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 #include "../kselftest.h"
  32
  33 #define CLOCK_REALTIME                  0
  34 #define CLOCK_MONOTONIC                 1
  35 #define CLOCK_PROCESS_CPUTIME_ID        2
  36 #define CLOCK_THREAD_CPUTIME_ID         3
  37 #define CLOCK_MONOTONIC_RAW             4
  38 #define CLOCK_REALTIME_COARSE           5
  39 #define CLOCK_MONOTONIC_COARSE          6
  40 #define CLOCK_BOOTTIME                  7
  41 #define CLOCK_REALTIME_ALARM            8
  42 #define CLOCK_BOOTTIME_ALARM            9
  43 #define CLOCK_HWSPECIFIC                10
  44 #define CLOCK_TAI                       11
  45 #define NR_CLOCKIDS                     12
  46
  47
  48 #define NSEC_PER_SEC 1000000000ULL
  49 #define UNRESONABLE_LATENCY 40000000 /* 40ms in nanosecs */
  50
  51 #define TIMER_SECS 1
  52 int alarmcount;
  53 int clock_id;
  54 struct timespec start_time;
  55 long long max_latency_ns;
  56 int timer_fired_early;
  57
  58 char *clockstring(int clockid)
  59 {
  60         switch (clockid) {
  61         case CLOCK_REALTIME:
  62                 return "CLOCK_REALTIME";
  63         case CLOCK_MONOTONIC:
  64                 return "CLOCK_MONOTONIC";
  65         case CLOCK_PROCESS_CPUTIME_ID:
  66                 return "CLOCK_PROCESS_CPUTIME_ID";
  67         case CLOCK_THREAD_CPUTIME_ID:
  68                 return "CLOCK_THREAD_CPUTIME_ID";
  69         case CLOCK_MONOTONIC_RAW:
  70                 return "CLOCK_MONOTONIC_RAW";
  71         case CLOCK_REALTIME_COARSE:
  72                 return "CLOCK_REALTIME_COARSE";
  73         case CLOCK_MONOTONIC_COARSE:
  74                 return "CLOCK_MONOTONIC_COARSE";
  75         case CLOCK_BOOTTIME:
  76                 return "CLOCK_BOOTTIME";
  77         case CLOCK_REALTIME_ALARM:
  78                 return "CLOCK_REALTIME_ALARM";
  79         case CLOCK_BOOTTIME_ALARM:
  80                 return "CLOCK_BOOTTIME_ALARM";
  81         case CLOCK_TAI:
  82                 return "CLOCK_TAI";
  83         };
  84         return "UNKNOWN_CLOCKID";
  85 }
  86
  87
  88 long long timespec_sub(struct timespec a, struct timespec b)
  89 {
  90         long long ret = NSEC_PER_SEC * b.tv_sec + b.tv_nsec;
  91
  92         ret -= NSEC_PER_SEC * a.tv_sec + a.tv_nsec;
  93         return ret;
  94 }
  95
  96
  97 void sigalarm(int signo)
  98 {
  99         long long delta_ns;
 100         struct timespec ts;
 101
 102         clock_gettime(clock_id, &ts);
 103         alarmcount++;
 104
 105         delta_ns = timespec_sub(start_time, ts);
 106         delta_ns -= NSEC_PER_SEC * TIMER_SECS * alarmcount;
 107
 108         if (delta_ns < 0)
 109                 timer_fired_early = 1;
 110
 111         if (delta_ns > max_latency_ns)
 112                 max_latency_ns = delta_ns;
 113 }
 114
 115 void describe_timer(int flags, int interval)
 116 {
 117         printf("%-22s %s %s ",
 118                         clockstring(clock_id),
 119                         flags ? "ABSTIME":"RELTIME",
 120                         interval ? "PERIODIC":"ONE-SHOT");
 121 }
 122
 123 int setup_timer(int clock_id, int flags, int interval, timer_t *tm1)
 124 {
 125         struct sigevent se;
 126         struct itimerspec its1, its2;
 127         int err;
 128
 129         /* Set up timer: */
 130         memset(&se, 0, sizeof(se));
 131         se.sigev_notify = SIGEV_SIGNAL;
 132         se.sigev_signo = SIGRTMAX;
 133         se.sigev_value.sival_int = 0;
 134
 135         max_latency_ns = 0;
 136         alarmcount = 0;
 137         timer_fired_early = 0;
 138
 139         err = timer_create(clock_id, &se, tm1);
 140         if (err) {
 141                 if ((clock_id == CLOCK_REALTIME_ALARM) ||
 142                     (clock_id == CLOCK_BOOTTIME_ALARM)) {
 143                         printf("%-22s %s missing CAP_WAKE_ALARM?    : [UNSUPPORTED]\n",
 144                                         clockstring(clock_id),
 145                                         flags ? "ABSTIME":"RELTIME");
 146                         /* Indicate timer isn't set, so caller doesn't wait */
 147                         return 1;
 148                 }
 149                 printf("%s - timer_create() failed\n", clockstring(clock_id));
 150                 return -1;
 151         }
 152
 153         clock_gettime(clock_id, &start_time);
 154         if (flags) {
 155                 its1.it_value = start_time;
 156                 its1.it_value.tv_sec += TIMER_SECS;
 157         } else {
 158                 its1.it_value.tv_sec = TIMER_SECS;
 159                 its1.it_value.tv_nsec = 0;
 160         }
 161         its1.it_interval.tv_sec = interval;
 162         its1.it_interval.tv_nsec = 0;
 163
 164         err = timer_settime(*tm1, flags, &its1, &its2);
 165         if (err) {
 166                 printf("%s - timer_settime() failed\n", clockstring(clock_id));
 167                 return -1;
 168         }
 169
 170         return 0;
 171 }
 172
 173 int check_timer_latency(int flags, int interval)
 174 {
 175         int err = 0;
 176
 177         describe_timer(flags, interval);
 178         printf("timer fired early: %7d : ", timer_fired_early);
 179         if (!timer_fired_early) {
 180                 printf("[OK]\n");
 181         } else {
 182                 printf("[FAILED]\n");
 183                 err = -1;
 184         }
 185
 186         describe_timer(flags, interval);
 187         printf("max latency: %10lld ns : ", max_latency_ns);
 188
 189         if (max_latency_ns < UNRESONABLE_LATENCY) {
 190                 printf("[OK]\n");
 191         } else {
 192                 printf("[FAILED]\n");
 193                 err = -1;
 194         }
 195         return err;
 196 }
 197
 198 int check_alarmcount(int flags, int interval)
 199 {
 200         describe_timer(flags, interval);
 201         printf("count: %19d : ", alarmcount);
 202         if (alarmcount == 1) {
 203                 printf("[OK]\n");
 204                 return 0;
 205         }
 206         printf("[FAILED]\n");
 207         return -1;
 208 }
 209
 210 int do_timer(int clock_id, int flags)
 211 {
 212         timer_t tm1;
 213         const int interval = TIMER_SECS;
 214         int err;
 215
 216         err = setup_timer(clock_id, flags, interval, &tm1);
 217         /* Unsupported case - return 0 to not fail the test */
 218         if (err)
 219                 return err == 1 ? 0 : err;
 220
 221         while (alarmcount < 5)
 222                 sleep(1);
 223
 224         timer_delete(tm1);
 225         return check_timer_latency(flags, interval);
 226 }
 227
 228 int do_timer_oneshot(int clock_id, int flags)
 229 {
 230         timer_t tm1;
 231         const int interval = 0;
 232         struct timeval timeout;
 233         int err;
 234
 235         err = setup_timer(clock_id, flags, interval, &tm1);
 236         /* Unsupported case - return 0 to not fail the test */
 237         if (err)
 238                 return err == 1 ? 0 : err;
 239
 240         memset(&timeout, 0, sizeof(timeout));
 241         timeout.tv_sec = 5;
 242         do {
 243                 err = select(0, NULL, NULL, NULL, &timeout);
 244         } while (err == -1 && errno == EINTR);
 245
 246         timer_delete(tm1);
 247         err = check_timer_latency(flags, interval);
 248         err |= check_alarmcount(flags, interval);
 249         return err;
 250 }
 251
 252 int main(void)
 253 {
 254         struct sigaction act;
 255         int signum = SIGRTMAX;
 256         int ret = 0;
 257
 258         /* Set up signal handler: */
 259         sigfillset(&act.sa_mask);
 260         act.sa_flags = 0;
 261         act.sa_handler = sigalarm;
 262         sigaction(signum, &act, NULL);
 263
 264         printf("Setting timers for every %i seconds\n", TIMER_SECS);
 265         for (clock_id = 0; clock_id < NR_CLOCKIDS; clock_id++) {
 266
 267                 if ((clock_id == CLOCK_PROCESS_CPUTIME_ID) ||
 268                                 (clock_id == CLOCK_THREAD_CPUTIME_ID) ||
 269                                 (clock_id == CLOCK_MONOTONIC_RAW) ||
 270                                 (clock_id == CLOCK_REALTIME_COARSE) ||
 271                                 (clock_id == CLOCK_MONOTONIC_COARSE) ||
 272                                 (clock_id == CLOCK_HWSPECIFIC))
 273                         continue;
 274
 275                 ret |= do_timer(clock_id, TIMER_ABSTIME);
 276                 ret |= do_timer(clock_id, 0);
 277                 ret |= do_timer_oneshot(clock_id, TIMER_ABSTIME);
 278                 ret |= do_timer_oneshot(clock_id, 0);
 279         }
 280         if (ret)
 281                 return ksft_exit_fail();
 282         return ksft_exit_pass();
 283 }