Multi-threaded RTOS debug

For the case of debugging with RTOS, CLion provides a view of FreeRTOS, Azure RTOS, and Zephyr tasks (threads). For FreeRTOS, you can also explore objects and heap.

Enable RTOS thread view

Go to Settings | Build, Execution, Deployment | Embedded Development | RTOS Integration.
Set the Enable RTOS Integration checkbox and select from the list of options:

RTOS integration is intended to work for any relevant run/debug configuration, such as Embedded GDB Server or OpenOCD Download & Run.

For example, here is how an Embedded GDB Server configuration can be set up using the QEMU emulator:

Embedded GDB Server configuration example

FreeRTOS / Azure RTOS / Zephyr tasks view

When debugging a configuration like the one given above, you will see the FreeRTOS / Azure RTOS / Zephyr tasks listed in the Threads & Variables pane of the debug tool window.

For each task, the variables are presented in the Variables pane.

The RTOS tasks view also works for Symmetric Multiprocessing (SMP). The processor cores must be identical and share the same memory.

FreeRTOS objects view

To explore FreeRTOS objects, switch to the FreeRTOS Objects tab. The Task table shows a list of tasks with status information; the Queue table shows currently active queues, semaphores, and mutexes; the Timer table lists the software timers:

For this tab to work correctly, configure the following definitions in FreeRTOSConfig.h:

Set configUSE_TRACE_FACILITY to 1, for displaying task numbers and queue types.
Set configMAX_TASK_NAME_LEN to a value greater than zero, for displaying the task name properly.
Set configRECORD_STACK_HIGH_ADDRESS to 1, for displaying the task stack info.
Set configUSE_TRACE_FACILITY and configGENERATE_RUN_TIME_STATS to 1 for collecting runtime info (runtime column of the task table).
Use configQUEUE_REGISTRY_SIZE greater than zero and vQueueAddToRegistry() to assign a name to a queue, semaphore, or mutex. This is useful as queues have no name by default, unlike tasks (which get a name at creation time).

CLion will show a warning in case some of the defines are missing:

FreeRTOS heap view

The FreeRTOS Heap tab shows the current heap usage and memory block allocation for all the default FreeRTOS memory management schemes.

Last modified: 05 September 2023