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 while shifting across CPUs. We don't test idle time
18 // monotonicity due to broken iowait task counting, cf: comment above
19 // get_cpu_idle_time_us()
20 #undef NDEBUG
21 #include <assert.h>
22 #include <errno.h>
23 #include <unistd.h>
24 #include <sys/syscall.h>
25 #include <stdlib.h>
26 #include <string.h>
27
28 #include <stdint.h>
29 #include <sys/types.h>
30 #include <sys/stat.h>
31 #include <fcntl.h>
32
33 #include "proc-uptime.h"
34
35 static inline int sys_sched_getaffinity(pid_t pid, unsigned int len, unsigned long *m)
36 {
37 return syscall(SYS_sched_getaffinity, pid, len, m);
38 }
39
40 static inline int sys_sched_setaffinity(pid_t pid, unsigned int len, unsigned long *m)
41 {
42 return syscall(SYS_sched_setaffinity, pid, len, m);
43 }
44
45 int main(void)
46 {
47 uint64_t u0, u1, c0, c1;
48 unsigned int len;
49 unsigned long *m;
50 unsigned int cpu;
51 int fd;
52
53 /* find out "nr_cpu_ids" */
54 m = NULL;
55 len = 0;
56 do {
57 len += sizeof(unsigned long);
58 free(m);
59 m = malloc(len);
60 } while (sys_sched_getaffinity(0, len, m) == -1 && errno == EINVAL);
61
62 fd = open("/proc/uptime", O_RDONLY);
63 assert(fd >= 0);
64
65 u0 = proc_uptime(fd);
66 c0 = clock_boottime();
67
68 for (cpu = 0; cpu < len * 8; cpu++) {
69 memset(m, 0, len);
70 m[cpu / (8 * sizeof(unsigned long))] |= 1UL << (cpu % (8 * sizeof(unsigned long)));
71
72 /* CPU might not exist, ignore error */
73 sys_sched_setaffinity(0, len, m);
74
75 u1 = proc_uptime(fd);
76 c1 = clock_boottime();
77
78 /* Is /proc/uptime monotonic ? */
79 assert(u1 >= u0);
80
81 /* Is CLOCK_BOOTTIME monotonic ? */
82 assert(c1 >= c0);
83
84 /* Is CLOCK_BOOTTIME VS /proc/uptime monotonic ? */
85 assert(c0 >= u0);
86
87 u0 = u1;
88 c0 = c1;
89 }
90
91 return 0;
92 }
93
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