Re: [dpdk-dev] [PATCH v5] app/testpmd: fix setting maximum packet length

[Lance Richardson <lance.richardson@broadcom.com>]

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Acked-by: Lance Richardson <lance.richardson@broadcom.com>

Thanks,
    Lance

On Mon, Jan 25, 2021 at 7:44 PM Ferruh Yigit <ferruh.yigit@intel.com> wrote:
>
> On 1/25/2021 7:41 PM, Lance Richardson wrote:
> > On Mon, Jan 25, 2021 at 1:15 PM Ferruh Yigit <ferruh.yigit@intel.com> wrote:
> >>
> >> From: Steve Yang <stevex.yang@intel.com>
> >>
> >> "port config all max-pkt-len" command fails because it doesn't set the
> >> 'DEV_RX_OFFLOAD_JUMBO_FRAME' offload flag properly.
> >>
> >> Commit in the fixes line moved the 'DEV_RX_OFFLOAD_JUMBO_FRAME' offload
> >> flag update from 'cmd_config_max_pkt_len_parsed()' to 'init_config()'.
> >> 'init_config()' function is only called during testpmd startup, but the
> >> flag status needs to be calculated whenever 'max_rx_pkt_len' changes.
> >>
> >> The issue can be reproduce as [1], where the 'max-pkt-len' reduced and
> >> 'DEV_RX_OFFLOAD_JUMBO_FRAME' offload flag should be cleared but it
> >> didn't.
> >>
> >> Adding the 'update_jumbo_frame_offload()' helper function to update
> >> 'DEV_RX_OFFLOAD_JUMBO_FRAME' offload flag and 'max_rx_pkt_len'. This
> >> function is called both by 'init_config()' and
> >> 'cmd_config_max_pkt_len_parsed()'.
> >>
> >> Default 'max-pkt-len' value set to zero, 'update_jumbo_frame_offload()'
> >> updates it to "RTE_ETHER_MTU + PMD specific Ethernet overhead" when it
> >> is zero.
> >> If '--max-pkt-len=N' argument provided, it will be used instead.
> >> And with each "port config all max-pkt-len" command, the
> >> 'DEV_RX_OFFLOAD_JUMBO_FRAME' offload flag, 'max-pkt-len' and MTU is
> >> updated.
> >>
> >> [1]
> >
> > <snip>
> >
> >> +/*
> >> + * Helper function to arrange max_rx_pktlen value and JUMBO_FRAME offload,
> >> + * MTU is also aligned if JUMBO_FRAME offload is not set.
> >> + *
> >> + * port->dev_info should be get before calling this function.
> >
> > Should this be "port->dev_info should be set ..." instead?
> >
>
> Ack.
>
> >
> > <snip>
> >
> >> +       if (rx_offloads != port->dev_conf.rxmode.offloads) {
> >> +               uint16_t qid;
> >> +
> >> +               port->dev_conf.rxmode.offloads = rx_offloads;
> >> +
> >> +               /* Apply JUMBO_FRAME offload configuration to Rx queue(s) */
> >> +               for (qid = 0; qid < port->dev_info.nb_rx_queues; qid++) {
> >> +                       if (on)
> >> +                               port->rx_conf[qid].offloads |= DEV_RX_OFFLOAD_JUMBO_FRAME;
> >> +                       else
> >> +                               port->rx_conf[qid].offloads &= ~DEV_RX_OFFLOAD_JUMBO_FRAME;
> >> +               }
> >
> > Is it correct to set per-queue offloads that aren't advertised by the PMD
> > as supported in rx_queue_offload_capa?
> >
>
> 'port->rx_conf[]' is testpmd struct, and 'port->dev_conf.rxmode.offloads' values
> are reflected to 'port->rx_conf[].offloads' for all queues.
>
> We should set the offload in 'port->rx_conf[].offloads' if it is set in
> 'port->dev_conf.rxmode.offloads'.
>
> If a port has capability for 'JUMBO_FRAME', 'port->rx_conf[].offloads' can have
> it. And the port level capability is already checked above.
>
> >> +       }
> >> +
> >> +       /* If JUMBO_FRAME is set MTU conversion done by ethdev layer,
> >> +        * if unset do it here
> >> +        */
> >> +       if ((rx_offloads & DEV_RX_OFFLOAD_JUMBO_FRAME) == 0) {
> >> +               ret = rte_eth_dev_set_mtu(portid,
> >> +                               port->dev_conf.rxmode.max_rx_pkt_len - eth_overhead);
> >> +               if (ret)
> >> +                       printf("Failed to set MTU to %u for port %u\n",
> >> +                               port->dev_conf.rxmode.max_rx_pkt_len - eth_overhead,
> >> +                               portid);
> >> +       }
> >> +
> >> +       return 0;
> >> +}
> >> +
> >
> > Applied and tested with a few iterations of configuring max packet size
> > back and forth between jumbo and non-jumbo sizes, also tried setting
> > max packet size using the command-line option, all seems good based
> > on rx offloads and packet forwarding.
> >
> > Two minor questions above, otherwise LGTM.
> >
>
> Thanks for testing. I will wait for more comments before new version.