[dpdk-dev] i40e: cannot change mtu to enable jumbo frame

[Julien Meunier]

On 02/09/2016 08:05 PM, Zhu, Heqing wrote:
> Helin is still in Chinese New Year Vacation. Will the below command option help ?
>
> 4.5.9. port config - max-pkt-len
> Set the maximum packet length:
>
> testpmd> port config all max-pkt-len (value)
> This is equivalent to the --max-pkt-len command-line option.
>
>
> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Julien Meunier
> Sent: Tuesday, February 9, 2016 9:36 AM
> To: Zhang, Helin <helin.zhang at intel.com>; dev at dpdk.org
> Subject: [dpdk-dev] i40e: cannot change mtu to enable jumbo frame
>
> Hello Helin,
>
> I tried to send jumbo frames to a i40e card. However, I observed that all frames are dropped. Moreover, set_mtu function is not implemented on i40e PMD.
>
>   > testpmd --log-level 8 --huge-dir=/mnt/huge -n 4 -l 2,18 --socket-mem
> 1024,1024 -w 0000:02:00.0 -w 0000:02:00.2 -- -i --nb-cores=1
> --nb-ports=2 --total-num-mbufs=65536
>
> =============
> Configuration
> =============
>
> +-----------+          +-------------+
> |           |          |             |
> | tgen      |          |             |
> |           +----------+ port 0      |
> |           |          |             |
> |           |          |             |
> |           |          |             |
> |           |          |             |
> |           +----------+ port 1      |
> |           |          |             |
> +-----------+          +-------------+
>
> DPDK: DPDK-v2.2
>
> ==========
> MTU = 1500
> ==========
> Packet sent from a tgen
>   > p = Ether / IP / UDP / Raw(MTU + HDR(Ethernet)- HDR(IP) - HDR(UDP))  > len(p) = 1514
>
> testpmd> start
> PMD: i40e_rxd_to_vlan_tci(): Mbuf vlan_tci: 0, vlan_tci_outer: 0
> testpmd> stop
> Telling cores to stop...
> Waiting for lcores to finish...
> PMD: i40e_update_vsi_stats(): *** VSI[13] stats start ***
> PMD: i40e_update_vsi_stats(): rx_bytes:            1518
> PMD: i40e_update_vsi_stats(): rx_unicast:          1
> PMD: i40e_update_vsi_stats(): *** VSI[13] stats end ***
> PMD: i40e_dev_stats_get(): *** PF stats start ***
> PMD: i40e_dev_stats_get(): rx_bytes:            1514
> PMD: i40e_dev_stats_get(): rx_unicast:          1
> PMD: i40e_dev_stats_get(): rx_unknown_protocol: 1
> PMD: i40e_dev_stats_get(): rx_size_1522:             1
> PMD: i40e_dev_stats_get(): *** PF stats end ***
>
>     -------------- Forward statistics for port 0  --------------
>     RX-packets: 1              RX-dropped: 0             RX-total: 1
>     TX-packets: 0              TX-dropped: 0             TX-total: 0
>
> ----------------------------------------------------------------------------
> PMD: i40e_update_vsi_stats(): *** VSI[14] stats start ***
> PMD: i40e_update_vsi_stats(): tx_bytes:            1514
> PMD: i40e_update_vsi_stats(): tx_unicast:          1
> PMD: i40e_update_vsi_stats(): *** VSI[14] stats end ***
> PMD: i40e_dev_stats_get(): *** PF stats start ***
> PMD: i40e_dev_stats_get(): tx_bytes:            1514
> PMD: i40e_dev_stats_get(): tx_unicast:          1
> PMD: i40e_dev_stats_get(): tx_size_1522:             1
> PMD: i40e_dev_stats_get(): *** PF stats end ***
>
>     -------------- Forward statistics for port 1 --------------
>     RX-packets: 0              RX-dropped: 0             RX-total: 0
>     TX-packets: 1              TX-dropped: 0             TX-total: 1
>
> ----------------------------------------------------------------------------
>
>     +++++ Accumulated forward statistics for all ports+++++
>     RX-packets: 1              RX-dropped: 0             RX-total: 1
>     TX-packets: 1              TX-dropped: 0             TX-total: 1
>
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>
> => OK
>
> ==========
> MTU = 1600
> ==========
> Packet sent
>   > p = Ether / IP / UDP / Raw(MTU + HDR(Ethernet)- HDR(IP) - HDR(UDP))  > len(p) = 1614
>
> testpmd> port config mtu 0 1600
> rte_eth_dev_set_mtu: Function not supported Set MTU failed. diag=-95
> testpmd> port config mtu 1 1600
> rte_eth_dev_set_mtu: Function not supported Set MTU failed. diag=-95
> testpmd> start
> testpmd> stop
> Telling cores to stop...
> Waiting for lcores to finish...
> PMD: i40e_update_vsi_stats(): *** VSI[13] stats start ***
> PMD: i40e_update_vsi_stats(): rx_bytes:            1618
> PMD: i40e_update_vsi_stats(): rx_unicast:          1
> PMD: i40e_update_vsi_stats(): *** VSI[13] stats end ***
> PMD: i40e_dev_stats_get(): *** PF stats start ***
> PMD: i40e_dev_stats_get(): rx_bytes:            1614
> PMD: i40e_dev_stats_get(): rx_unicast:          1
> PMD: i40e_dev_stats_get(): rx_unknown_protocol: 1
> PMD: i40e_dev_stats_get(): rx_size_big:              1
> PMD: i40e_dev_stats_get(): *** PF stats end ***
>
>     -------------- Forward statistics for port 0  --------------
>     RX-packets: 1              RX-dropped: 0             RX-total: 1
>     TX-packets: 0              TX-dropped: 0             TX-total: 0
>
> ----------------------------------------------------------------------------
> PMD: i40e_update_vsi_stats(): *** VSI[14] stats start ***
> PMD: i40e_update_vsi_stats(): tx_bytes:            0
> PMD: i40e_update_vsi_stats(): tx_unicast:          0
> PMD: i40e_update_vsi_stats(): *** VSI[14] stats end ***
> PMD: i40e_dev_stats_get(): *** PF stats start ***
> PMD: i40e_dev_stats_get(): tx_bytes:            0
> PMD: i40e_dev_stats_get(): tx_unicast:          0
> PMD: i40e_dev_stats_get(): tx_size_big:              0
> PMD: i40e_dev_stats_get(): *** PF stats end ***
>
>     -------------- Forward statistics for port 1  --------------
>     RX-packets: 0              RX-dropped: 0             RX-total: 0
>     TX-packets: 0              TX-dropped: 0             TX-total: 0
>
> ----------------------------------------------------------------------------
>
>     +++++ Accumulated forward statistics for all ports+++++
>     RX-packets: 1              RX-dropped: 0             RX-total: 1
>     TX-packets: 0              TX-dropped: 0             TX-total: 0
>
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>
> Done.
>
> => Frame correctly received on port 0, but never forwarded or xmit on port 1.
>
> Does a mtu_set function will be developed soon in order to support jumbo frame ?
>
> Regards,
>
> --
> Julien MEUNIER
> 6WIND
>

On testpmd, this command enables jumbo frame, you are right.

However, all ports need to be stopped: jumbo frame cannot be enabled at 
runtime through the DPDK API on i40e PMD. Other Intel PMD, like ixgbe, 
support this feature with the set_mtu API. Why not on i40e ?

Regards,

-- 
Julien MEUNIER
6WIND