[RFC] ethdev: sharing indirect actions between ports

[Andrew Rybchenko]

On 1/18/23 19:37, Slava Ovsiienko wrote:
> 
> 
>> -----Original Message-----
>> From: Thomas Monjalon <thomas at monjalon.net>
>> Sent: Wednesday, January 18, 2023 6:22 PM
>> To: Slava Ovsiienko <viacheslavo at nvidia.com>; Ori Kam
>> <orika at nvidia.com>
>> Cc: dev at dpdk.org; Matan Azrad <matan at nvidia.com>; Raslan Darawsheh
>> <rasland at nvidia.com>; andrew.rybchenko at oktetlabs.ru;
>> ivan.malov at oktetlabs.ru; ferruh.yigit at amd.com
>> Subject: Re: [RFC] ethdev: sharing indirect actions between ports
>>
>> 18/01/2023 16:17, Ori Kam:
>>> From: Thomas Monjalon <thomas at 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.

Maybe 'owner_port_id' or 'rsrc_port_id' ?