How to use --vdev Options for ./dpdk-l3fwd?

[Stephen Hemminger]

On Tue, 11 Apr 2023 12:51:54 -0400
Dinesh Kumar <raidinesh at utexas.edu> wrote:

> Hi Stephen ,
> 
> Thanks for your suggestions.I am able to resolve --vdev error  however I am
> having another issue related to buffer.
> .*/dpdk-l3fwd -c f -n 4 --vdev=net_tap3 -- -p 0x3
> --config="(0,0,1),(0,1,2)"*
> EAL: Detected CPU lcores: 8
> EAL: Detected NUMA nodes: 1
> EAL: Detected static linkage of DPDK
> EAL: Multi-process socket /var/run/dpdk/rte/mp_socket
> EAL: Selected IOVA mode 'PA'
> EAL: No available 1048576 kB hugepages reported
> EAL: VFIO support initialized
> EAL: Probe PCI driver: net_virtio (1af4:1000) device: 0000:00:03.0 (socket
> 0)
> eth_virtio_pci_init(): Failed to init PCI device
> EAL: Requested device 0000:00:03.0 cannot be used
> EAL: Probe PCI driver: net_iavf (8086:154c) device: 0000:00:05.0 (socket 0)
> EAL: Probe PCI driver: net_iavf (8086:154c) device: 0000:00:06.0 (socket 0)
> TELEMETRY: No legacy callbacks, legacy socket not created
> Neither LPM, EM, or FIB selected, defaulting to LPM
> Initializing port 0 ... Creating queues: nb_rxq=2 nb_txq=4... Port 0
> modified RSS hash function based on hardware support,requested:0xa38c
> configured:0x238c
> 
> 
> 
> *iavf_dev_init_vlan(): Failed to update vlan offloadiavf_dev_configure():
> configure VLAN failed: -95EAL: Error - exiting with code: 1  Cause: Cannot
> init mbuf pool on socket 0*
> 
> Do I need to update any parameters?
> Do I need to add a routing rule parameter?
> Any help /pointers will be really appreciated.
> FYI. I just want to testL3  forwarding via DPDK using the Tap interface The
> flow is :
> On Vm1 .*/dpdk-l3fwd will create a Tap interface and then I will link this
> interface with a network namespace and then ping a destination address via
> the DPDK application running on VM1 and get captured on DPDK application
> running on another VM2 and I am stuck with creation Tap interface on VM1
> via *  .
> */dpdk-l3fwd.*
> Regards,
> Dinesh Kumar
> 
> 
> 
> On Mon, Apr 10, 2023 at 7:08 PM Stephen Hemminger <
> stephen at networkplumber.org> wrote:  
> 
> > On Mon, 10 Apr 2023 18:47:59 -0400
> > Dinesh Kumar <raidinesh at utexas.edu> wrote:
> >  
> > > Hi There,
> > > I am new to the DPDK example and having issue with using  --vdev options
> > > for DPDK example and it is throwing the below error.
> > >
> > > ./dpdk-l3fwd --log-level *:debug -c f -n 4 -- -p 0x3 --vdev
> > > 'net_pcap0,rx_pcap=input.pcap,tx_pcap=output.pcap'
> > >
> > > -----------------------
> > > iavf_check_api_version(): Peer is supported PF host
> > > iavf_read_msg_from_pf(): Can't read msg from AQ
> > > iavf_read_msg_from_pf(): AQ from pf carries opcode 3, retval 0
> > > iavf_dev_alarm_handler(): ICR01_ADMINQ is reported
> > > iavf_handle_pf_event_msg(): VIRTCHNL_EVENT_LINK_CHANGE event
> > > iavf_handle_virtchnl_msg(): adminq response is received, opcode = 26
> > > EAL: lib.telemetry log level changed from disabled to debug
> > > TELEMETRY: Attempting socket bind to path
> > > '/var/run/dpdk/rte/dpdk_telemetry.v2'
> > > TELEMETRY: Socket creation and binding ok
> > > TELEMETRY: Telemetry initialized ok
> > > TELEMETRY: No legacy callbacks, legacy socket not created
> > > *./dpdk-l3fwd: unrecognized option '--vdev'*
> > > ./dpdk-l3fwd [EAL options] -- -p PORTMASK [-P] [--lookup] --config
> > > (port,queue,lcore)[,(port,queue,lcore)] [--rx-queue-size NPKTS]
> > > [--tx-queue-size NPKTS] [--eth-dest=X,MM:MM:MM:MM:MM:MM] [--max-pkt-len
> > > PKTLEN] [--no-numa] [--hash-entry-num] [--ipv6] [--parse-ptype]
> > > [--per-port-pool] [--mode] [--eventq-sched] [--event-vector
> > > [--event-vector-size SIZE] [--event-vector-tmo NS]] [-E] [-L]
> > >
> > > please let me know if I am missing some options that need to be added  
> > with  
> > > --vdev  
> >
> >
> > DPDK options are split into the options for the DPDK infrastructure (EAL)
> > and those
> > used by the applications. They are separated by the -- option.
> >
> > In your example, the vdev option belongs to the DPDK infrastructure not
> > the application.
> > Put it it before the -- and it should work
> >  

I think you are assuming that the DPDK tap device is for using an
existing tap device. That is not correct.
The DPDK tap interface makes a tap device for its use.