260. Sample Application Tests: Hello World Example

This example is one of the most simple RTE application that can be done. The program will just print a “helloworld” message on every enabled lcore.

Command Usage:

./dpdk-helloworld -c COREMASK [-m NB] [-r NUM] [-n NUM]

  EAL option list:
    -c COREMASK: hexadecimal bitmask of cores we are running on
    -m MB      : memory to allocate (default = size of hugemem)
    -n NUM     : force number of memory channels (don't detect)
    -r NUM     : force number of memory ranks (don't detect)
    --huge-file: base filename for hugetlbfs entries
  debug options:
    --no-huge  : use malloc instead of hugetlbfs
    --no-pci   : disable pci
    --no-hpet  : disable hpet
    --no-shconf: no shared config (mmap'd files)

260.1. Prerequisites

Support igb_uio and vfio driver, if used vfio, kernel need 3.6+ and enable vt-d in bios. When used vfio , used “modprobe vfio” and “modprobe vfio-pci” insmod vfio driver, then used ”./tools/dpdk_nic_bind.py –bind=vfio-pci device_bus_id” to bind vfio driver to test driver.

To find out the mapping of lcores (processor) to core id and socket (physical id), the command below can be used:

$ grep "processor\|physical id\|core id\|^$" /proc/cpuinfo

The total logical core number will be used as helloworld input parameters.

260.2. Test Case: run hello world on single lcores

To run example in single lcore

$ ./dpdk-helloworld -c 1
  hello from core 0

Check the output is exact the lcore 0

260.3. Test Case: run hello world on every lcores

To run the example in all the enabled lcore

$ ./dpdk-helloworld -cffffff
  hello from core 1
  hello from core 2
  hello from core 3
  hello from core 0

Verify the output of according to all the core masks.