/****************************************************************************
* 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>
#ifdef CONFIG_ARCH_SIM
# include <nuttx/arch.h>
#endif
#include "ostest.h"
#if defined(CONFIG_PRIORITY_INHERITANCE) && !defined(CONFIG_DISABLE_SIGNALS) && !defined(CONFIG_DISABLE_PTHREAD)
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
enum thstate_e
{
NOTSTARTED = 0,
RUNNING,
WAITING,
DONE
};
static sem_t g_sem;
static volatile enum thstate_e g_middlestate = NOTSTARTED;
static volatile enum thstate_e g_highstate = NOTSTARTED;
static volatile enum thstate_e g_lowstate = NOTSTARTED;
static int g_highpri;
static int g_medpri;
static int g_lowpri;
/****************************************************************************
* Name: highpri_thread
****************************************************************************/
static void *highpri_thread(void *parameter)
{
int ret;
printf("highpri_thread: Started\n");
fflush(stdout);
g_highstate = WAITING;
ret = sem_wait(&g_sem);
g_highstate = DONE;
if (ret != 0)
{
printf("highpri_thread: sem_take failed: %d\n", ret);
}
else if (g_middlestate == RUNNING)
{
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: hog_cpu
****************************************************************************/
static inline void hog_cpu(void)
{
#ifdef CONFIG_ARCH_SIM
/* The simulator doesn't have any mechanism to do asynchronous pre-emption
* (basically because it doesn't have any interupts/asynchronous events).
* The simulator does "fake" a timer interrupt in up_idle() -- the idle
* thread that only executes when nothing else is running. In the simulator,
* we cannot suspend the middle priority task, or we wouldn't have the
* test that we want. So, we have no option but to pump the fake clock
* here by calling up_idle(). Sigh!
*/
up_idle();
#else
/* On real platforms with a real timer interrupt, we really can hog the
* CPU. When the sleep() goes off in priority_inheritance(), it will
* wake up and start the high priority thread.
*/
volatile int i;
for (i = 0; i < INT_MAX; i++);
#endif
}
/****************************************************************************
* Name: medpri_thread
****************************************************************************/
static void *medpri_thread(void *parameter)
{
printf("medpri_thread: Started ... I won't let go of the CPU!\n");
g_middlestate = RUNNING;
fflush(stdout);
/* The following loop will completely block lowpri_thread from running.
* UNLESS priority inheritance is working. In that case, its priority
* will be boosted.
*/
while (g_highstate != DONE)
{
hog_cpu();
}
printf("medpri_thread: Okay... I'm done!\n");
fflush(stdout);
g_middlestate = DONE;
return NULL;
}
/****************************************************************************
* Name: lowpri_thread
****************************************************************************/
static void *lowpri_thread(void *parameter)
{
void *retval = (void*)-1;
struct sched_param sparam;
int policy;
int ret;
g_lowstate = RUNNING;
printf("lowpri_thread: Started\n");
ret = pthread_getschedparam(pthread_self(), &policy, &sparam);
if (ret != 0)
{
printf("lowpri_thread: ERROR pthread_getschedparam failed: %d\n", ret);
}
else
{
printf("lowpri_thread: initial priority: %d\n", sparam.sched_priority);
if (sparam.sched_priority != g_lowpri)
{
printf(" ERROR should have been %d\n", g_lowpri);
}
}
g_lowstate = WAITING;
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_middlestate == NOTSTARTED && g_highstate != WAITING)
{
printf("lowpri_thread: Waiting for the midle pri task to run\n");
printf(" g_middlestate=%d g_highstate=%d\n", (int)g_middlestate, (int)g_highstate);
printf(" I still have the semaphore\n");
fflush(stdout);
sleep(1);
}
/* The middle priority task is running, let go of the semaphore */
if (g_middlestate == RUNNING && g_highstate == WAITING)
{
/* 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(" g_middlestate=%d g_highstate=%d\n", (int)g_middlestate, (int)g_highstate);
}
}
ret = pthread_getschedparam(pthread_self(), &policy, &sparam);
sem_post(&g_sem);
if (ret != 0)
{
printf("lowpri_thread: ERROR pthread_getschedparam failed: %d\n", ret);
}
else
{
printf("lowpri_thread: Priority before sem_post: %d\n", sparam.sched_priority);
if (sparam.sched_priority != g_highpri)
{
printf(" ERROR should have been %d\n", g_highpri);
}
}
ret = pthread_getschedparam(pthread_self(), &policy, &sparam);
if (ret != 0)
{
printf("lowpri_thread: ERROR pthread_getschedparam failed: %d\n", ret);
}
else
{
printf("lowpri_thread: Final priority: %d\n", sparam.sched_priority);
if (sparam.sched_priority != g_lowpri)
{
printf(" ERROR should have been %d\n", g_lowpri);
}
}
printf("lowpri_thread: Okay... I'm done!\n");
fflush(stdout);
g_lowstate = DONE;
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 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;
g_highpri = sched_get_priority_max(SCHED_FIFO);
g_lowpri = sched_get_priority_min(SCHED_FIFO);
g_medpri = my_pri - 1;
sem_init(&g_sem, 0, 1);
/* Start the low priority task */
printf("priority_inheritance: Starting lowpri_thread at %d\n", g_lowpri);
status = pthread_attr_init(&attr);
if (status != 0)
{
printf("priority_inheritance: pthread_attr_init failed, status=%d\n", status);
}
sparam.sched_priority = g_lowpri;
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(2);
/* Start the medium priority task */
printf("priority_inheritance: Starting medpri_thread at %d\n", g_medpri);
status = pthread_attr_init(&attr);
if (status != 0)
{
printf("priority_inheritance: pthread_attr_init failed, status=%d\n", status);
}
sparam.sched_priority = g_medpri;
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);
}
fflush(stdout);
status = pthread_create(&medpri, &attr, medpri_thread, NULL);
if (status != 0)
{
printf("priority_inheritance: pthread_create failed, status=%d\n", status);
}
printf("priority_inheritance: Waiting...\n");
sleep(1);
/* Start the high priority task */
printf("priority_inheritance: Starting highpri_thread at %d\n", g_highpri);
status = pthread_attr_init(&attr);
if (status != 0)
{
printf("priority_inheritance: pthread_attr_init failed, status=%d\n", status);
}
sparam.sched_priority = g_highpri;
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);
}
fflush(stdout);
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");
fflush(stdout);
(void)pthread_join(highpri, &result);
printf("priority_inheritance: Waiting for medpri_thread to complete\n");
fflush(stdout);
(void)pthread_join(medpri, &result);
printf("priority_inheritance: Waiting for lowpri_thread to complete\n");
fflush(stdout);
(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 */
}