Re: [dpdk-dev] [PATCH v8] net/iavf: support flex desc metadata extraction

[Olivier Matz <olivier.matz@6wind.com>]

Hi,

On Wed, Oct 14, 2020 at 01:31:39PM +0100, Ferruh Yigit wrote:
> On 10/13/2020 9:17 AM, Jeff Guo wrote:
> > Enable metadata extraction for flexible descriptors in AVF, that would
> > allow network function directly get metadata without additional parsing
> > which would reduce the CPU cost for VFs. The enabling metadata
> > extractions involve the metadata of VLAN/IPv4/IPv6/IPv6-FLOW/TCP/MPLS
> > flexible descriptors, and the VF could negotiate the capability of
> > the flexible descriptor with PF and correspondingly configure the
> > specific offload at receiving queues.
> > 
> > Signed-off-by: Jeff Guo <jia.guo@intel.com>
> > Acked-by: Haiyue Wang <haiyue.wang@intel.com>

[...]

> > +EXPERIMENTAL {
> > +        global:
> > +
> > +        # added in 20.11
> > +        rte_net_iavf_dynfield_proto_xtr_metadata_offs;
> > +        rte_net_iavf_dynflag_proto_xtr_vlan_mask;
> > +        rte_net_iavf_dynflag_proto_xtr_ipv4_mask;
> > +        rte_net_iavf_dynflag_proto_xtr_ipv6_mask;
> > +        rte_net_iavf_dynflag_proto_xtr_ipv6_flow_mask;
> > +        rte_net_iavf_dynflag_proto_xtr_tcp_mask;
> > +        rte_net_iavf_dynflag_proto_xtr_ip_offset_mask;
> 
> As a namespace previously "rte_pmd_xxx" was used for PMD specific APIs, can
> you please switch to that?
> 'rte_net_' is used by the 'librte_net' library.
> 
> Above list is the dynfield values, what is the correct usage for dynfields,
> 1- Put dynfileds names in to the header, and application does a lookup
> ('rte_mbuf_dynfield_lookup()') to get the dynfield values.
> or
> 2- Expose dynfield values to be accessed directly from application, as done above.
> 
> @Oliver, can you please support.
> 
> I can see (1) has advantage of portability if more than one PMD supports
> same dynfield names, but that sees not a case for above ones.

If I understand the question correctly, this is the same that was
discussed here:

  http://inbox.dpdk.org/dev/20191030165626.w3flq5wdpitpsv2v@platinum/

To me, exporting the variables containing the dynfield offsets is easier
to use: we don't need to have additional private variables to store them
in each API users (usually one static variable per file, which can be
heavy).

Olivier