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 values in /proc/uptime increment monotonically 17 // while shifting across CPUs. 18 #undef NDEBUG 19 #include <assert.h> 20 #include <errno.h> 21 #include <unistd.h> 22 #include <sys/syscall.h> 23 #include <stdlib.h> 24 #include <string.h> 25 26 #include <stdint.h> 27 #include <sys/types.h> 28 #include <sys/stat.h> 29 #include <fcntl.h> 30 31 #include "proc-uptime.h" 32 33 static inline int sys_sched_getaffinity(pid_t pid, unsigned int len, unsigned long *m) 34 { 35 return syscall(SYS_sched_getaffinity, pid, len, m); 36 } 37 38 static inline int sys_sched_setaffinity(pid_t pid, unsigned int len, unsigned long *m) 39 { 40 return syscall(SYS_sched_setaffinity, pid, len, m); 41 } 42 43 int main(void) 44 { 45 unsigned int len; 46 unsigned long *m; 47 unsigned int cpu; 48 uint64_t u0, u1, i0, i1; 49 int fd; 50 51 /* find out "nr_cpu_ids" */ 52 m = NULL; 53 len = 0; 54 do { 55 len += sizeof(unsigned long); 56 free(m); 57 m = malloc(len); 58 } while (sys_sched_getaffinity(0, len, m) == -1 && errno == EINVAL); 59 60 fd = open("/proc/uptime", O_RDONLY); 61 assert(fd >= 0); 62 63 proc_uptime(fd, &u0, &i0); 64 for (cpu = 0; cpu < len * 8; cpu++) { 65 memset(m, 0, len); 66 m[cpu / (8 * sizeof(unsigned long))] |= 1UL << (cpu % (8 * sizeof(unsigned long))); 67 68 /* CPU might not exist, ignore error */ 69 sys_sched_setaffinity(0, len, m); 70 71 proc_uptime(fd, &u1, &i1); 72 assert(u1 >= u0); 73 assert(i1 >= i0); 74 u0 = u1; 75 i0 = i1; 76 } 77 78 return 0; 79 } 80