Re: [PATCH V2 0/6] pipeline: make the hash function configurable per table

[Thomas Monjalon <thomas@monjalon.net>]

19/08/2022 21:52, Cristian Dumitrescu:
> The exact match and learner tables use a hash function for the lookup
> operation. This patch set makes the hash function configurable and
> removes some limitations.
> 
> The hash function previously used by these table types had the
> following limitations:
> a) Not configurable: An internally hardcoded version was used;
> b) Mask-based: This prevents using most of the available
>    hash functions, as they are not mask-based;
> c) Key size limited to 64 bytes or less.
> 
> The new hash function is:
> a) Configurable;
> b) Not mask-based;
> c) Not limited to key sizes to less than or equal to 64 bytes.
> 
> Also, since this flexibility has some performance cost, this patch set
> also introduces key comparison functions specialized for each key size
> value. Since the key size is fixed for each table, the key comparison
> function can be selected at initialization as opposed to using a
> generic function that can handle any key size. This strategy result in
> a performance improvement for the table lookup operation of around 5%.
> 
> Depends-on: series-24117 ("pipeline: pipeline configuration and build improvements")
> 
> Change log:
> 
> V2:
> -Added check for table match fields to be contiguous for exact match tables.
> -Fixed bug in the specification file parsing related to hash function configuration.
> 
> Cristian Dumitrescu (6):
>   table: add hash function prototype
>   table: add key comparison functions
>   table: configure the hash function for regular tables
>   pipeline: configure the hash function for regular tables
>   table: configure the hash function for learner tables
>   pipeline: configure the hash function for learner tables

Applied, thanks.