condvar.c

最新rtlinux内核源码

/*
 * Added user signals to condition variable test, 
 * Dec, 2002 Josep Vidal <[e-mail]> (OCERA)
 */

#include <rtl.h>
#include <time.h>
#include <pthread.h>

static pthread_t thread;
static pthread_mutex_t mutex /* = PTHREAD_MUTEX_INITIALIZER */;
static pthread_cond_t cond;
static int timed=1;
MODULE_PARM(timed,"i");

void sig_handler(int sig_rec) {

  rtl_printf("I'm RT-thread, really blocked on a condition variable ...\n");
  rtl_printf("but signals handlers are executed regardless being blocked in a condition variable\n");
  rtl_printf("After finishing handler execution for signal:%d, I will remain suspended\n",sig_rec);
}

static void * start_routine(void *arg) {
  int ret;
  hrtime_t t;
  hrtime_t t2;
  struct sigaction sa;
  rtl_sigset_t mask;

  struct sched_param p;
  p . sched_priority = 1;
  pthread_setschedparam (pthread_self(), SCHED_FIFO, &p);

  sa.sa_handler=sig_handler;

  rtl_sigfillset(&mask);
  rtl_sigdelset(&mask,RTL_SIGRTMIN);
  pthread_sigmask(SIG_SETMASK,&mask,NULL);

  if ((ret=sigaction(RTL_SIGRTMIN,&sa,NULL))<0 ) {
    rtl_printf("sigaction(%d,&sa,NULL) FAILING, ret:%d.\n",RTL_SIGRTMIN,ret);
  }

  rtl_printf("RTLinux thread starts on CPU%d\n", rtl_getcpuid());
  if (timed) {
    rtl_printf("RT-thread: about to pthread_cond_timedwait\n");
    t = clock_gethrtime(CLOCK_REALTIME);

    pthread_mutex_lock (&mutex);
    ret = pthread_cond_timedwait (&cond, &mutex, hrt2ts(t + 2000000));
    pthread_mutex_unlock (&mutex);

    t2 = clock_gethrtime(CLOCK_REALTIME);

    rtl_printf("RT-thread: pthread_cond_timedwait returned %d (%d ns elapsed)\n", ret, (unsigned) (t2 - t));
  }


  rtl_printf("RT-thread: about to pthread_cond_wait\n");
  t = clock_gethrtime(CLOCK_REALTIME);
  rtl_printf("RT-thread: about to kill itself with RTL_SIGRTMIN\n");
  ret=pthread_kill(pthread_self(),RTL_SIGRTMIN);
  rtl_printf("RT-thread: pthread_kill returned %d\n",ret);
  pthread_mutex_lock (&mutex);
  ret = pthread_cond_wait (&cond, &mutex);
  pthread_mutex_unlock (&mutex);

  t2 = clock_gethrtime(CLOCK_REALTIME);

  rtl_printf("RT-thread: pthread_cond_wait returned %d (%d ns elapsed)\n", ret, (unsigned) (t2 - t));

  return (void *) 35;
}


int init_module(void) {
  int ret;
  hrtime_t t;
  int sleep = 500000000;
  pthread_attr_t attr;

  rtl_printf("RTLinux condvar test starts on CPU%d\n", rtl_getcpuid());
  pthread_attr_init (&attr);
  /* try to run the thread on another CPU */
  if (rtl_cpu_exists(!rtl_getcpuid())) {
    pthread_attr_setcpu_np(&attr, !rtl_getcpuid());
  }

  pthread_mutex_init (&mutex, NULL);
  pthread_cond_init (&cond, NULL);

  ret = pthread_create (&thread, &attr, start_routine, 0);
  if (ret) {
    rtl_printf("failed to create a thread\n");
    return ret;
  }

  rtl_printf("Linux thread is about to busy-wait for %d ns\n", sleep);
  t = gethrtime();
  while (gethrtime() < t + sleep)
    ;

  rtl_printf("Linux thread is about to signal the condition\n");
  pthread_mutex_lock (&mutex);
  ret = pthread_cond_signal (&cond);
  pthread_mutex_unlock (&mutex);
  rtl_printf("Linux thread: pthread_cond_signal returned %d\n", ret);

  return 0;
}


void cleanup_module(void) {
  void *retval;
  pthread_cancel (thread);
  pthread_join (thread, &retval);
  /* 	rtl_printf("RTLinux mutex: joined thread returned %d\n", (int) retval); */
  pthread_mutex_destroy (&mutex);
}