NuttX RTOS

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3 42af7a65-404d-4744-a932-0658087f49c3

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
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+++ b/nuttx/examples/ostest/cond.c
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+/***********************************************************************
+ * 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);
+}