Re: [PATCH v9 0/4] hash: add SVE support for bulk key lookup

[David Marchand <david.marchand@redhat.com>]

On Tue, Apr 30, 2024 at 6:28 PM Yoan Picchi <yoan.picchi@arm.com> wrote:
>
> 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
>
> Yoan Picchi (4):
>   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/arch/arm/compare_signatures.h    | 117 +++++++++++++
>  lib/hash/arch/common/compare_signatures.h |  37 ++++
>  lib/hash/arch/x86/compare_signatures.h    |  53 ++++++
>  lib/hash/rte_cuckoo_hash.c                | 199 ++++++++++++----------
>  lib/hash/rte_cuckoo_hash.h                |   1 +
>  7 files changed, 393 insertions(+), 115 deletions(-)
>  create mode 100644 lib/hash/arch/arm/compare_signatures.h
>  create mode 100644 lib/hash/arch/common/compare_signatures.h
>  create mode 100644 lib/hash/arch/x86/compare_signatures.h
>

Can any of you have a look at this series?
Thanks.


-- 
David Marchand