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FreeRTOS-Kernel/FreeRTOS-Plus/Demo/FreeRTOS_IoT_Libraries/task_pool/DemoTasks/SimpleTaskPoolExamples.c

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/*
* FreeRTOS Kernel V10.2.1
* 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.
*
* 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!
*/
/* Kernel includes. */
#include "FreeRTOS.h"
#include "task.h"
/* Standard includes. */
#include <stdio.h>
/* IoT SDK includes. */
#include "iot_taskpool.h"
/* The priority at which that tasks in the task pool (the worker tasks) get
created. */
#define tpTASK_POOL_WORKER_PRIORITY 1
/*
* Prototypes for the functions that demonstrate the task pool API.
* See the implementation of the prvTaskPoolDemoTask() function within this file
* for a description of the individual functions. A configASSERT() is hit if
* any of the demos encounter any unexpected behaviour.
*/
static void prvExample_BasicSingleJob( void );
static void prvExample_DeferredJobAndCancellingJobs( void );
static void prvExample_BasicRecyclableJob( void );
static void prvExample_ReuseRecyclableJobFromLowPriorityTask( void );
static void prvExample_ReuseRecyclableJobFromHighPriorityTask( void );
/*
* Prototypes of the callback functions used in the examples. The callback
* simply sends a signal (in the form of a direct task notification) to the
* prvTaskPoolDemoTask() task to let the task know that the callback execute.
* The handle of the prvTaskPoolDemoTask() task is not accessed directly, but
* instead passed into the task pool job as the job's context.
*/
static void prvSimpleTaskNotifyCallback( IotTaskPool_t pTaskPool, IotTaskPoolJob_t pJob, void *pUserContext );
/*
* The task used to demonstrate the task pool API. This task just loops through
* each demo in turn.
*/
static void prvTaskPoolDemoTask( void *pvParameters );
/*-----------------------------------------------------------*/
/* Parameters used to create the system task pool - see TBD for more information
* as the task pool used in this example is a slimmed down version of the full
* library - the slimmed down version being intended specifically for FreeRTOS
* kernel use cases. */
static const IotTaskPoolInfo_t xTaskPoolParameters = {
/* Minimum number of threads in a task pool.
* Note the slimmed down version of the task
* pool used by this library does not autoscale
* the number of tasks in the pool so in this
* case this sets the number of tasks in the
* pool. */
2,
/* Maximum number of threads in a task pool.
* Note the slimmed down version of the task
* pool used by this library does not autoscale
* the number of tasks in the pool so in this
* case this parameter is just ignored. */
2,
/* Stack size for every task pool thread - in
* bytes, hence multiplying by the number of bytes
* in a word as configMINIMAL_STACK_SIZE is
* specified in words. */
configMINIMAL_STACK_SIZE * sizeof( portSTACK_TYPE ),
/* Priority for every task pool thread. */
tpTASK_POOL_WORKER_PRIORITY,
};
/*-----------------------------------------------------------*/
void vStartSimpleTaskPoolDemo( void )
{
/* This example uses a single application task, which in turn is used to
* create and send jobs to task pool tasks. */
xTaskCreate( prvTaskPoolDemoTask, /* Function that implements the task. */
"PoolDemo", /* Text name for the task - only used for debugging. */
configMINIMAL_STACK_SIZE, /* Size of stack (in words, not bytes) to allocate for the task. */
NULL, /* Task parameter - not used in this case. */
tskIDLE_PRIORITY, /* Task priority, must be between 0 and configMAX_PRIORITIES - 1. */
NULL ); /* Used to pass out a handle to the created task - not used in this case. */
}
/*-----------------------------------------------------------*/
static void prvTaskPoolDemoTask( void *pvParameters )
{
IotTaskPoolError_t xResult;
uint32_t ulLoops = 0;
/* Remove compiler warnings about unused parameters. */
( void ) pvParameters;
/* The task pool must be created before it can be used. The system task
* pool is the task pool managed by the task pool library itself - the storage
* used by the task pool is provided by the library. */
xResult = IotTaskPool_CreateSystemTaskPool( &xTaskPoolParameters );
configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
/* Attempting to create the task pool again should then appear to succeed
* (in case it is initialised by more than one library), but have no effect. */
xResult = IotTaskPool_CreateSystemTaskPool( &xTaskPoolParameters );
configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
for( ;; )
{
/* Demonstrate the most basic use case where a non persistent job is
* created and scheduled to run immediately. The task pool worker tasks
* (in which the job callback function executes) have a priority above the
* priority of this task so the job's callback executes as soon as it is
* scheduled. */
prvExample_BasicSingleJob();
/* Demonstrate a job being scheduled to run at some time in the
* future, and how a job scheduled to run in the future can be cancelled
* if it has not yet started executing. */
prvExample_DeferredJobAndCancellingJobs();
/* Demonstrate the most basic use of a recyclable job. This is similar
* to prvExample_BasicSingleJob() but using a recyclable job. Creating a
* recyclable job will re-use a previously created and now spare job from
* the task pool's job cache if one is available, or otherwise dynamically
* create a new job if a spare job is not available in the cache but space
* remains in the cache. */
prvExample_BasicRecyclableJob();
/* Demonstrate a recyclable job being created, used, and then re-used.
* In this the task pool worker tasks (in which the job callback
* functions execute) have a priority above the priority of this task so
* the job's callback functions execute as soon as they are scheduled. */
prvExample_ReuseRecyclableJobFromLowPriorityTask();
/* Again demonstrate a recyclable job being created, used, and then
* re-usedbut this time the priority of the task pool worker tasks (in
* which the job callback functions execute) are lower than the priority
* of this task so the job's callback functions don't execute until this
* task enters the blocked state. */
prvExample_ReuseRecyclableJobFromHighPriorityTask();
ulLoops++;
if( ( ulLoops % 10UL ) == 0 )
{
configPRINTF( ( "prvTaskPoolDemoTask() performed %u iterations without hitting an assert.\r\n", ulLoops ) );
fflush( stdout );
}
}
}
/*-----------------------------------------------------------*/
static void prvSimpleTaskNotifyCallback( IotTaskPool_t pTaskPool, IotTaskPoolJob_t pJob, void *pUserContext )
{
/* The jobs context is the handle of the task to which a notification should
* be sent. */
TaskHandle_t xTaskToNotify = ( TaskHandle_t ) pUserContext;
/* Remove warnings about unused parameters. */
( void ) pTaskPool;
( void ) pJob;
/* Notify the task that created this job. */
xTaskNotifyGive( xTaskToNotify );
}
/*-----------------------------------------------------------*/
static void prvExample_BasicSingleJob( void )
{
IotTaskPoolJobStorage_t xJobStorage;
IotTaskPoolJob_t xJob;
IotTaskPoolError_t xResult;
uint32_t ulReturn;
const uint32_t ulNoFlags = 0UL;
const TickType_t xNoDelay = ( TickType_t ) 0;
size_t xFreeHeapBeforeCreatingJob = xPortGetFreeHeapSize();
IotTaskPoolJobStatus_t xJobStatus;
/* Don't expect any notifications to be pending yet. */
configASSERT( ulTaskNotifyTake( pdTRUE, xNoDelay ) == 0 );
/* Create and schedule a job using the handle of this task as the job's
* context and the function that sends a notification to the task handle as
* the job's callback function. This is not a recyclable job so the storage
* required to hold information about the job is provided by this task - in
* this case the storage is on the stack of this task so no memory is allocated
* dynamically but the stack frame must remain in scope for the lifetime of
* the job. */
xResult = IotTaskPool_CreateJob( prvSimpleTaskNotifyCallback, /* Callback function. */
( void * ) xTaskGetCurrentTaskHandle(), /* Job context. */
&xJobStorage,
&xJob );
configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
/* The job has been created but not scheduled so is now ready. */
IotTaskPool_GetStatus( NULL, xJob, &xJobStatus );
configASSERT( xJobStatus == IOT_TASKPOOL_STATUS_READY );
/* This is not a persistent (recyclable) job and its storage is on the
* stack of this function, so the amount of heap space available should not
* have changed since entering this function. */
configASSERT( xFreeHeapBeforeCreatingJob == xPortGetFreeHeapSize() );
/* In the full task pool implementation the first parameter is used to
* pass the handle of the task pool to schedule. The lean task pool
* implementation used in this demo only supports a single task pool, which
* is created internally within the library, so the first parameter is NULL. */
xResult = IotTaskPool_Schedule( NULL, xJob, ulNoFlags );
configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
/* Look for the notification coming from the job's callback function. The
* priority of the task pool worker task that executes the callback is higher
* than the priority of this task so a block time is not needed - the task pool
* worker task preempts this task and sends the notification (from the job's
* callback) as soon as the job is scheduled. */
ulReturn = ulTaskNotifyTake( pdTRUE, xNoDelay );
configASSERT( ulReturn );
/* The job's callback has executed so the job has now completed. */
IotTaskPool_GetStatus( NULL, xJob, &xJobStatus );
configASSERT( xJobStatus == IOT_TASKPOOL_STATUS_COMPLETED );
}
/*-----------------------------------------------------------*/
static void prvExample_DeferredJobAndCancellingJobs( void )
{
IotTaskPoolJobStorage_t xJobStorage;
IotTaskPoolJob_t xJob;
IotTaskPoolError_t xResult;
uint32_t ulReturn;
const uint32_t ulShortDelay_ms = 100UL;
const TickType_t xNoDelay = ( TickType_t ) 0, xAllowableMargin = ( TickType_t ) 5; /* Large margin for Windows port, which is not real time. */
TickType_t xTimeBefore, xElapsedTime, xShortDelay_ticks;
size_t xFreeHeapBeforeCreatingJob = xPortGetFreeHeapSize();
IotTaskPoolJobStatus_t xJobStatus;
/* Don't expect any notifications to be pending yet. */
configASSERT( ulTaskNotifyTake( pdTRUE, xNoDelay ) == 0 );
/* Create a job using the handle of this task as the job's context and the
* function that sends a notification to the task handle as the job's callback
* function. The job is created using storage allocated on the stack of this
* function - so no memory is allocated. */
xResult = IotTaskPool_CreateJob( prvSimpleTaskNotifyCallback, /* Callback function. */
( void * ) xTaskGetCurrentTaskHandle(), /* Job context. */
&xJobStorage,
&xJob );
configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
/* The job has been created but not scheduled so is now ready. */
IotTaskPool_GetStatus( NULL, xJob, &xJobStatus );
configASSERT( xJobStatus == IOT_TASKPOOL_STATUS_READY );
/* This is not a persistent (recyclable) job and its storage is on the
* stack of this function, so the amount of heap space available should not
* have changed since entering this function. */
configASSERT( xFreeHeapBeforeCreatingJob == xPortGetFreeHeapSize() );
/* Schedule the job to run its callback in ulShortDelay_ms milliseconds time.
* In the full task pool implementation the first parameter is used to pass the
* handle of the task pool to schedule. The lean task pool implementation used
* in this demo only supports a single task pool, which is created internally
* within the library, so the first parameter is NULL. */
xResult = IotTaskPool_ScheduleDeferred( NULL, xJob, ulShortDelay_ms );
configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
/* The scheduled job should not have executed yet, so don't expect any
* notifications and expect the job's status to be 'deferred'. */
ulReturn = ulTaskNotifyTake( pdTRUE, xNoDelay );
configASSERT( ulReturn == 0 );
IotTaskPool_GetStatus( NULL, xJob, &xJobStatus );
configASSERT( xJobStatus == IOT_TASKPOOL_STATUS_DEFERRED );
/* As the job has not yet been executed it can be cancelled. */
xResult = IotTaskPool_TryCancel( NULL, xJob, &xJobStatus );
configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
IotTaskPool_GetStatus( NULL, xJob, &xJobStatus );
configASSERT( xJobStatus == IOT_TASKPOOL_STATUS_CANCELED );
/* Schedule the job again, and this time wait until its callback is
* executed (the callback function sends a notification to this task) to see
* that it executes at the right time. */
xTimeBefore = xTaskGetTickCount();
xResult = IotTaskPool_ScheduleDeferred( NULL, xJob, ulShortDelay_ms );
configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
/* Wait twice the deferred execution time to ensure the callback is executed
* before the call below times out. */
ulReturn = ulTaskNotifyTake( pdTRUE, pdMS_TO_TICKS( ulShortDelay_ms * 2UL ) );
xElapsedTime = xTaskGetTickCount() - xTimeBefore;
/* A single notification should have been received... */
configASSERT( ulReturn == 1 );
/* ...and the time since scheduling the job should be greater than or
* equal to the deferred execution time - which is converted to ticks for
* comparison. */
xShortDelay_ticks = pdMS_TO_TICKS( ulShortDelay_ms );
configASSERT( ( xElapsedTime >= xShortDelay_ticks ) && ( xElapsedTime < ( xShortDelay_ticks + xAllowableMargin ) ) );
}
/*-----------------------------------------------------------*/
static void prvExample_BasicRecyclableJob( void )
{
IotTaskPoolJob_t xJob;
IotTaskPoolError_t xResult;
uint32_t ulReturn;
const uint32_t ulNoFlags = 0UL;
const TickType_t xNoDelay = ( TickType_t ) 0;
size_t xFreeHeapBeforeCreatingJob = xPortGetFreeHeapSize();
/* Don't expect any notifications to be pending yet. */
configASSERT( ulTaskNotifyTake( pdTRUE, xNoDelay ) == 0 );
/* Create and schedule a job using the handle of this task as the job's
* context and the function that sends a notification to the task handle as
* the job's callback function. The job is created as a recyclable job and in
* this case the memory used to hold the job status is allocated inside the
* create function. As the job is persistent it can be used multiple times,
* as demonstrated in other examples within this demo. In the full task pool
* implementation the first parameter is used to pass the handle of the task
* pool this recyclable job is to be associated with. In the lean
* implementation of the task pool used by this demo there is only one task
* pool (the system task pool created within the task pool library) so the
* first parameter is NULL. */
xResult = IotTaskPool_CreateRecyclableJob( NULL,
prvSimpleTaskNotifyCallback,
(void * ) xTaskGetCurrentTaskHandle(),
&xJob );
configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
/* This recyclable job is persistent, and in this case created dynamically,
* so expect there to be less heap space than when entering the function. */
configASSERT( xPortGetFreeHeapSize() < xFreeHeapBeforeCreatingJob );
/* In the full task pool implementation the first parameter is used to
* pass the handle of the task pool to schedule. The lean task pool
* implementation used in this demo only supports a single task pool, which
* is created internally within the library, so the first parameter is NULL. */
xResult = IotTaskPool_Schedule( NULL, xJob, ulNoFlags );
configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
/* Look for the notification coming from the job's callback function. The
* priority of the task pool worker task that executes the callback is higher
* than the priority of this task so a block time is not needed - the task pool
* worker task preempts this task and sends the notification (from the job's
* callback) as soon as the job is scheduled. */
ulReturn = ulTaskNotifyTake( pdTRUE, xNoDelay );
configASSERT( ulReturn );
/* Clean up recyclable job. In the full implementation of the task pool
* the first parameter is used to pass a handle to the task pool the job is
* associated with. In the lean implementation of the task pool used by this
* demo there is only one task pool (the system task pool created in the
* task pool library itself) so the first parameter is NULL. */
IotTaskPool_DestroyRecyclableJob( NULL, xJob );
/* Once the job has been deleted the memory used to hold the job is
* returned, so the available heap should be exactly as when entering this
* function. */
configASSERT( xPortGetFreeHeapSize() == xFreeHeapBeforeCreatingJob );
}
/*-----------------------------------------------------------*/
static void prvExample_ReuseRecyclableJobFromLowPriorityTask( void )
{
IotTaskPoolError_t xResult;
uint32_t ulNotificationValue;
const uint32_t ulNoFlags = 0UL;
const TickType_t xNoDelay = ( TickType_t ) 0;
IotTaskPoolJob_t xJob, xJobRecycled;
size_t xFreeHeapBeforeCreatingJob = xPortGetFreeHeapSize(), xFreeHeapAfterCreatingJob = 0;
IotTaskPoolJobStatus_t xJobStatus;
/* Don't expect any notifications to be pending yet. */
configASSERT( ulTaskNotifyTake( pdTRUE, xNoDelay ) == 0 );
/* Create a recycleable job using the handle of this task as the job's
* context and the function that sends a notification to the task handle as
* the job's callback function. In the full task pool implementation the
* first parameter is used to pass the handle of the task pool this
* recyclable job is to be associated with. In the lean implementation of
* the task pool used by this demo there is only one task pool (the system
* task pool created within the task pool library) so the first parameter is
* NULL. */
xResult = IotTaskPool_CreateRecyclableJob( NULL,
prvSimpleTaskNotifyCallback,
(void * ) xTaskGetCurrentTaskHandle(),
&( xJob ) );
configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
/* The job is created as a recyclable job and in this case the memory to
* store the job information is allocated within the create function as at
* this time there are no recyclable jobs in the task pool jobs cache. So
* expect there to be less heap space than when entering the function. */
xFreeHeapAfterCreatingJob = xPortGetFreeHeapSize();
configASSERT( xFreeHeapAfterCreatingJob < xFreeHeapBeforeCreatingJob );
/* The job has been created but not scheduled so is now ready. */
IotTaskPool_GetStatus( NULL, xJob, &xJobStatus );
configASSERT( xJobStatus == IOT_TASKPOOL_STATUS_READY );
/* In the full task pool implementation the first parameter is used to
* pass the handle of the task pool to schedule. The lean task pool
* implementation used in this demo only supports a single task pool, which
* is created internally within the library, so the first parameter is NULL. */
xResult = IotTaskPool_Schedule( NULL, xJob, ulNoFlags );
configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
/* The priority of the task pool task(s) is higher than the priority
* of this task, so the job's callback function should have already
* executed, sending a notification to this task, and incrementing this
* task's notification value. */
xTaskNotifyWait( 0UL, /* Don't clear any bits on entry. */
0UL, /* Don't clear any bits on exit. */
&ulNotificationValue, /* Obtain the notification value. */
xNoDelay ); /* No block time, return immediately. */
configASSERT( ulNotificationValue == 1 );
/* The job's callback has executed so the job is now completed. */
IotTaskPool_GetStatus( NULL, xJob, &xJobStatus );
configASSERT( xJobStatus == IOT_TASKPOOL_STATUS_COMPLETED );
/* Return the job to the task pool's job cache. */
IotTaskPool_RecycleJob( NULL, xJob );
/* Create a recycleable job again using the handle of this task as the job's
* context and the function that sends a notification to the task handle as
* the job's callback function. In the full task pool implementation the
* first parameter is used to pass the handle of the task pool this
* recyclable job is to be associated with. In the lean implementation of
* the task pool used by this demo there is only one task pool (the system
* task pool created within the task pool library) so the first parameter is
* NULL. */
xResult = IotTaskPool_CreateRecyclableJob( NULL,
prvSimpleTaskNotifyCallback,
(void * ) xTaskGetCurrentTaskHandle(),
&( xJobRecycled ) );
configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
/* Since this time the task pool's job cache had a recycleable job, it must
* have been re-used. Thefore expect the free heap space to be same as after
* the creation of first job */
configASSERT( xPortGetFreeHeapSize() == xFreeHeapAfterCreatingJob );
/* Expect the task pool to re-use the job in its cache as opposed to
* allocating a new one. */
configASSERT( xJobRecycled == xJob );
/* In the full task pool implementation the first parameter is used to
* pass the handle of the task pool to schedule. The lean task pool
* implementation used in this demo only supports a single task pool, which
* is created internally within the library, so the first parameter is NULL. */
xResult = IotTaskPool_Schedule( NULL, xJobRecycled, ulNoFlags );
configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
/* The priority of the task pool task(s) is higher than the priority
* of this task, so the job's callback function should have already
* executed, sending a notification to this task, and incrementing this
* task's notification value. */
xTaskNotifyWait( 0UL, /* Don't clear any bits on entry. */
0UL, /* Don't clear any bits on exit. */
&ulNotificationValue, /* Obtain the notification value. */
xNoDelay ); /* No block time, return immediately. */
configASSERT( ulNotificationValue == 2 );
/* The job's callback has executed so the job is now completed. */
IotTaskPool_GetStatus( NULL, xJobRecycled, &xJobStatus );
configASSERT( xJobStatus == IOT_TASKPOOL_STATUS_COMPLETED );
/* Clean up the recyclable job. In the full implementation of the task
* pool the first parameter is used to pass a handle to the task pool the job
* is associated with. In the lean implementation of the task pool used by
* this demo there is only one task pool (the system task pool created in the
* task pool library itself) so the first parameter is NULL. */
xResult = IotTaskPool_DestroyRecyclableJob( NULL, xJobRecycled );
configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
/* Clear all the notification value bits ready for the next example. */
xTaskNotifyWait( portMAX_DELAY, /* Clear all bits on entry - portMAX_DELAY is used as it is a portable way of having all bits set. */
0UL, /* Don't clear any bits on exit. */
NULL, /* Don't need the notification value this time. */
xNoDelay ); /* No block time, return immediately. */
configASSERT( ulTaskNotifyTake( pdTRUE, xNoDelay ) == 0 );
/* Once the job has been deleted the memory used to hold the job is
* returned, so the available heap should be exactly as when entering this
* function. */
configASSERT( xPortGetFreeHeapSize() == xFreeHeapBeforeCreatingJob );
}
/*-----------------------------------------------------------*/
static void prvExample_ReuseRecyclableJobFromHighPriorityTask( void )
{
IotTaskPoolError_t xResult;
uint32_t ulNotificationValue;
const uint32_t ulNoFlags = 0UL;
const TickType_t xNoDelay = ( TickType_t ) 0;
TickType_t xShortDelay = pdMS_TO_TICKS( 150 );
IotTaskPoolJob_t xJob, xJobRecycled;
size_t xFreeHeapBeforeCreatingJob = xPortGetFreeHeapSize(), xFreeHeapAfterCreatingJob = 0;
IotTaskPoolJobStatus_t xJobStatus;
/* Don't expect any notifications to be pending yet. */
configASSERT( ulTaskNotifyTake( pdTRUE, xNoDelay ) == 0 );
/* prvExample_ReuseRecyclableJobFromLowPriorityTask() executes in a task
* that has a lower [task] priority than the task pool's worker tasks.
* Therefore a task pool worker preempts the task that calls
* prvExample_ReuseRecyclableJobFromHighPriorityTask() as soon as the job is
* scheduled. prvExample_ReuseRecyclableJobFromHighPriorityTask() reverses the
* priorities - prvExample_ReuseRecyclableJobFromHighPriorityTask() raises its
* priority to above the task pool's worker tasks, so the worker tasks do not
* execute until the calling task enters the blocked state. First raise the
* priority - passing NULL means raise the priority of the calling task. */
vTaskPrioritySet( NULL, tpTASK_POOL_WORKER_PRIORITY + 1 );
/* Create a recycleable job using the handle of this task as the job's
* context and the function that sends a notification to the task handle as
* the job's callback function. In the full task pool implementation the
* first parameter is used to pass the handle of the task pool this
* recyclable job is to be associated with. In the lean implementation of
* the task pool used by this demo there is only one task pool (the system
* task pool created within the task pool library) so the first parameter is
* NULL. */
xResult = IotTaskPool_CreateRecyclableJob( NULL,
prvSimpleTaskNotifyCallback,
(void * ) xTaskGetCurrentTaskHandle(),
&( xJob ) );
configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
/* The job is created as a recyclable job and in this case the memory to
* store the job information is allocated within the create function as at
* this time there are no recyclable jobs in the task pool jobs cache. So
* expect there to be less heap space than when entering the function. */
xFreeHeapAfterCreatingJob = xPortGetFreeHeapSize();
configASSERT( xFreeHeapAfterCreatingJob < xFreeHeapBeforeCreatingJob );
/* The job has been created but not scheduled so is now ready. */
IotTaskPool_GetStatus( NULL, xJob, &xJobStatus );
configASSERT( xJobStatus == IOT_TASKPOOL_STATUS_READY );
/* In the full task pool implementation the first parameter is used to
* pass the handle of the task pool to schedule. The lean task pool
* implementation used in this demo only supports a single task pool, which
* is created internally within the library, so the first parameter is NULL. */
xResult = IotTaskPool_Schedule( NULL, xJob, ulNoFlags );
configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
/* The priority of the task pool task(s) is lower than the priority
* of this task, so the job's callback function should not have executed
* yet, so don't expect the notification value for this task to have
* changed. */
xTaskNotifyWait( 0UL, /* Don't clear any bits on entry. */
0UL, /* Don't clear any bits on exit. */
&ulNotificationValue, /* Obtain the notification value. */
xNoDelay ); /* No block time, return immediately. */
configASSERT( ulNotificationValue == 0 );
/* When this task blocks to wait for a notification, a worker thread will be
* able to execute - but as soon as its callback function sends a
* notification to this task, this task will preempt it (because it has a
* higher priority). So this task expects to receive one notification. */
xTaskNotifyWait( 0UL, /* Don't clear any bits on entry. */
0UL, /* Don't clear any bits on exit. */
&ulNotificationValue, /* Obtain the notification value. */
xShortDelay ); /* Short delay to allow a task pool worker to execute. */
configASSERT( ulNotificationValue == 1 );
/* Since the scheduled job has now executed, so waiting for another
* notification should timeout without the notification value changing. */
xTaskNotifyWait( 0UL, /* Don't clear any bits on entry. */
0UL, /* Don't clear any bits on exit. */
&ulNotificationValue, /* Obtain the notification value. */
xShortDelay ); /* Short delay to allow a task pool worker to execute. */
configASSERT( ulNotificationValue == 1 );
/* The job's callback has executed so the job is now completed. */
IotTaskPool_GetStatus( NULL, xJob, &xJobStatus );
configASSERT( xJobStatus == IOT_TASKPOOL_STATUS_COMPLETED );
/* Return the job to the task pool's job cache. */
IotTaskPool_RecycleJob( NULL, xJob );
/* Create a recycleable job again using the handle of this task as the job's
* context and the function that sends a notification to the task handle as
* the job's callback function. In the full task pool implementation the
* first parameter is used to pass the handle of the task pool this
* recyclable job is to be associated with. In the lean implementation of
* the task pool used by this demo there is only one task pool (the system
* task pool created within the task pool library) so the first parameter is
* NULL. */
xResult = IotTaskPool_CreateRecyclableJob( NULL,
prvSimpleTaskNotifyCallback,
(void * ) xTaskGetCurrentTaskHandle(),
&( xJobRecycled ) );
configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
/* Since this time the task pool's job cache had a recycleable job, it must
* have been re-used. Thefore expect the free heap space to be same as after
* the creation of first job */
configASSERT( xPortGetFreeHeapSize() == xFreeHeapAfterCreatingJob );
/* Expect the task pool to re-use the job in its cache as opposed to
* allocating a new one. */
configASSERT( xJobRecycled == xJob );
/* In the full task pool implementation the first parameter is used to
* pass the handle of the task pool to schedule. The lean task pool
* implementation used in this demo only supports a single task pool, which
* is created internally within the library, so the first parameter is NULL. */
xResult = IotTaskPool_Schedule( NULL, xJobRecycled, ulNoFlags );
configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
/* The priority of the task pool task(s) is lower than the priority
* of this task, so the job's callback function should not have executed
* yet, so don't expect the notification value for this task to have
* changed. */
xTaskNotifyWait( 0UL, /* Don't clear any bits on entry. */
0UL, /* Don't clear any bits on exit. */
&ulNotificationValue, /* Obtain the notification value. */
xNoDelay ); /* No block time, return immediately. */
configASSERT( ulNotificationValue == 1 );
/* When this task blocks to wait for a notification, a worker thread will be
* able to execute - but as soon as its callback function sends a
* notification to this task, this task will preempt it (because it has a
* higher priority). So this task expects to receive one notification. */
xTaskNotifyWait( 0UL, /* Don't clear any bits on entry. */
0UL, /* Don't clear any bits on exit. */
&ulNotificationValue, /* Obtain the notification value. */
xShortDelay ); /* Short delay to allow a task pool worker to execute. */
configASSERT( ulNotificationValue == 2 );
/* Since the scheduled job has now executed, so waiting for another
* notification should timeout without the notification value changing. */
xTaskNotifyWait( 0UL, /* Don't clear any bits on entry. */
0UL, /* Don't clear any bits on exit. */
&ulNotificationValue, /* Obtain the notification value. */
xShortDelay ); /* Short delay to allow a task pool worker to execute. */
configASSERT( ulNotificationValue == 2 );
/* The job's callback has executed so the job is now completed. */
IotTaskPool_GetStatus( NULL, xJobRecycled, &xJobStatus );
configASSERT( xJobStatus == IOT_TASKPOOL_STATUS_COMPLETED );
/* Clean up the recyclable job. In the full implementation of the task
* pool the first parameter is used to pass a handle to the task pool the job
* is associated with. In the lean implementation of the task pool used by
* this demo there is only one task pool (the system task pool created in the
* task pool library itself) so the first parameter is NULL. */
xResult = IotTaskPool_DestroyRecyclableJob( NULL, xJobRecycled );
configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
/* Reset this task's priority. */
vTaskPrioritySet( NULL, tskIDLE_PRIORITY );
/* Clear all the notification value bits ready for the next example. */
xTaskNotifyWait( portMAX_DELAY, /* Clear all bits on entry - portMAX_DELAY is used as it is a portable way of having all bits set. */
0UL, /* Don't clear any bits on exit. */
NULL, /* Don't need the notification value this time. */
xNoDelay ); /* No block time, return immediately. */
configASSERT( ulTaskNotifyTake( pdTRUE, xNoDelay ) == 0 );
/* Once the job has been deleted the memory used to hold the job is
* returned, so the available heap should be exactly as when entering this
* function. */
configASSERT( xPortGetFreeHeapSize() == xFreeHeapBeforeCreatingJob );
}
/*-----------------------------------------------------------*/
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