[ovs-dev] [PATCH v2 0/4] dpcls subtable miniflow optimizations

[Harry van Haaren]

Hi Folks,

This patchset is a v2 on previous patches as in this bundle:
https://patchwork.ozlabs.org/bundle/hvanhaar/dpcls_func_ptr_opt/

The work contained in this patchset achieves the following;

Patch 1:
Refactor dpcls_lookup and the subtable for flexibility.
In particular, add a function pointer to the subtable
structure, which enables "plugging-in" a lookup function
at runtime. This enables a number of optimizations in future.

Patch 2 & 3:
With the function pointer in place, we refactor the existing
dpcls_lookup matching code into its own function, and later its
own file. To split it to its own file requires making various
dpcls data-structures available in the dpif-netdev.h header.

Patch 4:
Re-implement and optimize dpcls_rule_matches_key() by removing
the "loopy-branch-ness" of the FOR_EACH() macros used. Instead
a popcount() approach is used, which is much more CPU performance
friendly, due to reduced branches/loads-stores and total work done.

Performance:
Patches 1, 2 and 3 are performance neutral in testing here. The
fourth patch provides a significant performance improvement when
dpcls or SMC are processing packets.

Feedback, reviews, performance numbers weclomed! -Harry


Harry van Haaren (4):
  dpif-netdev: implement function pointers/subtable
  dpif-netdev: move dpcls lookup structures to .h
  dpif-netdev: split out generic lookup function
  dpif-netdev: optimized dpcls_rule_matches_key()

 lib/automake.mk                  |   1 +
 lib/dpif-netdev-lookup-generic.c |  95 +++++++++++++++++++++++
 lib/dpif-netdev.c                | 124 +++----------------------------
 lib/dpif-netdev.h                | 118 +++++++++++++++++++++++++++++
 4 files changed, 226 insertions(+), 112 deletions(-)
 create mode 100644 lib/dpif-netdev-lookup-generic.c

-- 
2.17.1