RE: [RFC] ethdev: sharing indirect actions between ports

[Slava Ovsiienko <viacheslavo@nvidia.com>]

> -----Original Message-----
> From: Thomas Monjalon <thomas@monjalon.net>
> Sent: Wednesday, January 18, 2023 6:22 PM
> To: Slava Ovsiienko <viacheslavo@nvidia.com>; Ori Kam
> <orika@nvidia.com>
> Cc: dev@dpdk.org; Matan Azrad <matan@nvidia.com>; Raslan Darawsheh
> <rasland@nvidia.com>; andrew.rybchenko@oktetlabs.ru;
> ivan.malov@oktetlabs.ru; ferruh.yigit@amd.com
> Subject: Re: [RFC] ethdev: sharing indirect actions between ports
> 
> 18/01/2023 16:17, Ori Kam:
> > From: Thomas Monjalon <thomas@monjalon.net>
> > > 28/12/2022 17:54, Viacheslav Ovsiienko:
> > > > The RTE Flow API implements the concept of shared objects, known
> > > > as indirect actions (RTE_FLOW_ACTION_TYPE_INDIRECT).
> > > > An application can create the indirect action of desired type and
> > > > configuration with rte_flow_action_handle_create call and then
> > > > specify the obtained action handle in multiple flows.
> > > >
> > > > The initial concept supposes the action handle has strict
> > > > attachment to the port it was created on and to be used
> > > > exclusively in the flows being installed on the port.
> > > >
> > > > Nowadays the multipath network topologies are quite common,
> > > > packets belonging to the same connection might arrive and be sent
> > > > over multiple ports, and there is the raising demand to handle
> > > > these "spread" connections. To fulfil this demand it is proposed
> > > > to extend indirect action sharing across the multiple ports. This
> > > > kind of sharing would be extremely useful for the meters and
> > > > counters, allowing to manage the single connection over the
> > > > multiple ports.
> > > >
> > > > This cross-port object sharing is hard to implement in generic way
> > > > merely with software on the upper layers, but can be provided by
> > > > the driver over the single hardware instance, where  multiple
> > > > ports reside on the same physical NIC and share the same hardware
> > > > context.
> > > >
> > > > To allow this action sharing application should specify the "host
> > > > port" during flow configuring to claim the intention to share the
> > > > indirect actions. All indirect actions reside within "host port"
> > > > context and can be shared in flows being installed
> > >
> > > I don't like the word "host" because it may refer to the host CPU.
> > > Also if I understand well, the application must choose one port
> > > between all ports of the NIC and keep using the same.
> > > I guess we don't want to create a NIC id.
> > > So I would suggest to rename to nic_ref_port or something like that.
> > >
> >
> > I think that host is the correct word since this port hosts all
> > resources for other ports. (this is also why the host is used in case
> > of CPU 😊)
> > I don't think it is correct to use bad wording due to the fact that
> > some one else also uses this word.
> > in rte_flow we never talk about host CPU so I don't think this is confusing.
> 
> The confusion is that we can think of a port on the host.

In my humble opinion, "_port_id" suffix explicitly specifies what field is and does not leave
too much space for confusion.

"root_port_id"? "base_port_id"?  "container_port_id" ? "mgmnt_port_id" ?
 Looks worse as for me and does not reflect the exact meaning.
As Ori mentioned this is DPDK port ID that embraces all the shared actions.
It plays a host role for them.

With best regards, Slava

> 
>