |  319 +++++
 doc/guides/prog_guide/img/efd_i12.svg             | 1008 ++++++++++++++++
 doc/guides/prog_guide/img/efd_i2.svg              |  280 +++++
 doc/guides/prog_guide/img/efd_i3.svg              |  634 ++++++++++
 doc/guides/prog_guide/img/efd_i4.svg              |  203 ++++
 doc/guides/prog_guide/img/efd_i5.svg              |  183 +++
 doc/guides/prog_guide/img/efd_i6.svg              | 1254 +++++++++++++++++++
 doc/guides/prog_guide/img/efd_i7.svg              |  790 ++++++++++++
 doc/guides/prog_guide/img/efd_i8.svg              |  182 +++
 doc/guides/prog_guide/img/efd_i9.svg              |  390 ++++++
 doc/guides/prog_guide/index.rst                   |   23 +
 doc/guides/rel_notes/release_17_02.rst            |   14 +
 doc/guides/sample_app_ug/flow_distributor.rst     |  494 ++++++++
 doc/guides/sample_app_ug/img/flow_distributor.svg | 1254 +++++++++++++++++++
 doc/guides/sample_app_ug/index.rst                |    1 +
 examples/Makefile                                 |    1 +
 examples/flow_distributor/Makefile                |   44 +
 examples/flow_distributor/distributor/Makefile    |   57 +
 examples/flow_distributor/distributor/args.c      |  200 +++
 examples/flow_distributor/distributor/args.h      |   39 +
 examples/flow_distributor/distributor/init.c      |  371 ++++++
 examples/flow_distributor/distributor/init.h      |   76 ++
 examples/flow_distributor/distributor/main.c      |  362 ++++++
 examples/flow_distributor/node/Makefile           |   48 +
 examples/flow_distributor/node/node.c             |  417 +++++++
 examples/flow_distributor/shared/common.h         |   99 ++
 lib/Makefile                                      |    3 +-
 lib/librte_eal/common/include/rte_log.h           |    3 +-
 lib/librte_efd/Makefile                           |   56 +
 lib/librte_efd/rte_efd.c                          | 1344 +++++++++++++++++++++
 lib/librte_efd/rte_efd.h                          |  300 +++++
 lib/librte_efd/rte_efd_version.map                |   13 +
 lib/librte_efd/rte_efd_x86.h                      |   86 ++
 mk/rte.app.mk                                     |    3 +-
 45 files changed, 12428 insertions(+), 5 deletions(-)
 create mode 100644 app/test/test_efd.c
 create mode 100644 app/test/test_efd_perf.c
 create mode 100644 doc/guides/prog_guide/efd_lib.rst
 create mode 100644 doc/guides/prog_guide/img/efd_i1.svg
 create mode 100644 doc/guides/prog_guide/img/efd_i10.svg
 create mode 100644 doc/guides/prog_guide/img/efd_i11.svg
 create mode 100644 doc/guides/prog_guide/img/efd_i12.svg
 create mode 100644 doc/guides/prog_guide/img/efd_i2.svg
 create mode 100644 doc/guides/prog_guide/img/efd_i3.svg
 create mode 100644 doc/guides/prog_guide/img/efd_i4.svg
 create mode 100644 doc/guides/prog_guide/img/efd_i5.svg
 create mode 100644 doc/guides/prog_guide/img/efd_i6.svg
 create mode 100644 doc/guides/prog_guide/img/efd_i7.svg
 create mode 100644 doc/guides/prog_guide/img/efd_i8.svg
 create mode 100644 doc/guides/prog_guide/img/efd_i9.svg
 create mode 100644 doc/guides/sample_app_ug/flow_distributor.rst
 create mode 100644 doc/guides/sample_app_ug/img/flow_distributor.svg
 create mode 100644 examples/flow_distributor/Makefile
 create mode 100644 examples/flow_distributor/distributor/Makefile
 create mode 100644 examples/flow_distributor/distributor/args.c
 create mode 100644 examples/flow_distributor/distributor/args.h
 create mode 100644 examples/flow_distributor/distributor/init.c
 create mode 100644 examples/flow_distributor/distributor/init.h
 create mode 100644 examples/flow_distributor/distributor/main.c
 create mode 100644 examples/flow_distributor/node/Makefile
 create mode 100644 examples/flow_distributor/node/node.c
 create mode 100644 examples/flow_distributor/shared/common.h
 create mode 100644 lib/librte_efd/Makefile
 create mode 100644 lib/librte_efd/rte_efd.c
 create mode 100644 lib/librte_efd/rte_efd.h
 create mode 100644 lib/librte_efd/rte_efd_version.map
 create mode 100644 lib/librte_efd/rte_efd_x86.h

-- 
2.7.4



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