Re: [dpdk-dev] [PATCH v2 13/15] net/mlx5: setup RSS flow regardless of queue count

["Nélio Laranjeiro" <nelio.laranjeiro@6wind.com>]

On Tue, Apr 10, 2018 at 09:34:13PM +0800, Xueming Li wrote:
> In some environments it is desirable to have the NIC perform RSS
> normally on the packet regardless of the number of queues configured.
> The RSS hash result that is stored in the mbuf can then be used by
> the application to make decisions about how to distribute workloads
> to threads, secondary processes, or even virtual machines if the
> application is a virtual switch.
>
> Signed-off-by: Xueming Li <xuemingl@mellanox.com>
> ---
>  drivers/net/mlx5/mlx5_flow.c | 71 +++++++++++++++++++-------------------------
>  1 file changed, 30 insertions(+), 41 deletions(-)
> 
> diff --git a/drivers/net/mlx5/mlx5_flow.c b/drivers/net/mlx5/mlx5_flow.c
> index 5784f2ee0..9efe00086 100644
> --- a/drivers/net/mlx5/mlx5_flow.c
> +++ b/drivers/net/mlx5/mlx5_flow.c
> @@ -1252,48 +1252,37 @@ mlx5_flow_convert_rss(struct rte_eth_dev *dev, struct mlx5_flow_parse *parser)
>  			parser->queue[i].ibv_attr = NULL;
>  		}
>  	}
> -	if (parser->rss_conf.types) {
> -		/* Remove impossible flow according to the RSS configuration. */
> -		for (i = hmin; i != (hmax + 1); ++i) {
> -			if (!parser->queue[i].ibv_attr)
> -				continue;
> -			if (parser->rss_conf.types &
> -			    hash_rxq_init[i].dpdk_rss_hf) {
> -				parser->queue[i].hash_fields =
> -					hash_rxq_init[i].hash_fields;
> -				found = 1;
> -				continue;
> -			}
> -			/* L4 flow could be used for L3 RSS. */
> -			if (i == parser->layer && i < ip &&
> -			    (hash_rxq_init[ip].dpdk_rss_hf &
> -			     parser->rss_conf.types)) {
> -				parser->queue[i].hash_fields =
> -					hash_rxq_init[ip].hash_fields;
> -				found = 1;
> -				continue;
> -			}
> -			/* L3 flow and L4 hash: non-rss L3 flow. */
> -			if (i == parser->layer && i == ip && found)
> -				/* IP pattern and L4 HF. */
> -				continue;
> -			rte_free(parser->queue[i].ibv_attr);
> -			parser->queue[i].ibv_attr = NULL;
> +	/* Remove impossible flow according to the RSS configuration. */
> +	for (i = hmin; i != (hmax + 1); ++i) {
> +		if (!parser->queue[i].ibv_attr)
> +			continue;
> +		if (parser->rss_conf.types &
> +		    hash_rxq_init[i].dpdk_rss_hf) {
> +			parser->queue[i].hash_fields =
> +				hash_rxq_init[i].hash_fields;
> +			found = 1;
> +			continue;
>  		}
> -		if (!found)
> -			DRV_LOG(WARNING,
> -				"port %u rss hash function doesn't match "
> -				"pattern", dev->data->port_id);
> -	} else {
> -		/* Remove any other flow. */
> -		for (i = hmin; i != (hmax + 1); ++i) {
> -			if (i == parser->layer || !parser->queue[i].ibv_attr)
> -				continue;
> -			rte_free(parser->queue[i].ibv_attr);
> -			parser->queue[i].ibv_attr = NULL;
> +		/* L4 flow could be used for L3 RSS. */
> +		if (i == parser->layer && i < ip &&
> +		    (hash_rxq_init[ip].dpdk_rss_hf &
> +		     parser->rss_conf.types)) {
> +			parser->queue[i].hash_fields =
> +				hash_rxq_init[ip].hash_fields;
> +			found = 1;
> +			continue;
>  		}
> -		parser->rss_conf.queue_num = 1;
> +		/* L3 flow and L4 hash: non-rss L3 flow. */
> +		if (i == parser->layer && i == ip && found)
> +			/* IP pattern and L4 HF. */
> +			continue;
> +		rte_free(parser->queue[i].ibv_attr);
> +		parser->queue[i].ibv_attr = NULL;
>  	}
> +	if (!found)
> +		DRV_LOG(WARNING,
> +			"port %u rss hash function doesn't match "
> +			"pattern", dev->data->port_id);
>  	return 0;
>  }
>  
> @@ -2326,8 +2315,8 @@ mlx5_flow_dump(struct rte_eth_dev *dev __rte_unused,
>  		(void *)flow->frxq[i].hrxq->ind_table,
>  		flow->frxq[i].hash_fields |
>  		(flow->tunnel &&
> -		 flow->rss_conf.rss_level ? (uint32_t)IBV_RX_HASH_INNER : 0),
> -		flow->queues_n,
> +		 flow->rss_conf.level ? (uint32_t)IBV_RX_HASH_INNER : 0),
> +		flow->rss_conf.queue_num,
>  		flow->frxq[i].ibv_attr->num_of_specs,
>  		flow->frxq[i].ibv_attr->size,
>  		flow->frxq[i].ibv_attr->priority,
> -- 
> 2.13.3

Seems, this code should make part of
"[PATCH v2 07/15] net/mlx5: support tunnel RSS level", as it re-works
the code added there, in addition this feature is already present in
tree for non tunnel packets.

Any reason why it is not merged in the previous commit?

Thanks,

-- 
Nélio Laranjeiro
6WIND