ref: https://github.com/DPDK/dpdk/tree/main/examples/helloworld
ref: https://doc.dpdk.org/guides/linux_gsg/linux_eal_parameters.html
ref experiment: Installing DPDK and running the helloworld application
The application is run with the command
./dpdk-helloworld -l 0-3 -n 4
The command-line args are for initializing EAL - explained here: https://doc.dpdk.org/guides/linux_gsg/build_sample_apps.html#running-a-sample-application
First let’s understand in depth, the command line args:
i.e. -l or the -c cli args
The core mask and core list are mandatory for running any dpdk application. This tells which cpu cores to use.
To see the number of CPUs available, run the command lscpu . It displays, in detail, the information about the CPU architecture. For example,
This shows that there are 40 CPUs, and the CPUs numbered 0-39 are available.
You can use these CPUs to run the helloworld application. Modify the command and see the output. example sudo ./dpdk-helloworld -l 0-10 -n 4 or sudo ./dpdk-helloworld -l 0-39 -n 5
The -l argument specifies the list of CPUs to use. Alternatively, you can specify the CPUs with the hexadecimal mask using the -c argument.
Example: setting the hex mask to 0xF8 ( 1111 1000 in binary ) will use the cores 3,4,5,6,7
sudo ./dpdk-helloworld -c 0xF8 -n 4
And using the hex mask 0xF7 (1111 0111 in binary) will use cores 0,1,2,4,5,6,7
The lscpu command also outputs details on NUMA
This tells that the CPU architecture has 2 NUMA nodes and shows the distribution of the cores on each node.