selftests/timers/set-timer-lat.c

0001 /* set_timer latency test
0002  *      John Stultz (john.stultz@linaro.org)
0003  *              (C) Copyright Linaro 2014
0004  *              Licensed under the GPLv2
0005  *
0006  *   This test makes sure the set_timer api is correct
0007  *
0008  *  To build:
0009  *  $ gcc set-timer-lat.c -o set-timer-lat -lrt
0010  *
0011  *   This program is free software: you can redistribute it and/or modify
0012  *   it under the terms of the GNU General Public License as published by
0013  *   the Free Software Foundation, either version 2 of the License, or
0014  *   (at your option) any later version.
0015  *
0016  *   This program is distributed in the hope that it will be useful,
0017  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
0018  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
0019  *   GNU General Public License for more details.
0020  */
0021
0022
0023 #include <errno.h>
0024 #include <stdio.h>
0025 #include <unistd.h>
0026 #include <time.h>
0027 #include <string.h>
0028 #include <signal.h>
0029 #include <stdlib.h>
0030 #include <pthread.h>
0031 #include "../kselftest.h"
0032
0033 #define CLOCK_REALTIME          0
0034 #define CLOCK_MONOTONIC         1
0035 #define CLOCK_PROCESS_CPUTIME_ID    2
0036 #define CLOCK_THREAD_CPUTIME_ID     3
0037 #define CLOCK_MONOTONIC_RAW     4
0038 #define CLOCK_REALTIME_COARSE       5
0039 #define CLOCK_MONOTONIC_COARSE      6
0040 #define CLOCK_BOOTTIME          7
0041 #define CLOCK_REALTIME_ALARM        8
0042 #define CLOCK_BOOTTIME_ALARM        9
0043 #define CLOCK_HWSPECIFIC        10
0044 #define CLOCK_TAI           11
0045 #define NR_CLOCKIDS         12
0046
0047
0048 #define NSEC_PER_SEC 1000000000ULL
0049 #define UNRESONABLE_LATENCY 40000000 /* 40ms in nanosecs */
0050
0051 #define TIMER_SECS 1
0052 int alarmcount;
0053 int clock_id;
0054 struct timespec start_time;
0055 long long max_latency_ns;
0056 int timer_fired_early;
0057
0058 char *clockstring(int clockid)
0059 {
0060     switch (clockid) {
0061     case CLOCK_REALTIME:
0062         return "CLOCK_REALTIME";
0063     case CLOCK_MONOTONIC:
0064         return "CLOCK_MONOTONIC";
0065     case CLOCK_PROCESS_CPUTIME_ID:
0066         return "CLOCK_PROCESS_CPUTIME_ID";
0067     case CLOCK_THREAD_CPUTIME_ID:
0068         return "CLOCK_THREAD_CPUTIME_ID";
0069     case CLOCK_MONOTONIC_RAW:
0070         return "CLOCK_MONOTONIC_RAW";
0071     case CLOCK_REALTIME_COARSE:
0072         return "CLOCK_REALTIME_COARSE";
0073     case CLOCK_MONOTONIC_COARSE:
0074         return "CLOCK_MONOTONIC_COARSE";
0075     case CLOCK_BOOTTIME:
0076         return "CLOCK_BOOTTIME";
0077     case CLOCK_REALTIME_ALARM:
0078         return "CLOCK_REALTIME_ALARM";
0079     case CLOCK_BOOTTIME_ALARM:
0080         return "CLOCK_BOOTTIME_ALARM";
0081     case CLOCK_TAI:
0082         return "CLOCK_TAI";
0083     };
0084     return "UNKNOWN_CLOCKID";
0085 }
0086
0087
0088 long long timespec_sub(struct timespec a, struct timespec b)
0089 {
0090     long long ret = NSEC_PER_SEC * b.tv_sec + b.tv_nsec;
0091
0092     ret -= NSEC_PER_SEC * a.tv_sec + a.tv_nsec;
0093     return ret;
0094 }
0095
0096
0097 void sigalarm(int signo)
0098 {
0099     long long delta_ns;
0100     struct timespec ts;
0101
0102     clock_gettime(clock_id, &ts);
0103     alarmcount++;
0104
0105     delta_ns = timespec_sub(start_time, ts);
0106     delta_ns -= NSEC_PER_SEC * TIMER_SECS * alarmcount;
0107
0108     if (delta_ns < 0)
0109         timer_fired_early = 1;
0110
0111     if (delta_ns > max_latency_ns)
0112         max_latency_ns = delta_ns;
0113 }
0114
0115 void describe_timer(int flags, int interval)
0116 {
0117     printf("%-22s %s %s ",
0118             clockstring(clock_id),
0119             flags ? "ABSTIME":"RELTIME",
0120             interval ? "PERIODIC":"ONE-SHOT");
0121 }
0122
0123 int setup_timer(int clock_id, int flags, int interval, timer_t *tm1)
0124 {
0125     struct sigevent se;
0126     struct itimerspec its1, its2;
0127     int err;
0128
0129     /* Set up timer: */
0130     memset(&se, 0, sizeof(se));
0131     se.sigev_notify = SIGEV_SIGNAL;
0132     se.sigev_signo = SIGRTMAX;
0133     se.sigev_value.sival_int = 0;
0134
0135     max_latency_ns = 0;
0136     alarmcount = 0;
0137     timer_fired_early = 0;
0138
0139     err = timer_create(clock_id, &se, tm1);
0140     if (err) {
0141         if ((clock_id == CLOCK_REALTIME_ALARM) ||
0142             (clock_id == CLOCK_BOOTTIME_ALARM)) {
0143             printf("%-22s %s missing CAP_WAKE_ALARM?    : [UNSUPPORTED]\n",
0144                     clockstring(clock_id),
0145                     flags ? "ABSTIME":"RELTIME");
0146             /* Indicate timer isn't set, so caller doesn't wait */
0147             return 1;
0148         }
0149         printf("%s - timer_create() failed\n", clockstring(clock_id));
0150         return -1;
0151     }
0152
0153     clock_gettime(clock_id, &start_time);
0154     if (flags) {
0155         its1.it_value = start_time;
0156         its1.it_value.tv_sec += TIMER_SECS;
0157     } else {
0158         its1.it_value.tv_sec = TIMER_SECS;
0159         its1.it_value.tv_nsec = 0;
0160     }
0161     its1.it_interval.tv_sec = interval;
0162     its1.it_interval.tv_nsec = 0;
0163
0164     err = timer_settime(*tm1, flags, &its1, &its2);
0165     if (err) {
0166         printf("%s - timer_settime() failed\n", clockstring(clock_id));
0167         return -1;
0168     }
0169
0170     return 0;
0171 }
0172
0173 int check_timer_latency(int flags, int interval)
0174 {
0175     int err = 0;
0176
0177     describe_timer(flags, interval);
0178     printf("timer fired early: %7d : ", timer_fired_early);
0179     if (!timer_fired_early) {
0180         printf("[OK]\n");
0181     } else {
0182         printf("[FAILED]\n");
0183         err = -1;
0184     }
0185
0186     describe_timer(flags, interval);
0187     printf("max latency: %10lld ns : ", max_latency_ns);
0188
0189     if (max_latency_ns < UNRESONABLE_LATENCY) {
0190         printf("[OK]\n");
0191     } else {
0192         printf("[FAILED]\n");
0193         err = -1;
0194     }
0195     return err;
0196 }
0197
0198 int check_alarmcount(int flags, int interval)
0199 {
0200     describe_timer(flags, interval);
0201     printf("count: %19d : ", alarmcount);
0202     if (alarmcount == 1) {
0203         printf("[OK]\n");
0204         return 0;
0205     }
0206     printf("[FAILED]\n");
0207     return -1;
0208 }
0209
0210 int do_timer(int clock_id, int flags)
0211 {
0212     timer_t tm1;
0213     const int interval = TIMER_SECS;
0214     int err;
0215
0216     err = setup_timer(clock_id, flags, interval, &tm1);
0217     /* Unsupported case - return 0 to not fail the test */
0218     if (err)
0219         return err == 1 ? 0 : err;
0220
0221     while (alarmcount < 5)
0222         sleep(1);
0223
0224     timer_delete(tm1);
0225     return check_timer_latency(flags, interval);
0226 }
0227
0228 int do_timer_oneshot(int clock_id, int flags)
0229 {
0230     timer_t tm1;
0231     const int interval = 0;
0232     struct timeval timeout;
0233     int err;
0234
0235     err = setup_timer(clock_id, flags, interval, &tm1);
0236     /* Unsupported case - return 0 to not fail the test */
0237     if (err)
0238         return err == 1 ? 0 : err;
0239
0240     memset(&timeout, 0, sizeof(timeout));
0241     timeout.tv_sec = 5;
0242     do {
0243         err = select(0, NULL, NULL, NULL, &timeout);
0244     } while (err == -1 && errno == EINTR);
0245
0246     timer_delete(tm1);
0247     err = check_timer_latency(flags, interval);
0248     err |= check_alarmcount(flags, interval);
0249     return err;
0250 }
0251
0252 int main(void)
0253 {
0254     struct sigaction act;
0255     int signum = SIGRTMAX;
0256     int ret = 0;
0257
0258     /* Set up signal handler: */
0259     sigfillset(&act.sa_mask);
0260     act.sa_flags = 0;
0261     act.sa_handler = sigalarm;
0262     sigaction(signum, &act, NULL);
0263
0264     printf("Setting timers for every %i seconds\n", TIMER_SECS);
0265     for (clock_id = 0; clock_id < NR_CLOCKIDS; clock_id++) {
0266
0267         if ((clock_id == CLOCK_PROCESS_CPUTIME_ID) ||
0268                 (clock_id == CLOCK_THREAD_CPUTIME_ID) ||
0269                 (clock_id == CLOCK_MONOTONIC_RAW) ||
0270                 (clock_id == CLOCK_REALTIME_COARSE) ||
0271                 (clock_id == CLOCK_MONOTONIC_COARSE) ||
0272                 (clock_id == CLOCK_HWSPECIFIC))
0273             continue;
0274
0275         ret |= do_timer(clock_id, TIMER_ABSTIME);
0276         ret |= do_timer(clock_id, 0);
0277         ret |= do_timer_oneshot(clock_id, TIMER_ABSTIME);
0278         ret |= do_timer_oneshot(clock_id, 0);
0279     }
0280     if (ret)
0281         return ksft_exit_fail();
0282     return ksft_exit_pass();
0283 }