1/* $NetBSD: t_clock_gettime.c,v 1.6 2023/07/09 19:19:40 riastradh Exp $ */
2
3/*-
4 * Copyright (c) 2008 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Frank Kardel.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32/*-
33 * Copyright (c) 2006 Frank Kardel
34 * All rights reserved.
35 *
36 * Redistribution and use in source and binary forms, with or without
37 * modification, are permitted provided that the following conditions
38 * are met:
39 * 1. Redistributions of source code must retain the above copyright
40 *    notice, this list of conditions and the following disclaimer.
41 * 2. Redistributions in binary form must reproduce the above copyright
42 *    notice, this list of conditions and the following disclaimer in the
43 *    documentation and/or other materials provided with the distribution.
44 *
45 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
46 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
47 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
48 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
49 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
50 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
51 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
52 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
53 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
54 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
55 * POSSIBILITY OF SUCH DAMAGE.
56 */
57
58#include <sys/cdefs.h>
59__COPYRIGHT("@(#) Copyright (c) 2008\
60 The NetBSD Foundation, inc. All rights reserved.");
61__RCSID("$NetBSD: t_clock_gettime.c,v 1.6 2023/07/09 19:19:40 riastradh Exp $");
62
63#include <sys/param.h>
64
65#include <sys/ioctl.h>
66#include <sys/sysctl.h>
67
68#include <atf-c.h>
69#include <errno.h>
70#include <fcntl.h>
71#include <limits.h>
72#include <stdint.h>
73#include <stdio.h>
74#include <stdlib.h>
75#include <string.h>
76#include <time.h>
77#include <unistd.h>
78
79#include "h_macros.h"
80
81#define MINPOSDIFF	15000000	/* 15 ms for now */
82#define TIMEOUT		5
83
84#define TC_HARDWARE	"kern.timecounter.hardware"
85#define TC_CHOICE	"kern.timecounter.choice"
86
87static void
88check_timecounter(void)
89{
90	struct timespec tsa, tsb, tsl, res;
91	long long mindiff = INTMAX_MAX;
92	time_t endlimit;
93
94#define CL(x) \
95	do { \
96		if ((x) != -1) \
97			break; \
98		atf_tc_fail_nonfatal("%s: %s", #x, strerror(errno)); \
99		return; \
100	} while (0)
101
102	CL(clock_gettime(CLOCK_REALTIME, &tsa));
103	tsl = tsa;
104
105	CL(time(&endlimit));
106	endlimit += TIMEOUT + 1;
107
108	while ((time_t)tsa.tv_sec < endlimit) {
109		long long diff;
110
111		CL(clock_gettime(CLOCK_REALTIME, &tsb));
112		diff = 1000000000LL * (tsb.tv_sec - tsa.tv_sec)
113		    + tsb.tv_nsec - tsa.tv_nsec;
114
115		if (diff > 0 && mindiff > diff)
116			mindiff = diff;
117
118		if (diff < 0 || diff > MINPOSDIFF) {
119			long long elapsed;
120			(void)printf("%stime TSA: 0x%jx.%08jx, TSB: 0x%jx.%08jx, "
121			    "diff = %lld nsec, ", (diff < 0) ? "BAD " : "",
122			    (uintmax_t)tsa.tv_sec, (uintmax_t)tsa.tv_nsec,
123			    (uintmax_t)tsb.tv_sec, (uintmax_t)tsb.tv_nsec, diff);
124
125			elapsed = 1000000000LL * (tsb.tv_sec - tsl.tv_sec)
126			    + tsb.tv_nsec - tsl.tv_nsec;
127
128
129			(void)printf("%lld nsec\n", elapsed);
130			tsl = tsb;
131
132			ATF_CHECK(diff >= 0);
133			if (diff < 0)
134				return;
135		}
136
137		tsa.tv_sec = tsb.tv_sec;
138		tsa.tv_nsec = tsb.tv_nsec;
139	}
140
141	if (clock_getres(CLOCK_REALTIME, &res) == 0) {
142		long long r = res.tv_sec * 1000000000 + res.tv_nsec;
143
144		(void)printf("Claimed resolution: %lld nsec (%f Hz) or "
145		    "better\n", r, 1.0 / r * 1e9);
146		(void)printf("Observed minimum non zero delta: %lld "
147		    "nsec\n", mindiff);
148	}
149
150#undef CL
151}
152
153ATF_TC(clock_gettime_real);
154ATF_TC_HEAD(clock_gettime_real, tc)
155{
156	atf_tc_set_md_var(tc, "require.user", "root");
157	atf_tc_set_md_var(tc, "descr",
158	    "Checks the monotonicity of the CLOCK_REALTIME implementation");
159	atf_tc_set_md_var(tc, "timeout", "300");
160}
161
162ATF_TC_BODY(clock_gettime_real, tc)
163{
164	char name[128], cbuf[512], ctrbuf[10240];
165	size_t cbufsiz = sizeof(cbuf);
166	size_t ctrbufsiz = sizeof(ctrbuf);
167	const char *p;
168	char *save;
169	int quality, n;
170
171	if (sysctlbyname(TC_HARDWARE, cbuf, &cbufsiz, NULL, 0) != 0) {
172		(void)printf("\nChecking legacy time implementation "
173		    "for %d seconds\n", TIMEOUT);
174		check_timecounter();
175		return;
176		/* NOTREACHED */
177	}
178	(void)printf("%s = %s\n", TC_HARDWARE, cbuf);
179	REQUIRE_LIBC(save = strdup(cbuf), NULL);
180
181	RL(sysctlbyname(TC_CHOICE, ctrbuf, &ctrbufsiz, NULL, 0));
182	(void)printf("%s = %s\n", TC_CHOICE, ctrbuf);
183
184	for (p = ctrbuf, n = 0; sscanf(p, "%127[^(](q=%d, f=%*u Hz)%*[ ]%n",
185	    name, &quality, &n) == 2; p += n) {
186		struct timespec ts;
187		int ret;
188
189		if (quality < 0)
190			continue;
191
192		(void)printf("\nChecking %s for %d seconds\n", name, TIMEOUT);
193		CHECK_LIBC(ret = sysctlbyname(TC_HARDWARE, NULL, 0,
194		    name, strlen(name)), -1);
195		if (ret == -1)
196			continue;
197
198		/* wait a bit to select new counter in clockinterrupt */
199		ts.tv_sec = 0;
200		ts.tv_nsec = 100000000;
201		(void)nanosleep(&ts, NULL);
202
203		check_timecounter();
204	}
205
206	RL(sysctlbyname(TC_HARDWARE, NULL, 0, save, strlen(save)));
207}
208
209static void
210waste_user_time(void)
211{
212	static char buf[4*4096];
213
214	arc4random_buf(buf, sizeof(buf));
215}
216
217static void __unused
218waste_system_time(void)
219{
220	static char buf[4*4096];
221	int fd[2];
222	int i, n;
223
224	RL(pipe2(fd, O_NONBLOCK));
225	RL(n = ioctl(fd[1], FIONSPACE));
226	n = MIN((unsigned)MAX(0, n), sizeof(buf));
227	for (i = 0; i < 16; i++) {
228		RL(write(fd[1], buf, n));
229		RL(read(fd[0], buf, n));
230	}
231	RL(close(fd[0]));
232	RL(close(fd[1]));
233}
234
235static void
236check_monotonicity(const char *clockname, clockid_t clockid,
237    void (*waste_time)(void))
238{
239	static const struct timespec maxtime = {5, 0};
240	struct timespec mono_t0, t0, mono_d;
241
242	RL(clock_gettime(CLOCK_MONOTONIC, &mono_t0));
243	RL(clock_gettime(clockid, &t0));
244
245	do {
246		struct timespec t1, mono_t1;
247
248		(*waste_time)();
249
250		RL(clock_gettime(clockid, &t1));
251		ATF_CHECK_MSG(timespeccmp(&t0, &t1, <=),
252		    "clock %s=0x%jx went backwards t0=%jd.%09ld t1=%jd.%09ld",
253		    clockname, (uintmax_t)clockid,
254		    (intmax_t)t0.tv_sec, t0.tv_nsec,
255		    (intmax_t)t1.tv_sec, t1.tv_nsec);
256
257		t0 = t1;
258
259		RL(clock_gettime(CLOCK_MONOTONIC, &mono_t1));
260		timespecsub(&mono_t1, &mono_t0, &mono_d);
261	} while (timespeccmp(&mono_d, &maxtime, <));
262}
263
264ATF_TC(clock_gettime_process_cputime_is_monotonic);
265ATF_TC_HEAD(clock_gettime_process_cputime_is_monotonic, tc)
266{
267	atf_tc_set_md_var(tc, "descr",
268	    "Checks that CLOCK_PROCESS_CPUTIME_ID is monotonic");
269}
270ATF_TC_BODY(clock_gettime_process_cputime_is_monotonic, tc)
271{
272	check_monotonicity("CLOCK_PROCESS_CPUTIME_ID",
273	    CLOCK_PROCESS_CPUTIME_ID, &waste_user_time);
274}
275
276ATF_TC(clock_gettime_thread_cputime_is_monotonic);
277ATF_TC_HEAD(clock_gettime_thread_cputime_is_monotonic, tc)
278{
279	atf_tc_set_md_var(tc, "descr",
280	    "Checks that CLOCK_THREAD_CPUTIME_ID is monotonic");
281}
282ATF_TC_BODY(clock_gettime_thread_cputime_is_monotonic, tc)
283{
284	check_monotonicity("CLOCK_THREAD_CPUTIME_ID",
285	    CLOCK_THREAD_CPUTIME_ID, &waste_user_time);
286}
287
288ATF_TP_ADD_TCS(tp)
289{
290
291	ATF_TP_ADD_TC(tp, clock_gettime_real);
292	ATF_TP_ADD_TC(tp, clock_gettime_process_cputime_is_monotonic);
293	ATF_TP_ADD_TC(tp, clock_gettime_thread_cputime_is_monotonic);
294
295	return atf_no_error();
296}
297