Add support for priority inheritance

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@1581 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 292 insertions, 0 deletions

diff --git a/nuttx/examples/ostest/prioinherit.c b/nuttx/examples/ostest/prioinherit.c
new file mode 100644
index 000000000..818f46b75
--- /dev/null
+++ b/nuttx/examples/ostest/prioinherit.c
@@ -0,0 +1,292 @@
+/****************************************************************************
+ * examples/ostest/prioinherit.c
+ *
+ *   Copyright (C) 2009 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 NuttX 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.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <sys/types.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <semaphore.h>
+#include <pthread.h>
+
+#include "ostest.h"
+
+#if defined(CONFIG_PRIORITY_INHERITANCE) && !defined(CONFIG_DISABLE_SIGNALS) && !defined(CONFIG_DISABLE_PTHREAD)
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+static sem_t g_sem;
+static volatile int g_middle = 0;
+
+/****************************************************************************
+ * Name: highpri_thread
+ ****************************************************************************/
+
+static void *highpri_thread(void *parameter)
+{
+  int ret;
+
+  printf("highpri_thread: Thread %d started\n");
+
+  ret = sem_wait(&g_sem);
+  if (ret != 0)
+    {
+      printf("highpri_thread: sem_take failed: %d\n", ret);
+    }
+  else if (g_middle == 1)
+    {
+      printf("highpri_thread: Success midpri_thread is still running!\n");
+    }
+  else
+    {
+      printf("highpri_thread: ERROR --  midpri_thread has already exited!\n");
+    }
+
+  sem_post(&g_sem);
+  printf("medpri_thread: Okay... I'm done!\n");
+  fflush(stdout);
+  return NULL;
+}
+
+/****************************************************************************
+ * Name: medpri_thread
+ ****************************************************************************/
+
+static void *medpri_thread(void *parameter)
+{
+  volatile long i;
+
+  printf("medpri_thread: Thread %d started ... I won't let go of the CPU!\n");
+  g_middle = 1;
+  for (i = 0; i < 0x7ffffff; i++);
+  printf("medpri_thread: Okay... I'm done!\n");
+  fflush(stdout);
+  return NULL;
+}
+
+/****************************************************************************
+ * Name: lowpri_thread
+ ****************************************************************************/
+
+static void *lowpri_thread(void *parameter)
+{
+  void *retval = (void*)-1;
+  int ret;
+
+  printf("lowpri_thread: Thread %d started\n");
+
+  ret = sem_wait(&g_sem);
+  if (ret != 0)
+    {
+      printf("lowpri_thread: sem_take failed: %d\n", ret);
+    }
+  else
+    {
+      /* Hang on to the thread until the middle priority thread runs */
+
+      while (g_middle == 0)
+        {
+          printf("lowpri_thread: Waiting for the midle pri task to run\n");
+          printf("lowpri_thread: I still have the semaphore\n");
+          sleep(1);
+        }
+
+      /* The middle priority task is running, let go of the semaphore */
+
+     if (g_middle == 1)
+       {
+         /* Good.. the middle priority task is still running but we got priority! */
+
+         retval = NULL;
+       }
+     else
+       {
+         printf("lowpri_thread: ERROR the middle priority task has already exitted!\n");
+       }
+    }
+
+  printf("lowpri_thread: Letting go of the semaphore\n");
+  sem_post(&g_sem);
+  printf("lowpri_thread: Okay... I'm done!\n");
+  fflush(stdout);
+  return retval;  
+}
+#endif /* CONFIG_PRIORITY_INHERITANCE && !CONFIG_DISABLE_SIGNALS && !CONFIG_DISABLE_PTHREAD */
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: priority_inheritance
+ ****************************************************************************/
+
+void priority_inheritance(void)
+{
+#if defined(CONFIG_PRIORITY_INHERITANCE) && !defined(CONFIG_DISABLE_SIGNALS) && !defined(CONFIG_DISABLE_PTHREAD)
+  pthread_t lowpri;
+  pthread_t medpri;
+  pthread_t highpri;
+  pthread_addr_t result;
+  pthread_attr_t attr;
+  struct sched_param sparam;
+  int my_pri;
+  int max_pri;
+  int mid_pri;
+  int min_pri;
+  int status;
+
+  printf("priority_inheritance: Started\n");
+
+  status = sched_getparam (getpid(), &sparam);
+  if (status != 0)
+    {
+      printf("priority_inheritance: sched_getparam failed\n");
+      sparam.sched_priority = PTHREAD_DEFAULT_PRIORITY;
+    }
+  my_pri  = sparam.sched_priority;
+
+  max_pri = sched_get_priority_max(SCHED_FIFO);
+  min_pri = sched_get_priority_min(SCHED_FIFO);
+  mid_pri = my_pri - 1;
+
+  sem_init(&g_sem, 0, 1);
+
+  /* Start the low priority task */
+
+  printf("priority_inheritance: Starting lowpri_thread at %d\n", min_pri);
+  status = pthread_attr_init(&attr);
+  if (status != 0)
+    {
+      printf("priority_inheritance: pthread_attr_init failed, status=%d\n", status);
+    }
+  sparam.sched_priority = min_pri;
+  status = pthread_attr_setschedparam(&attr,& sparam);
+  if (status != OK)
+    {
+      printf("priority_inheritance: pthread_attr_setschedparam failed, status=%d\n", status);
+    }
+  else
+    {
+      printf("priority_inheritance: Set lowpri_thread priority to %d\n", sparam.sched_priority);
+    }
+
+  status = pthread_create(&lowpri, &attr, lowpri_thread, NULL);
+  if (status != 0)
+    {
+      printf("priority_inheritance: pthread_create failed, status=%d\n", status);
+    }
+
+  printf("priority_inheritance: Waiting...\n");
+  sleep(5);
+
+  /* Start the medium priority task */
+
+  printf("priority_inheritance: Starting medpri_thread at %d\n", mid_pri);
+  status = pthread_attr_init(&attr);
+  if (status != 0)
+    {
+      printf("priority_inheritance: pthread_attr_init failed, status=%d\n", status);
+    }
+
+  sparam.sched_priority = mid_pri;
+  status = pthread_attr_setschedparam(&attr,& sparam);
+  if (status != OK)
+    {
+      printf("priority_inheritance: pthread_attr_setschedparam failed, status=%d\n", status);
+    }
+  else
+    {
+      printf("priority_inheritance: Set medpri_thread priority to %d\n", sparam.sched_priority);
+    }
+
+  status = pthread_create(&medpri, &attr, medpri_thread, NULL);
+  if (status != 0)
+    {
+      printf("priority_inheritance: pthread_create failed, status=%d\n", status);
+    }
+
+  /* Start the high priority task */
+
+  printf("priority_inheritance: Starting highpri_thread at %d\n", max_pri);
+  status = pthread_attr_init(&attr);
+  if (status != 0)
+    {
+      printf("priority_inheritance: pthread_attr_init failed, status=%d\n", status);
+    }
+
+  sparam.sched_priority = max_pri;
+  status = pthread_attr_setschedparam(&attr,& sparam);
+  if (status != OK)
+    {
+      printf("priority_inheritance: pthread_attr_setschedparam failed, status=%d\n", status);
+    }
+  else
+    {
+      printf("priority_inheritance: Set highpri_thread priority to %d\n", sparam.sched_priority);
+    }
+
+  status = pthread_create(&medpri, &attr, highpri_thread, NULL);
+  if (status != 0)
+    {
+      printf("priority_inheritance: pthread_create failed, status=%d\n", status);
+    }
+
+  /* Wait for all thread instances to complete */
+
+  printf("priority_inheritance: Waiting for highpri_thread to complete\n");
+  (void)pthread_join(highpri, &result);
+  printf("priority_inheritance: Waiting for medpri_thread to complete\n");
+  (void)pthread_join(medpri, &result);
+  printf("priority_inheritance: Waiting for lowpri_thread to complete\n");
+  (void)pthread_join(lowpri, &result);
+
+  printf("priority_inheritance: Finished\n");
+  sem_destroy(&g_sem);
+  fflush(stdout);
+#endif /* CONFIG_PRIORITY_INHERITANCE && !CONFIG_DISABLE_SIGNALS && !CONFIG_DISABLE_PTHREAD */
+}