[dpdk-dev] [PATCH v2] doc: update RSS action with best effort

[Ori Kam]

Hi All,

Can you please review and ack it? so it will be merged in 20.08 version.

Thanks,
Ori

> -----Original Message-----
> From: Ori Kam <orika at mellanox.com>
> 
> Using the rte_flow action RSS types field,
> may result in undefined outcome.
> 
> For example selecting both UDP and TCP,
> selecting TCP RSS type but the pattern is targeting UDP traffic.
> another option is that the PMD doesn't support all requested types.
> 
> Until now, it wasn't clear what will happen in such cases.
> This commit clarify this issue by stating that the PMD
> will work in the best-effort mode.
> 
> Signed-off-by: Ori Kam <orika at mellanox.com>
> ---
> v2:
>  * Based on ML, update that using only unsupported hash type
>    may cause the flow to be rejected by PMD.
> ---
>  doc/guides/prog_guide/rte_flow.rst | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/doc/guides/prog_guide/rte_flow.rst
> b/doc/guides/prog_guide/rte_flow.rst
> index 3e5cd1e..d730b66 100644
> --- a/doc/guides/prog_guide/rte_flow.rst
> +++ b/doc/guides/prog_guide/rte_flow.rst
> @@ -1735,6 +1735,17 @@ unspecified "best-effort" settings from the
> underlying PMD, which depending
>  on the flow rule, may result in anything ranging from empty (single queue)
>  to all-inclusive RSS.
> 
> +Best effort will be used, in case there is a conflict inside the rule.
> +The conflict can be the result of:
> +
> +- Conflicting RSS types, for example setting both UDP and TCP.
> +
> +- Conflicting between RSS types and the requested pattern to match,
> +  for example matching on UDP and hashing RSS on TCP.
> +
> +If requested RSS hash type is not supported,
> +and no supported hash type is requested then the PMD may reject the flow.
> +
>  Note: RSS hash result is stored in the ``hash.rss`` mbuf field which
>  overlaps ``hash.fdir.lo``. Since `Action: MARK`_ sets the ``hash.fdir.hi``
>  field only, both can be requested simultaneously.
> --
> 1.8.3.1