On 8/6/19 11:47 AM, Pavan Nikhilesh Bhagavatula wrote:
-----Original Message-----
From: Hemant Agrawal <hemant.agra...@nxp.com>
Sent: Tuesday, August 6, 2019 1:49 PM
To: Pavan Nikhilesh Bhagavatula <pbhagavat...@marvell.com>; Jerin
Jacob Kollanukkaran <jer...@marvell.com>
Cc: dev@dpdk.org
Subject: RE: [dpdk-dev] [RFC 0/3] ethdev: add ptype as Rx offload
Add PTYPE to DEV_RX_OFFLOAD_* flags.
Currently, most of the NICs already support PTYPE parsing and update
the
mbuf->packet_type through an internal lookup table, but there is no
way to
disable the lookup if the application is not intrested in ptypes
returned by
`rte_eth_dev_get_supported_ptypes`.
[Hemant] it will also mean introducing another check in datapath, if the
application has asked for PTYPE offload - copy the results to mbuf-
packet_type otherwise don't do it.
I think that having the check would give better performance than loading ptype
table to L1
doing a lookup and copying it to mbuf when the application doesn't need it.
Anyway, if PMD decides that it is better to always provide packet type
information - there is no harm. Basically if the offload is not requested
it makes packet_type undefined in mbuf.
Your second patch is incomplete in the sense that it only adds the
capability. But it does not disable the lookups?
It is upto the maintainer of the PMD to disable the lookup in data path. If
there is a scope of optimization
then they could do it. There is no harm in exposing PTYPE even
RX_OFFLOAD_PTYPE is not enabled.
I was hesitant to touch data path as it would be impossible to verify
performance effect on all NICs.
I think it is the right way to approach it especially taking transition
into account.
