[dpdk-users] Issue with Pktgen and OVS-DPDK

[Gabriel Ionescu]

Hi,

I am using DPDK-Pktgen with an OVS bridge that has two vHost-user ports and I am seeing an issue where Pktgen does not look like it generates packets correctly.

For this setup I am using DPDK 17.02, Pktgen 3.2.8 and OVS 2.7.0.

The OVS bridge is created with:
ovs-vsctl add-br ovsbr0 -- set bridge ovsbr0 datapath_type=netdev
ovs-vsctl add-port ovsbr0 vhost-user1 -- set Interface vhost-user1 type=dpdkvhostuser ofport_request=1
ovs-vsctl add-port ovsbr0 vhost-user2 -- set Interface vhost-user2 type=dpdkvhostuser ofport_request=2
ovs-ofctl add-flow ovsbr0 in_port=1,action=output:2
ovs-ofctl add-flow ovsbr0 in_port=2,action=output:1

DPDK-Pktgen is launched with the following command so that packets generated through port 0 are received by port 1 and viceversa:
pktgen -c 0xF --file-prefix pktgen --no-pci \
                                --vdev=virtio_user0,path=/tmp/vhost-user1 \
                                --vdev=virtio_user1,path=/tmp/vhost-user2 \
                                -- -P -m "[0:1].0, [2:3].1"

In Pktgen, the default settings are used for both ports:

-          Tx Count: Forever

-          Rate: 100%

-          PktSize: 64

-          Tx Burst: 32

Whenever I start generating packets through one of the ports (in this example port 0 by running start 0), the OVS logs throw warnings similar to:
2017-05-02T09:23:04.741Z|00022|netdev_dpdk(pmd9)|WARN|Dropped 1194956 log messages in last 49 seconds (most recently, 41 seconds ago) due to excessive rate
2017-05-02T09:23:04.741Z|00023|netdev_dpdk(pmd9)|WARN|vhost-user2: Too big size 1524 max_packet_len 1518
2017-05-02T09:23:04.741Z|00024|netdev_dpdk(pmd9)|WARN|vhost-user2: Too big size 1524 max_packet_len 1518
2017-05-02T09:23:04.741Z|00025|netdev_dpdk(pmd9)|WARN|vhost-user2: Too big size 1524 max_packet_len 1518
2017-05-02T09:23:04.741Z|00026|netdev_dpdk(pmd9)|WARN|vhost-user2: Too big size 1524 max_packet_len 1518
2017-05-02T09:23:15.761Z|00027|netdev_dpdk(pmd9)|WARN|Dropped 1344988 log messages in last 11 seconds (most recently, 0 seconds ago) due to excessive rate
2017-05-02T09:23:15.761Z|00028|netdev_dpdk(pmd9)|WARN|vhost-user2: Too big size 57564 max_packet_len 1518
Port 1 does not receive any packets.

When running Pktgen with the -socket-mem option (e.g. --socket-mem 512), the behavior is different, but with the same warnings thrown by OVS: port 1 receives some packages, but with different sizes, even though they are generated on port 0 with a 64b size:
  Flags:Port      :   P--------------:0   P--------------:1
Link State        :       <UP-10000-FD>       <UP-10000-FD>     ----TotalRate----
Pkts/s Max/Rx     :                 0/0             35136/0               35136/0
       Max/Tx     :        238144/25504                 0/0          238144/25504
MBits/s Rx/Tx     :             0/13270                 0/0               0/13270
Broadcast         :                   0                   0
Multicast         :                   0                   0
  64 Bytes        :                   0                 288
  65-127          :                   0                1440
  128-255         :                   0                2880
  256-511         :                   0                6336
  512-1023        :                   0               12096
  1024-1518       :                   0               12096
Runts/Jumbos      :                 0/0                 0/0
Errors Rx/Tx      :                 0/0                 0/0
Total Rx Pkts     :                   0               35136
      Tx Pkts     :             1571584                   0
      Rx MBs      :                   0                 227
      Tx MBs      :              412777                   0
ARP/ICMP Pkts     :                 0/0                 0/0
                  :
Pattern Type      :             abcd...             abcd...
Tx Count/% Rate   :       Forever /100%       Forever /100%
PktSize/Tx Burst  :           64 /   32           64 /   32
Src/Dest Port     :         1234 / 5678         1234 / 5678
Pkt Type:VLAN ID  :     IPv4 / TCP:0001     IPv4 / TCP:0001
Dst  IP Address   :         192.168.1.1         192.168.0.1
Src  IP Address   :      192.168.0.1/24      192.168.1.1/24
Dst MAC Address   :   a6:71:4e:2f:ee:5d   b6:38:dd:34:b2:93
Src MAC Address   :   b6:38:dd:34:b2:93   a6:71:4e:2f:ee:5d
VendID/PCI Addr   :   0000:0000/00:00.0   0000:0000/00:00.0

-- Pktgen Ver: 3.2.8 (DPDK 17.02.0)  Powered by Intel(r) DPDK -------------------

If packets are generated from an external source and testpmd is used to forward traffic between the two vHost-user ports, the warnings are not thrown by the OVS bridge.

Should this setup work?
Is this an issue or am I setting something up wrong?

Thank you,
Gabriel Ionescu