Remove unreliable parts of rt/tst-cpuclock2

  This is a follow-up to the tst-cpuclock1.c change here:
9a29f1a2ae3d4bb253ee368e0d71db0ca9494120

This test, like tst-cpuclock1, may fail on heavily loaded VM
servers (and has occasionally failed on the 32bit trybot),
so tests that rely on "wall time" have been removed.
  

On 05/10/2021 16:34, DJ Delorie via Libc-alpha wrote:
> 
> This is a follow-up to the tst-cpuclock1.c change here:
> 9a29f1a2ae3d4bb253ee368e0d71db0ca9494120
> 
> This test, like tst-cpuclock1, may fail on heavily loaded VM
> servers (and has occasionally failed on the 32bit trybot),
> so tests that rely on "wall time" have been removed.
> 
> diff --git a/rt/tst-cpuclock2.c b/rt/tst-cpuclock2.c

Thanks, these pieces are too flaky and generated a lot of false
positives.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

> index eebc3609d0a..32a1b75c2f3 100644
> --- a/rt/tst-cpuclock2.c
> +++ b/rt/tst-cpuclock2.c
> @@ -62,22 +62,9 @@ chew_cpu (void *arg)
>    return NULL;
>  }
>  
> -static unsigned long long int
> -tsdiff (const struct timespec *before, const struct timespec *after)
> -{
> -  struct timespec diff = { .tv_sec = after->tv_sec - before->tv_sec,
> -			   .tv_nsec = after->tv_nsec - before->tv_nsec };
> -  while (diff.tv_nsec < 0)
> -    {
> -      --diff.tv_sec;
> -      diff.tv_nsec += 1000000000;
> -    }
> -  return diff.tv_sec * 1000000000ULL + diff.tv_nsec;
> -}
> -
> -static unsigned long long int
> +static void
>  test_nanosleep (clockid_t clock, const char *which,
> -		const struct timespec *before, int *bad)
> +		int *bad)
>  {
>    const struct timespec sleeptime = { .tv_nsec = 100000000 };
>    int e = clock_nanosleep (clock, 0, &sleeptime, NULL);
> @@ -85,13 +72,13 @@ test_nanosleep (clockid_t clock, const char *which,
>      {
>        printf ("clock_nanosleep not supported for %s CPU clock: %s\n",
>  	      which, strerror (e));
> -      return 0;
> +      return;
>      }
>    if (e != 0)
>      {
>        printf ("clock_nanosleep on %s CPU clock: %s\n", which, strerror (e));
>        *bad = 1;
> -      return 0;
> +      return;
>      }
>  
>    struct timespec after;
> @@ -100,16 +87,7 @@ test_nanosleep (clockid_t clock, const char *which,
>        printf ("clock_gettime on %s CPU clock %lx => %s\n",
>  	      which, (unsigned long int) clock, strerror (errno));
>        *bad = 1;
> -      return 0;
> -    }
> -
> -  unsigned long long int diff = tsdiff (before, &after);
> -  if (diff < sleeptime.tv_nsec || diff > sleeptime.tv_nsec * 2)
> -    {
> -      printf ("clock_nanosleep on %s slept %llu (outside reasonable range)\n",
> -	      which, diff);
> -      *bad = 1;
> -      return diff;
> +      return;
>      }
>  
>    struct timespec sleeptimeabs = sleeptime;
> @@ -126,7 +104,7 @@ test_nanosleep (clockid_t clock, const char *which,
>        printf ("absolute clock_nanosleep on %s CPU clock: %s\n",
>  	      which, strerror (e));
>        *bad = 1;
> -      return diff;
> +      return;
>      }
>  
>    struct timespec afterabs;
> @@ -135,28 +113,10 @@ test_nanosleep (clockid_t clock, const char *which,
>        printf ("clock_gettime on %s CPU clock %lx => %s\n",
>  	      which, (unsigned long int) clock, strerror (errno));
>        *bad = 1;
> -      return diff;
> -    }
> -
> -  unsigned long long int sleepdiff = tsdiff (&sleeptimeabs, &afterabs);
> -  if (sleepdiff > sleeptime.tv_nsec)
> -    {
> -      printf ("\
> -absolute clock_nanosleep on %s %llu past target (outside reasonable range)\n",
> -	      which, sleepdiff);
> -      *bad = 1;
> +      return;
>      }
>  
> -  unsigned long long int diffabs = tsdiff (&after, &afterabs);
> -  if (diffabs < sleeptime.tv_nsec || diffabs > sleeptime.tv_nsec * 2)
> -    {
> -      printf ("\
> -absolute clock_nanosleep on %s slept %llu (outside reasonable range)\n",
> -	      which, diffabs);
> -      *bad = 1;
> -    }
> -
> -  return diff + diffabs;
> +  return;
>  }
>  
>  
> @@ -290,37 +250,12 @@ do_test (void)
>    printf ("self thread after sleep => %ju.%.9ju\n",
>  	  (uintmax_t) me_after.tv_sec, (uintmax_t) me_after.tv_nsec);
>  
> -  unsigned long long int th_diff = tsdiff (&before, &after);
> -  unsigned long long int pdiff = tsdiff (&process_before, &process_after);
> -  unsigned long long int my_diff = tsdiff (&me_before, &me_after);
> -
> -  if (th_diff < 100000000 || th_diff > 600000000)
> -    {
> -      printf ("live thread before - after %llu outside reasonable range\n",
> -	      th_diff);
> -      result = 1;
> -    }
> -
> -  if (my_diff > 100000000)
> -    {
> -      printf ("self thread before - after %llu outside reasonable range\n",
> -	      my_diff);
> -      result = 1;
> -    }
> -
> -  if (pdiff < th_diff)
> -    {
> -      printf ("process before - after %llu outside reasonable range (%llu)\n",
> -	      pdiff, th_diff);
> -      result = 1;
> -    }
> -
> -  process_after.tv_nsec += test_nanosleep (th_clock, "live thread",
> -					   &after, &result);
> -  process_after.tv_nsec += test_nanosleep (process_clock, "process",
> -					   &process_after, &result);
> +  test_nanosleep (th_clock, "live thread",
> +		  &result);
> +  test_nanosleep (process_clock, "process",
> +		  &result);
>    test_nanosleep (CLOCK_PROCESS_CPUTIME_ID,
> -		  "PROCESS_CPUTIME_ID", &process_after, &result);
> +		  "PROCESS_CPUTIME_ID", &result);
>  
>    pthread_cancel (th);
>  
>
  

Thanks!  Pushed.