1  /* Test of getting resource utilization.
       2     Copyright (C) 2012-2023 Free Software Foundation, Inc.
       3  
       4     This program is free software: you can redistribute it and/or modify
       5     it under the terms of the GNU General Public License as published by
       6     the Free Software Foundation, either version 3 of the License, or
       7     (at your option) any later version.
       8  
       9     This program is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      12     GNU General Public License for more details.
      13  
      14     You should have received a copy of the GNU General Public License
      15     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      16  
      17  /* Written by Bruno Haible <bruno@clisp.org>, 2012.  */
      18  
      19  #include <config.h>
      20  
      21  #include <sys/resource.h>
      22  
      23  #include "signature.h"
      24  SIGNATURE_CHECK (getrusage, int, (int, struct rusage *));
      25  
      26  #include <sys/time.h>
      27  
      28  #include "macros.h"
      29  
      30  volatile unsigned int counter;
      31  
      32  int
      33  main (void)
      34  {
      35    struct rusage before;
      36    struct rusage after;
      37    int ret;
      38  
      39    ret = getrusage (RUSAGE_SELF, &before);
      40    ASSERT (ret == 0);
      41  
      42    /* Busy-loop for one second.  */
      43    {
      44      struct timeval t0;
      45      ASSERT (gettimeofday (&t0, NULL) == 0);
      46  
      47      for (;;)
      48        {
      49          struct timeval t;
      50          int i;
      51  
      52          for (i = 0; i < 1000000; i++)
      53            counter++;
      54  
      55          ASSERT (gettimeofday (&t, NULL) == 0);
      56          if (t.tv_sec - t0.tv_sec > 1
      57              || (t.tv_sec - t0.tv_sec == 1 && t.tv_usec >= t0.tv_usec))
      58            break;
      59        }
      60    }
      61  
      62    ret = getrusage (RUSAGE_SELF, &after);
      63    ASSERT (ret == 0);
      64  
      65    ASSERT (after.ru_utime.tv_sec >= before.ru_utime.tv_sec);
      66    ASSERT (after.ru_stime.tv_sec >= before.ru_stime.tv_sec);
      67    {
      68      /* Compute time spent during busy-looping (in usec).  */
      69      unsigned int spent_utime =
      70        (after.ru_utime.tv_sec > before.ru_utime.tv_sec
      71         ? (after.ru_utime.tv_sec - before.ru_utime.tv_sec - 1) * 1000000U
      72           + after.ru_utime.tv_usec + (1000000U - before.ru_utime.tv_usec)
      73         : after.ru_utime.tv_usec - before.ru_utime.tv_usec);
      74      unsigned int spent_stime =
      75        (after.ru_stime.tv_sec > before.ru_stime.tv_sec
      76         ? (after.ru_stime.tv_sec - before.ru_stime.tv_sec - 1) * 1000000U
      77           + after.ru_stime.tv_usec + (1000000U - before.ru_stime.tv_usec)
      78         : after.ru_stime.tv_usec - before.ru_stime.tv_usec);
      79  
      80      ASSERT (spent_utime + spent_stime <= 2 * 1000000U);
      81      /* Assume that the load during this busy-looping was less than 100.  */
      82      ASSERT (spent_utime + spent_stime > 10000U);
      83    }
      84  
      85    return 0;
      86  }