Re: [dpdk-dev] [PATCH] examples/ip_reassembly: enable scatter mode for Mellanox PMDs

[Stephen Hemminger <stephen@networkplumber.org>]

On Mon, 18 Nov 2019 12:18:33 -0600
Thinh Tran <thinhtr@linux.vnet.ibm.com> wrote:

> Simple change to enable scatter for Mellanox CX4/CX5 PMDs
> to run this example
> 
> Signed-off-by: Thinh Tran <thinhtr@linux.vnet.ibm.com>
> ---
>  examples/ip_reassembly/main.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/examples/ip_reassembly/main.c b/examples/ip_reassembly/main.c
> index d59e6d02f..f881b89d1 100644
> --- a/examples/ip_reassembly/main.c
> +++ b/examples/ip_reassembly/main.c
> @@ -1109,6 +1109,9 @@ main(int argc, char **argv)
>  				port_conf.rx_adv_conf.rss_conf.rss_hf,
>  				local_port_conf.rx_adv_conf.rss_conf.rss_hf);
>  		}
> +		/* Mellanox PMDs needs scatter mode to be explicitly enabled */
> +		if (!strcmp(dev_info.driver_name, "net_mlx5")) 
> +			local_port_conf.rxmode.offloads |= DEV_RX_OFFLOAD_SCATTER;

This is a bad, bad precedent.
Either fix MLX driver or enable it for all PMD's.

Forcing applications to do workarounds indicates a poor design abstraction.