/* * POSIX.4 Timers test program * * Written by J. Vidal * Copyright (C) Dec, 2002 OCERA Consortium. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * published by the Free Software Foundation version 2. * * Name: accuracity.c * Description: Measures timer accuracity for both relative  * and absolute timer specifications. * * Procedure: 1.- Create a thread. *            2.- Program a periodic timer with some period (relative spec) or  *            a one-shot timer for absolute specification.  *            3.- Let expire the timer n times. If it is absolute, reprogram each time *            the timer by adding the period to the absolute time specification. *            4.- After n expirations, calculate the teoric time transcurred (n*period) *            and the real (end_time -start_time). *            5.- Print the error (difference between the teoric time transcurred  *            and the real one) * */#include <rtl.h>#include <rtl_sched.h>#include <time.h>#include <signal.h>pthread_t th;timer_t timer;#define TEST_CLOCK CLOCK_REALTIMEstruct itimerspec interval;struct timespec currenttime;int absflag=1;int tflags;int exitflag=0;int numtimes=1000;hrtime_t spintime= 10*1000*1000;hrtime_t inctime = 20*1000*1000;hrtime_t starttime=0;hrtime_t endtime=0;hrtime_t total_time=0;hrtime_t calctime=0;/* spinit executes during ntime nanoseconds a loop before returning.*/ static int spinit(hrtime_t ntime){  hrtime_t timenow,timeend;  if (spintime == 0)    return 0;  if ((timenow=clock_gethrtime(CLOCK_REALTIME))<0){    return -1;  }    timeend=timenow+ntime;  while (timenow<timeend)    if ((timenow=clock_gethrtime(CLOCK_REALTIME))<0){      rtl_printf("clock_gethrtime fails in handler\n");      return -1;    }  return 0;}/* handlers */static void alarm_handler(int signo){    static hrtime_t timesentered=0;    timesentered++;    if (timesentered < numtimes){    if (inctime < 0 )      return;    if (spinit(spintime) == -1){      rtl_printf("Spin failed in alarm_handler\n");      pthread_exit(NULL);    }        if (absflag){      timespec_add_ns(&interval.it_value,inctime);      if (timer_settime(timer,tflags,&interval,NULL) < 0){	rtl_printf("Error. Could not start timer n handler\n");	pthread_exit(NULL);      }    }    } else {    exitflag=1;  }}void *test_routine(void *arg){  struct sigaction sa;  rtl_sigset_t sigset;  struct sched_param p;  struct timespec res;  int param=(unsigned) arg;    p . sched_priority =param;  pthread_setschedparam (pthread_self(), SCHED_FIFO, &p);  rtl_sigfillset(&sigset);  rtl_sigdelset(&sigset,RTL_SIGUSR1);  pthread_sigmask(SIG_SETMASK,&sigset,NULL);    sa.sa_handler=alarm_handler;    if (sigaction(RTL_SIGUSR1,&sa,NULL)<0){    rtl_printf("Error in sigaction(RTL_SIGUSR2,..);\n");    return (void *)-1;  }    if (clock_getres(CLOCK_REALTIME, &res)){    rtl_printf("Error. Can not get clock resolution");    pthread_exit(NULL);  } else {    rtl_printf("Clock resolution is %d nanoseconds\n",(int)timespec_to_ns(&res));  }    interval.it_interval.tv_sec=0;  interval.it_interval.tv_nsec=0;  if (clock_gettime(CLOCK_REALTIME,&currenttime)<0){    rtl_printf("Error. Can not get current time");    pthread_exit(NULL);  }  starttime= timespec_to_ns(&currenttime);  if (absflag){    rtl_printf("abs time: interrupts: %d at ",numtimes);     rtl_printf("%d nsecs ",(int)inctime);    rtl_printf(", spinning %d nsecs\n",(int)spintime);    tflags= TIMER_ABSTIME;    interval.it_value=currenttime;  } else {    rtl_printf("rel time: interrupts: %d at ",numtimes);    rtl_printf("%d nsecs ",(int)inctime);    rtl_printf(", spinning %d nsecs\n",(int)spintime);    tflags=0;    interval.it_value.tv_sec=0;    interval.it_value.tv_nsec=1;    interval.it_interval.tv_sec=0;    interval.it_interval.tv_nsec=(long)inctime;    //    timespec_normalize(&interval.it_interval);     }  timespec_add_ns(&interval.it_value,inctime);  if (timer_settime(timer,tflags,&interval,NULL)<0){    rtl_printf("Error. Could not start timer\n");    pthread_exit(NULL);  }  for ( ; ; ) {    sigsuspend(&sigset);    if (exitflag){      if (clock_gettime(CLOCK_REALTIME,&currenttime) < 0){	rtl_printf("Error. Can no get current time");	pthread_exit(NULL);      }      endtime= timespec_to_ns(&currenttime);      total_time=endtime -starttime;      calctime= numtimes*inctime;      //      rtl_printf("calculated time: %\n",(unsigned long)calctime);      rtl_printf("error:%ld\n",(long)total_time-calctime);      pthread_exit(NULL);    }  }    return (void *)0;}int init_module(void){  sigevent_t evp;   int ret=0;  evp.sigev_notify=SIGEV_SIGNAL;  evp.sigev_signo=RTL_SIGUSR1;  ret=timer_create(TEST_CLOCK,&evp,&(timer));    if (!ret) rtl_printf("Timer created succesfully\n");  else {    rtl_printf("Error creating timer. errno=%d\n",errno);    return -1;  }    pthread_create(&th,NULL,test_routine,(int *) 1);    return ret;}void cleanup_module(void) {  pthread_delete_np (th);  timer_delete(timer);}