Re: [PATCH] net/intel: deprecate some SSE paths

[Bruce Richardson <bruce.richardson@intel.com>]

On Thu, Jul 03, 2025 at 12:16:24PM +0000, Ciara Loftus wrote:
> The SSE rx and tx paths will be removed from the i40e, iavf and ice
> drivers in the 25.11 release. Each of these drivers have faster vector
> paths (AVX2 and AVX-512) which have feature parity with the soon to be
> removed SSE paths. In environments where AVX2 or AVX-512 are not
> supported, the scalar path will still be used, which also has feature
> parity.
> 
> Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
> ---
>  doc/guides/rel_notes/deprecation.rst | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
> index e2d4125308..7b9b6beaa5 100644
> --- a/doc/guides/rel_notes/deprecation.rst
> +++ b/doc/guides/rel_notes/deprecation.rst
> @@ -80,6 +80,11 @@ Deprecation Notices
>    and the header struct ``rte_vxlan_gpe_hdr`` with the macro ``RTE_ETHER_VXLAN_GPE_HLEN``
>    will be removed in DPDK 25.11.
>  
> +* net/intel: drivers that have an SSE vector path alongside other vector paths, namely
> +  i40e, iavf and ice, will have their SSE vector paths removed in DPDK 25.11. This change
> +  will not result in any feature loss, as the fallback scalar paths which have feature
> +  parity with SSE will be used in the cases where the SSE paths would have been used.
> +

Hi Ciara,

I think it would be good to mention AVX in the deprecation notice as well
as in the commit log, since it's not as though we are removing the SSE to
have all apps drop down to scalar. Instead, it's being deprecated because
modern x86 systems all support AVX2, if not AXV-512, so SSE code path
should be unnecessary in new deployments.

/Bruce

>  * ethdev: The flow API matching pattern structures, ``struct rte_flow_item_*``,
>    should start with relevant protocol header structure from lib/net/.
>    The individual protocol header fields and the protocol header struct
> -- 
> 2.34.1
>