257. Virtio_user as an exceptional path test plan¶

This test plan will test exceptional path with virtio_user and measure throughput by iperf.

257.1. Prerequisites¶

257.2. Test Case1:test exceptional path with virtio_user¶

Flow:tap0–>vhost-net–>virtio_user–>nic0–>nic1: tap0<–vhost-net<–virtio_user<–nic0<–nic1

Connect two nic port directly, put nic1 into another namesapce:

ip netns del ns1
ip netns add ns1
ip link set [enp216s0f0] netns ns1       # [enp216s0f0] is the name of nic1
ip netns exec ns1 ifconfig [enp216s0f0] 1.1.1.8 up

Modprobe vhost-net and make sure it’s under /dev folder:
```
modprobe vhost-net
```

Bind nic0 to vfio-pci and launch the virtio_user with testpmd:

./dpdk-devbind.py -b vfio-pci xx:xx.x        # xx:xx.x is the pci addr of nic0
./<build_target>/app/dpdk-testpmd -c 0xc0000 -n 4 --file-prefix=test2 \
--vdev=virtio_user0,mac=00:01:02:03:04:05,path=/dev/vhost-net,queue_size=1024 -- -i --rxd=1024 --txd=1024
testpmd>set fwd csum
testpmd>csum mac-swap off 0
testpmd>csum mac-swap off 1
testpmd>stop
testpmd>port stop 0
testpmd>port stop 1
testpmd>port config 0 tx_offload tcp_cksum on
testpmd>port config 0 tx_offload ipv4_cksum on
testpmd>csum set tcp hw 0
testpmd>csum set ip hw 0
testpmd>csum set ip sw 1
testpmd>csum set tcp hw 1
testpmd>set port 0 gso on
testpmd>tso set 1448 0
testpmd>port start 0
testpmd>port start 1
testpmd>start

Check if there is a tap device generated and set the ip for tap0 device:
```
ls /sys/class/net/tap0
ifconfig tap0 1.1.1.2 up
```

Set sw ipv4_csum for virtio_user by setting testpmd cmd:

testpmd>stop
testpmd>port stop 1
testpmd>csum set ip sw 1
testpmd>port start 1
testpmd>start

Run iperf server at host and iperf client at ns1 namespace, get the performance from nic in kernel to the tap0:
```
iperf -s -i 1
ip netns exec ns1 iperf -c 1.1.1.2 -i 1 -t 60
```
Change iperf server and client, run iperf server at ns1 namespace and iperf client at host, get the performance from tap0 to the nic in kernel:
```
ip netns exec ns1 iperf -s -i 1
iperf -c 1.1.1.8 -i 1 -t 60
```

257.3. Test Case2:test vhost-net/virtio_user single queue performance¶

Flow: tap0<–>vhost-net<–>virtio_user<–>nic0<–>TG

Disable ufw, otherwise virio-user can’t received packets back from tap0:
```
ufw disable
```

Bind the physical port to vfio-pci, launch testpmd with one queue for virtio_user:

./dpdk-devbind.py -b vfio-pci xx:xx.x        # xx:xx.x is the pci addr of nic0
./<build_target>/app/dpdk-testpmd -l 1-2 -n 4  --file-prefix=test2 --vdev=virtio_user0,mac=00:01:02:03:04:05,path=/dev/vhost-net,queue_size=1024,queues=1 -- -i --rxd=1024 --txd=1024

Check if there is a tap device generated:

ls /sys/class/net/tap0
ifconfig tap0 up

Set route table to let tap0 forward packets back to virtio-user port:

ifconfig tap0 2.2.2.2/24 up
route add -net 2.2.2.0/24 gw 2.2.2.1 dev tap0
arp -s 2.2.2.1 68:01:02:03:04:05

Send 64 bytes traffic to the physical nic with dest mac= tap0’s mac address, dest ip=2.2.2.x(except 2.2.2.2).
Bind vhost-net kthread with logical core: firstly check process by “ps -ef|grep vhost”, check vhost-net kthread by “ps -T xxxx”, then bind the pid to the core at the same socket as the nic port by taskset.
Try different line rate with ixia to find a point that rx_throughput=tx_throughput, for example if using ninatic 10G nic, the balance line rate is about 2.5.

257.4. Test Case3: test vhost-net/virtio_user multiple queue¶

Flow: tap0<–>vhost-net<–>virtio_user<–>nic0<–>TG

1.Disable ufw, otherwise virtio-user can’t received packets back from tap0:

ufw disable

Bind the physical port to vfio-pci, launch testpmd with two queues for virtio_user:

./dpdk-devbind.py -b vfio-pci xx:xx.x        # xx:xx.x is the pci addr of nic0
./<build_target>/app/dpdk-testpmd -l 1-2 -n 4  --file-prefix=test2 --vdev=virtio_user0,mac=00:01:02:03:04:05,path=/dev/vhost-net,queue_size=1024,queues=2 -- -i --rxd=1024 --txd=1024 --txq=2 --rxq=2 --nb-cores=1

Check if there is a tap device generated:

ls /sys/class/net/tap0
ifconfig tap0 up

Set route table to let tap0 forward packets back to virtio-user port:

ifconfig tap0 2.2.2.2/24 up
route add -net 2.2.2.0/24 gw 2.2.2.1 dev tap0
arp -s 2.2.2.1 68:01:02:03:04:05

Send 64 bytes multi-ips traffic to the physical nic with dest mac= tap0’s mac address, dest ip=2.2.2.x(except 2.2.2.2).
Bind vhost-net kthread with logical core: firstly check process by “ps -ef|grep vhost”, check vhost-net kthread by “ps -T xxxx”, for multiple queues, there are multiple vhost kthreads, then bind the pids to different logical cores at the same socket as the nic port by taskset.
Try different line rate with ixia to find a point that rx_throughput=tx_throughput, for example if using ninatic 10G nic, the balance line rate is about 5 (should be double of case 2).