tools/testing/selftests/timers/set-timer-lat.c

   1 /* set_timer latency test
   2  *              John Stultz (john.stultz@linaro.org)
   3  *              (C) Copyright Linaro 2014
   4  *              Licensed under the GPLv2
   5  *
   6  *   This test makes sure the set_timer api is correct
   7  *
   8  *  To build:
   9  *      $ gcc set-timer-lat.c -o set-timer-lat -lrt
  10  *
  11  *   This program is free software: you can redistribute it and/or modify
  12  *   it under the terms of the GNU General Public License as published by
  13  *   the Free Software Foundation, either version 2 of the License, or
  14  *   (at your option) any later version.
  15  *
  16  *   This program is distributed in the hope that it will be useful,
  17  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  *   GNU General Public License for more details.
  20  */
  21
  22
  23 #include <errno.h>
  24 #include <stdio.h>
  25 #include <unistd.h>
  26 #include <time.h>
  27 #include <string.h>
  28 #include <signal.h>
  29 #include <stdlib.h>
  30 #include <pthread.h>
  31 #ifdef KTEST
  32 #include "../kselftest.h"
  33 #else
  34 static inline int ksft_exit_pass(void)
  35 {
  36         exit(0);
  37 }
  38 static inline int ksft_exit_fail(void)
  39 {
  40         exit(1);
  41 }
  42 #endif
  43
  44 #define CLOCK_REALTIME                  0
  45 #define CLOCK_MONOTONIC                 1
  46 #define CLOCK_PROCESS_CPUTIME_ID        2
  47 #define CLOCK_THREAD_CPUTIME_ID         3
  48 #define CLOCK_MONOTONIC_RAW             4
  49 #define CLOCK_REALTIME_COARSE           5
  50 #define CLOCK_MONOTONIC_COARSE          6
  51 #define CLOCK_BOOTTIME                  7
  52 #define CLOCK_REALTIME_ALARM            8
  53 #define CLOCK_BOOTTIME_ALARM            9
  54 #define CLOCK_HWSPECIFIC                10
  55 #define CLOCK_TAI                       11
  56 #define NR_CLOCKIDS                     12
  57
  58
  59 #define NSEC_PER_SEC 1000000000ULL
  60 #define UNRESONABLE_LATENCY 40000000 /* 40ms in nanosecs */
  61
  62 #define TIMER_SECS 1
  63 int alarmcount;
  64 int clock_id;
  65 struct timespec start_time;
  66 long long max_latency_ns;
  67 int timer_fired_early;
  68
  69 char *clockstring(int clockid)
  70 {
  71         switch (clockid) {
  72         case CLOCK_REALTIME:
  73                 return "CLOCK_REALTIME";
  74         case CLOCK_MONOTONIC:
  75                 return "CLOCK_MONOTONIC";
  76         case CLOCK_PROCESS_CPUTIME_ID:
  77                 return "CLOCK_PROCESS_CPUTIME_ID";
  78         case CLOCK_THREAD_CPUTIME_ID:
  79                 return "CLOCK_THREAD_CPUTIME_ID";
  80         case CLOCK_MONOTONIC_RAW:
  81                 return "CLOCK_MONOTONIC_RAW";
  82         case CLOCK_REALTIME_COARSE:
  83                 return "CLOCK_REALTIME_COARSE";
  84         case CLOCK_MONOTONIC_COARSE:
  85                 return "CLOCK_MONOTONIC_COARSE";
  86         case CLOCK_BOOTTIME:
  87                 return "CLOCK_BOOTTIME";
  88         case CLOCK_REALTIME_ALARM:
  89                 return "CLOCK_REALTIME_ALARM";
  90         case CLOCK_BOOTTIME_ALARM:
  91                 return "CLOCK_BOOTTIME_ALARM";
  92         case CLOCK_TAI:
  93                 return "CLOCK_TAI";
  94         };
  95         return "UNKNOWN_CLOCKID";
  96 }
  97
  98
  99 long long timespec_sub(struct timespec a, struct timespec b)
 100 {
 101         long long ret = NSEC_PER_SEC * b.tv_sec + b.tv_nsec;
 102
 103         ret -= NSEC_PER_SEC * a.tv_sec + a.tv_nsec;
 104         return ret;
 105 }
 106
 107
 108 void sigalarm(int signo)
 109 {
 110         long long delta_ns;
 111         struct timespec ts;
 112
 113         clock_gettime(clock_id, &ts);
 114         alarmcount++;
 115
 116         delta_ns = timespec_sub(start_time, ts);
 117         delta_ns -= NSEC_PER_SEC * TIMER_SECS * alarmcount;
 118
 119         if (delta_ns < 0)
 120                 timer_fired_early = 1;
 121
 122         if (delta_ns > max_latency_ns)
 123                 max_latency_ns = delta_ns;
 124 }
 125
 126 void describe_timer(int flags, int interval)
 127 {
 128         printf("%-22s %s %s ",
 129                         clockstring(clock_id),
 130                         flags ? "ABSTIME":"RELTIME",
 131                         interval ? "PERIODIC":"ONE-SHOT");
 132 }
 133
 134 int setup_timer(int clock_id, int flags, int interval, timer_t *tm1)
 135 {
 136         struct sigevent se;
 137         struct itimerspec its1, its2;
 138         int err;
 139
 140         /* Set up timer: */
 141         memset(&se, 0, sizeof(se));
 142         se.sigev_notify = SIGEV_SIGNAL;
 143         se.sigev_signo = SIGRTMAX;
 144         se.sigev_value.sival_int = 0;
 145
 146         max_latency_ns = 0;
 147         alarmcount = 0;
 148         timer_fired_early = 0;
 149
 150         err = timer_create(clock_id, &se, tm1);
 151         if (err) {
 152                 if ((clock_id == CLOCK_REALTIME_ALARM) ||
 153                     (clock_id == CLOCK_BOOTTIME_ALARM)) {
 154                         printf("%-22s %s missing CAP_WAKE_ALARM?    : [UNSUPPORTED]\n",
 155                                         clockstring(clock_id),
 156                                         flags ? "ABSTIME":"RELTIME");
 157                         return 0;
 158                 }
 159                 printf("%s - timer_create() failed\n", clockstring(clock_id));
 160                 return -1;
 161         }
 162
 163         clock_gettime(clock_id, &start_time);
 164         if (flags) {
 165                 its1.it_value = start_time;
 166                 its1.it_value.tv_sec += TIMER_SECS;
 167         } else {
 168                 its1.it_value.tv_sec = TIMER_SECS;
 169                 its1.it_value.tv_nsec = 0;
 170         }
 171         its1.it_interval.tv_sec = interval;
 172         its1.it_interval.tv_nsec = 0;
 173
 174         err = timer_settime(*tm1, flags, &its1, &its2);
 175         if (err) {
 176                 printf("%s - timer_settime() failed\n", clockstring(clock_id));
 177                 return -1;
 178         }
 179
 180         return 0;
 181 }
 182
 183 int check_timer_latency(int flags, int interval)
 184 {
 185         int err = 0;
 186
 187         describe_timer(flags, interval);
 188         printf("timer fired early: %7d : ", timer_fired_early);
 189         if (!timer_fired_early) {
 190                 printf("[OK]\n");
 191         } else {
 192                 printf("[FAILED]\n");
 193                 err = -1;
 194         }
 195
 196         describe_timer(flags, interval);
 197         printf("max latency: %10lld ns : ", max_latency_ns);
 198
 199         if (max_latency_ns < UNRESONABLE_LATENCY) {
 200                 printf("[OK]\n");
 201         } else {
 202                 printf("[FAILED]\n");
 203                 err = -1;
 204         }
 205         return err;
 206 }
 207
 208 int check_alarmcount(int flags, int interval)
 209 {
 210         describe_timer(flags, interval);
 211         printf("count: %19d : ", alarmcount);
 212         if (alarmcount == 1) {
 213                 printf("[OK]\n");
 214                 return 0;
 215         }
 216         printf("[FAILED]\n");
 217         return -1;
 218 }
 219
 220 int do_timer(int clock_id, int flags)
 221 {
 222         timer_t tm1;
 223         const int interval = TIMER_SECS;
 224         int err;
 225
 226         err = setup_timer(clock_id, flags, interval, &tm1);
 227         if (err)
 228                 return err;
 229
 230         while (alarmcount < 5)
 231                 sleep(1);
 232
 233         timer_delete(tm1);
 234         return check_timer_latency(flags, interval);
 235 }
 236
 237 int do_timer_oneshot(int clock_id, int flags)
 238 {
 239         timer_t tm1;
 240         const int interval = 0;
 241         struct timeval timeout;
 242         fd_set fds;
 243         int err;
 244
 245         err = setup_timer(clock_id, flags, interval, &tm1);
 246         if (err)
 247                 return err;
 248
 249         memset(&timeout, 0, sizeof(timeout));
 250         timeout.tv_sec = 5;
 251         FD_ZERO(&fds);
 252         do {
 253                 err = select(FD_SETSIZE, &fds, NULL, NULL, &timeout);
 254         } while (err == -1 && errno == EINTR);
 255
 256         timer_delete(tm1);
 257         err = check_timer_latency(flags, interval);
 258         err |= check_alarmcount(flags, interval);
 259         return err;
 260 }
 261
 262 int main(void)
 263 {
 264         struct sigaction act;
 265         int signum = SIGRTMAX;
 266         int ret = 0;
 267
 268         /* Set up signal handler: */
 269         sigfillset(&act.sa_mask);
 270         act.sa_flags = 0;
 271         act.sa_handler = sigalarm;
 272         sigaction(signum, &act, NULL);
 273
 274         printf("Setting timers for every %i seconds\n", TIMER_SECS);
 275         for (clock_id = 0; clock_id < NR_CLOCKIDS; clock_id++) {
 276
 277                 if ((clock_id == CLOCK_PROCESS_CPUTIME_ID) ||
 278                                 (clock_id == CLOCK_THREAD_CPUTIME_ID) ||
 279                                 (clock_id == CLOCK_MONOTONIC_RAW) ||
 280                                 (clock_id == CLOCK_REALTIME_COARSE) ||
 281                                 (clock_id == CLOCK_MONOTONIC_COARSE) ||
 282                                 (clock_id == CLOCK_HWSPECIFIC))
 283                         continue;
 284
 285                 ret |= do_timer(clock_id, TIMER_ABSTIME);
 286                 ret |= do_timer(clock_id, 0);
 287                 ret |= do_timer_oneshot(clock_id, TIMER_ABSTIME);
 288                 ret |= do_timer_oneshot(clock_id, 0);
 289         }
 290         if (ret)
 291                 return ksft_exit_fail();
 292         return ksft_exit_pass();
 293 }