[dpdk-dev] [BUG] net/af_xdp: Current code can only create one af_xdp device

[Ye Xiaolong]

Hi, Markus

On 04/23, Markus Theil wrote:
>Hi Xiaolong,
>
>I tested your commit "net/af_xdp: fix creating multiple instance" on the
>current master branch. It does not work for me in the following minimal
>test setting:
>
>1) allocate 2x 1GB huge pages for DPDK
>
>2) ip link add p1 type veth peer name p2
>
>3) ./dpdk-testpmd --vdev=net_af_xdp0,iface=p1
>--vdev=net_af_xdp1,iface=p2 (I also tested this with two igb devices,
>with the same errors)

I've tested 19.05-rc2, started testpmd with 2 af_xdp vdev (with two i40e devices),
and it works for me.

$ ./x86_64-native-linuxapp-gcc/app/testpmd -l 5,6 -n 4 --log-level=pmd.net.af_xdp:info -b 82:00.1 --no-pci --vdev net_af_xdp0,iface=ens786f1 --vdev net_af_xdp1,iface=ens786f0
EAL: Detected 88 lcore(s)
EAL: Detected 2 NUMA nodes
EAL: Multi-process socket /var/run/dpdk/rte/mp_socket
EAL: Probing VFIO support...
rte_pmd_af_xdp_probe(): Initializing pmd_af_xdp for net_af_xdp0
rte_pmd_af_xdp_probe(): Initializing pmd_af_xdp for net_af_xdp1
testpmd: create a new mbuf pool <mbuf_pool_socket_0>: n=155456, size=2176, socket=0
testpmd: preferred mempool ops selected: ring_mp_mc
Configuring Port 0 (socket 0)
Port 0: 3C:FD:FE:C5:E2:41
Configuring Port 1 (socket 0)
Port 1: 3C:FD:FE:C5:E2:40
Checking link statuses...
Done
No commandline core given, start packet forwarding
io packet forwarding - ports=2 - cores=1 - streams=2 - NUMA support enabled, MP allocation mode: native
Logical Core 6 (socket 0) forwards packets on 2 streams:
  RX P=0/Q=0 (socket 0) -> TX P=1/Q=0 (socket 0) peer=02:00:00:00:00:01
  RX P=1/Q=0 (socket 0) -> TX P=0/Q=0 (socket 0) peer=02:00:00:00:00:00

  io packet forwarding packets/burst=32
  nb forwarding cores=1 - nb forwarding ports=2
  port 0: RX queue number: 1 Tx queue number: 1
    Rx offloads=0x0 Tx offloads=0x0
    RX queue: 0
      RX desc=0 - RX free threshold=0
      RX threshold registers: pthresh=0 hthresh=0  wthresh=0
      RX Offloads=0x0
    TX queue: 0
      TX desc=0 - TX free threshold=0
      TX threshold registers: pthresh=0 hthresh=0  wthresh=0
      TX offloads=0x0 - TX RS bit threshold=0
  port 1: RX queue number: 1 Tx queue number: 1
    Rx offloads=0x0 Tx offloads=0x0
    RX queue: 0
      RX desc=0 - RX free threshold=0
      RX threshold registers: pthresh=0 hthresh=0  wthresh=0
      RX Offloads=0x0
    TX queue: 0
      TX desc=0 - TX free threshold=0
      TX threshold registers: pthresh=0 hthresh=0  wthresh=0
      TX offloads=0x0 - TX RS bit threshold=0
Press enter to exit

Could you paste your whole failure log here?
>
>I'm using Linux 5.1-rc6 and an up to date libbpf. The setup works for
>the first device and fails for the second device when creating bpf maps
>in libbpf ("qidconf_map" or "xsks_map"). It seems, that these maps also
>need unique names and cannot exist twice under the same name.

So far as I know, there should not be such contraint, the bpf maps creations 
are wrapped in libbpf.

>Furthermore if running step 3 again after it failed for the first time,
>xdp vdev allocation already fails for the first xdp vdev and does not
>reach the second one. Please let me know if you need some program output
>or more information from me.
>
>Best regards,
>Markus
>

Thanks,
Xiaolong

>
>On 4/18/19 3:05 AM, Ye Xiaolong wrote:
>> Hi, Markus
>>
>> On 04/17, Markus Theil wrote:
>>> I tested the new af_xdp based device on the current master branch and
>>> noticed, that the usage of static mempool names allows only for the
>>> creation of a single af_xdp vdev. If a second vdev of the same type gets
>>> created, the mempool allocation fails.
>> Thanks for reporting, could you paste the cmdline you used and the error log?
>> Are you referring to ring creation or mempool creation?
>>
>>
>> Thanks,
>> Xiaolong
>>> Best regards,
>>> Markus Theil
>