multiple thread in CMSIS RTOS - STM32 nucleo L053R8 - multithreading

Question

Today I developing RTOS (CMSIS RTOS) for kit STM32 nucleo L053R8. I have issue relate to multiple task.
I create 4 task(task_1, task_2, task_3, task_4), however only 3 task run.
This is part of my code:
#include "main.h"
#include "stm32l0xx_hal.h"
#include "cmsis_os.h"
osMutexId stdio_mutex;
osMutexDef(stdio_mutex);
int main(void){
.....
stdio_mutex = osMutexCreate(osMutex(stdio_mutex));
osThreadDef(defaultTask_1, StartDefaultTask_1, osPriorityNormal, 0, 128);
defaultTaskHandle = osThreadCreate(osThread(defaultTask_1), NULL);
osThreadDef(defaultTask_2, StartDefaultTask_2, osPriorityNormal, 0, 128);
defaultTaskHandle = osThreadCreate(osThread(defaultTask_2), NULL);
osThreadDef(defaultTask_3, StartDefaultTask_3, osPriorityNormal, 0, 128);
defaultTaskHandle = osThreadCreate(osThread(defaultTask_3), NULL);
osThreadDef(defaultTask_4, StartDefaultTask_4, osPriorityNormal, 0, 600);
defaultTaskHandle = osThreadCreate(osThread(defaultTask_4), NULL);
}
void StartDefaultTask_1(void const * argument){
for(;;){
osMutexWait(stdio_mutex, osWaitForever);
printf("%s\n\r", __func__);
osMutexRelease(stdio_mutex);
osDelay(1000);
}
}
void StartDefaultTask_2(void const * argument){
for(;;){
osMutexWait(stdio_mutex, osWaitForever);
printf("%s\n\r", __func__);
osMutexRelease(stdio_mutex);
osDelay(1000);
}
}
void StartDefaultTask_3(void const * argument){
for(;;){
osMutexWait(stdio_mutex, osWaitForever);
printf("%s\n\r", __func__);
osMutexRelease(stdio_mutex);
osDelay(1000);
}
}
void StartDefaultTask_4(void const * argument){
for(;;){
osMutexWait(stdio_mutex, osWaitForever);
printf("%s\n\r", __func__);
osMutexRelease(stdio_mutex);
osDelay(1000);
}
}
this is reslut in console (uart):
when I change stack size for task 4 from 600 -> 128 as below:
osThreadDef(defaultTask_4, StartDefaultTask_4, osPriorityNormal, 0, 128);
defaultTaskHandle = osThreadCreate(osThread(defaultTask_4), NULL);
then don't have any task run.
Actualy I want make many thread for my application, however this issue cause difficult to implement.
Could you let me know root cause of prblem? and how to resolve it.
Thank you advance!!

Answer 1

There is no common easy method of the stack calculation. It depends on many factors.
I would suggest to avoid stack greedy functions like printf scanf etc. Write your own ones, not as "smart" and universal but less resources greedy.
Avoid large local variables. Be very careful when you allocate the memory

Answer 2

As your Suggestions, I checked by debug and see root cause is heap size is small.
I resolve by 2 method
increase heap size: #define configTOTAL_HEAP_SIZE ((size_t)5120)
decrease stack size: #define configMINIMAL_STACK_SIZE ((uint16_t)64)
osThreadDef(defaultTask_6, StartDefaultTask_6, osPriorityNormal, 0, 64);
Do you know how to determine max of heap size? Please let me known.
Thank you so much