Re: [dpdk-dev] [PATCH v2 3/3] ethdev: improve flow mark Rx offload deprecation notice

[Andrew Rybchenko <arybchenko@solarflare.com>]

On 11/22/19 1:01 AM, Thomas Monjalon wrote:
> 19/11/2019 13:12, Andrew Rybchenko:
>> The deprecation notice is required since it adds more requirements
>> when RTE flow mark and flag actions may be used and require
>> changes in applications.
> I am still not sure what is the best solution here.
> I continued to think about it in this thread:
> 	http://mails.dpdk.org/archives/dev/2019-November/151960.html
>
> I think we cannot require any application change until 20.11
> in order to keep API (and behaviour) compatibility.

Expected, but still very disappointing.

The feature is implemented by Pavan (@ Marvell), supported by me,
used by Qi (@ Intel), looks better than alternatives from application
developer point of view [1] and finally postponed for 1 year without really
strong motivation. I disagree that it is tightly related to moving
mark/flag to
dynamic field/flag and absolutely blocked by it. Yes, I know that the are
concerns from the very beginning, but the problem is explained [2] and clear
and no full-featured alternative solution is suggested. Solution suggested
by Ori has many significant drawbacks as explained in [2] and highlighted
in further discussion.

[1] http://inbox.dpdk.org/dev/1573203631946.15959@kth.se/
[2]
http://inbox.dpdk.org/dev/f170105b-9c60-1b04-cb18-52e0951ddcdb@solarflare.com/

> If something would be implemented in 20.02,
> it must be a new and optional API.

Flow mark and flag may work without the offload with some drivers,
but some drivers require the offload to make it work. Flow API error
should contain message which says that the offload is disabled and
must be enabled.

> That's why I think no deprecation notice is required.
>
> [...]
>> +* ethdev: New offload flag ``DEV_RX_OFFLOAD_FLOW_MARK`` will be added in 20.02.
>> +  This will provide application an information if ``RTE_FLOW_ACTION_TYPE_MARK``
>> +  or ``RTE_FLOW_ACTION_TYPE_FLAG`` is supported and, what is more important,
>> +  allow an application to let PMD know that it would like to use these
>> +  features.
>> +  PMD may use the information to choose optimal datapath implementation and
>> +  configure HW appropriately to optimize performance and/or resources usage.