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 }
284