36. Eventdev Pipeline SW PMD Sample Application

The eventdev pipeline sample application is a sample app that demonstrates the usage of the eventdev API using the software PMD. It shows how an application can configure a pipeline and assign a set of worker cores to perform the processing required.

The application has a range of command line arguments allowing it to be configured for various numbers worker cores, stages,queue depths and cycles per stage of work. This is useful for performance testing as well as quickly testing a particular pipeline configuration.

36.1. Compiling the Application

To compile the application:

  1. Go to the sample application directory:

    export RTE_SDK=/path/to/rte_sdk
cd ${RTE_SDK}/examples/eventdev_pipeline_sw_pmd

  2. Set the target (a default target is used if not specified). For example:

    export RTE_TARGET=x86_64-native-linuxapp-gcc

    See the DPDK Getting Started Guide for possible RTE_TARGET values.

  3. Build the application:

    make

36.2. Running the Application

The application has a lot of command line options. This allows specification of the eventdev PMD to use, and a number of attributes of the processing pipeline options.

An example eventdev pipeline running with the software eventdev PMD using these settings is shown below:

  • -r1: core mask 0x1 for RX
  • -t1: core mask 0x1 for TX
  • -e4: core mask 0x4 for the software scheduler
  • -w FF00: core mask for worker cores, 8 cores from 8th to 16th
  • -s4: 4 atomic stages
  • -n0: process infinite packets (run forever)
  • -c32: worker dequeue depth of 32
  • -W1000: do 1000 cycles of work per packet in each stage
  • -D: dump statistics on exit
./build/eventdev_pipeline_sw_pmd --vdev event_sw0 -- -r1 -t1 -e4 -w FF00 -s4 -n0 -c32 -W1000 -D

The application has some sanity checking built-in, so if there is a function (eg; the RX core) which doesn’t have a cpu core mask assigned, the application will print an error message:

Core part of pipeline was not assigned any cores. This will stall the
pipeline, please check core masks (use -h for details on setting core masks):
        rx: 0
        tx: 1

Configuration of the eventdev is covered in detail in the programmers guide, see the Event Device Library section.

36.3. Observing the Application

At runtime the eventdev pipeline application prints out a summary of the configuration, and some runtime statistics like packets per second. On exit the worker statistics are printed, along with a full dump of the PMD statistics if required. The following sections show sample output for each of the output types.

36.3.1. Configuration

This provides an overview of the pipeline, scheduling type at each stage, and parameters to options such as how many flows to use and what eventdev PMD is in use. See the following sample output for details:

Config:
      ports: 2
      workers: 8
      packets: 0
      priorities: 1
      Queue-prio: 0
      qid0 type: atomic
      Cores available: 44
      Cores used: 10
      Eventdev 0: event_sw
Stages:
      Stage 0, Type Atomic    Priority = 128
      Stage 1, Type Atomic    Priority = 128
      Stage 2, Type Atomic    Priority = 128
      Stage 3, Type Atomic    Priority = 128

36.3.2. Runtime

At runtime, the statistics of the consumer are printed, stating the number of packets received, runtime in milliseconds, average mpps, and current mpps.

# consumer RX= xxxxxxx, time yyyy ms, avg z.zzz mpps [current w.www mpps]

36.3.3. Shutdown

At shutdown, the application prints the number of packets received and transmitted, and an overview of the distribution of work across worker cores.

Signal 2 received, preparing to exit...
  worker 12 thread done. RX=4966581 TX=4966581
  worker 13 thread done. RX=4963329 TX=4963329
  worker 14 thread done. RX=4953614 TX=4953614
  worker 0 thread done. RX=0 TX=0
  worker 11 thread done. RX=4970549 TX=4970549
  worker 10 thread done. RX=4986391 TX=4986391
  worker 9 thread done. RX=4970528 TX=4970528
  worker 15 thread done. RX=4974087 TX=4974087
  worker 8 thread done. RX=4979908 TX=4979908
  worker 2 thread done. RX=0 TX=0

Port Workload distribution:
worker 0 :      12.5 % (4979876 pkts)
worker 1 :      12.5 % (4970497 pkts)
worker 2 :      12.5 % (4986359 pkts)
worker 3 :      12.5 % (4970517 pkts)
worker 4 :      12.5 % (4966566 pkts)
worker 5 :      12.5 % (4963297 pkts)
worker 6 :      12.5 % (4953598 pkts)
worker 7 :      12.5 % (4974055 pkts)

To get a full dump of the state of the eventdev PMD, pass the -D flag to this application. When the app is terminated using Ctrl+C, the rte_event_dev_dump() function is called, resulting in a dump of the statistics that the PMD provides. The statistics provided depend on the PMD used, see the Event Device Drivers section for a list of eventdev PMDs.