2 * by: john stultz (johnstul@us.ibm.com)
3 * (C) Copyright IBM 2004, 2005, 2006, 2012
4 * Licensed under the GPLv2
7 * $ gcc threadtest.c -o threadtest -lrt
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.
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.
25 #include "../kselftest.h"
27 static inline int ksft_exit_pass(void)
31 static inline int ksft_exit_fail(void)
38 /* serializes shared list access */
39 pthread_mutex_t list_lock = PTHREAD_MUTEX_INITIALIZER;
40 /* serializes console output */
41 pthread_mutex_t print_lock = PTHREAD_MUTEX_INITIALIZER;
44 #define MAX_THREADS 128
49 struct timespec global_list[LISTSIZE];
53 void checklist(struct timespec *list, int size)
56 struct timespec *a, *b;
59 for (i = 0; i < size-1; i++) {
63 /* look for any time inconsistencies */
64 if ((b->tv_sec <= a->tv_sec) &&
65 (b->tv_nsec < a->tv_nsec)) {
67 /* flag other threads */
70 /*serialize printing to avoid junky output*/
71 pthread_mutex_lock(&print_lock);
75 for (j = 0; j < size; j++) {
77 printf("---------------\n");
78 printf("%lu:%lu\n", list[j].tv_sec, list[j].tv_nsec);
80 printf("---------------\n");
84 pthread_mutex_unlock(&print_lock);
89 /* The shared thread shares a global list
90 * that each thread fills while holding the lock.
91 * This stresses clock syncronization across cpus.
93 void *shared_thread(void *arg)
96 /* protect the list */
97 pthread_mutex_lock(&list_lock);
99 /* see if we're ready to check the list */
100 if (listcount >= LISTSIZE) {
101 checklist(global_list, LISTSIZE);
104 clock_gettime(CLOCK_MONOTONIC, &global_list[listcount++]);
106 pthread_mutex_unlock(&list_lock);
112 /* Each independent thread fills in its own
113 * list. This stresses clock_gettime() lock contention.
115 void *independent_thread(void *arg)
117 struct timespec my_list[LISTSIZE];
122 for (count = 0; count < LISTSIZE; count++)
123 clock_gettime(CLOCK_MONOTONIC, &my_list[count]);
124 checklist(my_list, LISTSIZE);
129 #define DEFAULT_THREAD_COUNT 8
130 #define DEFAULT_RUNTIME 30
132 int main(int argc, char **argv)
135 time_t start, now, runtime;
137 pthread_t pth[MAX_THREADS];
141 void *(*thread)(void *) = shared_thread;
143 thread_count = DEFAULT_THREAD_COUNT;
144 runtime = DEFAULT_RUNTIME;
146 /* Process arguments */
147 while ((opt = getopt(argc, argv, "t:n:i")) != -1) {
150 runtime = atoi(optarg);
153 thread_count = atoi(optarg);
156 thread = independent_thread;
157 printf("using independent threads\n");
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");
168 if (thread_count > MAX_THREADS)
169 thread_count = MAX_THREADS;
172 setbuf(stdout, NULL);
175 strftime(buf, 255, "%a, %d %b %Y %T %z", localtime(&start));
177 printf("Testing consistency with %i threads for %ld seconds: ", thread_count, runtime);
180 for (i = 0; i < thread_count; i++)
181 pthread_create(&pth[i], 0, thread, 0);
183 while (time(&now) < start + runtime) {
187 strftime(buf, 255, "%a, %d %b %Y %T %z", localtime(&now));
197 for (i = 0; i < thread_count; i++)
198 pthread_join(pth[i], &tret);
203 return ksft_exit_pass();