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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(const struct timespec *list, int size){	int i, j;	const 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();	ksft_exit_pass();}