313 lines
9.2 KiB
C
313 lines
9.2 KiB
C
/****************************************************************************
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* cond.c
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*
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* Copyright (C) 2007, 2008, 2013 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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#include <stdio.h>
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#include <pthread.h>
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#include <unistd.h>
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#include "ostest.h"
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#ifndef NULL
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# define NULL (void*)0
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#endif
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static volatile enum { RUNNING, MUTEX_WAIT, COND_WAIT} waiter_state;
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static pthread_mutex_t mutex;
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static pthread_cond_t cond;
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static volatile int data_available = 0;
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static int waiter_nloops = 0;
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static int waiter_waits = 0;
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static int waiter_nerrors = 0;
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static int signaler_nloops = 0;
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static int signaler_already = 0;
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static int signaler_state = 0;
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static int signaler_nerrors = 0;
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static void *thread_waiter(void *parameter)
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{
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int status;
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printf("waiter_thread: Started\n");
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for (;;)
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{
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/* Take the mutex */
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waiter_state = MUTEX_WAIT;
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status = pthread_mutex_lock(&mutex);
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waiter_state = RUNNING;
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if (status != 0)
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{
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printf("waiter_thread: ERROR pthread_mutex_lock failed, status=%d\n", status);
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waiter_nerrors++;
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}
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/* Check if data is available -- if data is not available then
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* wait for it
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*/
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if (!data_available)
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{
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/* We are higher priority than the signaler thread so the
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* only time that the signaler thread will have a chance to run is when
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* we are waiting for the condition variable. In this case, pthread_cond_wait
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* will automatically release the mutex for the signaler (then re-acquire
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* the mutex before returning.
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*/
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waiter_state = COND_WAIT;
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status = pthread_cond_wait(&cond, &mutex);
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waiter_state = RUNNING;
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if (status != 0)
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{
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printf("waiter_thread: ERROR pthread_cond_wait failed, status=%d\n", status);
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waiter_nerrors++;
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}
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waiter_waits++;
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}
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/* Now data should be available */
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if (!data_available)
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{
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printf("waiter_thread: ERROR data not available after wait\n");
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waiter_nerrors++;
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}
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/* Clear data available */
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data_available = 0;
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/* Release the mutex */
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status = pthread_mutex_unlock(&mutex);
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if (status != 0)
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{
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printf("waiter_thread: ERROR waiter: pthread_mutex_unlock failed, status=%d\n", status);
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waiter_nerrors++;
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}
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waiter_nloops++;
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}
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return NULL;
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}
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static void *thread_signaler(void *parameter)
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{
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int status;
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int i;
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printf("thread_signaler: Started\n");
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for (i = 0; i < 32; i++)
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{
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/* Take the mutex. The waiter is higher priority and should
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* run until it waits for the condition. So, at this point
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* signaler should be waiting for the condition.
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*/
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status = pthread_mutex_lock(&mutex);
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if (status != 0)
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{
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printf("thread_signaler: ERROR pthread_mutex_lock failed, status=%d\n", status);
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signaler_nerrors++;
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}
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/* Verify the state */
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if (waiter_state != COND_WAIT)
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{
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printf("thread_signaler: ERROR waiter state = %d != COND_WAITING\n", waiter_state);
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signaler_state++;
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}
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if (data_available)
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{
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printf("thread_signaler: ERROR data already available, waiter_state=%d\n", waiter_state);
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signaler_already++;
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}
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/* Set data available and signal the waiter */
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data_available = 1;
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status = pthread_cond_signal(&cond);
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if (status != 0)
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{
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printf("thread_signaler: ERROR pthread_cond_signal failed, status=%d\n", status);
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signaler_nerrors++;
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}
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/* Release the mutex */
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status = pthread_mutex_unlock(&mutex);
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if (status != 0)
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{
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printf("thread_signaler: ERROR pthread_mutex_unlock failed, status=%d\n", status);
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signaler_nerrors++;
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}
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#if defined(CONFIG_SMP) && (CONFIG_SMP_NCPUS > 1)
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/* Workaround for SMP:
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* In multi-core environment, thread_signaler would be excecuted prior
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* to the thread_waiter, even though priority of thread_signaler is
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* lower than the thread_waiter. In this case, thread_signaler will
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* aquire mutex before the thread_waiter aquires it and will show
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* the error message such as "thread_signaler: ERROR waiter state...".
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* To avoid this situaltion, we add the following usleep()
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*/
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usleep(10 * 1000);
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#endif
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signaler_nloops++;
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}
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printf("thread_signaler: Terminating\n");
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pthread_exit(NULL);
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return NULL; /* Non-reachable -- needed for some compilers */
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}
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void cond_test(void)
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{
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pthread_t waiter;
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pthread_t signaler;
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pthread_attr_t attr;
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#ifdef SDCC
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pthread_addr_t result;
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#endif
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struct sched_param sparam;
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int prio_min;
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int prio_max;
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int prio_mid;
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int status;
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/* Initialize the mutex */
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printf("cond_test: Initializing mutex\n");
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status = pthread_mutex_init(&mutex, NULL);
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if (status != 0)
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{
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printf("cond_test: ERROR pthread_mutex_init failed, status=%d\n", status);
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}
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/* Initialize the condition variable */
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printf("cond_test: Initializing cond\n");
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status = pthread_cond_init(&cond, NULL);
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if (status != 0)
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{
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printf("cond_test: ERROR pthread_condinit failed, status=%d\n", status);
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}
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/* Start the waiter thread at higher priority */
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printf("cond_test: Starting waiter\n");
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status = pthread_attr_init(&attr);
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if (status != 0)
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{
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printf("cond_test: pthread_attr_init failed, status=%d\n", status);
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}
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prio_min = sched_get_priority_min(SCHED_FIFO);
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prio_max = sched_get_priority_max(SCHED_FIFO);
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prio_mid = (prio_min + prio_max) / 2;
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sparam.sched_priority = prio_mid;
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status = pthread_attr_setschedparam(&attr,&sparam);
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if (status != OK)
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{
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printf("cond_test: pthread_attr_setschedparam failed, status=%d\n", status);
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}
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else
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{
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printf("cond_test: Set thread 1 priority to %d\n", sparam.sched_priority);
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}
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status = pthread_create(&waiter, &attr, thread_waiter, NULL);
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if (status != 0)
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{
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printf("cond_test: pthread_create failed, status=%d\n", status);
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}
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printf("cond_test: Starting signaler\n");
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status = pthread_attr_init(&attr);
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if (status != 0)
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{
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printf("cond_test: pthread_attr_init failed, status=%d\n", status);
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}
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sparam.sched_priority = (prio_min + prio_mid) / 2;
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status = pthread_attr_setschedparam(&attr,&sparam);
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if (status != OK)
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{
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printf("cond_test: pthread_attr_setschedparam failed, status=%d\n", status);
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}
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else
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{
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printf("cond_test: Set thread 2 priority to %d\n", sparam.sched_priority);
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}
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status = pthread_create(&signaler, &attr, thread_signaler, NULL);
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if (status != 0)
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{
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printf("cond_test: pthread_create failed, status=%d\n", status);
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}
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/* Wait for the threads to stop */
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#ifdef SDCC
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pthread_join(signaler, &result);
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#else
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pthread_join(signaler, NULL);
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#endif
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printf("cond_test: signaler terminated, now cancel the waiter\n");
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pthread_detach(waiter);
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pthread_cancel(waiter);
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printf("cond_test: \tWaiter\tSignaler\n");
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printf("cond_test: Loops\t%d\t%d\n", waiter_nloops, signaler_nloops);
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printf("cond_test: Errors\t%d\t%d\n", waiter_nerrors, signaler_nerrors);
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printf("cond_test:\n");
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printf("cond_test: %d times, waiter did not have to wait for data\n",
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waiter_nloops - waiter_waits);
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printf("cond_test: %d times, data was already available when the signaler run\n",
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signaler_already);
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printf("cond_test: %d times, the waiter was in an unexpected state when the signaler ran\n",
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signaler_state);
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}
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