lab15.c

#include <stdio.h>
#include <signal.h>
#include <unistd.h>
#include <sys/mman.h>

#include <native/task.h>
#include <native/timer.h>
#include <native/sem.h>

#include <rtdk.h>
#include <sys/io.h>

#define NTASKS 3

RT_TASK demo_task[NTASKS];
RT_SEM mysync;

// set new baseperiod for the clock :
// - clock only increments counter when a base period is passed
// - the unit of the clock counter is called a jiffie, which in fact
//   represents that a baseperiod is passed
//   e.g. If 10 baseperiods are passed, the clock gives an increase
//   in 10 jiffies

#define BASEPERIOD 1e6 // baseperiod in ns.

// when base period is set, all times in the api are expressed in jiffies
#define EXECTIME 200 // execution time in jiffies
#define SPINTIME 10 // spin time in jiffies

void demo(void *arg)
{
  RTIME starttime, runtime;

  int num=*(int *)arg;

  RT_TASK *curtask;
  RT_TASK_INFO curtaskinfo;

  rt_printf("Task : %d\n",num);
  rt_sem_p(&mysync,TM_INFINITE);

  rt_task_set_mode(0,T_RRB ,NULL);

  // let the task run RUNTIME(=200) jiffies in steps of SPINTIME(=20) jiffies
  runtime = 0;

  while(runtime < EXECTIME) {
    rt_timer_spin(SPINTIME*BASEPERIOD); // spin cpu doing nothing

    // note: rt_timer_spin function does not accept jiffies only nanoseconds
    //    deviates from timing conventions throughout the Xenomai API

    runtime = runtime + SPINTIME;

    rt_printf("Running Task : %d at time : %d\n",num,runtime);
  }
  rt_printf("End Task : %d\n",num);
}

//startup code
void startup()
{
  int i;
  char str[10] ;

  // semaphore to sync task startup on
  rt_sem_create(&mysync,"MySemaphore",0,S_FIFO);

  // change to period mode because round robin does not work
  // in one shot mode
  rt_timer_set_mode(BASEPERIOD);// set tick period

  for(i=0; i < NTASKS; i++) {
    rt_printf("start task : %d\n",i);
    sprintf(str,"task%d",i);

    rt_task_create(&demo_task[i], str, 0, 50, 0);
    rt_task_slice(&demo_task[i], 5);
    rt_task_start(&demo_task[i], &demo, &i);
  }

  rt_printf("wake up all tasks\n");
  rt_sem_broadcast(&mysync);
}

void init_xenomai() {
  /* Avoids memory swapping for this program */
  mlockall(MCL_CURRENT|MCL_FUTURE);

  /* Perform auto-init of rt_print buffers if the task doesn't do so */
  rt_print_auto_init(1);
}

int main(int argc, char* argv[])
{
  printf("\nType CTRL-C to end this program\n\n" );

  // code to set things to run xenomai
  init_xenomai();

  //startup code
  startup();

  // wait for CTRL-c is typed to end the program
  pause();
}