82. Link Status Detection Tests

This tests for Detect Link Status feature can be run on linux userspace. It is to check if the userspace interrupt can be received after plugging in/out the cable/fiber on specified NIC port, and if the link status can be updated correctly. Furthermore, it would be better to check if packets can be received and sent on a specified port after its link has just up. So it may need layer 2 forwarding at the same time.

For layer 2 forwarding, a packet received on a RX port (RX_PORT), it would be transmitted from a TX port (TX_PORT=RX_PORT+1) if RX_PORT is even; otherwise from a TX port (TX_PORT=RX_PORT-1) if RX_PORT is odd. Before being transmitted, the source mac address of the packet would be replaced by the mac address of the TX port, while the destination mac address would be replaced by 00:09:c0:00:00:TX_PORT_ID. The test application should be run with the wanted paired ports configured using the coremask parameter via the command line. i.e. port 0 and 1 is a valid pair, while port 1 and 2 isn’t. The test is performed by running the test application and using a traffic generator.

The link_status_interrupt application is run with EAL parameters and parameters for the application itself. This application supports three parameters for itself.

• -p PORTMASK: hexadecimal bitmask of ports to config
• -q NQ: number of queue per lcore (default is 1)
• -T PERIOD: refresh period in seconds (0/10/86400: disable/default/maximum)

82.1. Prerequisites

If using vfio the kernel must be >= 3.6+ and VT-d must be enabled in bios.When using vfio, use the following commands to load the vfio driver and bind it to the device under test:

modprobe vfio
modprobe vfio-pci
usertools/dpdk-devbind.py --bind=vfio-pci device_bus_id

The test app need add a cmdline, --vfio-intr=int_x.

Assume port 0 and 1 are connected to the remote ports, e.g. packet generator. To run the test application in linuxapp environment with 4 lcores, 2 ports and 2 RX queues per lcore:

$ ./link_status_interrupt -c f -- -q 2 -p 0x3

Also, if the ports need to be tested are different, the port mask should be changed. The lcore used to run the test application and the number of queues per lcore could be changed.

82.2. Test Case: Link Status Change

Run the test application as above command. Then plug out the cable/fiber, or simulate a disconnection. After several seconds, check if the link is actually off. Then plug in the cable/fiber, or simulate a connection. After several seconds, check if the link is actually up, and print its information about duplex and speed.

82.3. Test Case: Port available

Run the test application as above command with cable/fiber plugged out from both port 0 and 1, then plug it in. After several seconds and the link of all the ports is up. Together with packet generator, do layer 2 forwarding, and check if the packets can be received on port 0/1 and sent out on port 1/0.