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

[Thomas Monjalon <thomas@monjalon.net>]

30/04/2024 18:27, 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

Waiting for a new version after comments sent in June please.

Note: we didn't have a review from the lib maintainers.