RE: [PATCH v7] ethdev: add special flags when creating async transfer table

[Rongwei Liu <rongweil@nvidia.com>]

HI Ferruh:

BR
Rongwei

> -----Original Message-----
> From: Ferruh Yigit <ferruh.yigit@amd.com>
> Sent: Wednesday, January 18, 2023 01:02
> To: Rongwei Liu <rongweil@nvidia.com>; Matan Azrad <matan@nvidia.com>;
> Slava Ovsiienko <viacheslavo@nvidia.com>; Ori Kam <orika@nvidia.com>;
> Aman Singh <aman.deep.singh@intel.com>; Yuying Zhang
> <yuying.zhang@intel.com>; Andrew Rybchenko
> <andrew.rybchenko@oktetlabs.ru>; Ivan Malov <ivan.malov@oktetlabs.ru>;
> NBU-Contact-Thomas Monjalon (EXTERNAL) <thomas@monjalon.net>
> Cc: dev@dpdk.org; Raslan Darawsheh <rasland@nvidia.com>
> Subject: Re: [PATCH v7] ethdev: add special flags when creating async transfer
> table
> 
> External email: Use caution opening links or attachments
> 
> 
> On 1/17/2023 3:13 PM, Ferruh Yigit wrote:
> > On 11/14/2022 11:59 AM, Rongwei Liu wrote:
> >> In case flow rules match only one kind of traffic in a flow table,
> >> then optimization can be done via allocation of this table.
> >> Such optimization is possible only if the application gives a hint
> >> about its usage of the table during initial configuration.
> >>
> >> The transfer domain rules may process traffic from wire or vport,
> >> which may correspond to two kinds of underlayer resources.
> >> That's why the first two hints introduced in this patch are about
> >> wire and vport traffic specialization.
> >> Wire means traffic arrives from the uplink port while vport means
> >> traffic initiated from VF/SF.
> >>
> >> There are two possible approaches for providing the hints.
> >> Using IPv4 as an example:
> >> 1. Use pattern item in both template table and flow rules.
> >>
> >>    pattern_template: pattern ANY_VPORT / eth / ipv4 is 1.1.1.1 / end
> >>    async flow create: pattern ANY_VPORT / eth / ipv4 is 1.1.1.2 / end
> >>
> >>    "ANY_VPORT" needs to be present in each flow rule even if it's
> >>    just a hint. No value to match because matching is already done by
> >>    IPv4 item.
> >>
> >> 2. Add special flags into table_attr.
> >>
> >>    template_table 0 create table_id 0 group 1 transfer vport_orig
> >>
> >> Approach 1 needs to specify the pattern in each flow rule which
> >> wastes memory and is not user friendly.
> >> This patch takes the 2nd approach and introduces one new member
> >> "specialize" into rte_flow_table_attr to indicate possible flow table
> >> optimization.
> >>
> >> By default, there is no hint, so the behavior of the transfer domain
> >> doesn't change.
> >> There is no guarantee that the hint will be used by the PMD.
> >>
> >> Signed-off-by: Rongwei Liu <rongweil@nvidia.com>
> >> Acked-by: Ori Kam <orika@nvidia.com>
> >
> > Hi Andrew, Ivan,
> >
> > Do you have objection/comment to latest version, if not I will proceed
> > with patch?
> >
> 
> BTW, there is an implementation of this flag in some driver, right?
Yes, NVIDIA NIC has an implementation ready.   Will pass the new RTE table attribute to PMD once API accepted.