tests/null/null.c

   1 /*
   2  * Copyright 2008, Google Inc.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met:
   8  *
   9  *     * Redistributions of source code must retain the above copyright
  10  * notice, this list of conditions and the following disclaimer.
  11  *     * Redistributions in binary form must reproduce the above
  12  * copyright notice, this list of conditions and the following disclaimer
  13  * in the documentation and/or other materials provided with the
  14  * distribution.
  15  *     * Neither the name of Google Inc. nor the names of its
  16  * contributors may be used to endorse or promote products derived from
  17  * this software without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  20  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  22  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  23  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  25  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  26  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  27  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  28  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  29  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <sys/time.h>
  36 #include <time.h>
  37 #include <unistd.h>
  38
  39
  40 extern void __nacl_null(void);
  41
  42 int main(int  ac,
  43          char **av) {
  44   int             opt;
  45   int             num_rep = 10000000;
  46   int             i;
  47   struct timeval  time_start;
  48   struct timeval  time_end;
  49   struct timeval  time_elapsed;
  50   double          time_per_call;
  51
  52   while (EOF != (opt = getopt(ac, av, "r:"))) switch (opt) {
  53     case 'r':
  54       num_rep = strtol(optarg, (char **) NULL, 0);
  55       break;
  56     default:
  57       fprintf(stderr, "Usage: null [-r repetition_count]\n");
  58       return 1;
  59   }
  60   gettimeofday(&time_start, (void *) NULL);
  61   for (i = num_rep; --i >= 0; ) {
  62     __nacl_null();
  63   }
  64   gettimeofday(&time_end, (void *) NULL);
  65   time_elapsed.tv_sec = time_end.tv_sec - time_start.tv_sec;
  66   time_elapsed.tv_usec = time_end.tv_usec - time_start.tv_usec;
  67   if (time_elapsed.tv_usec < 0) {
  68     --time_elapsed.tv_sec;
  69     time_elapsed.tv_usec += 1000000;
  70   }
  71   printf("Number of null syscalls: %d\n", num_rep);
  72   printf("Elapsed time: %d.%06dS\n",
  73          (int) time_elapsed.tv_sec,
  74          (int) time_elapsed.tv_usec);
  75   time_per_call = ((time_elapsed.tv_sec + time_elapsed.tv_usec / 1.0e6)
  76                    / num_rep);
  77   printf("Time per call: %gS or %fnS\n",
  78          time_per_call,
  79          1.0e9 * time_per_call);
  80   printf("Calls per sec: %d\n", (int) (1.0 / time_per_call));
  81   return 0;
  82 }