Expecting round robin scheduling but only first task executed

Kernel
1

STM32F411RE, CubeIDE

I have 4 tasks, all of equal priority, each with their own task profile counter,

void acquire_tsk(void *pvParameters);
void noise_tsk(void *pvParameters);
void combine_tsk(void *pvParameters);
void filter_tsk(void *pvParameters);

uint32_t task1Profiler, task3Profiler, task3Profiler, task4Profiler;

main()
{

    xTaskCreate(acquire_tsk,  "get signal",  100, NULL, 1, NULL);
    xTaskCreate(noise_tsk,  "get noise",  100, NULL, 1, NULL);
    xTaskCreate(combine_tsk, "combine signal", 100, NULL, 1, NULL); 
    xTaskCreate(filter_tsk, "filter signal", 100, NULL, 1, NULL);

    vTaskStartScheduler();

    while(){}

}

void acquire_tsk(void *pvParameters)
{
    while(1)
    {
        task1Profiler++;
    }
}

void noise_tsk(void *pvParameters)
{
    while(1)
    {
        task2Profiler++;
    }
}

void combine_tsk(void *pvParameters)
{
    while(1)
    {
        task3Profiler++;
    }
}

void filter_tsk(void *pvParameters)
{
    while(1)
    {
        task1Profiler++;
    }
}

When I open up my debugger & track the task profilers only task1Profiler counts up, all the others remain at 0.
I was expecting round robin scheduling & to see all the task profilers to count up. What am I missing here?

2

Did you configure your FreeRTOS app accordingly ?

3

I am using the default config which according to the docs,

By default, FreeRTOS uses a fixed-priority preemptive scheduling policy, with round-robin time-slicing of equal priority tasks

4

Seems right then.
So … maybe the SysTick isn’t running or not setup correctly ?
You could put a breakpoint @ xTaskIncrementTick to see if it’s hit periodically or halt the target and check that the (global) xTickCount variable is incremented.

5

Put a break point @TaskIncrementTick it is never hit
xTickCount variable is never incremented.

6

Although HAL timebase functions are declared as weak, do you think this might a problem with HAL using SysTick as well as RTOS using it?

7

Yes it was the HAL messing with FreeRTOS’s handling of SysTick, thanks for the pointer.

Changed HAL’s clock by changing SYS clock to TIM1 & all is working as expected.

8

FreeRTOS tasks are not supposed to exit. You need to either make them infinite loop or call vTaskDelete:

void acquire_tsk(void *pvParameters)
{
    for( ;; )
    {
        task1Profiler++;
        vTaskDelay( pdMS_TO_TICKS( 1000 ) );
    }
}

OR 

void acquire_tsk(void *pvParameters)
{
    task1Profiler++;
    vTaskDelete( NULL );
}
9

OOps my bad they are all in a while(1){} loop. In my haste I forgot to include that, will edit the OP accordingly.