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Diffstat (limited to 'nuttx/examples/ostest/cond.c')
-rw-r--r-- | nuttx/examples/ostest/cond.c | 284 |
1 files changed, 284 insertions, 0 deletions
diff --git a/nuttx/examples/ostest/cond.c b/nuttx/examples/ostest/cond.c new file mode 100644 index 000000000..be995fa08 --- /dev/null +++ b/nuttx/examples/ostest/cond.c @@ -0,0 +1,284 @@ +/*********************************************************************** + * cond.c + * + * Copyright (C) 2007 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <spudmonkey@racsa.co.cr> + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. 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. + * 3. Neither the name Gregory Nutt nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "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 + * COPYRIGHT OWNER OR CONTRIBUTORS 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 <stdio.h> +#include <pthread.h> +#include <unistd.h> +#include "ostest.h" + +#ifndef NULL +# define NULL (void*)0 +#endif + +static volatile enum { RUNNING, MUTEX_WAIT, COND_WAIT} waiter_state; + +static pthread_mutex_t mutex; +static pthread_cond_t cond; +static volatile int data_available = 0; +static int waiter_nloops = 0; +static int waiter_waits = 0; +static int waiter_nerrors = 0; +static int signaler_nloops = 0; +static int signaler_already = 0; +static int signaler_state = 0; +static int signaler_nerrors = 0; + +static void *thread_waiter(void *parameter) +{ + int status; + + printf("%s: Started\n", __FUNCTION__); + + for(;;) + { + /* Take the mutex */ + + waiter_state = MUTEX_WAIT; + status = pthread_mutex_lock(&mutex); + waiter_state = RUNNING; + + if (status != 0) + { + printf("%s: ERROR pthread_mutex_lock failed, status=%d\n", __FUNCTION__, status); + waiter_nerrors++; + } + + /* Check if data is available -- if data is not available then + * wait for it + */ + + if (!data_available) + { + /* We are higher priority than the signaler thread so the + * only time that the signaler thread will have a chance to run is when + * we are waiting for the condition variable. In this case, pthread_cond_wait + * will automatically release the mutex for the signaler (then re-acquire + * the mutex before returning. + */ + + waiter_state = COND_WAIT; + status = pthread_cond_wait(&cond, &mutex); + waiter_state = RUNNING; + + if (status != 0) + { + printf("%s: ERROR pthread_cond_wait failed, status=%d\n", __FUNCTION__, status); + waiter_nerrors++; + } + waiter_waits++; + } + + /* Now data should be available */ + + if (!data_available) + { + printf("%s: ERROR data not available after wait\n", __FUNCTION__); + waiter_nerrors++; + } + + /* Clear data available */ + + data_available = 0; + + /* Release the mutex */ + + status = pthread_mutex_unlock(&mutex); + if (status != 0) + { + printf("%s: ERROR waiter: pthread_mutex_unlock failed, status=%d\n", __FUNCTION__, status); + waiter_nerrors++; + } + + waiter_nloops++; + } +} + +static void *thread_signaler(void *parameter) +{ + int status; + int i; + + printf("%s: Started\n", __FUNCTION__); + for (i = 0; i < 32; i++) + { + /* Take the mutex. The waiter is higher priority and should + * run until it waits for the condition. So, at this point + * signaler should be waiting for the condition. + */ + + status = pthread_mutex_lock(&mutex); + if (status != 0) + { + printf("%s: ERROR pthread_mutex_lock failed, status=%d\n", __FUNCTION__, status); + signaler_nerrors++; + } + + /* Verify the state */ + + if (waiter_state != COND_WAIT) + { + printf("%s: ERROR waiter state = %d != COND_WAITING\n", __FUNCTION__, waiter_state); + signaler_state++; + } + + if (data_available) + { + printf("%s: ERROR data already available, waiter_state=%d\n", __FUNCTION__, waiter_state); + signaler_already++; + } + + /* Set data available and signal the waiter */ + + data_available = 1; + status = pthread_cond_signal(&cond); + if (status != 0) + { + printf("%s: ERROR pthread_cond_signal failed, status=%d\n", __FUNCTION__, status); + signaler_nerrors++; + } + + /* Release the mutex */ + + status = pthread_mutex_unlock(&mutex); + if (status != 0) + { + printf("%s: ERROR pthread_mutex_unlock failed, status=%d\n", __FUNCTION__, status); + signaler_nerrors++; + } + + signaler_nloops++; + } + + printf("%s: Terminating\n", __FUNCTION__); + pthread_exit(NULL); +} + +void cond_test(void) +{ + pthread_t waiter; + pthread_t signaler; + pthread_attr_t attr; + struct sched_param sparam; + int prio_min; + int prio_max; + int prio_mid; + int status; + + /* Initialize the mutex */ + + printf("%s: Initializing mutex\n", __FUNCTION__); + status = pthread_mutex_init(&mutex, NULL); + if (status != 0) + { + printf("%s: ERROR pthread_mutex_init failed, status=%d\n", __FUNCTION__, status); + } + + /* Initialize the condition variable */ + + printf("%s: Initializing cond\n", __FUNCTION__); + status = pthread_cond_init(&cond, NULL); + if (status != 0) + { + printf("%s: ERROR pthread_condinit failed, status=%d\n", __FUNCTION__, status); + } + + /* Start the waiter thread at higher priority */ + + printf("%s: Starting waiter\n", __FUNCTION__); + status = pthread_attr_init(&attr); + if (status != 0) + { + printf("%s: pthread_attr_init failed, status=%d\n", __FUNCTION__, status); + } + + prio_min = sched_get_priority_min(SCHED_FIFO); + prio_max = sched_get_priority_max(SCHED_FIFO); + prio_mid = (prio_min + prio_max) / 2; + + sparam.sched_priority = prio_mid; + status = pthread_attr_setschedparam(&attr,&sparam); + if (status != OK) + { + printf("%s: pthread_attr_setschedparam failed, status=%d\n", __FUNCTION__, status); + } + else + { + printf("%s: Set thread 1 priority to %d\n", __FUNCTION__, sparam.sched_priority); + } + + status = pthread_create(&waiter, &attr, thread_waiter, NULL); + if (status != 0) + { + printf("%s: pthread_create failed, status=%d\n", __FUNCTION__, status); + } + + printf("%s: Starting signaler\n", __FUNCTION__); + status = pthread_attr_init(&attr); + if (status != 0) + { + printf("%s: pthread_attr_init failed, status=%d\n", __FUNCTION__, status); + } + + sparam.sched_priority = (prio_min + prio_mid) / 2; + status = pthread_attr_setschedparam(&attr,&sparam); + if (status != OK) + { + printf("%s: pthread_attr_setschedparam failed, status=%d\n", __FUNCTION__, status); + } + else + { + printf("%s: Set thread 2 priority to %d\n", __FUNCTION__, sparam.sched_priority); + } + + status = pthread_create(&signaler, &attr, thread_signaler, NULL); + if (status != 0) + { + printf("%s: pthread_create failed, status=%d\n", __FUNCTION__, status); + } + + /* Wait for the threads to stop */ + + pthread_join(signaler, NULL); + printf("%s: signaler terminated, now cancel the waiter\n", __FUNCTION__); + pthread_detach(waiter); + pthread_cancel(waiter); + + printf("%s: \tWaiter\tSignaler\n", __FUNCTION__); + printf("%s: Loops\t%d\t%d\n", __FUNCTION__, waiter_nloops, signaler_nloops); + printf("%s: Errors\t%d\t%d\n", __FUNCTION__, waiter_nerrors, signaler_nerrors); + printf("%s: \n%d times, waiter did not have to wait for data\n", __FUNCTION__, waiter_nloops - waiter_waits); + printf("%s: %d times, data was already available when the signaler run\n", __FUNCTION__, signaler_already); + printf("%s: %d times, the waiter was in an unexpected state when the signaler ran\n", __FUNCTION__, signaler_state); +} |