source: mainline/kernel/test/synch/semaphore1.c

/*
 * Copyright (c) 2001-2004 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <test.h>
#include <arch.h>
#include <atomic.h>
#include <proc/thread.h>
#include <synch/waitq.h>
#include <synch/semaphore.h>

#define AT_ONCE    3
#define PRODUCERS  50
#define CONSUMERS  50

static semaphore_t sem;

static waitq_t can_start;
static atomic_size_t items_produced;
static atomic_size_t items_consumed;

static void producer(void *arg)
{
        waitq_sleep(&can_start);

        semaphore_down(&sem);
        atomic_inc(&items_produced);
        thread_usleep(250);
        semaphore_up(&sem);
}

static void consumer(void *arg)
{
        waitq_sleep(&can_start);

        semaphore_down(&sem);
        atomic_inc(&items_consumed);
        thread_usleep(500);
        semaphore_up(&sem);
}

const char *test_semaphore1(void)
{
        int i, j, k;
        size_t consumers;
        size_t producers;

        waitq_initialize(&can_start);
        semaphore_initialize(&sem, AT_ONCE);

        for (i = 1; i <= 3; i++) {
                thread_t *thrd;

                atomic_store(&items_produced, 0);
                atomic_store(&items_consumed, 0);

                consumers = i * CONSUMERS;
                producers = (4 - i) * PRODUCERS;

                TPRINTF("Creating %zu consumers and %zu producers...",
                    consumers, producers);

                for (j = 0; j < (CONSUMERS + PRODUCERS) / 2; j++) {
                        for (k = 0; k < i; k++) {
                                thrd = thread_create(consumer, NULL, TASK,
                                    THREAD_FLAG_NONE, "consumer");
                                if (thrd) {
                                        thread_start(thrd);
                                        thread_detach(thrd);
                                } else {
                                        TPRINTF("could not create consumer %d\n", i);
                                }
                        }
                        for (k = 0; k < (4 - i); k++) {
                                thrd = thread_create(producer, NULL, TASK,
                                    THREAD_FLAG_NONE, "producer");
                                if (thrd) {
                                        thread_start(thrd);
                                        thread_detach(thrd);
                                } else {
                                        TPRINTF("could not create producer %d\n", i);
                                }
                        }
                }

                TPRINTF("ok\n");

                thread_sleep(1);
                waitq_wake_all(&can_start);

                while ((items_consumed != consumers) || (items_produced != producers)) {
                        TPRINTF("%zu consumers remaining, %zu producers remaining\n",
                            consumers - items_consumed, producers - items_produced);
                        thread_sleep(1);
                }
        }

        return NULL;
}