1. gzyueqian
      13352868059
      首頁 > 新聞中心 > > 正文

      Linux操作系統下實時定時器posix_timer

      更新時間: 2008-04-10 13:49:22來源: 粵嵌教育瀏覽量:711

        其實Linux下還有一種高精度的定時器,那就是posix_timer。原理上來說,可以在變頻的時候也使用rdtsc指令,因為CPU的頻率我們也是知道的,變頻的時候內核也是知道的。

        下面是我的timer_create的例子,編譯的時候要加上rt庫,這是linux的realtime庫:

      gcc -o test test.c
                  #include
                  #include
                  #include
                  #include
                  #include
                  #define rdtsc(low,high) __asm__ __volatile__("rdtsc" : "=a" (low), "=d" (high))
                  timer_t tt;
                  void handler (int sig, siginfo_t * extra, void *cruft)
                  ...{
                  static last_i=0;
                  unsigned int i, j;
                  rdtsc(i,j);
                  printf ("time:%u, %u, [%u] %uHZ ", j, i, i-last_i, (i-last_i)*10/1000000);
                  last_i = i;
                  }
                  int main ()
                  ...{
                  int i=0;
                  sigset_t sigset;
                  sigfillset (&sigset);
                  sigdelset (&sigset, SIGRTMIN);
                  sigprocmask (SIG_SETMASK, &sigset, NULL);
                  struct sigaction sa;
                  sigfillset (&sa.sa_mask);
                  sa.sa_flags = SA_SIGINFO;
                  sa.sa_sigaction = handler;
                  if (sigaction (SIGRTMIN, &sa, NULL) < 0)
                  ...{
                  perror ("sigaction failed ");
                  exit (-1);
                  }
                  struct sigevent timer_event;
                  struct itimerspec timer;
                  timer.it_interval.tv_sec = 0;
                  timer.it_interval.tv_nsec = 100 * 1000 * 1000;
                  timer.it_value = timer.it_interval;
                  timer_event.sigev_notify = SIGEV_SIGNAL;
                  timer_event.sigev_signo = SIGRTMIN;
                  timer_event.sigev_value.sival_ptr = (void *) &tt;
                  if (timer_create (CLOCK_REALTIME, &timer_event, &tt) < 0)
                  ...{
                  perror ("timer_create failed");
                  exit (-1);
                  }
                  if (timer_settime (tt, 0, &timer, NULL) < 0)
                  ...{
                  perror ("timer_settime failed");
                  exit (-1);
                  }
                  while (i++ < 10)
                  ...{
                  pause ();
                  }
                  return 0;
                  }

        輸出結果:

      time:166081, 1934350847, [1934350847] 2163HZ
                  time:166081, 2120528291, [186177444] 1861HZ
                  time:166081, 2306679576, [186151285] 1861HZ
                  time:166081, 2494695630, [188016054] 1880HZ
                  time:166081, 2680865389, [186169759] 1861HZ
                  time:166081, 2867018473, [186153084] 1861HZ
                  time:166081, 3053152230, [186133757] 1861HZ
                  time:166081, 3239309935, [186157705] 1861HZ
                  time:166081, 3425467261, [186157326] 1861HZ
                  time:166081, 3611639266, [186172005] 1861HZ


      免費預約試聽課

      亚洲另类欧美综合久久图片区_亚洲中文字幕日产无码2020_欧美日本一区二区三区桃色视频_亚洲AⅤ天堂一区二区三区

      
      

      1. 亚洲激情国产激情在线 | 亚洲天堂久久精品 | 久久久综合色88一本到鬼色 | 亚洲一级二级视频在线观看 | 亚洲第一网站a√在线观看 午夜福利网站你懂得 | 亚洲国产日韩一区二区三区 |