tools/testing/selftests/timers/skew_consistency.c

   1 /* ADJ_FREQ Skew consistency test
   2  *              by: john stultz (johnstul@us.ibm.com)
   3  *              (C) Copyright IBM 2012
   4  *              Licensed under the GPLv2
   5  *
   6  *  NOTE: This is a meta-test which cranks the ADJ_FREQ knob back
   7  *  and forth and watches for consistency problems. Thus this test requires
   8  *  that the inconsistency-check tests be present in the same directory it
   9  *  is run from.
  10  *
  11  *  To build:
  12  *      $ gcc skew_consistency.c -o skew_consistency -lrt
  13  *
  14  *   This program is free software: you can redistribute it and/or modify
  15  *   it under the terms of the GNU General Public License as published by
  16  *   the Free Software Foundation, either version 2 of the License, or
  17  *   (at your option) any later version.
  18  *
  19  *   This program is distributed in the hope that it will be useful,
  20  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  *   GNU General Public License for more details.
  23  */
  24
  25
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <unistd.h>
  29 #include <sys/time.h>
  30 #include <sys/timex.h>
  31 #include <time.h>
  32 #include <sys/types.h>
  33 #include <sys/stat.h>
  34 #include <fcntl.h>
  35 #include <string.h>
  36 #include <sys/wait.h>
  37 #include "../kselftest.h"
  38
  39 int main(int argc, char **argv)
  40 {
  41         struct timex tx;
  42         int ret, ppm;
  43         pid_t pid;
  44
  45
  46         printf("Running Asynchronous Frequency Changing Tests...\n");
  47
  48         pid = fork();
  49         if (!pid)
  50                 return system("./inconsistency-check -c 1 -t 600");
  51
  52         ppm = 500;
  53         ret = 0;
  54
  55         while (pid != waitpid(pid, &ret, WNOHANG)) {
  56                 ppm = -ppm;
  57                 tx.modes = ADJ_FREQUENCY;
  58                 tx.freq = ppm << 16;
  59                 adjtimex(&tx);
  60                 usleep(500000);
  61         }
  62
  63         /* Set things back */
  64         tx.modes = ADJ_FREQUENCY;
  65         tx.offset = 0;
  66         adjtimex(&tx);
  67
  68
  69         if (ret) {
  70                 printf("[FAILED]\n");
  71                 ksft_exit_fail();
  72         }
  73         printf("[OK]\n");
  74         ksft_exit_pass();
  75 }