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/* 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 synchronization 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);
fflush(stdout);
/* 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();
}
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