2 * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>
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.
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.
16 // Test that values in /proc/uptime increment monotonically
17 // while shifting across CPUs.
22 #include <sys/syscall.h>
27 #include <sys/types.h>
31 #include "proc-uptime.h"
33 static inline int sys_sched_getaffinity(pid_t pid, unsigned int len, unsigned long *m)
35 return syscall(SYS_sched_getaffinity, pid, len, m);
38 static inline int sys_sched_setaffinity(pid_t pid, unsigned int len, unsigned long *m)
40 return syscall(SYS_sched_setaffinity, pid, len, m);
48 uint64_t u0, u1, i0, i1;
51 /* find out "nr_cpu_ids" */
55 len += sizeof(unsigned long);
58 } while (sys_sched_getaffinity(0, len, m) == -EINVAL);
60 fd = open("/proc/uptime", O_RDONLY);
63 proc_uptime(fd, &u0, &i0);
64 for (cpu = 0; cpu < len * 8; cpu++) {
66 m[cpu / (8 * sizeof(unsigned long))] |= 1UL << (cpu % (8 * sizeof(unsigned long)));
68 /* CPU might not exist, ignore error */
69 sys_sched_setaffinity(0, len, m);
71 proc_uptime(fd, &u1, &i1);