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 ksft_exit_fail();
282 ksft_exit_pass();
283 }
284
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