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