Task is going in an infinite loop

Kernel
1

I’m new here. I’ve searched the forum, but can’t find anything related to this. So, I thought about posting here.

The problem statement is that, we have 2 tasks - matrix and communication.

  1. Matrix has higher priority than communication.
  2. Calculate the execution time of both the tasks using vApplicationTickHook()
  3. If communication has execution time >1000ms, increase it’s priority to 4 or if it’s execution time is <200ms, decrease it’s priority to 2. This has to be done in a separate task.

My problem is that first priority_set_task() is executed then matrix() and then communication. After that the simulator is caught in an infinite loop ( I think so, because I don’t receive any output after it. I think it’s priority_set_task(), but I’m not sure about it) I can’t seem to understand where I’m going wrong. I’m sure you guys will notice it, because it’s definitely something silly.

#define SIZE 10
#define ROW SIZE
#define COL SIZE

int count_matrix = 0;
int count_communication = 0;
int count_priority = 0;

uint32_t count = 0;
xTaskHandle matrix_handle, communication_handle, prioritysettask_handle;
int comm_priority = 1;

static void matrix_task()
{
	vApplicationTickHook();
	printf("Matrix_task is started\n");
	fflush(stdout);
	int i;
	double** a = (double**)pvPortMalloc(ROW * sizeof(double*));
	for (i = 0; i < ROW; i++) a[i] = (double*)pvPortMalloc(COL * sizeof(double));
	double** b = (double**)pvPortMalloc(ROW * sizeof(double*));
	for (i = 0; i < ROW; i++) b[i] = (double*)pvPortMalloc(COL * sizeof(double));
	double** c = (double**)pvPortMalloc(ROW * sizeof(double*));
	for (i = 0; i < ROW; i++) c[i] = (double*)pvPortMalloc(COL * sizeof(double));

	double sum = 0.0;
	int j, k, l;

	for (i = 0; i < SIZE; i++) {
		for (j = 0; j < SIZE; j++) {
			a[i][j] = 1.5;
			b[i][j] = 2.6;
		}
	}

	while (1) {
		/*
		* In an embedded systems, matrix multiplication would block the CPU for a long time
		* but since this is a PC simulator we must add one additional dummy delay.
		*/
		count_matrix = count;
		long simulationdelay;
		for (simulationdelay = 0; simulationdelay < 1000000000; simulationdelay++)
			;
		for (i = 0; i < SIZE; i++) {
			for (j = 0; j < SIZE; j++) {
				c[i][j] = 0.0;
			}
		}

		for (i = 0; i < SIZE; i++) {
			for (j = 0; j < SIZE; j++) {
				sum = 0.0;
				for (k = 0; k < SIZE; k++) {
					for (l = 0; l < 10; l++) {
						sum = sum + a[i][k] * b[k][j];
					}
				}
				c[i][j] = sum;
			}
		}
		vTaskDelay(100);
		count_matrix = count - count_matrix;
		vTaskPrioritySet(prioritysettask_handle, 5);
		printf("matrix_task has stopped\n");
		fflush(stdout);
		printf("Execution time of matrix_task is %i ms\n", count_matrix);
		fflush(stdout);
		count_matrix = count;
		
	}
	
}

static void communication_task()
{
	while (1) {
		count_priority = count;
		vTaskSuspend(prioritysettask_handle);
		printf("Sending data..................................................................\n");
		fflush(stdout);
		vTaskDelay(100);
		printf("Data sent!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!\n");
		fflush(stdout);
		vTaskDelay(100);
		count_communication = count - count_communication;
		printf("Execution time of communication_task is %i ms\n", count_communication);
		fflush(stdout);
		count_communication = count;
		vTaskResume(prioritysettask_handle);
		vTaskPrioritySet(prioritysettask_handle, 5);
	}
	
}

 static void priority_set_task()
{
	 printf("Priority task has begun execution. Comm_priority is : %d. ", comm_priority);

		if ((count_communication > 1000) && (comm_priority != 4))
		{
			comm_priority = 4;
			printf("Execution time of communication_task is %i ms, increasing priority to 4\n", count_communication);
			fflush(stdout);
			vTaskPrioritySet(communication_handle, comm_priority);
			//count_communication = 0;
		}
		else if ((count_communication < 200) && (comm_priority != 2))
		{
			comm_priority = 2;
			printf("Execution time of communication_task is %i ms, decreasing priority to 2\n", count_communication);
			fflush(stdout);
			vTaskPrioritySet(communication_handle, comm_priority);
			//count_communication = 0;
		}

		printf("priority set task has finished execution once. Its Execution time is %d ms\n", count_priority);
		fflush(stdout);
		count_priority = 0;
		vTaskPrioritySet(prioritysettask_handle, 1);
	
}

int main(void)
{
	prvInitialiseHeap();

	vTraceEnable(TRC_START);

	xTaskCreate((pdTASK_CODE)matrix_task, (signed char*)"Matrix", 1000, NULL, 3, &matrix_handle);
	xTaskCreate((pdTASK_CODE)communication_task, (signed char*)"Communication", configMINIMAL_STACK_SIZE, NULL, 1, &communication_handle);
	xTaskCreate(priority_set_task, "priority_set", configMINIMAL_STACK_SIZE, NULL, 5, &prioritysettask_handle);

	vTaskStartScheduler();
	for (;;);
	return 0;
}

void vApplicationTickHook(void)
{
	if (count == 0xFFFFFFFF)
	{
		count = 0;
		count_matrix = 0;
		count_communication = 0;
	}
	else
	{
		count++;
	}

	#if ( mainCREATE_SIMPLE_BLINKY_DEMO_ONLY != 1 )
	{
		vFullDemoTickHookFunction();
	}
	#endif /* mainCREATE_SIMPLE_BLINKY_DEMO_ONLY */
}
2

You should use </> for code quoting. Otherwise it’s messed up and unreadable.
image

3

Not reading the code i detail, but my first suggestion is that is SOUNDS like the communications task should just have the higher priority, and just be naturally limiting its CPU usage to what it needs to be sending the data. Being I/O bound, it shouldn’t be impacting the calculation thread that much.

4

I agree with that. That would definitely be a better way to do it. The thing is that, I’m doing an online course on FreeRTOS and this is the problem statement given to me.

5

My bad. I’ve changed it.

6

Shouldn’t really be a task, just a function so no need to have a task there. Especially since you don’t have a for(;:wink: loop inside it thus it exits.

7

Yeah. I realized that the task was just executing once. I added an infinite while loop and it worked properly.