xref: /linux/tools/testing/selftests/timers/inconsistency-check.c (revision 67f8bc848ee31831336bd478e57d2f993551902e)
1 /* Time inconsistency check test
2  *		by: john stultz (johnstul@us.ibm.com)
3  *		(C) Copyright IBM 2003, 2004, 2005, 2012
4  *		(C) Copyright Linaro Limited 2015
5  *		Licensed under the GPLv2
6  *
7  *  To build:
8  *	$ gcc inconsistency-check.c -o inconsistency-check -lrt
9  *
10  *   This program is free software: you can redistribute it and/or modify
11  *   it under the terms of the GNU General Public License as published by
12  *   the Free Software Foundation, either version 2 of the License, or
13  *   (at your option) any later version.
14  *
15  *   This program is distributed in the hope that it will be useful,
16  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
17  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
18  *   GNU General Public License for more details.
19  */
20 
21 
22 
23 #include <stdio.h>
24 #include <unistd.h>
25 #include <stdlib.h>
26 #include <time.h>
27 #include <sys/time.h>
28 #include <sys/timex.h>
29 #include <string.h>
30 #include <signal.h>
31 #include "clock-helpers.h"
32 #include "kselftest.h"
33 
34 /* CLOCK_HWSPECIFIC == CLOCK_SGI_CYCLE (Deprecated) */
35 #define CLOCK_HWSPECIFIC		10
36 
37 #define CALLS_PER_LOOP 64
38 
39 /* returns 1 if a <= b, 0 otherwise */
40 static inline int in_order(struct timespec a, struct timespec b)
41 {
42 	/* use unsigned to avoid false positives on 2038 rollover */
43 	if ((unsigned long)a.tv_sec < (unsigned long)b.tv_sec)
44 		return 1;
45 	if ((unsigned long)a.tv_sec > (unsigned long)b.tv_sec)
46 		return 0;
47 	if (a.tv_nsec > b.tv_nsec)
48 		return 0;
49 	return 1;
50 }
51 
52 
53 
54 int consistency_test(int clock_type, unsigned long seconds)
55 {
56 	struct timespec list[CALLS_PER_LOOP];
57 	int i, inconsistent;
58 	long now, then;
59 	time_t t;
60 	char *start_str;
61 
62 	clock_gettime(clock_type, &list[0]);
63 	now = then = list[0].tv_sec;
64 
65 	/* timestamp start of test */
66 	t = time(0);
67 	start_str = ctime(&t);
68 
69 	while (seconds == -1 || now - then < seconds) {
70 		inconsistent = -1;
71 
72 		/* Fill list */
73 		for (i = 0; i < CALLS_PER_LOOP; i++)
74 			clock_gettime(clock_type, &list[i]);
75 
76 		/* Check for inconsistencies */
77 		for (i = 0; i < CALLS_PER_LOOP - 1; i++)
78 			if (!in_order(list[i], list[i+1]))
79 				inconsistent = i;
80 
81 		/* display inconsistency */
82 		if (inconsistent >= 0) {
83 			unsigned long long delta;
84 
85 			ksft_print_msg("\%s\n", start_str);
86 			for (i = 0; i < CALLS_PER_LOOP; i++) {
87 				if (i == inconsistent)
88 					ksft_print_msg("--------------------\n");
89 				ksft_print_msg("%lu:%lu\n", list[i].tv_sec,
90 							list[i].tv_nsec);
91 				if (i == inconsistent + 1)
92 					ksft_print_msg("--------------------\n");
93 			}
94 			delta = list[inconsistent].tv_sec * NSEC_PER_SEC;
95 			delta += list[inconsistent].tv_nsec;
96 			delta -= list[inconsistent+1].tv_sec * NSEC_PER_SEC;
97 			delta -= list[inconsistent+1].tv_nsec;
98 			ksft_print_msg("Delta: %llu ns\n", delta);
99 			fflush(0);
100 			/* timestamp inconsistency*/
101 			t = time(0);
102 			ksft_print_msg("%s\n", ctime(&t));
103 			return -1;
104 		}
105 		now = list[0].tv_sec;
106 	}
107 	return 0;
108 }
109 
110 
111 int main(int argc, char *argv[])
112 {
113 	int clockid, opt;
114 	int userclock = CLOCK_REALTIME;
115 	int maxclocks = CLOCK_TAI + 1;
116 	int runtime = 10;
117 	struct timespec ts;
118 
119 	/* Process arguments */
120 	while ((opt = getopt(argc, argv, "t:c:")) != -1) {
121 		switch (opt) {
122 		case 't':
123 			runtime = atoi(optarg);
124 			break;
125 		case 'c':
126 			userclock = atoi(optarg);
127 			maxclocks = userclock + 1;
128 			break;
129 		default:
130 			printf("Usage: %s [-t <secs>] [-c <clockid>]\n", argv[0]);
131 			printf("	-t: Number of seconds to run\n");
132 			printf("	-c: clockid to use (default, all clockids)\n");
133 			exit(-1);
134 		}
135 	}
136 
137 	setbuf(stdout, NULL);
138 
139 	ksft_print_header();
140 	ksft_set_plan(maxclocks - userclock);
141 
142 	for (clockid = userclock; clockid < maxclocks; clockid++) {
143 
144 		if (clockid == CLOCK_HWSPECIFIC || clock_gettime(clockid, &ts)) {
145 			ksft_test_result_skip("%-31s\n", clock_name(clockid));
146 			continue;
147 		}
148 
149 		if (consistency_test(clockid, runtime)) {
150 			ksft_test_result_fail("%-31s\n", clock_name(clockid));
151 			ksft_exit_fail();
152 		} else {
153 			ksft_test_result_pass("%-31s\n", clock_name(clockid));
154 		}
155 	}
156 	ksft_exit_pass();
157 }
158