Bug#47035: setitimer lacks feature

[Marcus Brinkmann <Marcus.Brinkmann@ruhr-uni-bochum.de>]

Package: libc0.2
Version: N/A

Hello,

(this is a repost, to get it in the BTS.)
(want to get binutils off my plate by fixing the hertz.c code for us.)

Ok, sysdeps/mach/hurd/setitimer.c is unfinished code (ITIMER_PROF and
ITIMER_VIRTUAL are not implemented at all), however, there is also a small
feature missing that would be extremely useful for binutils/gprof:

Something like the following code is used to measure the hertz value:

====================================================================
#include <sys/time.h>
#include <unistd.h>

int
hertz (int timer)
{
  struct itimerval tim;

  tim.it_interval.tv_sec = 0;
  tim.it_interval.tv_usec = 1;
  tim.it_value.tv_sec = 0;
  tim.it_value.tv_usec = 0;
  setitimer (timer, &tim, 0);
  setitimer (timer, 0, &tim);

  printf("tim.it_interval.tv_sec = %i\n", tim.it_interval.tv_sec);
  printf("tim.it_interval.tv_usec = %i\n", tim.it_interval.tv_usec);
  printf("tim.it_value.tv_sec = %i\n", tim.it_value.tv_sec);
  printf("tim.it_value.tv_usec = %i\n", tim.it_value.tv_usec);

  if (tim.it_interval.tv_usec < 2)
    {
      return -1;
    }
  return 1000000 / tim.it_interval.tv_usec;
}

main() {
  printf("ITIMER_REAL: %i, _SC_CLK_TCK: %i\n",
         hertz(ITIMER_REAL), sysconf (_SC_CLK_TCK));
}
====================================================================

Under Linux, I get the following output:

tim.it_interval.tv_sec = 0
tim.it_interval.tv_usec = 10000
tim.it_value.tv_sec = 0
tim.it_value.tv_usec = 0
ITIMER_REAL: 100, _SC_CLK_TCK: 100


Under the Hurd, I get the following:

tim.it_interval.tv_sec = 0
tim.it_interval.tv_usec = 1
tim.it_value.tv_sec = 0
tim.it_value.tv_usec = 0
ITIMER_REAL: -1, _SC_CLK_TCK: 100

The code in binutils/gprof/hertz.c does only try _SC_CLK_TCK if setitimer is
not available. Do you think this code should be rearranged? Can you fix the
glibc code to support the above use of setitimer?

Thanks,
Marcus

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