xref: /linux/tools/testing/selftests/timers/skew_consistency.c (revision ca55b2fef3a9373fcfc30f82fd26bc7fccbda732)
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 <stdlib.h>
36 #include <string.h>
37 #include <sys/wait.h>
38 #ifdef KTEST
39 #include "../kselftest.h"
40 #else
41 static inline int ksft_exit_pass(void)
42 {
43 	exit(0);
44 }
45 static inline int ksft_exit_fail(void)
46 {
47 	exit(1);
48 }
49 #endif
50 
51 #define NSEC_PER_SEC 1000000000LL
52 
53 int main(int argv, char **argc)
54 {
55 	struct timex tx;
56 	int ret, ppm;
57 	pid_t pid;
58 
59 
60 	printf("Running Asyncrhonous Frequency Changing Tests...\n");
61 
62 	pid = fork();
63 	if (!pid)
64 		return system("./inconsistency-check -c 1 -t 600");
65 
66 	ppm = 500;
67 	ret = 0;
68 
69 	while (pid != waitpid(pid, &ret, WNOHANG)) {
70 		ppm = -ppm;
71 		tx.modes = ADJ_FREQUENCY;
72 		tx.freq = ppm << 16;
73 		adjtimex(&tx);
74 		usleep(500000);
75 	}
76 
77 	/* Set things back */
78 	tx.modes = ADJ_FREQUENCY;
79 	tx.offset = 0;
80 	adjtimex(&tx);
81 
82 
83 	if (ret) {
84 		printf("[FAILED]\n");
85 		return ksft_exit_fail();
86 	}
87 	printf("[OK]\n");
88 	return ksft_exit_pass();
89 }
90