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