1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Copyright (C) 2013 Red Hat, Inc., Frederic Weisbecker <fweisbec@redhat.com> |
4 | * |
5 | * Selftests for a few posix timers interface. |
6 | * |
7 | * Kernel loop code stolen from Steven Rostedt <srostedt@redhat.com> |
8 | */ |
9 | |
10 | #include <sys/time.h> |
11 | #include <stdio.h> |
12 | #include <signal.h> |
13 | #include <unistd.h> |
14 | #include <time.h> |
15 | #include <pthread.h> |
16 | |
17 | #include "../kselftest.h" |
18 | |
19 | #define DELAY 2 |
20 | #define USECS_PER_SEC 1000000 |
21 | |
22 | static volatile int done; |
23 | |
24 | /* Busy loop in userspace to elapse ITIMER_VIRTUAL */ |
25 | static void user_loop(void) |
26 | { |
27 | while (!done); |
28 | } |
29 | |
30 | /* |
31 | * Try to spend as much time as possible in kernelspace |
32 | * to elapse ITIMER_PROF. |
33 | */ |
34 | static void kernel_loop(void) |
35 | { |
36 | void *addr = sbrk(0); |
37 | int err = 0; |
38 | |
39 | while (!done && !err) { |
40 | err = brk(addr + 4096); |
41 | err |= brk(addr); |
42 | } |
43 | } |
44 | |
45 | /* |
46 | * Sleep until ITIMER_REAL expiration. |
47 | */ |
48 | static void idle_loop(void) |
49 | { |
50 | pause(); |
51 | } |
52 | |
53 | static void sig_handler(int nr) |
54 | { |
55 | done = 1; |
56 | } |
57 | |
58 | /* |
59 | * Check the expected timer expiration matches the GTOD elapsed delta since |
60 | * we armed the timer. Keep a 0.5 sec error margin due to various jitter. |
61 | */ |
62 | static int check_diff(struct timeval start, struct timeval end) |
63 | { |
64 | long long diff; |
65 | |
66 | diff = end.tv_usec - start.tv_usec; |
67 | diff += (end.tv_sec - start.tv_sec) * USECS_PER_SEC; |
68 | |
69 | if (llabs(diff - DELAY * USECS_PER_SEC) > USECS_PER_SEC / 2) { |
70 | printf("Diff too high: %lld.." , diff); |
71 | return -1; |
72 | } |
73 | |
74 | return 0; |
75 | } |
76 | |
77 | static int check_itimer(int which) |
78 | { |
79 | const char *name; |
80 | int err; |
81 | struct timeval start, end; |
82 | struct itimerval val = { |
83 | .it_value.tv_sec = DELAY, |
84 | }; |
85 | |
86 | if (which == ITIMER_VIRTUAL) |
87 | name = "ITIMER_VIRTUAL" ; |
88 | else if (which == ITIMER_PROF) |
89 | name = "ITIMER_PROF" ; |
90 | else if (which == ITIMER_REAL) |
91 | name = "ITIMER_REAL" ; |
92 | else |
93 | return -1; |
94 | |
95 | done = 0; |
96 | |
97 | if (which == ITIMER_VIRTUAL) |
98 | signal(SIGVTALRM, sig_handler); |
99 | else if (which == ITIMER_PROF) |
100 | signal(SIGPROF, sig_handler); |
101 | else if (which == ITIMER_REAL) |
102 | signal(SIGALRM, sig_handler); |
103 | |
104 | err = gettimeofday(&start, NULL); |
105 | if (err < 0) { |
106 | ksft_perror(msg: "Can't call gettimeofday()" ); |
107 | return -1; |
108 | } |
109 | |
110 | err = setitimer(which, &val, NULL); |
111 | if (err < 0) { |
112 | ksft_perror(msg: "Can't set timer" ); |
113 | return -1; |
114 | } |
115 | |
116 | if (which == ITIMER_VIRTUAL) |
117 | user_loop(); |
118 | else if (which == ITIMER_PROF) |
119 | kernel_loop(); |
120 | else if (which == ITIMER_REAL) |
121 | idle_loop(); |
122 | |
123 | err = gettimeofday(&end, NULL); |
124 | if (err < 0) { |
125 | ksft_perror(msg: "Can't call gettimeofday()" ); |
126 | return -1; |
127 | } |
128 | |
129 | ksft_test_result(check_diff(start, end) == 0, "%s\n" , name); |
130 | |
131 | return 0; |
132 | } |
133 | |
134 | static int check_timer_create(int which) |
135 | { |
136 | const char *type; |
137 | int err; |
138 | timer_t id; |
139 | struct timeval start, end; |
140 | struct itimerspec val = { |
141 | .it_value.tv_sec = DELAY, |
142 | }; |
143 | |
144 | if (which == CLOCK_THREAD_CPUTIME_ID) { |
145 | type = "thread" ; |
146 | } else if (which == CLOCK_PROCESS_CPUTIME_ID) { |
147 | type = "process" ; |
148 | } else { |
149 | ksft_print_msg(msg: "Unknown timer_create() type %d\n" , which); |
150 | return -1; |
151 | } |
152 | |
153 | done = 0; |
154 | err = timer_create(which, NULL, &id); |
155 | if (err < 0) { |
156 | ksft_perror(msg: "Can't create timer" ); |
157 | return -1; |
158 | } |
159 | signal(SIGALRM, sig_handler); |
160 | |
161 | err = gettimeofday(&start, NULL); |
162 | if (err < 0) { |
163 | ksft_perror(msg: "Can't call gettimeofday()" ); |
164 | return -1; |
165 | } |
166 | |
167 | err = timer_settime(id, 0, &val, NULL); |
168 | if (err < 0) { |
169 | ksft_perror(msg: "Can't set timer" ); |
170 | return -1; |
171 | } |
172 | |
173 | user_loop(); |
174 | |
175 | err = gettimeofday(&end, NULL); |
176 | if (err < 0) { |
177 | ksft_perror(msg: "Can't call gettimeofday()" ); |
178 | return -1; |
179 | } |
180 | |
181 | ksft_test_result(check_diff(start, end) == 0, |
182 | "timer_create() per %s\n" , type); |
183 | |
184 | return 0; |
185 | } |
186 | |
187 | static pthread_t ctd_thread; |
188 | static volatile int ctd_count, ctd_failed; |
189 | |
190 | static void ctd_sighandler(int sig) |
191 | { |
192 | if (pthread_self() != ctd_thread) |
193 | ctd_failed = 1; |
194 | ctd_count--; |
195 | } |
196 | |
197 | static void *ctd_thread_func(void *arg) |
198 | { |
199 | struct itimerspec val = { |
200 | .it_value.tv_sec = 0, |
201 | .it_value.tv_nsec = 1000 * 1000, |
202 | .it_interval.tv_sec = 0, |
203 | .it_interval.tv_nsec = 1000 * 1000, |
204 | }; |
205 | timer_t id; |
206 | |
207 | /* 1/10 seconds to ensure the leader sleeps */ |
208 | usleep(10000); |
209 | |
210 | ctd_count = 100; |
211 | if (timer_create(CLOCK_PROCESS_CPUTIME_ID, NULL, &id)) |
212 | return "Can't create timer\n" ; |
213 | if (timer_settime(id, 0, &val, NULL)) |
214 | return "Can't set timer\n" ; |
215 | |
216 | while (ctd_count > 0 && !ctd_failed) |
217 | ; |
218 | |
219 | if (timer_delete(id)) |
220 | return "Can't delete timer\n" ; |
221 | |
222 | return NULL; |
223 | } |
224 | |
225 | /* |
226 | * Test that only the running thread receives the timer signal. |
227 | */ |
228 | static int check_timer_distribution(void) |
229 | { |
230 | const char *errmsg; |
231 | |
232 | signal(SIGALRM, ctd_sighandler); |
233 | |
234 | errmsg = "Can't create thread\n" ; |
235 | if (pthread_create(&ctd_thread, NULL, ctd_thread_func, NULL)) |
236 | goto err; |
237 | |
238 | errmsg = "Can't join thread\n" ; |
239 | if (pthread_join(ctd_thread, (void **)&errmsg) || errmsg) |
240 | goto err; |
241 | |
242 | if (!ctd_failed) |
243 | ksft_test_result_pass(msg: "check signal distribution\n" ); |
244 | else if (ksft_min_kernel_version(min_major: 6, min_minor: 3)) |
245 | ksft_test_result_fail(msg: "check signal distribution\n" ); |
246 | else |
247 | ksft_test_result_skip(msg: "check signal distribution (old kernel)\n" ); |
248 | return 0; |
249 | err: |
250 | ksft_print_msg(msg: "%s" , errmsg); |
251 | return -1; |
252 | } |
253 | |
254 | int main(int argc, char **argv) |
255 | { |
256 | ksft_print_header(); |
257 | ksft_set_plan(plan: 6); |
258 | |
259 | ksft_print_msg(msg: "Testing posix timers. False negative may happen on CPU execution \n" ); |
260 | ksft_print_msg(msg: "based timers if other threads run on the CPU...\n" ); |
261 | |
262 | if (check_itimer(ITIMER_VIRTUAL) < 0) |
263 | return ksft_exit_fail(); |
264 | |
265 | if (check_itimer(ITIMER_PROF) < 0) |
266 | return ksft_exit_fail(); |
267 | |
268 | if (check_itimer(ITIMER_REAL) < 0) |
269 | return ksft_exit_fail(); |
270 | |
271 | if (check_timer_create(CLOCK_THREAD_CPUTIME_ID) < 0) |
272 | return ksft_exit_fail(); |
273 | |
274 | /* |
275 | * It's unfortunately hard to reliably test a timer expiration |
276 | * on parallel multithread cputime. We could arm it to expire |
277 | * on DELAY * nr_threads, with nr_threads busy looping, then wait |
278 | * the normal DELAY since the time is elapsing nr_threads faster. |
279 | * But for that we need to ensure we have real physical free CPUs |
280 | * to ensure true parallelism. So test only one thread until we |
281 | * find a better solution. |
282 | */ |
283 | if (check_timer_create(CLOCK_PROCESS_CPUTIME_ID) < 0) |
284 | return ksft_exit_fail(); |
285 | |
286 | if (check_timer_distribution() < 0) |
287 | return ksft_exit_fail(); |
288 | |
289 | ksft_finished(); |
290 | } |
291 | |