aboutsummaryrefslogtreecommitdiff
path: root/rt/tst-cpuclock2.c
blob: cf58a3f1dd3de6fbe5a60d99681c727c9075dddf (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
/* Test program for process and thread CPU clocks.
   Copyright (C) 2005-2017 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <unistd.h>
#include <stdint.h>

#if (_POSIX_THREADS - 0) <= 0

# define TEST_FUNCTION 0

#else

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
#include <pthread.h>

static pthread_barrier_t barrier;

/* This function is intended to rack up both user and system time.  */
static void *
chew_cpu (void *arg)
{
  pthread_barrier_wait (&barrier);

  while (1)
    {
      static volatile char buf[4096];
      for (int i = 0; i < 100; ++i)
	for (size_t j = 0; j < sizeof buf; ++j)
	  buf[j] = 0xaa;
      int nullfd = open ("/dev/null", O_WRONLY);
      for (int i = 0; i < 100; ++i)
	for (size_t j = 0; j < sizeof buf; ++j)
	  buf[j] = 0xbb;
      write (nullfd, (char *) buf, sizeof buf);
      close (nullfd);
    }

  return NULL;
}

static unsigned long long int
tsdiff (const struct timespec *before, const struct timespec *after)
{
  struct timespec diff = { .tv_sec = after->tv_sec - before->tv_sec,
			   .tv_nsec = after->tv_nsec - before->tv_nsec };
  while (diff.tv_nsec < 0)
    {
      --diff.tv_sec;
      diff.tv_nsec += 1000000000;
    }
  return diff.tv_sec * 1000000000ULL + diff.tv_nsec;
}

static unsigned long long int
test_nanosleep (clockid_t clock, const char *which,
		const struct timespec *before, int *bad)
{
  const struct timespec sleeptime = { .tv_nsec = 100000000 };
  int e = clock_nanosleep (clock, 0, &sleeptime, NULL);
  if (e == EINVAL || e == ENOTSUP || e == ENOSYS)
    {
      printf ("clock_nanosleep not supported for %s CPU clock: %s\n",
	      which, strerror (e));
      return 0;
    }
  if (e != 0)
    {
      printf ("clock_nanosleep on %s CPU clock: %s\n", which, strerror (e));
      *bad = 1;
      return 0;
    }

  struct timespec after;
  if (clock_gettime (clock, &after) < 0)
    {
      printf ("clock_gettime on %s CPU clock %lx => %s\n",
	      which, (unsigned long int) clock, strerror (errno));
      *bad = 1;
      return 0;
    }

  unsigned long long int diff = tsdiff (before, &after);
  if (diff < sleeptime.tv_nsec || diff > sleeptime.tv_nsec * 2)
    {
      printf ("clock_nanosleep on %s slept %llu (outside reasonable range)\n",
	      which, diff);
      *bad = 1;
      return diff;
    }

  struct timespec sleeptimeabs = sleeptime;
  sleeptimeabs.tv_sec += after.tv_sec;
  sleeptimeabs.tv_nsec += after.tv_nsec;
  while (sleeptimeabs.tv_nsec >= 1000000000)
    {
      ++sleeptimeabs.tv_sec;
      sleeptimeabs.tv_nsec -= 1000000000;
    }
  e = clock_nanosleep (clock, TIMER_ABSTIME, &sleeptimeabs, NULL);
  if (e != 0)
    {
      printf ("absolute clock_nanosleep on %s CPU clock: %s\n",
	      which, strerror (e));
      *bad = 1;
      return diff;
    }

  struct timespec afterabs;
  if (clock_gettime (clock, &afterabs) < 0)
    {
      printf ("clock_gettime on %s CPU clock %lx => %s\n",
	      which, (unsigned long int) clock, strerror (errno));
      *bad = 1;
      return diff;
    }

  unsigned long long int sleepdiff = tsdiff (&sleeptimeabs, &afterabs);
  if (sleepdiff > sleeptime.tv_nsec)
    {
      printf ("\
absolute clock_nanosleep on %s %llu past target (outside reasonable range)\n",
	      which, sleepdiff);
      *bad = 1;
    }

  unsigned long long int diffabs = tsdiff (&after, &afterabs);
  if (diffabs < sleeptime.tv_nsec || diffabs > sleeptime.tv_nsec * 2)
    {
      printf ("\
absolute clock_nanosleep on %s slept %llu (outside reasonable range)\n",
	      which, diffabs);
      *bad = 1;
    }

  return diff + diffabs;
}



static int
do_test (void)
{
  int result = 0;
  clockid_t process_clock, th_clock, my_thread_clock;
  int e;
  pthread_t th;

  e = clock_getcpuclockid (0, &process_clock);
  if (e != 0)
    {
      printf ("clock_getcpuclockid on self => %s\n", strerror (e));
      return 1;
    }

  e = pthread_getcpuclockid (pthread_self (), &my_thread_clock);
  if (e != 0)
    {
      printf ("pthread_getcpuclockid on self => %s\n", strerror (e));
      return 1;
    }

  /* This is a kludge.  This test fails if the semantics of thread and
     process clocks are wrong.  The old code using hp-timing without kernel
     support has bogus semantics if there are context switches.  We don't
     fail to report failure when the proper functionality is not available
     in the kernel.  It so happens that Linux kernels without correct CPU
     clock support also lack CPU timer support, so we use use that to guess
     that we are using the bogus code and not test it.  */
  timer_t t;
  if (timer_create (my_thread_clock, NULL, &t) != 0)
    {
      printf ("timer_create: %m\n");
      puts ("No support for CPU clocks with good semantics, skipping test");
      return 0;
    }
  timer_delete (t);


  pthread_barrier_init (&barrier, NULL, 2);

  e = pthread_create (&th, NULL, chew_cpu, NULL);
  if (e != 0)
    {
      printf ("pthread_create: %s\n", strerror (e));
      return 1;
    }

  e = pthread_getcpuclockid (th, &th_clock);
  if (e == ENOENT || e == ENOSYS || e == ENOTSUP)
    {
      puts ("pthread_getcpuclockid does not support other threads");
      return 1;
    }

  pthread_barrier_wait (&barrier);

  struct timespec res;
  if (clock_getres (th_clock, &res) < 0)
    {
      printf ("clock_getres on live thread clock %lx => %s\n",
	      (unsigned long int) th_clock, strerror (errno));
      result = 1;
      return 1;
    }
  printf ("live thread clock %lx resolution %ju.%.9ju\n",
	  (unsigned long int) th_clock,
	  (uintmax_t) res.tv_sec, (uintmax_t) res.tv_nsec);

  struct timespec process_before, process_after;
  if (clock_gettime (process_clock, &process_before) < 0)
    {
      printf ("clock_gettime on process clock %lx => %s\n",
	      (unsigned long int) process_clock, strerror (errno));
      return 1;
    }

  struct timespec before, after;
  if (clock_gettime (th_clock, &before) < 0)
    {
      printf ("clock_gettime on live thread clock %lx => %s\n",
	      (unsigned long int) th_clock, strerror (errno));
      return 1;
    }
  printf ("live thread before sleep => %ju.%.9ju\n",
	  (uintmax_t) before.tv_sec, (uintmax_t) before.tv_nsec);

  struct timespec me_before, me_after;
  if (clock_gettime (my_thread_clock, &me_before) < 0)
    {
      printf ("clock_gettime on self thread clock %lx => %s\n",
	      (unsigned long int) my_thread_clock, strerror (errno));
      return 1;
    }
  printf ("self thread before sleep => %ju.%.9ju\n",
	  (uintmax_t) me_before.tv_sec, (uintmax_t) me_before.tv_nsec);

  struct timespec sleeptime = { .tv_nsec = 500000000 };
  if (nanosleep (&sleeptime, NULL) != 0)
    {
      perror ("nanosleep");
      return 1;
    }

  if (clock_gettime (th_clock, &after) < 0)
    {
      printf ("clock_gettime on live thread clock %lx => %s\n",
	      (unsigned long int) th_clock, strerror (errno));
      return 1;
    }
  printf ("live thread after sleep => %ju.%.9ju\n",
	  (uintmax_t) after.tv_sec, (uintmax_t) after.tv_nsec);

  if (clock_gettime (process_clock, &process_after) < 0)
    {
      printf ("clock_gettime on process clock %lx => %s\n",
	      (unsigned long int) process_clock, strerror (errno));
      return 1;
    }

  if (clock_gettime (my_thread_clock, &me_after) < 0)
    {
      printf ("clock_gettime on self thread clock %lx => %s\n",
	      (unsigned long int) my_thread_clock, strerror (errno));
      return 1;
    }
  printf ("self thread after sleep => %ju.%.9ju\n",
	  (uintmax_t) me_after.tv_sec, (uintmax_t) me_after.tv_nsec);

  unsigned long long int th_diff = tsdiff (&before, &after);
  unsigned long long int pdiff = tsdiff (&process_before, &process_after);
  unsigned long long int my_diff = tsdiff (&me_before, &me_after);

  if (th_diff < 100000000 || th_diff > 600000000)
    {
      printf ("live thread before - after %llu outside reasonable range\n",
	      th_diff);
      result = 1;
    }

  if (my_diff > 100000000)
    {
      printf ("self thread before - after %llu outside reasonable range\n",
	      my_diff);
      result = 1;
    }

  if (pdiff < th_diff)
    {
      printf ("process before - after %llu outside reasonable range (%llu)\n",
	      pdiff, th_diff);
      result = 1;
    }

  process_after.tv_nsec += test_nanosleep (th_clock, "live thread",
					   &after, &result);
  process_after.tv_nsec += test_nanosleep (process_clock, "process",
					   &process_after, &result);
  test_nanosleep (CLOCK_PROCESS_CPUTIME_ID,
		  "PROCESS_CPUTIME_ID", &process_after, &result);

  pthread_cancel (th);

  e = clock_nanosleep (CLOCK_THREAD_CPUTIME_ID, 0, &sleeptime, NULL);
  if (e != EINVAL)
    {
      printf ("clock_nanosleep CLOCK_THREAD_CPUTIME_ID: %s\n",
	      strerror (e));
      result = 1;
    }

  return result;
}
# define TIMEOUT 8
# define TEST_FUNCTION do_test ()
#endif

#include "../test-skeleton.c"