Hi, Jerin
> -----Original Message-----
> From: Jerin Jacob <jerinjac...@gmail.com>
> Sent: Thursday, October 15, 2020 13:28
> To: Slava Ovsiienko <viachesl...@nvidia.com>
> Cc: dpdk-dev <dev@dpdk.org>; NBU-Contact-Thomas Monjalon
> <tho...@monjalon.net>; Stephen Hemminger
> <step...@networkplumber.org>; Ferruh Yigit <ferruh.yi...@intel.com>;
> Olivier Matz <olivier.m...@6wind.com>; Maxime Coquelin
> <maxime.coque...@redhat.com>; David Marchand
> <david.march...@redhat.com>; Andrew Rybchenko
> <arybche...@solarflare.com>
> Subject: Re: [PATCH v6 1/6] ethdev: introduce Rx buffer split
>
[..snip..]
>
> struct rte_eth_rxseg {
> enum rte_eth_rxseg_mode mode ;
> union {
> struct rte_eth_rxseg_mode xxx {
> struct rte_mempool *mp; /**< Memory pool to
> allocate
> segment from. */
> uint16_t length; /**< Segment data length,
> configures split
> point. */
> uint16_t offset; /**< Data offset from
> beginning of mbuf data
> buffer. */
> uint32_t reserved; /**< Reserved field. */
> }
> }
There is an array of rte_eth_rxseg. It would introduce multiple "enum
rte_eth_rxseg_mode mode"
and would cause some ambiguity. About mode selection - please, see below.
Union seems to be good idea, let's adopt.
>
> Another mode, Marvell PMD has it(I believe Intel also) i.e When we say:
>
> seg0 - pool0, len0=2000B, off0=0
> seg1 - pool1, len1=2001B, off1=0
>
> packet size up to, 2000B goes to pool 0 and if is >=2001 goes to pool1.
> I think, it is better to have mode param in rte_eth_rxseg for avoiding ABI
> changes.(Just like clean rte_flow APIs)
It is supposed to choose with RTE_ETH_RX_OFFLOAD_xxx flags.
For packet sorting it should be something like this RTE_ETH_RX_OFFLOAD_SORT.
PMD reports it supports the feature, the flag is set in rx_conf->offloads
and rxseg structure is interpreted according to these flags.
Please, note, there is intentionally no check for RTE_ETH_RX_OFFLOAD_xxx
in rte_eth_dev_rx_queue_setup() - it should be done on PMD side.
>
> > > If we see some of the features of such kind or other PMDs adopts the
> > > split feature - we'll try to find the common root and consider the way how
> to report it.
> >
> > My only concern with that approach will be ABI break again if
> > something needs to exposed over rte_eth_dev_info().
Let's reserve the pointer to struct rte_eth_rxseg_limitations
in the rte_eth_dev_info to avoid ABI break?
With best regards, Slava
