Re: [dpdk-dev] [PATCH v1] net/mlx4: report on supported RSS hash functions

[Shahaf Shuler <shahafs@mellanox.com>]

Hi Ophir,

Tuesday, May 8, 2018 6:43 PM, Ophir Munk:
> Subject: [PATCH v1] net/mlx4: report on supported RSS hash functions
> 
> Report on mlx4 supported RSS functions as part of dev_infos_get callback.
> Previous to this commit RSS support was reported as none. Since the
> introduction of [1] it is required that all RSS configurations will be verified.
> 
> [1] commit 8863a1fbfc66 ("ethdev: add supported hash function check")
> 
> Signed-off-by: Ophir Munk <ophirmu@mellanox.com>
> ---
>  drivers/net/mlx4/mlx4_ethdev.c | 51
> ++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 51 insertions(+)
> 
> diff --git a/drivers/net/mlx4/mlx4_ethdev.c
> b/drivers/net/mlx4/mlx4_ethdev.c index 9a76670..2a1533c 100644
> --- a/drivers/net/mlx4/mlx4_ethdev.c
> +++ b/drivers/net/mlx4/mlx4_ethdev.c
> @@ -545,6 +545,55 @@ mlx4_mac_addr_set(struct rte_eth_dev *dev, struct
> ether_addr *mac_addr)  }
> 
>  /**
> + * Convert verbs RSS types to their DPDK equivalents.
> + *
> + * This function returns a group of RSS dpdk types given their
> +equivalent group
> + * of verbs types.
> + * For example both source IPv4 and destination IPv4 verbs types are
> +converted
> + * into their equivalent RSS group types. If each of these verbs types
> +existed
> + * exclusively - no conversion would take place.
> + *
> + * @param types
> + *   RSS hash types in verbs format
> + *
> + * @return
> + *   A valid dpdk RSS hash fields supported by mlx4 (may return 0)
> + */
> +static uint64_t
> +mlx4_ibv_to_dpdk_rss_types(uint64_t types) {
> +	enum { IPV4, IPV6, TCP, UDP, };
> +	const uint64_t in[] = {
> +		[IPV4] = IBV_RX_HASH_SRC_IPV4 |
> IBV_RX_HASH_DST_IPV4,
> +		[IPV6] = IBV_RX_HASH_SRC_IPV6 |
> IBV_RX_HASH_DST_IPV6,
> +		[TCP] = IBV_RX_HASH_SRC_PORT_TCP |
> IBV_RX_HASH_DST_PORT_TCP,
> +		[UDP] = IBV_RX_HASH_SRC_PORT_UDP |
> IBV_RX_HASH_DST_PORT_UDP,
> +	};
> +	const uint64_t out[RTE_DIM(in)] = {
> +		[IPV4] = (ETH_RSS_IPV4 |
> +			  ETH_RSS_FRAG_IPV4 |
> +			  ETH_RSS_NONFRAG_IPV4_OTHER),
> +		[IPV6] = (ETH_RSS_IPV6 |
> +			  ETH_RSS_FRAG_IPV6 |
> +			  ETH_RSS_NONFRAG_IPV6_OTHER |
> +			  ETH_RSS_IPV6_EX),
> +		[TCP] = (ETH_RSS_NONFRAG_IPV4_TCP |
> +			 ETH_RSS_NONFRAG_IPV6_TCP |
> +			 ETH_RSS_IPV6_TCP_EX),
> +		[UDP] = (ETH_RSS_NONFRAG_IPV4_UDP |
> +			 ETH_RSS_NONFRAG_IPV6_UDP |
> +			 ETH_RSS_IPV6_UDP_EX),
> +	};

Since above are constants, why not defining a global array of structs containing the ibv_hash and the equivalent dpdk_hash, instead of recreating it for each call? 
There is a similar concept on mlx5_flow.c:

/* Initialization data for hash RX queues. */              
 const struct hash_rxq_init hash_rxq_init[] = {             
         [HASH_RXQ_TCPV4] = {                               
                 .hash_fields = (IBV_RX_HASH_SRC_IPV4 |     
                                 IBV_RX_HASH_DST_IPV4 |     
                                 IBV_RX_HASH_SRC_PORT_TCP | 
                                 IBV_RX_HASH_DST_PORT_TCP), 
                 .dpdk_rss_hf = ETH_RSS_NONFRAG_IPV4_TCP,   
                 .flow_priority = 0,                        
                 .ip_version = MLX5_IPV4,                   
         },                                                 

> +	uint64_t conv = 0;
> +	unsigned int i;
> +
> +	for (i = 0; i != RTE_DIM(in); ++i)
> +		if ((types & in[i]) == in[i])
> +			conv |= out[i];
> +	return conv;
> +}
> +
> +/**
>   * DPDK callback to get information about the device.
>   *
>   * @param dev
> @@ -587,6 +636,8 @@ mlx4_dev_infos_get(struct rte_eth_dev *dev, struct
> rte_eth_dev_info *info)
>  			ETH_LINK_SPEED_20G |
>  			ETH_LINK_SPEED_40G |
>  			ETH_LINK_SPEED_56G;
> +	info->flow_type_rss_offloads = mlx4_ibv_to_dpdk_rss_types(
> +			priv->hw_rss_sup);
>  }
> 
>  /**
> --
> 2.7.4