Make runtime stats working with compiler optimization enabled

the78mole · May 22, 2020, 4:08pm

Hi forums,

I’m currently on profiling a FreeRTOS application and it’s my first time to use the run-time statistics feature of FreeRTOS together with the Eclipse “FreeRTOS Task List” view.

When switching on compiler optimization (above -O0), the runtime stats vanish. A workaround is described at the end of this blog post on Atollic and FreeRTOS:

To solve the issue sustainably, I would recommend to declare ulTotalRunTime = 0UL in tasks.c as volatile.

github.com

FreeRTOS/FreeRTOS-Kernel/blob/10bbbcf0b9bcab1869b3bac3987d32116f351718/tasks.c#L396


kernel to move the task from the pending ready list into the real ready list

when the scheduler is unsuspended.  The pending ready list itself can only be

accessed from a critical section. */

PRIVILEGED_DATA static volatile UBaseType_t uxSchedulerSuspended	= ( UBaseType_t ) pdFALSE;



#if ( configGENERATE_RUN_TIME_STATS == 1 )



	/* Do not move these variables to function scope as doing so prevents the

	code working with debuggers that need to remove the static qualifier. */

	PRIVILEGED_DATA static uint32_t ulTaskSwitchedInTime = 0UL;	/*< Holds the value of a timer/counter the last time a task was switched in. */

	PRIVILEGED_DATA static uint32_t ulTotalRunTime = 0UL;		/*< Holds the total amount of execution time as defined by the run time counter clock. */



#endif



/*lint -restore */



/*-----------------------------------------------------------*/



/* Callback function prototypes. --------------------------*/

#if(  configCHECK_FOR_STACK_OVERFLOW > 0 )

The second suggestion of the blog post, to disable optimization for tasks.c completely, affects performance too much.

Is it worth to raise an issue for that on GitHub?

Regards,
Daniel

rtel · May 22, 2020, 4:23pm

Please just create a pull request on Github with the volatile added - thanks.

the78mole · May 22, 2020, 5:20pm

Done: