1/* threadtest.c
2 *		by: john stultz (johnstul@us.ibm.com)
3 *		(C) Copyright IBM 2004, 2005, 2006, 2012
4 *		Licensed under the GPLv2
5 *
6 *  To build:
7 *	$ gcc threadtest.c -o threadtest -lrt
8 *
9 *   This program is free software: you can redistribute it and/or modify
10 *   it under the terms of the GNU General Public License as published by
11 *   the Free Software Foundation, either version 2 of the License, or
12 *   (at your option) any later version.
13 *
14 *   This program is distributed in the hope that it will be useful,
15 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
16 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17 *   GNU General Public License for more details.
18 */
19#include <stdio.h>
20#include <unistd.h>
21#include <stdlib.h>
22#include <sys/time.h>
23#include <pthread.h>
24#ifdef KTEST
25#include "../kselftest.h"
26#else
27static inline int ksft_exit_pass(void)
28{
29	exit(0);
30}
31static inline int ksft_exit_fail(void)
32{
33	exit(1);
34}
35#endif
36
37
38/* serializes shared list access */
39pthread_mutex_t list_lock = PTHREAD_MUTEX_INITIALIZER;
40/* serializes console output */
41pthread_mutex_t print_lock = PTHREAD_MUTEX_INITIALIZER;
42
43
44#define MAX_THREADS 128
45#define LISTSIZE 128
46
47int done = 0;
48
49struct timespec global_list[LISTSIZE];
50int listcount = 0;
51
52
53void checklist(struct timespec *list, int size)
54{
55	int i, j;
56	struct timespec *a, *b;
57
58	/* scan the list */
59	for (i = 0; i < size-1; i++) {
60		a = &list[i];
61		b = &list[i+1];
62
63		/* look for any time inconsistencies */
64		if ((b->tv_sec <= a->tv_sec) &&
65			(b->tv_nsec < a->tv_nsec)) {
66
67			/* flag other threads */
68			done = 1;
69
70			/*serialize printing to avoid junky output*/
71			pthread_mutex_lock(&print_lock);
72
73			/* dump the list */
74			printf("\n");
75			for (j = 0; j < size; j++) {
76				if (j == i)
77					printf("---------------\n");
78				printf("%lu:%lu\n", list[j].tv_sec, list[j].tv_nsec);
79				if (j == i+1)
80					printf("---------------\n");
81			}
82			printf("[FAILED]\n");
83
84			pthread_mutex_unlock(&print_lock);
85		}
86	}
87}
88
89/* The shared thread shares a global list
90 * that each thread fills while holding the lock.
91 * This stresses clock syncronization across cpus.
92 */
93void *shared_thread(void *arg)
94{
95	while (!done) {
96		/* protect the list */
97		pthread_mutex_lock(&list_lock);
98
99		/* see if we're ready to check the list */
100		if (listcount >= LISTSIZE) {
101			checklist(global_list, LISTSIZE);
102			listcount = 0;
103		}
104		clock_gettime(CLOCK_MONOTONIC, &global_list[listcount++]);
105
106		pthread_mutex_unlock(&list_lock);
107	}
108	return NULL;
109}
110
111
112/* Each independent thread fills in its own
113 * list. This stresses clock_gettime() lock contention.
114 */
115void *independent_thread(void *arg)
116{
117	struct timespec my_list[LISTSIZE];
118	int count;
119
120	while (!done) {
121		/* fill the list */
122		for (count = 0; count < LISTSIZE; count++)
123			clock_gettime(CLOCK_MONOTONIC, &my_list[count]);
124		checklist(my_list, LISTSIZE);
125	}
126	return NULL;
127}
128
129#define DEFAULT_THREAD_COUNT 8
130#define DEFAULT_RUNTIME 30
131
132int main(int argc, char **argv)
133{
134	int thread_count, i;
135	time_t start, now, runtime;
136	char buf[255];
137	pthread_t pth[MAX_THREADS];
138	int opt;
139	void *tret;
140	int ret = 0;
141	void *(*thread)(void *) = shared_thread;
142
143	thread_count = DEFAULT_THREAD_COUNT;
144	runtime = DEFAULT_RUNTIME;
145
146	/* Process arguments */
147	while ((opt = getopt(argc, argv, "t:n:i")) != -1) {
148		switch (opt) {
149		case 't':
150			runtime = atoi(optarg);
151			break;
152		case 'n':
153			thread_count = atoi(optarg);
154			break;
155		case 'i':
156			thread = independent_thread;
157			printf("using independent threads\n");
158			break;
159		default:
160			printf("Usage: %s [-t <secs>] [-n <numthreads>] [-i]\n", argv[0]);
161			printf("	-t: time to run\n");
162			printf("	-n: number of threads\n");
163			printf("	-i: use independent threads\n");
164			return -1;
165		}
166	}
167
168	if (thread_count > MAX_THREADS)
169		thread_count = MAX_THREADS;
170
171
172	setbuf(stdout, NULL);
173
174	start = time(0);
175	strftime(buf, 255, "%a, %d %b %Y %T %z", localtime(&start));
176	printf("%s\n", buf);
177	printf("Testing consistency with %i threads for %ld seconds: ", thread_count, runtime);
178
179	/* spawn */
180	for (i = 0; i < thread_count; i++)
181		pthread_create(&pth[i], 0, thread, 0);
182
183	while (time(&now) < start + runtime) {
184		sleep(1);
185		if (done) {
186			ret = 1;
187			strftime(buf, 255, "%a, %d %b %Y %T %z", localtime(&now));
188			printf("%s\n", buf);
189			goto out;
190		}
191	}
192	printf("[OK]\n");
193	done = 1;
194
195out:
196	/* wait */
197	for (i = 0; i < thread_count; i++)
198		pthread_join(pth[i], &tret);
199
200	/* die */
201	if (ret)
202		ksft_exit_fail();
203	return ksft_exit_pass();
204}
205