Retrieve the size and maximum usage of the stack per task

Kernel
1

mastupristi wrote on Wednesday, January 30, 2019:

For reasons related to debugging our application we use the function uxTaskGetSystemState(). It populates a vector of structures TaskStatus_t. In this structure is also present the field usStackHighWaterMark, whose comment says:

/ * The minimum amount of stack space that has remained for the task since the task was created. The closer this value is to zero the closer the task has come to overflowing its stack. * /

For the same reasons of debugging, we also need to know the size of the stack, and the maximum usage percentage of it.

How can I get this information with the functions and structures available?

best regards
Max

2

rtel wrote on Wednesday, January 30, 2019:

If you set configRECORD_STACK_HIGH_ADDRESS to 1 in FreeRTOSConfig.h then
the other end of the stack is also recorded in the task’s TCB -
depending on which version of FreeRTOS you are using (its quite a new
feature), but I don’t think there is a function to retrieve it so you
would have to look in the TCB manually.

However, as the size of a task’s stack is defined by the application
writer when the task is created I would suggest you already know the
total size of the stack.

3

mastupristi wrote on Wednesday, January 30, 2019:

It would be better if we could get the information from the process structures, because it’s true that I know the information when I create tasks, but it’s also true that in the moment in which the vector of TaskStatus_t is populated it’s difficult, if not impossible, to access such information.
However, I use version 10.0.1

4

rtel wrote on Wednesday, January 30, 2019:

If you look at the bottom of tasks.c you will see that, with the correct
#defines, you can insert your own code into tasks.c by providing header
files that are included into the c file directly. That enables any
extensions you want for your project without the need to edit the
kernel’s source files.

5

mastupristi wrote on Wednesday, January 30, 2019:

I did as you say, and I was successful, thank you.
Is this patch considering itself an addition to FreeRTOS? Do I have to share the code?

best regards

6

rtel wrote on Wednesday, January 30, 2019:

It’s always nice when people share code, but you don’t have to.

7

mastupristi wrote on Thursday, January 31, 2019:

Here’s the patch. I tried to follow the FreeRTOS coding rules, but I’m not sure I did it all.

diff --git a/FW/amazon-freertos/lib/FreeRTOS/tasks.c b/FW/amazon-freertos/lib/FreeRTOS/tasks.c
index 20c3962..6393e8f 100644
--- a/FW/amazon-freertos/lib/FreeRTOS/tasks.c
+++ b/FW/amazon-freertos/lib/FreeRTOS/tasks.c
@@ -5042,4 +5042,27 @@ when performing module tests). */
 
 #endif
 
+#if( ( FREERTOS_ADDITIONAL_FEATURE_TOTAL_STACK_API == 1 ) && ( configRECORD_STACK_HIGH_ADDRESS == 1 ) )
 
+
+uint32_t uxTaskGetStackSize( TaskHandle_t xTask )
+{
+	uint32_t uxReturn;
+	TCB_t *pxTCB;
+
+	if( xTask != NULL )
+	{
+		pxTCB = ( TCB_t * ) xTask;
+		uxReturn = (pxTCB->pxEndOfStack - pxTCB->pxStack) * sizeof(StackType_t);
+	}
+	else
+	{
+		uxReturn = 0;
+	}
+
+	return uxReturn;
+}
+
+#endif
diff --git a/FW/amazon-freertos/lib/include/task.h b/FW/amazon-freertos/lib/include/task.h
index d53b4dd..2a36eef 100644
--- a/FW/amazon-freertos/lib/include/task.h
+++ b/FW/amazon-freertos/lib/include/task.h
@@ -2359,6 +2359,12 @@ void *pvTaskIncrementMutexHeldCount( void ) PRIVILEGED_FUNCTION;
 void vTaskInternalSetTimeOutState( TimeOut_t * const pxTimeOut ) PRIVILEGED_FUNCTION;
 
 
+#if( ( FREERTOS_ADDITIONAL_FEATURE_TOTAL_STACK_API == 1 ) && ( configRECORD_STACK_HIGH_ADDRESS == 1 ) )
+
+uint32_t uxTaskGetStackSize( TaskHandle_t xTask );
+
+#endif
+
 #ifdef __cplusplus
 }
 #endif

To enable this function is necessary that also the symbol FREERTOS_ADDITIONAL_FEATURE_TOTAL_STACK_API is defined to 1. I do it on the command line when I launch make.

best regards
Max