Attachment 234088 Details for Bug 264131 – reproducing test program

reproducing test program

repro_timer.c (text/plain), 2.33 KB, created by Conor Hughes on 2022-05-21 19:21:41 UTC

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Creator: Conor Hughes

Created: 2022-05-21 19:21:41 UTC

Size: 2.33 KB

patch

obsolete

>#include <sys/event.h>
>#include <sys/types.h>
>#include <stdio.h>
>#include <err.h>
>#include <sysexits.h>
>#include <stdbool.h>
>#include <time.h>
>
>#ifndef NSEC_PER_SEC
>#define NSEC_PER_SEC 1000000000ULL
>#endif // ndef NSEC_PER_SEC
>
>int cmh_timespec_cmp(struct timespec lhs, struct timespec rhs)
>{
>  if ( lhs.tv_sec > rhs.tv_sec ) {
>    return 1;
>  } else if ( lhs.tv_sec < rhs.tv_sec ) {
>    return -1;
>  } else if ( lhs.tv_nsec > rhs.tv_nsec ) {
>    return 1;
>  } else if ( lhs.tv_nsec < rhs.tv_nsec ) {
>    return -1;
>  } else {
>    return 0;
>  }
>}
>
>bool cmh_timespec_sub(struct timespec lhs, struct timespec rhs,
>                      struct timespec *out)
>{
>  bool negative = cmh_timespec_cmp(lhs, rhs) < 0;
>  if ( negative ) {
>    struct timespec tmp = lhs;
>    lhs = rhs;
>    rhs = tmp;
>  }
>
>  if ( out ) {
>    if ( lhs.tv_nsec < rhs.tv_nsec ) {
>      // borrow
>      lhs.tv_sec -= 1;
>      // This is safe for a normalized timespec.
>      lhs.tv_nsec += NSEC_PER_SEC;
>    }
>
>    out->tv_nsec = lhs.tv_nsec - rhs.tv_nsec;
>    out->tv_sec = lhs.tv_sec - rhs.tv_sec;
>  }
>
>  return negative;
>}
>
>
>int main(void)
>{
>  static const int64_t milliseconds_wait = 500;
>  struct kevent kev;
>  EV_SET(&kev, 1, EVFILT_TIMER, EV_ADD | EV_ENABLE, 0, milliseconds_wait, NULL);
>  int kq = kqueue();
>  if ( kq < 0 ) {
>    err(EX_OSERR, "kqueue");
>  }
>
>  struct timespec last_fire;
>  if ( clock_gettime(CLOCK_MONOTONIC, &last_fire) ) {
>    err(EX_OSERR, "clock_gettime");
>  }
>
>  // Add timer.
>  if ( kevent(kq, &kev, 1, NULL, 0, NULL) < 0 ) {
>    err(EX_OSERR, "kevent (add)");
>  }
>
>  for ( ; ; ) {
>    // Wait for events.
>    int nevents = kevent(kq, NULL, 0, &kev, 1, NULL);
>    if ( nevents < 0 ) {
>      err(EX_OSERR, "kevent (wait)");
>    } else if ( nevents != 1 ) {
>      fprintf(stderr, "bogus number of events %d?\n", nevents);
>      continue;
>    }
>
>    struct timespec now;
>    if ( clock_gettime(CLOCK_MONOTONIC, &now) ) {
>      err(EX_OSERR, "clock_gettime");
>    }
>    struct timespec diff;
>    if ( cmh_timespec_sub(now, last_fire, &diff) ) {
>      errx(EX_OSERR, "clock_gettime(CLOCK_MONOTONIC) went backwards?");
>    }
>
>    fprintf(stderr, "got event, ident %llu, filter %d, data %lld; last fire was %ld ms ago\n",
>            (unsigned long long)kev.ident, kev.filter, (long long)kev.data, (long)((diff.tv_sec * 1000) + (diff.tv_nsec / 1000000)));
>
>    last_fire = now;
>  }
>
>  return 0;
>}

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Attachments on bug 264131: 234088