Re: [dpdk-dev] [patch v4] doc: announce API change in ethdev offload flags

[Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>]

Hi,

>-----Original Message-----
>From: Ananyev, Konstantin <konstantin.ananyev@intel.com>
>Sent: Friday, August 9, 2019 2:17 PM
>To: Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>; Jerin
>Jacob Kollanukkaran <jerinj@marvell.com>;
>stephen@networkplumber.org; arybchenko@solarflare.com;
>hemant.agrawal@nxp.com; thomas@monjalon.net; Yigit, Ferruh
><ferruh.yigit@intel.com>; Richardson, Bruce
><bruce.richardson@intel.com>; Neil Horman
><nhorman@tuxdriver.com>; Mcnamara, John
><john.mcnamara@intel.com>; Kovacevic, Marko
><marko.kovacevic@intel.com>
>Cc: dev@dpdk.org
>Subject: RE: [dpdk-dev] [patch v4] doc: announce API change in
>ethdev offload flags
>Hi
>
>>
>> From: Pavan Nikhilesh <pbhagavatula@marvell.com>
>>
>> Add new offload flags ``DEV_RX_OFFLOAD_RSS`` and
>``DEV_RX_OFFLOAD_FLOW_MARK``.
>> Add new function ``rte_eth_dev_set_supported_ptypes`` to allow
>application to
>> set specific ptypes to be updated in ``rte_mbuf::packet_type``
>>
>> Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
>> Acked-by: Andrew Rybchenko <arybchenko@solarflare.com>
>> Acked-by: Jerin Jacob <jerinj@marvell.com>
>> Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>
>> ---
>>  doc/guides/rel_notes/deprecation.rst | 23
>+++++++++++++++++++++++
>>  1 file changed, 23 insertions(+)
>>
>> diff --git a/doc/guides/rel_notes/deprecation.rst
>b/doc/guides/rel_notes/deprecation.rst
>> index 37b8592b6..e4e2a85d7 100644
>> --- a/doc/guides/rel_notes/deprecation.rst
>> +++ b/doc/guides/rel_notes/deprecation.rst
>> @@ -78,3 +78,26 @@ Deprecation Notices
>>    to set new power environment if power environment was already
>initialized.
>>    In this case the function will return -1 unless the environment is
>unset first
>>    (using ``rte_power_unset_env``). Other function usage scenarios
>will not change.
>> +
>> +* ethdev: New offload flags ``DEV_RX_OFFLOAD_RSS_HASH`` and
>``DEV_RX_OFFLOAD_FLOW_MARK``
>> +  will be added in 19.11.
>> +  This will allow application to enable or disable PMDs from updating
>> +  ``rte_mbuf::hash::rss`` and ``rte_mbuf::hash::fdir`` respectively.
>> +  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 fields even when the offloads are
>not
>> +  enabled.
>> +
>> +* ethdev: New function ``rte_eth_dev_set_supported_ptypes`` will
>be added in
>> +  19.11.
>
>As I said in my previous mail, I do support the idea, though few nits
>below.
>
>> +  This will allow application to request PMD to set specific ptypes
>defined
>> +  through ``rte_eth_dev_set_supported_ptypes`` in
>``rte_mbuf::packet_type``.
>> +  If application doesn't want any ptype information it can call
>> +  ``rte_eth_dev_set_supported_ptypes(ethdev_id,
>RTE_PTYPE_UNKNOWN)``
>
>Probably worth to mention that in that case packet_type will be set to 0
>(PMD still need to set the value).

Ack, will update in v5.

>
>> +  If application doesn't call ``rte_eth_dev_set_supported_ptypes``
>PMD can
>> +  return ``rte_mbuf::packet_type`` with
>``rte_eth_dev_get_supported_ptypes``.
>> +  If application is interested only in L2/L3 layer, it can inform the PMD
>to update
>> + ``rte_mbuf::packet_type`` with L2/L3 ptype by calling
>> + ``rte_eth_dev_set_supported_ptypes(ethdev_id,
>RTE_PTYPE_L2_MASK | RTE_PTYPE_L3_MASK)``.
>> +  This scheme will allow PMDs to avoid writes to ``rte_mbuf`` fields
>on Rx and
>
>As I understand, PMD will still need to write ptype value.
>Though it will help PMD to avoid figuring out ptype values, when user
>don't need that information.

I will reword to ``will allow PMDs to avoid lookup to internal ptype table``.

>
>> +  thereby improve Rx performance if application wishes do so.
>> --
>> 2.17.1

Thanks,
Pavan.