Re: [dpdk-dev] [EXT] Re: [RFC 1/3] ethdev: add ptype as an Rx offload

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

>-----Original Message-----
>From: Andrew Rybchenko <arybchenko@solarflare.com>
>Sent: Tuesday, August 6, 2019 2:30 PM
>To: Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>; Jerin
>Jacob Kollanukkaran <jerinj@marvell.com>; John McNamara
><john.mcnamara@intel.com>; Marko Kovacevic
><marko.kovacevic@intel.com>; Thomas Monjalon
><thomas@monjalon.net>; Ferruh Yigit <ferruh.yigit@intel.com>
>Cc: dev@dpdk.org
>Subject: [EXT] Re: [dpdk-dev] [RFC 1/3] ethdev: add ptype as an Rx
>offload
>
>External Email
>
>----------------------------------------------------------------------
>On 8/6/19 11:02 AM, pbhagavatula@marvell.com wrote:
>> From: Pavan Nikhilesh <pbhagavatula@marvell.com>
>>
>> Add ptype to DEV_RX_OFFLOAD_* flags which can be used to
>enable/disable
>> packet type parsing.
>>
>> Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
>
>I like the idea. I think there are few more Rx features which
>lack Rx offload bit:
>  - delivery of RSS hash in mbuf (it is not always required when
>    RSS is used to distribute packets across Rx queues)

Especially when applications use custom hash functions to store flows.

>  - maybe Rx mark, since it is an extra information which could
>    be passed by NIC to CPU and it is better to know in advance
>    at Rx queue setup if it should be requested and processed

Are you referring to RTE_FLOW_ACTION_TYPE_MARK?

>
>API breakage should be considered here. I think it is OK to
>introduce it in the next release cycle in a dummy way which
>does not affect packet type delivery for existing PMDs
>(i.e. add offload capability and advertise in PMD, but do not
>take it into account when Rx mbuf is filled in) and
>submit deprecation notice that it may be taken into account
>by PMDs in 20.02 to avoid packet type delivery if the offload
>is not requested. It will allow applications to make transition
>smoother.

Couldn’t agree with you more. I could extend the current RFC to include 
RSS and RX mark as we would be modifying the same offload fields across 
all drivers. Easier for PMD maintainers too.

>
>Acked-by: Andrew Rybchenko <arybchenko@solarflare.com>