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
52int alarmcount;
53int clock_id;
54struct timespec start_time;
55long long max_latency_ns;
56int timer_fired_early;
57
58char *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
88long 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
97void 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
115void 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
123int 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
173int 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
198int 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
210int 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
228int 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
252int 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