Re: [dpdk-dev] [RFC] ethdev: support symmetric hash function

[Adrien Mazarguil <adrien.mazarguil@6wind.com>]

On Thu, Jul 04, 2019 at 12:46:07PM +0800, simei wrote:
> From: Simei Su <simei.su@intel.com>
> 
> Currently, there are DEFAULT,TOEPLITZ and SIMPLE_XOR hash funtion.
> To support symmetric hash by rte_flow RSS action, this RFC introduces
> SYMMETRIC_TOEPLITZ to rte_eth_hash_function.
> 
> Signed-off-by: Simei Su <simei.su@intel.com>
> ---
>  lib/librte_ethdev/rte_flow.h | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/lib/librte_ethdev/rte_flow.h b/lib/librte_ethdev/rte_flow.h
> index f3a8fb1..e3c4fe5 100644
> --- a/lib/librte_ethdev/rte_flow.h
> +++ b/lib/librte_ethdev/rte_flow.h
> @@ -1744,6 +1744,7 @@ enum rte_eth_hash_function {
>  	RTE_ETH_HASH_FUNCTION_DEFAULT = 0,
>  	RTE_ETH_HASH_FUNCTION_TOEPLITZ, /**< Toeplitz */
>  	RTE_ETH_HASH_FUNCTION_SIMPLE_XOR, /**< Simple XOR */
> +	RTE_ETH_HASH_FUNCTION_SYMMETRIC_TOEPLITZ, /**< Symmetric TOEPLITZ */

"Symmetric TOEPLITZ" => "Symmetric Toeplitz."

>  	RTE_ETH_HASH_FUNCTION_MAX,
>  };

Other than that, no problem with this change (no ABI impact, no need for
deprecation). Please update testpmd a part of the same patch:

- Wherever "toeplitz" is mentioned in test-pmd/cmdline.c.

- Ditto for flow command, i.e. add ACTION_RSS_FUNC_SYMMETRIC_TOEPLITZ to
  test-pmd/cmdline_flow.c.

- Update "set_hash_global_config" documentation section in
  testpmd_app_ug/testpmd_funcs.rst.

Note to Shahaf/Yongseok, since mlx5 supports both but defaults to symmetric
Toeplitz on vanilla Linux and standard Toeplitz when using OFED, how about
using this chance to make the algorithm configurable as well?

Thanks.

-- 
Adrien Mazarguil
6WIND