Execution of Two Tasks using TaskScheduler executes only one task

Hello Community members,
I’m running a simple code that creates two tasks and then starts the task scheduler.

  • Both the tasks are having same priority.
  • Both the tasks does the same functionality (printing a statement)
  • task stack size is also same for both.

Code is as follows:

#include <stdint.h>

 

/* POSIX Header files */

#include <pthread.h>

 

/* RTOS header files */

#include "FreeRTOS.h"

#include "task.h"

 

/* TI-DRIVERS Header files */

#include "ti_drivers_config.h"

 

/* TI-RTOS Header files */

#include <ti/drivers/GPIO.h>

 

extern void * mainThread(void *arg0);

// extern void * second_thread(void *arg0);

 

/* Stack size in bytes */

#define THREADSTACKSIZE   1024

 

 

void task1(void *pvParameters)

{

    const char *pcTaskName = "Task1 is running \r\n";

    volatile uint32_t ul;

    volatile long int mainDELAY_LOOP_COUNT=100000;

    while(1)

    {

        unsigned long int a = 0;

        printf("This is task1");

        printf("\n");

        for(a=1;a<=100000; a++)

        {

            ;

        }

    }

}

 

void task2(void *pvParameters)

{

    const char *pcTaskName = "Task2 is running \r\n";

    volatile uint32_t ul;

    volatile long int mainDELAY_LOOP_COUNT=100000;

    unsigned long int a = 0;

    printf("This is task2");

    printf("\n");

    for(a=1;a<=100000; a++)

    {

        ;

    }

}

 

/*

*  ======== main ========

*/

int main(void)

{

    int retc = 0;

    TaskHandle_t main_task_Handle;

 

 

    /* Call board init functions */

    Board_init();

 

    retc = xPortGetFreeHeapSize();

 

    retc = xTaskCreate( task1, /* Pointer to the function that implements the task. */

                        "task1",/* Text name for the task. This is to facilitate debugging only. */

                        THREADSTACKSIZE, /* Stack depth - small microcontrollers will use much less stack than this. */

                        NULL, /* This example does not use the task parameter. */

                        1, /* This task will run at Maximum priority. */

                        NULL ); /* This example does not use the task handle. */

 

    if(retc != pdPASS)

    {

        printf("\n\n");

        printf("Main Task Creation failed!!!");

        printf("\n\n");

        while(1)

        {

            ;

        }

    }

 

    if(retc == pdPASS)

    {

        printf("\n\n");

        printf("Main Task Creation Succeeded !!!");

        printf("\n\n");

    }

 

    retc = xPortGetFreeHeapSize();

 

    retc = xTaskCreate( task2, /* Pointer to the function that implements the task. */

                        "task2",/* Text name for the task. This is to facilitate debugging only. */

                        THREADSTACKSIZE, /* Stack depth - small microcontrollers will use much less stack than this. */

                        NULL, /* This example does not use the task parameter. */

                        1, /* This task will run at Maximum priority. */

                        NULL ); /* This example does not use the task handle. */

 

    if(retc != pdPASS)

    {

        printf("\n\n");

        printf("Main Task Creation failed!!!");

        printf("\n\n");

        while(1)

        {

            ;

        }

    }

 

    if(retc == pdPASS)

    {

        printf("\n\n");

        printf("Main Task Creation Succeeded !!!");

        printf("\n\n");

    }

 

    retc = xPortGetFreeHeapSize();

 

    /* Start the FreeRTOS scheduler */

    vTaskStartScheduler();

 

    return (0);

}

 

//*****************************************************************************

//

//! \brief Application defined malloc failed hook

//!

//! \param  none

//!

//! \return none

//!

//*****************************************************************************

void vApplicationMallocFailedHook()

{

    /* Handle Memory Allocation Errors */

    while(1)

    {

    }

}

 

//*****************************************************************************

//

//! \brief Application defined stack overflow hook

//!

//! \param  none

//!

//! \return none

//!

//*****************************************************************************

void vApplicationStackOverflowHook(TaskHandle_t pxTask,

                                   char *pcTaskName)

{

    //Handle FreeRTOS Stack Overflow

    while(1)

    {

    }

}

 

void vApplicationTickHook(void)

{

    /*

     * This function will be called by each tick interrupt if

     * configUSE_TICK_HOOK is set to 1 in FreeRTOSConfig.h.  User code can be

     * added here, but the tick hook is called from an interrupt context, so

     * code must not attempt to block, and only the interrupt safe FreeRTOS API

     * functions can be used (those that end in FromISR()).

     */

}

 

void vPreSleepProcessing(uint32_t ulExpectedIdleTime)

{

}

 

//*****************************************************************************

//

//! \brief Application defined idle task hook

//!

//! \param  none

//!

//! \return none

//!

//*****************************************************************************

void

vApplicationIdleHook(void)

{

    /* Handle Idle Hook for Profiling, Power Management etc */

}

 

//*****************************************************************************

//

//! \brief  Overwrite the GCC _sbrk function which check the heap limit related

//!         to the stack pointer.

//!         In case of freertos this checking will fail.

//! \param  none

//!

//! \return none

//!

//*****************************************************************************

#if defined (__GNUC__)

void * _sbrk(uint32_t delta)

{

    extern char _end;     /* Defined by the linker */

    extern char __HeapLimit;

    static char *heap_end;

    static char *heap_limit;

    char *prev_heap_end;

 

    if(heap_end == 0)

    {

        heap_end = &_end;

        heap_limit = &__HeapLimit;

    }

 

    prev_heap_end = heap_end;

    if(prev_heap_end + delta > heap_limit)

    {

        return((void *) -1L);

    }

    heap_end += delta;

    return((void *) prev_heap_end);

}

 

#endif

Question:

  1. Upon execution of code, only task 1 runs continuously. Task 2 never gets executed? Why so?
  2. Even though stack size of 1024 have been allotted to each task, running the function xPortGetFreeHeapSize returns values as follows:
    * Before creation of any task: 32592
    * after creating task 1: 28088
    * after creating task 2: 23864
    Can someone please elaborate the calculation ?

Regards,
H C Trivedi

Hi @hctrivedi3,
Thanks for your feedback. Here are some questions to better figure out.

  1. Could you share your FreeRTOSConfig.h?
  2. What platform is FreeRTOS running on?

As mentioned in xTaskCreate(), usStackDepth(1024 in your case) is not the stack size in bytes. It’s totally configSTACK_DEPTH_TYPE * usStackDepth bytes. So it needs your configurations in FreeRTOSConfig.h to be calculated with.

Thanks.

hello @ActoryOu ,
code in FreeRTOSConfig.h is as follows (could not upload the file as it was not allowed for me):

/*

* FreeRTOS Kernel V10.0.0

* Copyright (C) 2017 Amazon.com, Inc. or its affiliates.  All Rights Reserved.

*

* Permission is hereby granted, free of charge, to any person obtaining a copy of

* this software and associated documentation files (the "Software"), to deal in

* the Software without restriction, including without limitation the rights to

* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of

* the Software, and to permit persons to whom the Software is furnished to do so,

* subject to the following conditions:

*

* The above copyright notice and this permission notice shall be included in all

* copies or substantial portions of the Software. If you wish to use our Amazon

* FreeRTOS name, please do so in a fair use way that does not cause confusion.

*

* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS

* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR

* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER

* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN

* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

*

* http://www.FreeRTOS.org

* http://aws.amazon.com/freertos

*

* 1 tab == 4 spaces!

*/

 

 

/******************************************************************************

    See http://www.freertos.org/a00110.html for an explanation of the

    definitions contained in this file.

******************************************************************************/

 

#ifndef FREERTOS_CONFIG_H

#define FREERTOS_CONFIG_H

 

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

* Application specific definitions.

*

* These definitions should be adjusted for your particular hardware and

* application requirements.

*

* THESE PARAMETERS ARE DESCRIBED WITHIN THE 'CONFIGURATION' SECTION OF THE

* FreeRTOS API DOCUMENTATION AVAILABLE ON THE FreeRTOS.org WEB SITE.

* http://www.freertos.org/a00110.html

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

 

/* Constants related to the behaviour or the scheduler. */

#define configUSE_PORT_OPTIMISED_TASK_SELECTION 1

#define configTICK_RATE_HZ              ( ( TickType_t ) 1000 )

#define configUSE_PREEMPTION            1

#define configUSE_TIME_SLICING          0

#define configMAX_PRIORITIES            ( 10UL )

#define configIDLE_SHOULD_YIELD         0

#define configUSE_16_BIT_TICKS          0 /* Only for 8 and 16-bit hardware. */

 

/* Constants used to specify if only static allocation is to be supported (in

which case a heap_n.c file is not required), only dynamic allocation is to be

supported, or if both static and dynamic allocation are supported. */

#define configSUPPORT_STATIC_ALLOCATION                 1

#define configSUPPORT_DYNAMIC_ALLOCATION                1

 

/* Constants that describe the hardware and memory usage. */

#define configCPU_CLOCK_HZ              ( ( unsigned long ) 80000000 )

/* Smallest stack size allowed in words */

#define configMINIMAL_STACK_SIZE        ( ( unsigned short ) 128 )

#define configMAX_TASK_NAME_LEN         ( 12 )

 

#define configTOTAL_HEAP_SIZE           ( ( size_t ) ( 0x8000 ) )

 

/* Idle task stack size in words */

#define configIDLE_TASK_STACK_DEPTH     (configMINIMAL_STACK_SIZE * 2)

 

/* Default stack size for TI-POSIX threads (in words) */

#define configPOSIX_STACK_SIZE          ( ( unsigned short ) 256 )

 

/* Constants that build features in or out. */

#define configUSE_MUTEXES               1

#define configUSE_TICKLESS_IDLE         1

#define configUSE_APPLICATION_TASK_TAG  1  /* Need by POSIX/pthread */

#define configUSE_CO_ROUTINES           0

#define configUSE_COUNTING_SEMAPHORES   1

#define configUSE_RECURSIVE_MUTEXES     1

#define configUSE_QUEUE_SETS            0

#define configUSE_TASK_NOTIFICATIONS    1

 

/* Constants that define which hook (callback) functions should be used. */

#define configUSE_IDLE_HOOK             0

#define configUSE_TICK_HOOK             0

#define configUSE_MALLOC_FAILED_HOOK    0

 

/* Constants provided for debugging and optimisation assistance. */

#define configCHECK_FOR_STACK_OVERFLOW  2

#define configASSERT( x ) if( ( x ) == 0 ) { taskDISABLE_INTERRUPTS(); for( ;; ); }

#define configQUEUE_REGISTRY_SIZE       0

 

/*

*  Minimum number of full tick periods of idle time required to run Power

*  sleep policy function.

*/

#define configEXPECTED_IDLE_TIME_BEFORE_SLEEP   5

 

/* Software timer definitions. */

#define configUSE_TIMERS                1

#define configTIMER_TASK_PRIORITY       (5)

#define configTIMER_QUEUE_LENGTH        (20)

/* Timer task stack size in words */

#define configTIMER_TASK_STACK_DEPTH    (configMINIMAL_STACK_SIZE * 2)

 

#define configENABLE_BACKWARD_COMPATIBILITY 0

 

#if defined(__TI_COMPILER_VERSION__) || defined(__ti_version__)

#include <ti/posix/freertos/PTLS.h>

#define traceTASK_DELETE( pxTCB ) PTLS_taskDeleteHook( pxTCB )

#elif defined(__IAR_SYSTEMS_ICC__)

#ifndef __IAR_SYSTEMS_ASM__

#include <ti/posix/freertos/Mtx.h>

#define traceTASK_DELETE( pxTCB ) Mtx_taskDeleteHook( pxTCB )

#endif

#endif

 

/*

*  Enable thread local storage

*

*  Assign TLS array index ownership here to avoid collisions.

*  TLS storage is needed to implement thread-safe errno with

*  TI and IAR compilers. With GNU compiler, we enable newlib.

*/

#if defined(__TI_COMPILER_VERSION__) || defined(__ti_version__) || defined(__IAR_SYSTEMS_ICC__)

 

#define configNUM_THREAD_LOCAL_STORAGE_POINTERS 1

 

#if defined(__TI_COMPILER_VERSION__) || defined(__ti_version__)

#define PTLS_TLS_INDEX 0  /* ti.posix.freertos.PTLS */

#elif defined(__IAR_SYSTEMS_ICC__)

#define MTX_TLS_INDEX 0  /* ti.posix.freertos.Mtx */

#endif

 

#elif defined(__GNUC__)

/* note: system locks required by newlib are not implemented */

#define configUSE_NEWLIB_REENTRANT 1

#endif

 

/*

* Set the following definitions to 1 to include the API function, or zero

* to exclude the API function.  NOTE:  Setting an INCLUDE_ parameter to 0 is only

* necessary if the linker does not automatically remove functions that are not

* referenced anyway.

*/

#define INCLUDE_vTaskPrioritySet                1

#define INCLUDE_uxTaskPriorityGet               1

#define INCLUDE_vTaskDelete                     1

#define INCLUDE_vTaskCleanUpResources           0

#define INCLUDE_vTaskSuspend                    1

#define INCLUDE_vTaskDelayUntil                 1

#define INCLUDE_vTaskDelay                      1

#define INCLUDE_uxTaskGetStackHighWaterMark     0

#define INCLUDE_xTaskGetIdleTaskHandle          0

#define INCLUDE_eTaskGetState                   1

#define INCLUDE_xTaskResumeFromISR              0

#define INCLUDE_xTaskGetCurrentTaskHandle       1

#define INCLUDE_xTaskGetSchedulerState          0

#define INCLUDE_xSemaphoreGetMutexHolder        0

#define INCLUDE_xTimerPendFunctionCall          0

 

/* Cortex-M3/4 interrupt priority configuration follows...................... */

 

/* Use the system definition, if there is one. */

#ifdef __NVIC_PRIO_BITS

    #define configPRIO_BITS       __NVIC_PRIO_BITS

#else

    #define configPRIO_BITS       3     /* 8 priority levels */

#endif

 

/* The lowest interrupt priority that can be used in a call to a "set priority"

function. */

#define configLIBRARY_LOWEST_INTERRUPT_PRIORITY         0x07

 

/*

* The highest interrupt priority that can be used by any interrupt service

* routine that makes calls to interrupt safe FreeRTOS API functions.  DO NOT CALL

* INTERRUPT SAFE FREERTOS API FUNCTIONS FROM ANY INTERRUPT THAT HAS A HIGHER

* PRIORITY THAN THIS! (higher priorities are lower numeric values.

*/

#define configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY    1

 

/*

*  Priority 7 (shifted 5 since only the top 3 bits are implemented).

*  Priority 7 is the lowest priority.

*/

#define configKERNEL_INTERRUPT_PRIORITY (configLIBRARY_LOWEST_INTERRUPT_PRIORITY << (8 - configPRIO_BITS))

 

/*

*  Priority 1 (shifted 5 since only the top 3 bits are implemented).

*  Priority 1 is the second highest priority.

*  Priority 0 is the highest priority.

*  !!!! configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to zero !!!!

*  See http://www.FreeRTOS.org/RTOS-Cortex-M3-M4.html.

*/

#define configMAX_SYSCALL_INTERRUPT_PRIORITY (configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY << (8 - configPRIO_BITS))

 

/* The trace facility is turned on to make some functions available for use in

CLI commands. */

#define configUSE_TRACE_FACILITY                1

 

/* Constants related to the generation of run time stats. */

#define configGENERATE_RUN_TIME_STATS           0

#define portCONFIGURE_TIMER_FOR_RUN_TIME_STATS()

#define portGET_RUN_TIME_COUNTER_VALUE()        0

 

/*

* Runtime Object View is a Texas Instrument host tool that helps visualize

* the application. When enabled, the ISR stack will be initialized in the

* startup_<device>_<compiler>.c file to 0xa5a5a5a5. The stack peak can then

* be displayed in Runtime Object View.

*/

#define configENABLE_ISR_STACK_INIT  1

 

#endif /* FREERTOS_CONFIG_H */

I’m running my code on CC3235S board from Texas Instruments.

Regards,
H C Trivedi

You‘ve disabled configUSE_TIME_SLICING. Hence only 1 task runs. See the documentation of configUSE_TIME_SLICING.
Alternatively you could add a delay like vTaskDelay( pdMS_TO_TICKS(500) ); to give the other task a chance to run.

2 Likes

Thanks for the help @hs2 . This made my code work.

Also, I had gone through memory assignment. FreeRTOSConfig.h specifies configMINIMALSTACKSIZE as 128. I’m providing stack Depth as 1024. And after each task creation, xPortGetFreeHeapSize gives me usage of 4504 (32592 initially, 28088 (32592 - 4504) after creation of task1 and 23864 (28088-4504) after creation of task 2). I could not settle down on the calculation. Can you please throw some light on this as well?

Regards,
H C Trivedi.

There is more to allocate for a task than just its stack. FreeRTOS also allocates a task control block used internally. See the xTaskCreate definition in tasks.c. If this was your point…

1 Like