1 /*
2 * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>
3 *
4 * Permission to use, copy, modify, and distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 */
16 // Test that boottime value in /proc/uptime and CLOCK_BOOTTIME increment
17 // monotonically. We don't test idle time monotonicity due to broken iowait
18 // task counting, cf: comment above get_cpu_idle_time_us()
19 #undef NDEBUG
20 #include <assert.h>
21 #include <stdint.h>
22 #include <sys/types.h>
23 #include <sys/stat.h>
24 #include <fcntl.h>
25
26 #include "proc-uptime.h"
27
28 int main(void)
29 {
30 uint64_t start, u0, u1, c0, c1;
31 int fd;
32
33 fd = open("/proc/uptime", O_RDONLY);
34 assert(fd >= 0);
35
36 u0 = proc_uptime(fd);
37 start = u0;
38 c0 = clock_boottime();
39
40 do {
41 u1 = proc_uptime(fd);
42 c1 = clock_boottime();
43
44 /* Is /proc/uptime monotonic ? */
45 assert(u1 >= u0);
46
47 /* Is CLOCK_BOOTTIME monotonic ? */
48 assert(c1 >= c0);
49
50 /* Is CLOCK_BOOTTIME VS /proc/uptime monotonic ? */
51 assert(c0 >= u0);
52
53 u0 = u1;
54 c0 = c1;
55 } while (u1 - start < 100);
56
57 return 0;
58 }
59
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.