On 12/1/18 9:52 PM, Matheus Pinto via Xenomai wrote:
> Hi,
>
> I want use the Xenomai library as underlayer for objects classes in C++.
> For that, I am using the follow system:
>
> -Ubuntu Mate 16.04.2 (Xenial)
> -Xenomai/cobalt v3.0.6
> -Raspberry Pi 3 with Broadcom BCM2837
>
> This prototype code is in a .cpp main file:
>
> #include "test_led.hpp"
> #include <stdio.h>
> #include <stdlib.h>
> #include <iostream>
> #include <signal.h>
> #include <unistd.h>
> #include <sys/mman.h>
> #include <alchemy/task.h>
> #include <alchemy/timer.h>
> #include <alchemy/heap.h>
>
> using namespace std;
>
> /*******************TASKS PROTOTYPES*********************/
>
> void PubFunc(void * arg);
>
> void ManFunc(void* arg);
>
> void TopicTaskFunc(void * args);
>
> /*******************************************************/
>
>
> class Topic
> {
> private:
> RT_TASK task;
> public:
>
> Topic(void)
> {
> rt_task_create(&task, "", 100000, 20, 0);
> }
>
> ~Topic(void)
> {
> rt_task_delete(&task);
> }
>
> RT_TASK* GetTask(void)
> {
> return &task;
> }
>
> private:
> friend void TopicTaskFunc(void* args);
> };
>
>
> class Communic{
> private:
> Topic *top;
> RT_HEAP heap;
> public:
>
> Communic():
> top(NULL)
> {
> /*******************Create heap to allocate dynamically the
> objects*********************/
> if(rt_heap_create(&(this->heap), "commHeap", 83886080, H_PRIO) != 0)
> {
> rt_printf("Impossible create heap.\n");
> exit(1);
> }
> }
>
> void InitComm()
> {
> void *temp;
>
>
> /*******************Allocate memory for Topic object and call
> constructor****************/
> if(rt_heap_alloc(&(this->heap),
> sizeof(Topic),
> TM_INFINITE,
> (void**)&(temp))
> != 0)
> {
> rt_printf("Problem to create topic: impossible allocate heap
> for topic.\n");
> exit(1);
> }
>
> this->top = new(temp) Topic();
>
> /*****************Initiate the topic task, that will start after
> management task sleep***/
> rt_task_start(this->top->GetTask(),
> TopicTaskFunc,
> (void*)this->top);
> }
>
> void DeinitComm(void)
> {
> this->top->~Topic();
> led_TurnOn(9); // This led never is ON.
> rt_heap_free(&(this->heap), this->top);
> }
>
> };
>
> /*******************TASKS IMPLEMENTATIONS*********************/
>
> void PubFunc(void * arg)
> {
> uint16_t id = *((uint16_t*)arg);
> size_t execNum = 0;
>
> RT_TASK_INFO info;
>
> rt_task_inquire(rt_task_self(), &info);
>
> rt_printf("Start Task with PID: %d.\n", info.pid);
>
> /*Sleep for 1 second and show the current execution number*/
> for(;;)
> {
> execNum++;
> rt_printf("Task %d -> Execution %d.\n", id, execNum);
> rt_task_sleep(1000000000);
> }
> }
>
> void ManFunc(void* arg)
> {
> RT_TASK taskHand;
> Communic comm;
> size_t id = 1;
>
> /* Create the task for "PubFunc above" and init the comm object.
> * After 5 seconds, sleep for "Pub Func execute and delete it and
> * deinitialize comm object (with its own task )"*/
> for(;;)
> {
> rt_task_create(&taskHand, "", 500, 5, 0);
> rt_task_start(&taskHand,
> PubFunc,
> (void*)&id);
>
> comm.InitComm();
> rt_task_sleep((uint64_t)(((uint64_t)1000000000)*5));
> comm.DeinitComm();
>
> rt_task_delete(&taskHand);
> rt_task_sleep(1000000000);
> }
> }
>
> void TopicTaskFunc(void * args)
> {
> RT_TASK_INFO info;
>
> rt_task_inquire(rt_task_self(), &info);
>
> rt_printf("topic task PID = %d.\n",info.pid);
>
> /* Just stay suspend and wait be deleted.
> * HINT: the task is awaken when management task call delete
> * through "comm.Deinit()", The led being ON confirmed that,
> * besides that the program is freeze when led is ON.*/
> for(;;)
> {
> rt_task_suspend(rt_task_self());
> led_TurnOn(8);
> }
> }
>
> /*************************************************************************/
>
> int main(int argc, char* argv[])
> {
> RT_TASK taskHand;
>
> // Lock memory : avoid memory swapping for this program
> mlockall(MCL_CURRENT|MCL_FUTURE);
>
> led_Init(8);
> led_Init(9);
> led_TurnOff(8);
> led_TurnOff(9);
>
> rt_task_create(&taskHand, "", 500, 40, 0);
> rt_task_start(&taskHand,
> ManFunc,
> NULL);
>
> for(;;)
> {
>
> getchar();
> }
> }
>
> The first thing I do was create a management task (ManFunc) in main with
> the higher priority (40). Inside this task another task (PubFunc) is create
> directly with priority 5, and other is create indirectly (TopicTaskFunc)
> with the call oh method "comm.InitComm" with priority 20.
>
> After creation, ManFunc sleep for 5 seconds, to PubFunc execute is
> workload (Just print). The TopicTaskFunc do nothing, because is stuck in a
> "rt_task_suspend" inside a loop.
>
> Passed the 5 seconds, the PubFunc stop its execution because its lower
> priority. However, in call of "comm.DeinitComm" the program freeze. It was
> confirmed that the reason is because in the call of "rt_task_delete"
> for TopicTaskFunc,
> it is awaken from its blocked state and get stuck in its own loop.
>
> This is a weird behavior, because:
> - rt_task_delete resumes the TopicTaskFunc, instead just removing it from
> schedule and:
Technically speaking, Linux threads cannot be "removed from schedule" by
other threads: they do block or exit, possibly as a result of a remote
action or event, typically signals. So the question would rather be: why
doesn't your thread receive the cancellation request sent on behalf of
rt_task_delete()?
> - TopicTaskFunc have a lower priority than ManFunc, but execute instead
> that.
>
> Any tip for this problem?
>
Try --enable-async-cancel when configuring.
--
Philippe.
