| 其实linux下还有一种高精度的定时器，那就是posix_timer。原理上来说，可以在变频的时候也使用rdtsc指令，因为CPU的频率我们也是知道的，变频的时候内核也是知道的。 下面是我的timer_create的例子，编译的时候要加上rt库，这是linux的realtime库： 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 = http://www.knowsky.com/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;} 输出结果： time:166081, 1934350847, [1934350847] 2163HZtime:166081, 2120528291, [186177444] 1861HZtime:166081, 2306679576, [186151285] 1861HZtime:166081, 2494695630, [188016054] 1880HZtime:166081, 2680865389, [186169759] 1861HZtime:166081, 2867018473, [186153084] 1861HZtime:166081, 3053152230, [186133757] 1861HZtime:166081, 3239309935, [186157705] 1861HZtime:166081, 3425467261, [186157326] 1861HZtime:166081, 3611639266, [186172005] 1861HZ |
