1. Introduction to the DPDK Sample Applications
The DPDK Sample Applications are small standalone applications which demonstrate various features of DPDK. They can be considered as a cookbook of DPDK features. Users interested in getting started with DPDK can take the applications, try out the features, and then extend them to fit their needs.
1.1. The DPDK Sample Applications
Table Table 1.1 shows a list of some of the main sample applications that are available in the examples directory of DPDK:
Table 1.1 Some of the DPDK Sample applications Bonding Netmap Compatibility Command Line Packet Ordering Distributor Performance Thread Ethtool Precision Time Protocol (PTP) Client Exception Path Quality of Service (QoS) Metering Hello World QoS Scheduler Internet Protocol (IP) Fragmentation Quota and Watermark IP Pipeline RX/TX Callbacks IP Reassembly Server node EFD IPsec Security Gateway Basic Forwarding/Skeleton App IPv4 multicast Tunnel End Point (TEP) termination Kernel NIC Interface Timer Network Layer 2 Forwarding + variants Vhost Network Layer 3 Forwarding + variants Vhost Xen Link Status Interrupt VMDQ Forwarding Load Balancer VMDQ and DCB Forwarding Multi-process VM Power Management
These examples range from simple to reasonably complex but most are designed to demonstrate one particular feature of DPDK. Some of the more interesting examples are highlighted below.
- Hello World: As with most introductions to a programming framework a good place to start is with the Hello World application. The Hello World example sets up the DPDK Environment Abstraction Layer (EAL), and prints a simple “Hello World” message to each of the DPDK enabled cores. This application doesn’t do any packet forwarding but it is a good way to test if the DPDK environment is compiled and set up properly.
- Basic Forwarding/Skeleton Application: The Basic Forwarding/Skeleton contains the minimum amount of code required to enable basic packet forwarding with DPDK. This allows you to test if your network interfaces are working with DPDK.
- Network Layer 2 forwarding: The Network Layer 2
forwarding, or
l2fwdapplication does forwarding based on Ethernet MAC addresses like a simple switch. - Network Layer 3 forwarding: The Network Layer3
forwarding, or
l3fwdapplication does forwarding based on Internet Protocol, IPv4 or IPv6 like a simple router. - Packet Distributor: The Packet Distributor demonstrates how to distribute packets arriving on an Rx port to different cores for processing and transmission.
- Multi-Process Application: The multi-process application shows how two DPDK processes can work together using queues and memory pools to share information.
- RX/TX callbacks Application: The RX/TX callbacks sample application is a packet forwarding application that demonstrates the use of user defined callbacks on received and transmitted packets. The application calculates the latency of a packet between RX (packet arrival) and TX (packet transmission) by adding callbacks to the RX and TX packet processing functions.
- IPSec Security Gateway: The IPSec Security Gateway application is minimal example of something closer to a real world example. This is also a good example of an application using the DPDK Cryptodev framework.
- Precision Time Protocol (PTP) client: The PTP client is another minimal implementation of a real world application. In this case the application is a PTP client that communicates with a PTP master clock to synchronize time on a Network Interface Card (NIC) using the IEEE1588 protocol.
- Quality of Service (QoS) Scheduler: The QoS Scheduler application demonstrates the use of DPDK to provide QoS scheduling.
There are many more examples shown in the following chapters. Each of the documented sample applications show how to compile, configure and run the application as well as explaining the main functionality of the code.