[PATCH v12 0/7] hash: add SVE support for bulk key lookup

[Yoan Picchi]

This patchset adds SVE support for the signature comparison in the cuckoo
hash lookup and improves the existing NEON implementation. These
optimizations required changes to the data format and signature of the
relevant functions to support dense hitmasks (no padding) and having the
primary and secondary hitmasks interleaved instead of being in their own
array each.

Benchmarking the cuckoo hash perf test, I observed this effect on speed:
  There are no significant changes on Intel (ran on Sapphire Rapids)
  Neon is up to 7-10% faster (ran on ampere altra)
  128b SVE is about 3-5% slower than the optimized neon (ran on a graviton
    3 cloud instance)
  256b SVE is about 0-3% slower than the optimized neon (ran on a graviton
    3 cloud instance)

V2->V3:
  Remove a redundant if in the test
  Change a couple int to uint16_t in compare_signatures_dense
  Several codding-style fix

V3->V4:
  Rebase

V4->V5:
  Commit message

V5->V6:
  Move the arch-specific code into new arch-specific files
  Isolate the data struture refactor from adding SVE

V6->V7:
  Commit message
  Moved RTE_HASH_COMPARE_SVE to the last commit of the chain

V7->V8:
  Commit message
  Typos and missing spaces

V8->V9:
  Use __rte_unused instead of (void)
  Fix an indentation mistake

V9->V10:
  Fix more formating and indentation
  Move the new compare signature file directly in hash instead of being
    in a new subdir
  Re-order includes
  Remove duplicated static check
  Move rte_hash_sig_compare_function's definition into a private header

V10->V11:
  Split the "pack the hitmask" commit into four commits:
    Move the compare function enum out of the ABI
    Move the compare function implementations into arch-specific files
    Add a missing check on RTE_HASH_BUCKET_ENTRIES in case we change it
      in the future
    Implement the dense hitmask
  Add missing header guards
  Move compare function enum into cuckoo_hash.c instead of its own header.

V11->V12:
  Change the name of the compare function file (remove the _pvt suffix)

Yoan Picchi (7):
  hash: make compare signature function enum private
  hash: split compare signature into arch-specific files
  hash: add a check on hash entry max size
  hash: pack the hitmask for hash in bulk lookup
  hash: optimize compare signature for NEON
  test/hash: check bulk lookup of keys after collision
  hash: add SVE support for bulk key lookup

 .mailmap                              |   2 +
 app/test/test_hash.c                  |  99 +++++++++---
 lib/hash/compare_signatures_arm.h     | 121 +++++++++++++++
 lib/hash/compare_signatures_generic.h |  40 +++++
 lib/hash/compare_signatures_x86.h     |  55 +++++++
 lib/hash/rte_cuckoo_hash.c            | 207 ++++++++++++++------------
 lib/hash/rte_cuckoo_hash.h            |  10 +-
 7 files changed, 410 insertions(+), 124 deletions(-)
 create mode 100644 lib/hash/compare_signatures_arm.h
 create mode 100644 lib/hash/compare_signatures_generic.h
 create mode 100644 lib/hash/compare_signatures_x86.h

-- 
2.25.1