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

Ananyev, Konstantin konstantin.ananyev at intel.com
Wed Feb 10 14:54:13 CET 2016


> 
> 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 ?


Yes, as I know mtu-set is not implemented on i40e and some other devices ...
Patches are welcome, I suppose :)
Though note that even with ixgbe you can't set new mtu if it is bigger then
related mempool's buffer size and scattered_rx is not enabled.
And to enable scattered_rx, you'll need to stop and re-configure device anyway. 
Konstantin

> 
> Regards,
> 
> --
> Julien MEUNIER
> 6WIND


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