v4.19.13 snapshot.
diff --git a/tools/testing/selftests/timers/threadtest.c b/tools/testing/selftests/timers/threadtest.c
new file mode 100644
index 0000000..759c9c0
--- /dev/null
+++ b/tools/testing/selftests/timers/threadtest.c
@@ -0,0 +1,192 @@
+/* threadtest.c
+ * by: john stultz (johnstul@us.ibm.com)
+ * (C) Copyright IBM 2004, 2005, 2006, 2012
+ * Licensed under the GPLv2
+ *
+ * To build:
+ * $ gcc threadtest.c -o threadtest -lrt
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ */
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <sys/time.h>
+#include <pthread.h>
+#include "../kselftest.h"
+
+/* serializes shared list access */
+pthread_mutex_t list_lock = PTHREAD_MUTEX_INITIALIZER;
+/* serializes console output */
+pthread_mutex_t print_lock = PTHREAD_MUTEX_INITIALIZER;
+
+
+#define MAX_THREADS 128
+#define LISTSIZE 128
+
+int done = 0;
+
+struct timespec global_list[LISTSIZE];
+int listcount = 0;
+
+
+void checklist(struct timespec *list, int size)
+{
+ int i, j;
+ struct timespec *a, *b;
+
+ /* scan the list */
+ for (i = 0; i < size-1; i++) {
+ a = &list[i];
+ b = &list[i+1];
+
+ /* look for any time inconsistencies */
+ if ((b->tv_sec <= a->tv_sec) &&
+ (b->tv_nsec < a->tv_nsec)) {
+
+ /* flag other threads */
+ done = 1;
+
+ /*serialize printing to avoid junky output*/
+ pthread_mutex_lock(&print_lock);
+
+ /* dump the list */
+ printf("\n");
+ for (j = 0; j < size; j++) {
+ if (j == i)
+ printf("---------------\n");
+ printf("%lu:%lu\n", list[j].tv_sec, list[j].tv_nsec);
+ if (j == i+1)
+ printf("---------------\n");
+ }
+ printf("[FAILED]\n");
+
+ pthread_mutex_unlock(&print_lock);
+ }
+ }
+}
+
+/* The shared thread shares a global list
+ * that each thread fills while holding the lock.
+ * This stresses clock syncronization across cpus.
+ */
+void *shared_thread(void *arg)
+{
+ while (!done) {
+ /* protect the list */
+ pthread_mutex_lock(&list_lock);
+
+ /* see if we're ready to check the list */
+ if (listcount >= LISTSIZE) {
+ checklist(global_list, LISTSIZE);
+ listcount = 0;
+ }
+ clock_gettime(CLOCK_MONOTONIC, &global_list[listcount++]);
+
+ pthread_mutex_unlock(&list_lock);
+ }
+ return NULL;
+}
+
+
+/* Each independent thread fills in its own
+ * list. This stresses clock_gettime() lock contention.
+ */
+void *independent_thread(void *arg)
+{
+ struct timespec my_list[LISTSIZE];
+ int count;
+
+ while (!done) {
+ /* fill the list */
+ for (count = 0; count < LISTSIZE; count++)
+ clock_gettime(CLOCK_MONOTONIC, &my_list[count]);
+ checklist(my_list, LISTSIZE);
+ }
+ return NULL;
+}
+
+#define DEFAULT_THREAD_COUNT 8
+#define DEFAULT_RUNTIME 30
+
+int main(int argc, char **argv)
+{
+ int thread_count, i;
+ time_t start, now, runtime;
+ char buf[255];
+ pthread_t pth[MAX_THREADS];
+ int opt;
+ void *tret;
+ int ret = 0;
+ void *(*thread)(void *) = shared_thread;
+
+ thread_count = DEFAULT_THREAD_COUNT;
+ runtime = DEFAULT_RUNTIME;
+
+ /* Process arguments */
+ while ((opt = getopt(argc, argv, "t:n:i")) != -1) {
+ switch (opt) {
+ case 't':
+ runtime = atoi(optarg);
+ break;
+ case 'n':
+ thread_count = atoi(optarg);
+ break;
+ case 'i':
+ thread = independent_thread;
+ printf("using independent threads\n");
+ break;
+ default:
+ printf("Usage: %s [-t <secs>] [-n <numthreads>] [-i]\n", argv[0]);
+ printf(" -t: time to run\n");
+ printf(" -n: number of threads\n");
+ printf(" -i: use independent threads\n");
+ return -1;
+ }
+ }
+
+ if (thread_count > MAX_THREADS)
+ thread_count = MAX_THREADS;
+
+
+ setbuf(stdout, NULL);
+
+ start = time(0);
+ strftime(buf, 255, "%a, %d %b %Y %T %z", localtime(&start));
+ printf("%s\n", buf);
+ printf("Testing consistency with %i threads for %ld seconds: ", thread_count, runtime);
+
+ /* spawn */
+ for (i = 0; i < thread_count; i++)
+ pthread_create(&pth[i], 0, thread, 0);
+
+ while (time(&now) < start + runtime) {
+ sleep(1);
+ if (done) {
+ ret = 1;
+ strftime(buf, 255, "%a, %d %b %Y %T %z", localtime(&now));
+ printf("%s\n", buf);
+ goto out;
+ }
+ }
+ printf("[OK]\n");
+ done = 1;
+
+out:
+ /* wait */
+ for (i = 0; i < thread_count; i++)
+ pthread_join(pth[i], &tret);
+
+ /* die */
+ if (ret)
+ ksft_exit_fail();
+ return ksft_exit_pass();
+}