> -----Original Message-----
> From: Ferruh Yigit <ferruh.yi...@intel.com>
> Sent: Wednesday, August 11, 2021 5:01 PM
> To: Rohit Raj <rohit....@nxp.com>
> Cc: dev@dpdk.org; Nipun Gupta <nipun.gu...@nxp.com>; Hemant Agrawal
> <hemant.agra...@nxp.com>; Sachin Saxena <sachin.sax...@nxp.com>;
> Vanshika Shukla <vanshika.shu...@nxp.com>
> Subject: Re: [dpdk-dev] [PATCH v1] examples/l3fwd: fix jumbo packet drop
> issue
>
> On 7/27/2021 10:25 AM, rohit....@nxp.com wrote:
> > From: Rohit Raj <rohit....@nxp.com>
> >
> > l3fwd uses mbufs with 2KB data size. If we enable jumbo packets, it is
> > not able to store packets with size greater than 2KB, hence these
> > packets are dropped.
> >
> > This patch fixes this issue by enabling scatter for jumbo packet, if
> > it is supported by NIC.
> >
> > If scatter is not supported by NIC and max jumbo packet length is
> > greater than default mbuf data size, then application exits with
> > proper error message.
> >
> > Fixes: f68aad7904f ("examples/l3fwd: update")
> >
> > Signed-off-by: Rohit Raj <rohit....@nxp.com>
> > Signed-off-by: Sachin Saxena <sachin.sax...@nxp.com>
> > Signed-off-by: Vanshika Shukla <vanshika.shu...@nxp.com>
> > ---
> > examples/l3fwd/main.c | 14 ++++++++++++++
> > 1 file changed, 14 insertions(+)
> >
> > diff --git a/examples/l3fwd/main.c b/examples/l3fwd/main.c index
> > 4cb800aa15..6aaaa8ecb5 100644
> > --- a/examples/l3fwd/main.c
> > +++ b/examples/l3fwd/main.c
> > @@ -1035,6 +1035,20 @@ l3fwd_poll_resource_setup(void)
> > "Error during getting device (port %u) info:
> > %s\n",
> > portid, strerror(-ret));
> >
> > + /* Enable Receive side SCATTER, if supported by NIC,
> > + * when jumbo packet is enabled.
> > + */
> > + if (local_port_conf.rxmode.offloads &
> > + DEV_RX_OFFLOAD_JUMBO_FRAME){
> > + if (dev_info.rx_offload_capa & DEV_RX_OFFLOAD_SCATTER)
> > + local_port_conf.rxmode.offloads |=
> > + DEV_RX_OFFLOAD_SCATTER;
> > + else if (local_port_conf.rxmode.max_rx_pkt_len >
> > + RTE_MBUF_DEFAULT_DATAROOM)
> > + rte_exit(EXIT_FAILURE,
> > + "Max packet length greater than
> > + default MBUF size\n");
>
> This is a configuration set by application. So application is failing itself
> because
> of configuration it sets, seems odd.
>
> I guess the jumbo frame can be enabled when user provides '--enable-jumbo'
> argument. What do you think adding above check where that argument is
> parsed.
We need to check if hardware supports Rx scatter. To do this, we need to get Rx
capability. Hence, this is a better place to perform this check.
>
> Btw, no need to enable scattered Rx if the packets fits into buffer, so above
> check can be done slightly different:
>
> if (max_rx_pkt_len > buffer_size)
> if (OFFLOAD_SCATTER supported)
> enable OFFLOAD_SCATTER
> else
> fail
Agreed. I will do this in next version of the patch.
>
>
> > + }
> > +
> > if (dev_info.tx_offload_capa & DEV_TX_OFFLOAD_MBUF_FAST_FREE)
> > local_port_conf.txmode.offloads |=
> > DEV_TX_OFFLOAD_MBUF_FAST_FREE;
> >
