mart/ex07/ex07a.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 3
  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     rt_printf("Task  : %d\n",num);
  40
  41     rt_sem_p(&mysync,TM_INFINITE);
  42
  43     // let the task run RUNTIME(=200) jiffies in steps of SPINTIME(=20) jiffies
  44     runtime = 0;
  45     while(runtime < EXECTIME) {
  46       rt_timer_spin(SPINTIME*BASEPERIOD);  // spin cpu doing nothing
  47       // note: rt_timer_spin function does not accept jiffies only nanoseconds
  48       //       deviates from timing conventions throughout the Xenomai API
  49
  50       runtime = runtime + SPINTIME;
  51
  52       rt_printf("Running Task  : %d  at time : %d\n",num,runtime);
  53     }
  54     rt_printf("End Task  : %d\n",num);
  55 }
  56
  57 //startup code
  58 void startup()
  59 {
  60   int i;
  61   char  str[10] ;
  62
  63   // semaphore to sync task startup on
  64   rt_sem_create(&mysync,"MySemaphore",0,S_FIFO);
  65
  66   // change to period mode because round robin does not work
  67   // in one shot mode
  68   rt_timer_set_mode(BASEPERIOD);// set tick period
  69   for(i=0; i < NTASKS; i++) {
  70     rt_printf("start task  : %d\n",i);
  71     sprintf(str,"task%d",i);
  72     rt_task_create(&demo_task[i], str, 0, 50, 0);
  73     rt_task_start(&demo_task[i], &demo, &i);
  74   }
  75   rt_printf("wake up all tasks\n");
  76   rt_sem_broadcast(&mysync);
  77 }
  78
  79 void init_xenomai() {
  80   /* Avoids memory swapping for this program */
  81   mlockall(MCL_CURRENT|MCL_FUTURE);
  82
  83   /* Perform auto-init of rt_print buffers if the task doesn't do so */
  84   rt_print_auto_init(1);
  85 }
  86
  87 int main(int argc, char* argv[])
  88 {
  89   printf("\nType CTRL-C to end this program\n\n" );
  90
  91   // code to set things to run xenomai
  92   init_xenomai();
  93
  94   //startup code
  95   startup();
  96
  97   // wait for CTRL-c is typed to end the program
  98   pause();
  99 }