Re: [dpdk-dev] [PATCH 1/3] ethdev: add RSS hash level

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

Hi Ajit,

> This patch adds ability to configure RSS hash level in hardware.
> This feature will allow an application to select RSS hash calculation
> on outer or inner headers for tunneled packets.
> 
> Signed-off-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
> ---
>  lib/librte_ethdev/rte_ethdev.h | 27 +++++++++++++++++++++++++++
>  1 file changed, 27 insertions(+)
> 
> diff --git a/lib/librte_ethdev/rte_ethdev.h b/lib/librte_ethdev/rte_ethdev.h
> index 18a9defc2..5189bdbab 100644
> --- a/lib/librte_ethdev/rte_ethdev.h
> +++ b/lib/librte_ethdev/rte_ethdev.h
> @@ -444,11 +444,35 @@ struct rte_vlan_filter_conf {
>   * The *rss_hf* field of the *rss_conf* structure indicates the different
>   * types of IPv4/IPv6 packets to which the RSS hashing must be applied.
>   * Supplying an *rss_hf* equal to zero disables the RSS feature.
> + *
> + * The *rss_level* field of the *rss_conf* structure indicates the
> + * Packet encapsulation level RSS hash @p types apply to.
> + *
> + * - @p 0 requests the default behavior. Depending on the packet
> + *   type, it can mean outermost, innermost, anything in between or
> + *   even no RSS.
> + *
> + *   It basically stands for the innermost encapsulation level RSS
> + *   can be performed on according to PMD and device capabilities.
> + *
> + * - @p 1 requests RSS to be performed on the outermost packet
> + *   encapsulation level.
> + *
> + * - @p 2 and subsequent values request RSS to be performed on the
> + *   specified inner packet encapsulation level, from outermost to
> + *   innermost (lower to higher values).

If it is just to add ability to do rss over inner header, then do we really need
all this concept of 'levels'?
Might be just:

#define DEV_RX_OFFLOAD_RSS_HASH		0x00080000
+#define DEV_RX_OFFLOAD_RSS_HASH_INNER	0x00100000 

and uint8_t in rte_eth_rss_conf (between key_len and rss_hf) to indicate
inner/outer?

> + *
> + * Support for values other than @p 0 is dependent on the underlying
> + * hardware in use.
> + *
> + * Requesting a specific RSS level on unrecognized traffic results
> + * in undefined behavior.
>   */
>  struct rte_eth_rss_conf {
>  	uint8_t *rss_key;    /**< If not NULL, 40-byte hash key. */
>  	uint8_t rss_key_len; /**< hash key length in bytes. */
>  	uint64_t rss_hf;     /**< Hash functions to apply - see below. */
> +	uint32_t rss_level;  /**< RSS hash level */
>  };
> 
>  /*
> @@ -599,6 +623,8 @@ rte_eth_rss_hf_refine(uint64_t rss_hf)
>  	ETH_RSS_GENEVE | \
>  	ETH_RSS_NVGRE)
> 
> +#define ETH_RSS_LEVEL_DEFAULT	0
> +
>  /*
>   * Definitions used for redirection table entry size.
>   * Some RSS RETA sizes may not be supported by some drivers, check the
> @@ -1103,6 +1129,7 @@ struct rte_eth_conf {
>  #define DEV_RX_OFFLOAD_SCTP_CKSUM	0x00020000
>  #define DEV_RX_OFFLOAD_OUTER_UDP_CKSUM  0x00040000
>  #define DEV_RX_OFFLOAD_RSS_HASH		0x00080000
> +#define DEV_RX_OFFLOAD_RSS_LEVEL	0x00100000
> 
>  #define DEV_RX_OFFLOAD_CHECKSUM (DEV_RX_OFFLOAD_IPV4_CKSUM | \
>  				 DEV_RX_OFFLOAD_UDP_CKSUM | \
> --
> 2.21.0 (Apple Git-122.2)