[v2] net/mlx5: add debug print of LRO minimal size

  Add debug printout showing HCA capability lro_min_mss_size - the
minimal size of TCP segment required for coalescing.
MLX5 PMD documentation is updated to note this condition.

Signed-off-by: Dekel Peled <dekelp@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>
---
 doc/guides/nics/mlx5.rst             | 3 +++
 drivers/common/mlx5/mlx5_devx_cmds.c | 2 ++
 drivers/common/mlx5/mlx5_devx_cmds.h | 1 +
 drivers/net/mlx5/linux/mlx5_os.c     | 3 +++
 4 files changed, 9 insertions(+)
  

Hi,

> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of Dekel Peled
> Sent: Thursday, October 15, 2020 4:37 PM
> To: Slava Ovsiienko <viacheslavo@nvidia.com>; Shahaf Shuler
> <shahafs@nvidia.com>; Matan Azrad <matan@nvidia.com>
> Cc: dev@dpdk.org
> Subject: [dpdk-dev] [PATCH v2] net/mlx5: add debug print of LRO minimal
> size
> 
> Add debug printout showing HCA capability lro_min_mss_size - the
> minimal size of TCP segment required for coalescing.
> MLX5 PMD documentation is updated to note this condition.
> 
> Signed-off-by: Dekel Peled <dekelp@nvidia.com>
> Acked-by: Matan Azrad <matan@nvidia.com>
> ---
>  doc/guides/nics/mlx5.rst             | 3 +++
>  drivers/common/mlx5/mlx5_devx_cmds.c | 2 ++
>  drivers/common/mlx5/mlx5_devx_cmds.h | 1 +
>  drivers/net/mlx5/linux/mlx5_os.c     | 3 +++
>  4 files changed, 9 insertions(+)
> 
> diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst
> index a071db2..f3afb24 100644
> --- a/doc/guides/nics/mlx5.rst
> +++ b/doc/guides/nics/mlx5.rst
> @@ -304,6 +304,9 @@ Limitations
>          eth (with or without vlan) / ipv4 or ipv6 / tcp / payload
> 
>      Other TCP packets (e.g. with MPLS label) received on Rx queue with LRO
> enabled, will be received with bad checksum.
> +  - LRO packet aggregation is performed by HW only for packet size larger
> than
> +    ``lro_min_mss_size``. This value is reported on device start, when debug
> +    mode is enabled.
> 
>  - CRC:
> 
> diff --git a/drivers/common/mlx5/mlx5_devx_cmds.c
> b/drivers/common/mlx5/mlx5_devx_cmds.c
> index fd4e3f2..d3e90b5 100644
> --- a/drivers/common/mlx5/mlx5_devx_cmds.c
> +++ b/drivers/common/mlx5/mlx5_devx_cmds.c
> @@ -819,6 +819,8 @@ struct mlx5_devx_obj *
>  			MLX5_GET(per_protocol_networking_offload_caps,
> hcattr,
>  				 lro_timer_supported_periods[i]);
>  	}
> +	attr->lro_min_mss_size =
> MLX5_GET(per_protocol_networking_offload_caps,
> +					  hcattr, lro_min_mss_size);
>  	attr->tunnel_stateless_geneve_rx =
> 
> MLX5_GET(per_protocol_networking_offload_caps,
>  				     hcattr, tunnel_stateless_geneve_rx);
> diff --git a/drivers/common/mlx5/mlx5_devx_cmds.h
> b/drivers/common/mlx5/mlx5_devx_cmds.h
> index cfa7a7b..c2d089c 100644
> --- a/drivers/common/mlx5/mlx5_devx_cmds.h
> +++ b/drivers/common/mlx5/mlx5_devx_cmds.h
> @@ -85,6 +85,7 @@ struct mlx5_hca_attr {
>  	uint32_t tunnel_lro_vxlan:1;
>  	uint32_t lro_max_msg_sz_mode:2;
>  	uint32_t
> lro_timer_supported_periods[MLX5_LRO_NUM_SUPP_PERIODS];
> +	uint16_t lro_min_mss_size;
>  	uint32_t flex_parser_protocols;
>  	uint32_t hairpin:1;
>  	uint32_t log_max_hairpin_queues:5;
> diff --git a/drivers/net/mlx5/linux/mlx5_os.c
> b/drivers/net/mlx5/linux/mlx5_os.c
> index 09d0944..e0a5a21 100644
> --- a/drivers/net/mlx5/linux/mlx5_os.c
> +++ b/drivers/net/mlx5/linux/mlx5_os.c
> @@ -1071,6 +1071,9 @@
>  				config-
> >hca_attr.lro_timer_supported_periods[0];
>  			DRV_LOG(DEBUG, "LRO session timeout set to %d
> usec",
>  				config->lro.timeout);
> +			DRV_LOG(DEBUG, "LRO minimal size of TCP segment
> "
> +				"required for coalescing is %d bytes",
> +				config->hca_attr.lro_min_mss_size);
>  		}
>  #if defined(HAVE_MLX5DV_DR) &&
> defined(HAVE_MLX5_DR_CREATE_ACTION_FLOW_METER)
>  		if (config->hca_attr.qos.sup &&
> --
> 1.8.3.1

Patch applied to next-net-mlx,

Kindest regards,
Raslan Darawsheh