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 #define NSEC_PER_SEC 1000000000LL
40 
main(int argc,char ** argv)41 int main(int argc, char **argv)
42 {
43 	struct timex tx;
44 	int ret, ppm;
45 	pid_t pid;
46 
47 
48 	printf("Running Asynchronous Frequency Changing Tests...\n");
49 
50 	pid = fork();
51 	if (!pid)
52 		return system("./inconsistency-check -c 1 -t 600");
53 
54 	ppm = 500;
55 	ret = 0;
56 
57 	while (pid != waitpid(pid, &ret, WNOHANG)) {
58 		ppm = -ppm;
59 		tx.modes = ADJ_FREQUENCY;
60 		tx.freq = ppm << 16;
61 		adjtimex(&tx);
62 		usleep(500000);
63 	}
64 
65 	/* Set things back */
66 	tx.modes = ADJ_FREQUENCY;
67 	tx.offset = 0;
68 	adjtimex(&tx);
69 
70 
71 	if (ret) {
72 		printf("[FAILED]\n");
73 		return ksft_exit_fail();
74 	}
75 	printf("[OK]\n");
76 	return ksft_exit_pass();
77 }
78