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1 /*
2  * This application is Copyright 2012 Red Hat, Inc.
3  *	Doug Ledford <dledford@redhat.com>
4  *
5  * mq_perf_tests is free software: you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation, version 3.
8  *
9  * mq_perf_tests is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * For the full text of the license, see <http://www.gnu.org/licenses/>.
15  *
16  * mq_perf_tests.c
17  *   Tests various types of message queue workloads, concentrating on those
18  *   situations that invole large message sizes, large message queue depths,
19  *   or both, and reports back useful metrics about kernel message queue
20  *   performance.
21  *
22  */
23 #define _GNU_SOURCE
24 #include <stdio.h>
25 #include <stdlib.h>
26 #include <unistd.h>
27 #include <fcntl.h>
28 #include <string.h>
29 #include <limits.h>
30 #include <errno.h>
31 #include <signal.h>
32 #include <pthread.h>
33 #include <sched.h>
34 #include <sys/types.h>
35 #include <sys/time.h>
36 #include <sys/resource.h>
37 #include <sys/stat.h>
38 #include <mqueue.h>
39 #include <popt.h>
40 #include <error.h>
41 
42 #include "../kselftest.h"
43 
44 static char *usage =
45 "Usage:\n"
46 "  %s [-c #[,#..] -f] path\n"
47 "\n"
48 "	-c #	Skip most tests and go straight to a high queue depth test\n"
49 "		and then run that test continuously (useful for running at\n"
50 "		the same time as some other workload to see how much the\n"
51 "		cache thrashing caused by adding messages to a very deep\n"
52 "		queue impacts the performance of other programs).  The number\n"
53 "		indicates which CPU core we should bind the process to during\n"
54 "		the run.  If you have more than one physical CPU, then you\n"
55 "		will need one copy per physical CPU package, and you should\n"
56 "		specify the CPU cores to pin ourself to via a comma separated\n"
57 "		list of CPU values.\n"
58 "	-f	Only usable with continuous mode.  Pin ourself to the CPUs\n"
59 "		as requested, then instead of looping doing a high mq\n"
60 "		workload, just busy loop.  This will allow us to lock up a\n"
61 "		single CPU just like we normally would, but without actually\n"
62 "		thrashing the CPU cache.  This is to make it easier to get\n"
63 "		comparable numbers from some other workload running on the\n"
64 "		other CPUs.  One set of numbers with # CPUs locked up running\n"
65 "		an mq workload, and another set of numbers with those same\n"
66 "		CPUs locked away from the test workload, but not doing\n"
67 "		anything to trash the cache like the mq workload might.\n"
68 "	path	Path name of the message queue to create\n"
69 "\n"
70 "	Note: this program must be run as root in order to enable all tests\n"
71 "\n";
72 
73 char *MAX_MSGS = "/proc/sys/fs/mqueue/msg_max";
74 char *MAX_MSGSIZE = "/proc/sys/fs/mqueue/msgsize_max";
75 
76 #define min(a, b) ((a) < (b) ? (a) : (b))
77 #define MAX_CPUS 64
78 char *cpu_option_string;
79 int cpus_to_pin[MAX_CPUS];
80 int num_cpus_to_pin;
81 pthread_t cpu_threads[MAX_CPUS];
82 pthread_t main_thread;
83 cpu_set_t *cpu_set;
84 int cpu_set_size;
85 int cpus_online;
86 
87 #define MSG_SIZE 16
88 #define TEST1_LOOPS 10000000
89 #define TEST2_LOOPS 100000
90 int continuous_mode;
91 int continuous_mode_fake;
92 
93 struct rlimit saved_limits, cur_limits;
94 int saved_max_msgs, saved_max_msgsize;
95 int cur_max_msgs, cur_max_msgsize;
96 FILE *max_msgs, *max_msgsize;
97 int cur_nice;
98 char *queue_path = "/mq_perf_tests";
99 mqd_t queue = -1;
100 struct mq_attr result;
101 int mq_prio_max;
102 
103 const struct poptOption options[] = {
104 	{
105 		.longName = "continuous",
106 		.shortName = 'c',
107 		.argInfo = POPT_ARG_STRING,
108 		.arg = &cpu_option_string,
109 		.val = 'c',
110 		.descrip = "Run continuous tests at a high queue depth in "
111 			"order to test the effects of cache thrashing on "
112 			"other tasks on the system.  This test is intended "
113 			"to be run on one core of each physical CPU while "
114 			"some other CPU intensive task is run on all the other "
115 			"cores of that same physical CPU and the other task "
116 			"is timed.  It is assumed that the process of adding "
117 			"messages to the message queue in a tight loop will "
118 			"impact that other task to some degree.  Once the "
119 			"tests are performed in this way, you should then "
120 			"re-run the tests using fake mode in order to check "
121 			"the difference in time required to perform the CPU "
122 			"intensive task",
123 		.argDescrip = "cpu[,cpu]",
124 	},
125 	{
126 		.longName = "fake",
127 		.shortName = 'f',
128 		.argInfo = POPT_ARG_NONE,
129 		.arg = &continuous_mode_fake,
130 		.val = 0,
131 		.descrip = "Tie up the CPUs that we would normally tie up in"
132 			"continuous mode, but don't actually do any mq stuff, "
133 			"just keep the CPU busy so it can't be used to process "
134 			"system level tasks as this would free up resources on "
135 			"the other CPU cores and skew the comparison between "
136 			"the no-mqueue work and mqueue work tests",
137 		.argDescrip = NULL,
138 	},
139 	{
140 		.longName = "path",
141 		.shortName = 'p',
142 		.argInfo = POPT_ARG_STRING | POPT_ARGFLAG_SHOW_DEFAULT,
143 		.arg = &queue_path,
144 		.val = 'p',
145 		.descrip = "The name of the path to use in the mqueue "
146 			"filesystem for our tests",
147 		.argDescrip = "pathname",
148 	},
149 	POPT_AUTOHELP
150 	POPT_TABLEEND
151 };
152 
153 static inline void __set(FILE *stream, int value, char *err_msg);
154 void shutdown(int exit_val, char *err_cause, int line_no);
155 void sig_action_SIGUSR1(int signum, siginfo_t *info, void *context);
156 void sig_action(int signum, siginfo_t *info, void *context);
157 static inline int get(FILE *stream);
158 static inline void set(FILE *stream, int value);
159 static inline int try_set(FILE *stream, int value);
160 static inline void getr(int type, struct rlimit *rlim);
161 static inline void setr(int type, struct rlimit *rlim);
162 static inline void open_queue(struct mq_attr *attr);
163 void increase_limits(void);
164 
__set(FILE * stream,int value,char * err_msg)165 static inline void __set(FILE *stream, int value, char *err_msg)
166 {
167 	rewind(stream);
168 	if (fprintf(stream, "%d", value) < 0)
169 		perror(err_msg);
170 }
171 
172 
shutdown(int exit_val,char * err_cause,int line_no)173 void shutdown(int exit_val, char *err_cause, int line_no)
174 {
175 	static int in_shutdown = 0;
176 	int errno_at_shutdown = errno;
177 	int i;
178 
179 	/* In case we get called by multiple threads or from an sighandler */
180 	if (in_shutdown++)
181 		return;
182 
183 	for (i = 0; i < num_cpus_to_pin; i++)
184 		if (cpu_threads[i]) {
185 			pthread_kill(cpu_threads[i], SIGUSR1);
186 			pthread_join(cpu_threads[i], NULL);
187 		}
188 
189 	if (queue != -1)
190 		if (mq_close(queue))
191 			perror("mq_close() during shutdown");
192 	if (queue_path)
193 		/*
194 		 * Be silent if this fails, if we cleaned up already it's
195 		 * expected to fail
196 		 */
197 		mq_unlink(queue_path);
198 	if (saved_max_msgs)
199 		__set(max_msgs, saved_max_msgs,
200 		      "failed to restore saved_max_msgs");
201 	if (saved_max_msgsize)
202 		__set(max_msgsize, saved_max_msgsize,
203 		      "failed to restore saved_max_msgsize");
204 	if (exit_val)
205 		error(exit_val, errno_at_shutdown, "%s at %d",
206 		      err_cause, line_no);
207 	exit(0);
208 }
209 
sig_action_SIGUSR1(int signum,siginfo_t * info,void * context)210 void sig_action_SIGUSR1(int signum, siginfo_t *info, void *context)
211 {
212 	if (pthread_self() != main_thread)
213 		pthread_exit(0);
214 	else {
215 		fprintf(stderr, "Caught signal %d in SIGUSR1 handler, "
216 				"exiting\n", signum);
217 		shutdown(0, "", 0);
218 		fprintf(stderr, "\n\nReturned from shutdown?!?!\n\n");
219 		exit(0);
220 	}
221 }
222 
sig_action(int signum,siginfo_t * info,void * context)223 void sig_action(int signum, siginfo_t *info, void *context)
224 {
225 	if (pthread_self() != main_thread)
226 		pthread_kill(main_thread, signum);
227 	else {
228 		fprintf(stderr, "Caught signal %d, exiting\n", signum);
229 		shutdown(0, "", 0);
230 		fprintf(stderr, "\n\nReturned from shutdown?!?!\n\n");
231 		exit(0);
232 	}
233 }
234 
get(FILE * stream)235 static inline int get(FILE *stream)
236 {
237 	int value;
238 	rewind(stream);
239 	if (fscanf(stream, "%d", &value) != 1)
240 		shutdown(4, "Error reading /proc entry", __LINE__);
241 	return value;
242 }
243 
set(FILE * stream,int value)244 static inline void set(FILE *stream, int value)
245 {
246 	int new_value;
247 
248 	rewind(stream);
249 	if (fprintf(stream, "%d", value) < 0)
250 		return shutdown(5, "Failed writing to /proc file", __LINE__);
251 	new_value = get(stream);
252 	if (new_value != value)
253 		return shutdown(5, "We didn't get what we wrote to /proc back",
254 				__LINE__);
255 }
256 
try_set(FILE * stream,int value)257 static inline int try_set(FILE *stream, int value)
258 {
259 	int new_value;
260 
261 	rewind(stream);
262 	fprintf(stream, "%d", value);
263 	new_value = get(stream);
264 	return new_value == value;
265 }
266 
getr(int type,struct rlimit * rlim)267 static inline void getr(int type, struct rlimit *rlim)
268 {
269 	if (getrlimit(type, rlim))
270 		shutdown(6, "getrlimit()", __LINE__);
271 }
272 
setr(int type,struct rlimit * rlim)273 static inline void setr(int type, struct rlimit *rlim)
274 {
275 	if (setrlimit(type, rlim))
276 		shutdown(7, "setrlimit()", __LINE__);
277 }
278 
279 /**
280  * open_queue - open the global queue for testing
281  * @attr - An attr struct specifying the desired queue traits
282  * @result - An attr struct that lists the actual traits the queue has
283  *
284  * This open is not allowed to fail, failure will result in an orderly
285  * shutdown of the program.  The global queue_path is used to set what
286  * queue to open, the queue descriptor is saved in the global queue
287  * variable.
288  */
open_queue(struct mq_attr * attr)289 static inline void open_queue(struct mq_attr *attr)
290 {
291 	int flags = O_RDWR | O_EXCL | O_CREAT | O_NONBLOCK;
292 	int perms = DEFFILEMODE;
293 
294 	queue = mq_open(queue_path, flags, perms, attr);
295 	if (queue == -1)
296 		shutdown(1, "mq_open()", __LINE__);
297 	if (mq_getattr(queue, &result))
298 		shutdown(1, "mq_getattr()", __LINE__);
299 	printf("\n\tQueue %s created:\n", queue_path);
300 	printf("\t\tmq_flags:\t\t\t%s\n", result.mq_flags & O_NONBLOCK ?
301 	       "O_NONBLOCK" : "(null)");
302 	printf("\t\tmq_maxmsg:\t\t\t%lu\n", result.mq_maxmsg);
303 	printf("\t\tmq_msgsize:\t\t\t%lu\n", result.mq_msgsize);
304 	printf("\t\tmq_curmsgs:\t\t\t%lu\n", result.mq_curmsgs);
305 }
306 
fake_cont_thread(void * arg)307 void *fake_cont_thread(void *arg)
308 {
309 	int i;
310 
311 	for (i = 0; i < num_cpus_to_pin; i++)
312 		if (cpu_threads[i] == pthread_self())
313 			break;
314 	printf("\tStarted fake continuous mode thread %d on CPU %d\n", i,
315 	       cpus_to_pin[i]);
316 	while (1)
317 		;
318 }
319 
cont_thread(void * arg)320 void *cont_thread(void *arg)
321 {
322 	char buff[MSG_SIZE];
323 	int i, priority;
324 
325 	for (i = 0; i < num_cpus_to_pin; i++)
326 		if (cpu_threads[i] == pthread_self())
327 			break;
328 	printf("\tStarted continuous mode thread %d on CPU %d\n", i,
329 	       cpus_to_pin[i]);
330 	while (1) {
331 		while (mq_send(queue, buff, sizeof(buff), 0) == 0)
332 			;
333 		mq_receive(queue, buff, sizeof(buff), &priority);
334 	}
335 }
336 
337 #define drain_queue() \
338 	while (mq_receive(queue, buff, MSG_SIZE, &prio_in) == MSG_SIZE)
339 
340 #define do_untimed_send() \
341 	do { \
342 		if (mq_send(queue, buff, MSG_SIZE, prio_out)) \
343 			shutdown(3, "Test send failure", __LINE__); \
344 	} while (0)
345 
346 #define do_send_recv() \
347 	do { \
348 		clock_gettime(clock, &start); \
349 		if (mq_send(queue, buff, MSG_SIZE, prio_out)) \
350 			shutdown(3, "Test send failure", __LINE__); \
351 		clock_gettime(clock, &middle); \
352 		if (mq_receive(queue, buff, MSG_SIZE, &prio_in) != MSG_SIZE) \
353 			shutdown(3, "Test receive failure", __LINE__); \
354 		clock_gettime(clock, &end); \
355 		nsec = ((middle.tv_sec - start.tv_sec) * 1000000000) + \
356 			(middle.tv_nsec - start.tv_nsec); \
357 		send_total.tv_nsec += nsec; \
358 		if (send_total.tv_nsec >= 1000000000) { \
359 			send_total.tv_sec++; \
360 			send_total.tv_nsec -= 1000000000; \
361 		} \
362 		nsec = ((end.tv_sec - middle.tv_sec) * 1000000000) + \
363 			(end.tv_nsec - middle.tv_nsec); \
364 		recv_total.tv_nsec += nsec; \
365 		if (recv_total.tv_nsec >= 1000000000) { \
366 			recv_total.tv_sec++; \
367 			recv_total.tv_nsec -= 1000000000; \
368 		} \
369 	} while (0)
370 
371 struct test {
372 	char *desc;
373 	void (*func)(int *);
374 };
375 
const_prio(int * prio)376 void const_prio(int *prio)
377 {
378 	return;
379 }
380 
inc_prio(int * prio)381 void inc_prio(int *prio)
382 {
383 	if (++*prio == mq_prio_max)
384 		*prio = 0;
385 }
386 
dec_prio(int * prio)387 void dec_prio(int *prio)
388 {
389 	if (--*prio < 0)
390 		*prio = mq_prio_max - 1;
391 }
392 
random_prio(int * prio)393 void random_prio(int *prio)
394 {
395 	*prio = random() % mq_prio_max;
396 }
397 
398 struct test test2[] = {
399 	{"\n\tTest #2a: Time send/recv message, queue full, constant prio\n",
400 		const_prio},
401 	{"\n\tTest #2b: Time send/recv message, queue full, increasing prio\n",
402 		inc_prio},
403 	{"\n\tTest #2c: Time send/recv message, queue full, decreasing prio\n",
404 		dec_prio},
405 	{"\n\tTest #2d: Time send/recv message, queue full, random prio\n",
406 		random_prio},
407 	{NULL, NULL}
408 };
409 
410 /**
411  * Tests to perform (all done with MSG_SIZE messages):
412  *
413  * 1) Time to add/remove message with 0 messages on queue
414  * 1a) with constant prio
415  * 2) Time to add/remove message when queue close to capacity:
416  * 2a) with constant prio
417  * 2b) with increasing prio
418  * 2c) with decreasing prio
419  * 2d) with random prio
420  * 3) Test limits of priorities honored (double check _SC_MQ_PRIO_MAX)
421  */
perf_test_thread(void * arg)422 void *perf_test_thread(void *arg)
423 {
424 	char buff[MSG_SIZE];
425 	int prio_out, prio_in;
426 	int i;
427 	clockid_t clock;
428 	pthread_t *t;
429 	struct timespec res, start, middle, end, send_total, recv_total;
430 	unsigned long long nsec;
431 	struct test *cur_test;
432 
433 	t = &cpu_threads[0];
434 	printf("\n\tStarted mqueue performance test thread on CPU %d\n",
435 	       cpus_to_pin[0]);
436 	mq_prio_max = sysconf(_SC_MQ_PRIO_MAX);
437 	if (mq_prio_max == -1)
438 		shutdown(2, "sysconf(_SC_MQ_PRIO_MAX)", __LINE__);
439 	if (pthread_getcpuclockid(cpu_threads[0], &clock) != 0)
440 		shutdown(2, "pthread_getcpuclockid", __LINE__);
441 
442 	if (clock_getres(clock, &res))
443 		shutdown(2, "clock_getres()", __LINE__);
444 
445 	printf("\t\tMax priorities:\t\t\t%d\n", mq_prio_max);
446 	printf("\t\tClock resolution:\t\t%lu nsec%s\n", res.tv_nsec,
447 	       res.tv_nsec > 1 ? "s" : "");
448 
449 
450 
451 	printf("\n\tTest #1: Time send/recv message, queue empty\n");
452 	printf("\t\t(%d iterations)\n", TEST1_LOOPS);
453 	prio_out = 0;
454 	send_total.tv_sec = 0;
455 	send_total.tv_nsec = 0;
456 	recv_total.tv_sec = 0;
457 	recv_total.tv_nsec = 0;
458 	for (i = 0; i < TEST1_LOOPS; i++)
459 		do_send_recv();
460 	printf("\t\tSend msg:\t\t\t%ld.%lus total time\n",
461 	       send_total.tv_sec, send_total.tv_nsec);
462 	nsec = ((unsigned long long)send_total.tv_sec * 1000000000 +
463 		 send_total.tv_nsec) / TEST1_LOOPS;
464 	printf("\t\t\t\t\t\t%lld nsec/msg\n", nsec);
465 	printf("\t\tRecv msg:\t\t\t%ld.%lus total time\n",
466 	       recv_total.tv_sec, recv_total.tv_nsec);
467 	nsec = ((unsigned long long)recv_total.tv_sec * 1000000000 +
468 		recv_total.tv_nsec) / TEST1_LOOPS;
469 	printf("\t\t\t\t\t\t%lld nsec/msg\n", nsec);
470 
471 
472 	for (cur_test = test2; cur_test->desc != NULL; cur_test++) {
473 		printf("%s:\n", cur_test->desc);
474 		printf("\t\t(%d iterations)\n", TEST2_LOOPS);
475 		prio_out = 0;
476 		send_total.tv_sec = 0;
477 		send_total.tv_nsec = 0;
478 		recv_total.tv_sec = 0;
479 		recv_total.tv_nsec = 0;
480 		printf("\t\tFilling queue...");
481 		fflush(stdout);
482 		clock_gettime(clock, &start);
483 		for (i = 0; i < result.mq_maxmsg - 1; i++) {
484 			do_untimed_send();
485 			cur_test->func(&prio_out);
486 		}
487 		clock_gettime(clock, &end);
488 		nsec = ((unsigned long long)(end.tv_sec - start.tv_sec) *
489 			1000000000) + (end.tv_nsec - start.tv_nsec);
490 		printf("done.\t\t%lld.%llds\n", nsec / 1000000000,
491 		       nsec % 1000000000);
492 		printf("\t\tTesting...");
493 		fflush(stdout);
494 		for (i = 0; i < TEST2_LOOPS; i++) {
495 			do_send_recv();
496 			cur_test->func(&prio_out);
497 		}
498 		printf("done.\n");
499 		printf("\t\tSend msg:\t\t\t%ld.%lus total time\n",
500 		       send_total.tv_sec, send_total.tv_nsec);
501 		nsec = ((unsigned long long)send_total.tv_sec * 1000000000 +
502 			 send_total.tv_nsec) / TEST2_LOOPS;
503 		printf("\t\t\t\t\t\t%lld nsec/msg\n", nsec);
504 		printf("\t\tRecv msg:\t\t\t%ld.%lus total time\n",
505 		       recv_total.tv_sec, recv_total.tv_nsec);
506 		nsec = ((unsigned long long)recv_total.tv_sec * 1000000000 +
507 			recv_total.tv_nsec) / TEST2_LOOPS;
508 		printf("\t\t\t\t\t\t%lld nsec/msg\n", nsec);
509 		printf("\t\tDraining queue...");
510 		fflush(stdout);
511 		clock_gettime(clock, &start);
512 		drain_queue();
513 		clock_gettime(clock, &end);
514 		nsec = ((unsigned long long)(end.tv_sec - start.tv_sec) *
515 			1000000000) + (end.tv_nsec - start.tv_nsec);
516 		printf("done.\t\t%lld.%llds\n", nsec / 1000000000,
517 		       nsec % 1000000000);
518 	}
519 	return 0;
520 }
521 
increase_limits(void)522 void increase_limits(void)
523 {
524 	cur_limits.rlim_cur = RLIM_INFINITY;
525 	cur_limits.rlim_max = RLIM_INFINITY;
526 	setr(RLIMIT_MSGQUEUE, &cur_limits);
527 	while (try_set(max_msgs, cur_max_msgs += 10))
528 		;
529 	cur_max_msgs = get(max_msgs);
530 	while (try_set(max_msgsize, cur_max_msgsize += 1024))
531 		;
532 	cur_max_msgsize = get(max_msgsize);
533 	if (setpriority(PRIO_PROCESS, 0, -20) != 0)
534 		shutdown(2, "setpriority()", __LINE__);
535 	cur_nice = -20;
536 }
537 
main(int argc,char * argv[])538 int main(int argc, char *argv[])
539 {
540 	struct mq_attr attr;
541 	char *option, *next_option;
542 	int i, cpu, rc;
543 	struct sigaction sa;
544 	poptContext popt_context;
545 	void *retval;
546 
547 	main_thread = pthread_self();
548 	num_cpus_to_pin = 0;
549 
550 	if (sysconf(_SC_NPROCESSORS_ONLN) == -1) {
551 		perror("sysconf(_SC_NPROCESSORS_ONLN)");
552 		exit(1);
553 	}
554 	cpus_online = min(MAX_CPUS, sysconf(_SC_NPROCESSORS_ONLN));
555 	cpu_set = CPU_ALLOC(cpus_online);
556 	if (cpu_set == NULL) {
557 		perror("CPU_ALLOC()");
558 		exit(1);
559 	}
560 	cpu_set_size = CPU_ALLOC_SIZE(cpus_online);
561 	CPU_ZERO_S(cpu_set_size, cpu_set);
562 
563 	popt_context = poptGetContext(NULL, argc, (const char **)argv,
564 				      options, 0);
565 
566 	while ((rc = poptGetNextOpt(popt_context)) > 0) {
567 		switch (rc) {
568 		case 'c':
569 			continuous_mode = 1;
570 			option = cpu_option_string;
571 			do {
572 				next_option = strchr(option, ',');
573 				if (next_option)
574 					*next_option = '\0';
575 				cpu = atoi(option);
576 				if (cpu >= cpus_online)
577 					fprintf(stderr, "CPU %d exceeds "
578 						"cpus online, ignoring.\n",
579 						cpu);
580 				else
581 					cpus_to_pin[num_cpus_to_pin++] = cpu;
582 				if (next_option)
583 					option = ++next_option;
584 			} while (next_option && num_cpus_to_pin < MAX_CPUS);
585 			/* Double check that they didn't give us the same CPU
586 			 * more than once */
587 			for (cpu = 0; cpu < num_cpus_to_pin; cpu++) {
588 				if (CPU_ISSET_S(cpus_to_pin[cpu], cpu_set_size,
589 						cpu_set)) {
590 					fprintf(stderr, "Any given CPU may "
591 						"only be given once.\n");
592 					exit(1);
593 				} else
594 					CPU_SET_S(cpus_to_pin[cpu],
595 						  cpu_set_size, cpu_set);
596 			}
597 			break;
598 		case 'p':
599 			/*
600 			 * Although we can create a msg queue with a
601 			 * non-absolute path name, unlink will fail.  So,
602 			 * if the name doesn't start with a /, add one
603 			 * when we save it.
604 			 */
605 			option = queue_path;
606 			if (*option != '/') {
607 				queue_path = malloc(strlen(option) + 2);
608 				if (!queue_path) {
609 					perror("malloc()");
610 					exit(1);
611 				}
612 				queue_path[0] = '/';
613 				queue_path[1] = 0;
614 				strcat(queue_path, option);
615 				free(option);
616 			}
617 			break;
618 		}
619 	}
620 
621 	if (continuous_mode && num_cpus_to_pin == 0) {
622 		fprintf(stderr, "Must pass at least one CPU to continuous "
623 			"mode.\n");
624 		poptPrintUsage(popt_context, stderr, 0);
625 		exit(1);
626 	} else if (!continuous_mode) {
627 		num_cpus_to_pin = 1;
628 		cpus_to_pin[0] = cpus_online - 1;
629 	}
630 
631 	if (getuid() != 0)
632 		ksft_exit_skip("Not running as root, but almost all tests "
633 			"require root in order to modify\nsystem settings.  "
634 			"Exiting.\n");
635 
636 	max_msgs = fopen(MAX_MSGS, "r+");
637 	max_msgsize = fopen(MAX_MSGSIZE, "r+");
638 	if (!max_msgs)
639 		shutdown(2, "Failed to open msg_max", __LINE__);
640 	if (!max_msgsize)
641 		shutdown(2, "Failed to open msgsize_max", __LINE__);
642 
643 	/* Load up the current system values for everything we can */
644 	getr(RLIMIT_MSGQUEUE, &saved_limits);
645 	cur_limits = saved_limits;
646 	saved_max_msgs = cur_max_msgs = get(max_msgs);
647 	saved_max_msgsize = cur_max_msgsize = get(max_msgsize);
648 	errno = 0;
649 	cur_nice = getpriority(PRIO_PROCESS, 0);
650 	if (errno)
651 		shutdown(2, "getpriority()", __LINE__);
652 
653 	/* Tell the user our initial state */
654 	printf("\nInitial system state:\n");
655 	printf("\tUsing queue path:\t\t\t%s\n", queue_path);
656 	printf("\tRLIMIT_MSGQUEUE(soft):\t\t\t%ld\n",
657 		(long) saved_limits.rlim_cur);
658 	printf("\tRLIMIT_MSGQUEUE(hard):\t\t\t%ld\n",
659 		(long) saved_limits.rlim_max);
660 	printf("\tMaximum Message Size:\t\t\t%d\n", saved_max_msgsize);
661 	printf("\tMaximum Queue Size:\t\t\t%d\n", saved_max_msgs);
662 	printf("\tNice value:\t\t\t\t%d\n", cur_nice);
663 	printf("\n");
664 
665 	increase_limits();
666 
667 	printf("Adjusted system state for testing:\n");
668 	if (cur_limits.rlim_cur == RLIM_INFINITY) {
669 		printf("\tRLIMIT_MSGQUEUE(soft):\t\t\t(unlimited)\n");
670 		printf("\tRLIMIT_MSGQUEUE(hard):\t\t\t(unlimited)\n");
671 	} else {
672 		printf("\tRLIMIT_MSGQUEUE(soft):\t\t\t%ld\n",
673 		       (long) cur_limits.rlim_cur);
674 		printf("\tRLIMIT_MSGQUEUE(hard):\t\t\t%ld\n",
675 		       (long) cur_limits.rlim_max);
676 	}
677 	printf("\tMaximum Message Size:\t\t\t%d\n", cur_max_msgsize);
678 	printf("\tMaximum Queue Size:\t\t\t%d\n", cur_max_msgs);
679 	printf("\tNice value:\t\t\t\t%d\n", cur_nice);
680 	printf("\tContinuous mode:\t\t\t(%s)\n", continuous_mode ?
681 	       (continuous_mode_fake ? "fake mode" : "enabled") :
682 	       "disabled");
683 	printf("\tCPUs to pin:\t\t\t\t%d", cpus_to_pin[0]);
684 	for (cpu = 1; cpu < num_cpus_to_pin; cpu++)
685 			printf(",%d", cpus_to_pin[cpu]);
686 	printf("\n");
687 
688 	sa.sa_sigaction = sig_action_SIGUSR1;
689 	sigemptyset(&sa.sa_mask);
690 	sigaddset(&sa.sa_mask, SIGHUP);
691 	sigaddset(&sa.sa_mask, SIGINT);
692 	sigaddset(&sa.sa_mask, SIGQUIT);
693 	sigaddset(&sa.sa_mask, SIGTERM);
694 	sa.sa_flags = SA_SIGINFO;
695 	if (sigaction(SIGUSR1, &sa, NULL) == -1)
696 		shutdown(1, "sigaction(SIGUSR1)", __LINE__);
697 	sa.sa_sigaction = sig_action;
698 	if (sigaction(SIGHUP, &sa, NULL) == -1)
699 		shutdown(1, "sigaction(SIGHUP)", __LINE__);
700 	if (sigaction(SIGINT, &sa, NULL) == -1)
701 		shutdown(1, "sigaction(SIGINT)", __LINE__);
702 	if (sigaction(SIGQUIT, &sa, NULL) == -1)
703 		shutdown(1, "sigaction(SIGQUIT)", __LINE__);
704 	if (sigaction(SIGTERM, &sa, NULL) == -1)
705 		shutdown(1, "sigaction(SIGTERM)", __LINE__);
706 
707 	if (!continuous_mode_fake) {
708 		attr.mq_flags = O_NONBLOCK;
709 		attr.mq_maxmsg = cur_max_msgs;
710 		attr.mq_msgsize = MSG_SIZE;
711 		open_queue(&attr);
712 	}
713 	for (i = 0; i < num_cpus_to_pin; i++) {
714 		pthread_attr_t thread_attr;
715 		void *thread_func;
716 
717 		if (continuous_mode_fake)
718 			thread_func = &fake_cont_thread;
719 		else if (continuous_mode)
720 			thread_func = &cont_thread;
721 		else
722 			thread_func = &perf_test_thread;
723 
724 		CPU_ZERO_S(cpu_set_size, cpu_set);
725 		CPU_SET_S(cpus_to_pin[i], cpu_set_size, cpu_set);
726 		pthread_attr_init(&thread_attr);
727 		pthread_attr_setaffinity_np(&thread_attr, cpu_set_size,
728 					    cpu_set);
729 		if (pthread_create(&cpu_threads[i], &thread_attr, thread_func,
730 				   NULL))
731 			shutdown(1, "pthread_create()", __LINE__);
732 		pthread_attr_destroy(&thread_attr);
733 	}
734 
735 	if (!continuous_mode) {
736 		pthread_join(cpu_threads[0], &retval);
737 		shutdown((long)retval, "perf_test_thread()", __LINE__);
738 	} else {
739 		while (1)
740 			sleep(1);
741 	}
742 	shutdown(0, "", 0);
743 }
744