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
39int 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 -t 60");
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}