Re: [dpdk-dev] [PATCH] doc: cleanup flow mark Rx offload deprecation notice

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

On 11/2/2021 2:09 PM, Andrew Rybchenko wrote:
> On 11/2/21 4:47 PM, Ferruh Yigit wrote:
>> On 11/2/2021 12:50 PM, Andrew Rybchenko wrote:
>>> The problem is solved using Rx metadata delivery negotiation API [1].
>>>
>>
>> Can this API replace RX_OFFLOAD_RSS_HASH too?
> 
> It can, but it should not. RSS hash is an offload since it is a
> calculation of the hash in HW and delivery of the result to SW.
> Like checksums: check in HW and delivery of the result to SW.
> 

There is a slight difference, RSS hash is always calculated if RSS is enabled,
independent from RSS offload enabled or not.

That is why some PMDs always provides RSS hash and force enables this offload,
I would be happy to get rid of this quirk if possible.

>>
>>> [1] commit f6d8a6d3fad7 ("ethdev: negotiate delivery of packet metadata from HW to PMD")
>>>
>>> Signed-off-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
>>> ---
>>>   doc/guides/rel_notes/deprecation.rst | 8 --------
>>>   1 file changed, 8 deletions(-)
>>>
>>> diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
>>> index 4366015b01..ec5073908f 100644
>>> --- a/doc/guides/rel_notes/deprecation.rst
>>> +++ b/doc/guides/rel_notes/deprecation.rst
>>> @@ -69,14 +69,6 @@ Deprecation Notices
>>>     and the related structures (``rte_fdir_*`` and ``rte_eth_fdir_*``),
>>>     will be removed in DPDK 20.11.
>>> -* ethdev: New offload flags ``RTE_ETH_RX_OFFLOAD_FLOW_MARK`` will be added in 19.11.
>>> -  This will allow application to enable or disable PMDs from updating
>>> -  ``rte_mbuf::hash::fdir``.
>>> -  This scheme will allow PMDs to avoid writes to ``rte_mbuf`` fields on Rx and
>>> -  thereby improve Rx performance if application wishes do so.
>>> -  In 19.11 PMDs will still update the field even when the offload is not
>>> -  enabled.
>>> -
>>>   * ethdev: Announce moving from dedicated modify function for each field,
>>>     to using the general ``rte_flow_modify_field`` action.
>>>
>