natanael/ex07/ex07c.c

   1 /* ex07a.c */
   2
   3 #include <stdio.h>
   4 #include <signal.h>
   5 #include <unistd.h>
   6 #include <sys/mman.h>
   7
   8 #include <native/task.h>
   9 #include <native/timer.h>
  10 #include <native/sem.h>
  11
  12 #include  <rtdk.h>
  13 #include <sys/io.h>
  14
  15 #define NTASKS 4
  16
  17 RT_TASK demo_task[NTASKS];
  18 RT_SEM mysync;
  19
  20 // set new baseperiod for the clock :
  21 // - clock only increments counter when a base period is passed
  22 // - the unit of the clock counter is called a jiffie, which in fact
  23 //   represents that a baseperiod is passed
  24 //   e.g. If 10 baseperiods are passed, the clock gives an increase
  25 //   in 10 jiffies
  26 #define BASEPERIOD 1e6   // baseperiod in ns.
  27
  28 // when base period is set, all times in the api are expressed in jiffies
  29 #define EXECTIME   200   // execution time in jiffies
  30 #define SPINTIME    10   // spin time in jiffies
  31
  32 void demo(void *arg)
  33 {
  34     RTIME starttime, runtime;
  35     int num=*(int *)arg;
  36     RT_TASK *curtask;
  37     RT_TASK_INFO curtaskinfo;
  38
  39         curtask=rt_task_self();
  40
  41         rt_task_set_mode(0,T_RRB ,NULL);
  42         rt_task_slice(curtask,EXECTIME/SPINTIME);
  43
  44     rt_printf("Task  : %d\n",num);
  45
  46     rt_sem_p(&mysync,TM_INFINITE);
  47
  48     // let the task run RUNTIME(=200) jiffies in steps of SPINTIME(=20) jiffies
  49     runtime = 0;
  50     while(runtime < EXECTIME) {
  51       rt_timer_spin(SPINTIME*BASEPERIOD);  // spin cpu doing nothing
  52       // note: rt_timer_spin function does not accept jiffies only nanoseconds
  53       //       deviates from timing conventions throughout the Xenomai API
  54
  55       runtime = runtime + SPINTIME;
  56
  57       rt_printf("Running Task  : %d  at time : %d\n",num,runtime);
  58     }
  59     rt_printf("End Task  : %d\n",num);
  60 }
  61
  62 //startup code
  63 void startup()
  64 {
  65   int i;
  66   char  str[10] ;
  67
  68   // semaphore to sync task startup on
  69   rt_sem_create(&mysync,"MySemaphore",0,S_FIFO);
  70
  71   // change to period mode because round robin does not work
  72   // in one shot mode
  73   rt_timer_set_mode(BASEPERIOD);// set tick period
  74   for(i=0; i < NTASKS; i++) {
  75     rt_printf("start task  : %d\n",i);
  76     sprintf(str,"task%d",i);
  77     rt_task_create(&demo_task[i], str, 0, 50, 0);
  78     rt_task_start(&demo_task[i], &demo, &i);
  79   }
  80   // Set the latest task priority higher
  81   rt_task_set_priority(&demo_task[3],80);
  82
  83   rt_printf("wake up all tasks\n");
  84   rt_sem_broadcast(&mysync);
  85 }
  86
  87 void init_xenomai() {
  88   /* Avoids memory swapping for this program */
  89   mlockall(MCL_CURRENT|MCL_FUTURE);
  90
  91   /* Perform auto-init of rt_print buffers if the task doesn't do so */
  92   rt_print_auto_init(1);
  93 }
  94
  95 int main(int argc, char* argv[])
  96 {
  97   printf("\nType CTRL-C to end this program\n\n" );
  98
  99   // code to set things to run xenomai
 100   init_xenomai();
 101
 102   //startup code
 103   startup();
 104
 105   // wait for CTRL-c is typed to end the program
 106   pause();
 107 }