IPC service

The IPC service sample demonstrates the functionality of the IPC service.

Overview

The sample application tests throughput of the IPC service with available backends. Currently, the sample supports OpenAMP RPMSG and ICMSG backends.

Each core periodically prints out data throughput in bytes per second.

Requirements

The sample supports the following development kits:

Hardware platforms

PCA

Board name

Build target

nRF5340 DK

PCA10095

nrf5340dk_nrf5340

nrf5340dk_nrf5340_cpuapp

Configuration

See Configuring your application for information about how to permanently or temporarily change the configuration.

Both application and network core send data to each other in the time interval specified by the CONFIG_APP_IPC_SERVICE_SEND_INTERVAL option. You can change the value and observe how the throughput on each core changes.

Note

Increasing the time interval to send data on one core, decreases the reading speed on the other core.

Configuration options

Check and configure the following Kconfig options:

CONFIG_APP_IPC_SERVICE_SEND_INTERVAL - Time interval to send data through the IPC service

The sample configuration defines the time interval to send data packages through IPC service in µs. Since the kernel timeout has a 1 ms resolution, this value is rounded off. If the value is lesser than 1000 µs, use k_busy_wait() instead of k_msleep() function.

Building and running

This sample can be found under samples/ipc/ipc_service in the nRF Connect SDK folder structure.

To build the sample with Visual Studio Code, follow the steps listed on the How to build an application page in the nRF Connect for VS Code extension documentation. See Building and programming an application for other building and programming scenarios and Testing and debugging an application for general information about testing and debugging in the nRF Connect SDK.

A set of overlays are available for the sample to verify the throughput that only one core is sending the data. You could use different overlay build commands for different testing scenarios, which are as follows:

  • To test the application where only the application core is sending data through the IPC service, specify -DOVERLAY_CONFIG=overlay-cpuapp-sending.conf overlay parameter with the build command:

    west build -p -b nrf5340dk_nrf5340_cpuapp -- -DOVERLAY_CONFIG=overlay-cpuapp-sending.conf

    The CMakeLists.txt of the application ensures adding a matching config overlay for the child image.

  • To test the application for a scenario where only the network core is sending data through the IPC service, specify the -DOVERLAY_CONFIG=overlay-cpunet-sending.conf overlay parameter with the build command:

    west build -p -b nrf5340dk_nrf5340_cpuapp -- -DOVERLAY_CONFIG=overlay-cpunet-sending.conf

    The CMakeLists.txt of the application ensures adding a matching config overlay for the child image.

  • To test the application with the ICMSG backend, specify the -DCONF_FILE=prj_icmsg.conf parameter along with the build command:

    west build -p -b nrf5340dk_nrf5340_cpuapp -- -DCONF_FILE=prj_icmsg.conf

    The CMakeLists.txt of the application ensures adding a matching config and DT overlay for the child image.

  • Combine the above options and test maximal core to core throughput with the ICMSG backend. To do so, build the application with the following commands:

    west build -p -b nrf5340dk_nrf5340_cpuapp -- -DCONF_FILE=prj_icmsg.conf -DOVERLAY_CONFIG=overlay-cpuapp-sending.conf
west build -p -b nrf5340dk_nrf5340_cpuapp -- -DCONF_FILE=prj_icmsg.conf -DOVERLAY_CONFIG=overlay-cpunet-sending.conf

Testing

In the default configuration, both application and network cores periodically print out the receiving speed of data that was sent by the other core.

After programming the sample to your development kit, test it by performing the following steps:

  1. Connect to the kit with a terminal emulator (for example, PuTTY). See How to connect with PuTTY for the required settings.

  2. Reset the kit.

  3. Observe the console output for both cores:

  • For the application core, the output is similar to the following one:

    *** Booting Zephyr OS build v3.0.99-ncs1  ***
IPC-service nrf5340dk_nrf5340_cpuapp demo started
Δpkt: 9391 (100 B/pkt) | throughput: 7512800 bit/s
Δpkt: 9389 (100 B/pkt) | throughput: 7511200 bit/s
Δpkt: 9388 (100 B/pkt) | throughput: 7510400 bit/s
Δpkt: 9390 (100 B/pkt) | throughput: 7512000 bit/s
Δpkt: 9396 (100 B/pkt) | throughput: 7516800 bit/s

  • For the network core, the output is similar to the following one:

    *** Booting Zephyr OS build v3.0.99-ncs1  ***
IPC-service nrf5340dk_nrf5340_cpunet demo started
Δpkt: 6665 (100 B/pkt) | throughput: 5332000 bit/s
Δpkt: 6664 (100 B/pkt) | throughput: 5331200 bit/s
Δpkt: 6658 (100 B/pkt) | throughput: 5326400 bit/s
Δpkt: 6665 (100 B/pkt) | throughput: 5332000 bit/s
Δpkt: 6671 (100 B/pkt) | throughput: 5336800 bit/s

Dependencies

The sample uses the following Zephyr subsystems:

  • include/ipc/ipc_service.h

  • Logging