[dpdk-dev] Questions Questions about hash function enum

[Ferruh Yigit]

On 6/1/2020 2:31 AM, oulijun wrote:
> Hi Ferruh Yigit and others
> 
>     I am learning data structure defined by dpdk framework and I noticed 
> a data structure definition below:
> 
> 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 */
>      /**
>       * Symmetric Toeplitz: src, dst will be replaced by
>       * xor(src, dst). For the case with src/dst only,
>       * src or dst address will xor with zero pair.
>       */
>      RTE_ETH_HASH_FUNCTION_SYMMETRIC_TOEPLITZ,
>      RTE_ETH_HASH_FUNCTION_MAX,
> };
> 
> I have a little difficulty understanding that for the comment:
> 
>     /**
>       * Symmetric Toeplitz: src, dst will be replaced by
>       * xor(src, dst). For the case with src/dst only,
>       * src or dst address will xor with zero pair.
>       */
> 
> if user configure rss func for symmetric toeplitz, Rss type must be 
> updated at the same time?
> 
> if user configure rss func for xor, rss type must be empty and the queue 
> number is zero?
> 
> Must it be restricted like this? If so, what is his benefit?
> 
> Looking forward to your reply

cc'ed Qi & Andrew

As far as I understand that comment is only describing the Symmetric Toeplitz
behavior. I don't see any rss type or queue number limitation.