Re: [dpdk-dev] [PATCH v2 1/5] net/mlx5: support flow count action handle

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 4/30/2021 10:01 AM, Slava Ovsiienko wrote:
> Hi, Ferruh
> 
>> -----Original Message-----
>> From: Ferruh Yigit <ferruh.yigit@intel.com>
>> Sent: Friday, April 30, 2021 11:35
>> To: Slava Ovsiienko <viacheslavo@nvidia.com>; dev@dpdk.org; Andrew
>> Rybchenko <andrew.rybchenko@oktetlabs.ru>
>> Cc: Raslan Darawsheh <rasland@nvidia.com>; Matan Azrad
>> <matan@nvidia.com>; Michael Baum <michaelba@nvidia.com>; NBU-
>> Contact-Thomas Monjalon <thomas@monjalon.net>
>> Subject: Re: [PATCH v2 1/5] net/mlx5: support flow count action handle
>>
>> On 4/29/2021 10:55 AM, Viacheslav Ovsiienko wrote:
>>> From: Michael Baum <michaelba@nvidia.com>
>>>
>>> Existing API supports counter action to count traffic of a single flow.
>>> The user can share the count action among different flows using the
>>> shared flag and the same counter ID in the count action configuration.
>>>
>>> Recent patch [1] introduced the indirect action API.
>>> Using this API, an action can be created as indirect, unattached to
>>> any flow rule.
>>> Multiple flows can then be created using the same indirect action.
>>> The new API also supports query operation of an indirect action.
>>>
>>> The new API is more efficient because the driver gets it's own handler
>>> for the count action instead of managing a mapping between the user ID
>>> to the driver handle.
>>>
>>> Support create, query and destroy indirect action operations for flow
>>> count action.
>>>
>>> Application will use the indirect action query operation to query this
>>> count action.
>>>
>>> In the meantime the old sharing mechanism (with the sharing flag)
>>> continues to be supported, and the user can choose the way he wants to
>>> share the counter.
>>> The new indirect action API is only supported in DevX, so sharing
>>> counter action in Verbs can only be done through the old mechanism.
>>>
>>
>> There is already a deprecation note to remove the 'shared' flag from counter
>> action [2] in favor of 'shared actions'.
>>
>> Shared action become "indirect actions" [3] which this patch implements
>>
>> Is it a good time to remove the old sharing mechanism from driver since
>> touching on it?
> 
> As I can see:
> - it is planned to 21.11 as deprecation note says

Yes, deprecation is for 21.11, but I though it might be easier for you to remove
it now while it is under rework, but I can see you prefer to keep it.

> - now there Is no support for new "indirect actions" with Verbs (not sure
>  we will provide), so shared counters API might be still useful
> - our CI did not migrate to the new counter approach yet (even DPDK patch is not merged yet 😊)
> - hence, l would prefer keep shared counter support (by id and flag) in 21.05 
>  (and very likely in 21.08), just to maintain maximal backward compatibility as long
> as possible
> 

OK

> With best regards,
> Slava
> 
>>
>>
>> [2]
>> https://git.dpdk.org/dpdk/tree/doc/guides/rel_notes/deprecation.rst?h=v2
>> 1.05-rc1#n95
>>
>> [3]
>> https://git.dpdk.org/dpdk/commit/?h=v21.05-rc1&id=4b61b8774be9
>>
>>
>>> [1] https://mails.dpdk.org/archives/dev/2020-July/174110.html
>>>
>>> Signed-off-by: Michael Baum <michaelba@nvidia.com>
>>> Acked-by: Matan Azrad <matan@nvidia.com>
>>
>> <...>