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px4-firmware/apps/examples/ostest/prioinherit.c

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/****************************************************************************
* examples/ostest/prioinherit.c
*
* Copyright (C) 2009, 2011 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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 <stdio.h>
#include <unistd.h>
#include <semaphore.h>
#include <pthread.h>
#include <errno.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
****************************************************************************/
#ifndef CONFIG_SEM_PREALLOCHOLDERS
# define CONFIG_SEM_PREALLOCHOLDERS 0
#endif
/* If resources were configured for lots of holders, then run 3 low priority
* threads. Otherwise, just one.
*/
#if CONFIG_SEM_PREALLOCHOLDERS > 3
# define NLOWPRI_THREADS 3
#else
# define NLOWPRI_THREADS 1
#endif
#ifndef CONFIG_SEM_NNESTPRIO
# define CONFIG_SEM_NNESTPRIO 0
#endif
/* Where resources configured for lots of waiters? If so then run 3 high
* priority threads. Otherwise, just one.
*/
#if CONFIG_SEM_NNESTPRIO > 3
# define NHIGHPRI_THREADS 3
#else
# define NHIGHPRI_THREADS 1
#endif
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
enum thstate_e
{
NOTSTARTED = 0,
RUNNING,
WAITING,
DONE
};
static sem_t g_sem;
static volatile enum thstate_e g_middlestate;
static volatile enum thstate_e g_highstate[NHIGHPRI_THREADS];
static volatile enum thstate_e g_lowstate[NLOWPRI_THREADS];
static int g_highpri;
static int g_medpri;
static int g_lowpri;
/****************************************************************************
* Name: nhighpri_waiting
****************************************************************************/
static int nhighpri_waiting(void)
{
int n = 0;
int i;
for (i = 0; i < NHIGHPRI_THREADS; i++)
{
if (g_highstate[i] == WAITING)
{
n++;
}
}
return n;
}
/****************************************************************************
* Name: nhighpri_running
****************************************************************************/
static int nhighpri_running(void)
{
int n = 0;
int i;
for (i = 0; i < NHIGHPRI_THREADS; i++)
{
if (g_highstate[i] != DONE)
{
n++;
}
}
return n;
}
/****************************************************************************
* Name: highpri_thread
****************************************************************************/
static void *highpri_thread(void *parameter)
{
int threadno = (int)parameter;
int ret;
g_highstate[threadno-1] = RUNNING;
printf("highpri_thread-%d: Started\n", threadno);
FFLUSH();
sleep(1);
printf("highpri_thread-%d: Calling sem_wait()\n", threadno);
g_highstate[threadno-1] = WAITING;
ret = sem_wait(&g_sem);
g_highstate[threadno-1] = DONE;
if (ret != 0)
{
printf("highpri_thread-%d: sem_take failed: %d\n", threadno, ret);
}
else if (g_middlestate == RUNNING)
{
printf("highpri_thread-%d: SUCCESS midpri_thread is still running!\n", threadno);
}
else
{
printf("highpri_thread-%d: ERROR -- midpri_thread has already exited!\n", threadno);
}
sem_post(&g_sem);
printf("highpri_thread-%d: Okay... I'm done!\n", threadno);
FFLUSH();
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();
/* The following loop will completely block lowpri_thread from running.
* UNLESS priority inheritance is working. In that case, its priority
* will be boosted.
*/
while (nhighpri_running() > 0)
{
hog_cpu();
}
printf("medpri_thread: Okay... I'm done!\n");
FFLUSH();
g_middlestate = DONE;
return NULL;
}
/****************************************************************************
* Name: lowpri_thread
****************************************************************************/
static void *lowpri_thread(void *parameter)
{
void *retval = (void*)-1;
struct sched_param sparam;
int threadno = (int)parameter;
int expected;
int count;
int policy;
int ret;
int nwaiting;
int i;
g_lowstate[threadno-1] = RUNNING;
printf("lowpri_thread-%d: Started\n", threadno);
ret = pthread_getschedparam(pthread_self(), &policy, &sparam);
if (ret != 0)
{
printf("lowpri_thread-%d: ERROR pthread_getschedparam failed: %d\n", threadno, ret);
}
else
{
printf("lowpri_thread-%d: initial priority: %d\n", threadno, sparam.sched_priority);
if (sparam.sched_priority != g_lowpri)
{
printf(" ERROR should have been %d\n", g_lowpri);
}
}
g_lowstate[threadno-1] = WAITING;
ret = sem_wait(&g_sem);
if (ret != 0)
{
printf("lowpri_thread-%d: sem_take failed: %d\n", threadno, ret);
}
else
{
/* Hang on to the thread until the middle priority thread runs */
while (g_middlestate == NOTSTARTED && nhighpri_waiting() < NHIGHPRI_THREADS)
{
printf("lowpri_thread-%d: Waiting for the midle pri task to run\n", threadno);
printf(" g_middlestate: %d\n", (int)g_middlestate);
for (i = 0; i < NHIGHPRI_THREADS; i++)
{
printf(" g_highstate[%d]: %d\n", i, (int)g_highstate[i]);
}
printf(" I still have a count on the semaphore\n");
sem_enumholders(&g_sem);
FFLUSH();
sleep(1);
}
/* Account for all of the semaphore counts. At any given time if there are 'n'
* running hight prioity tasks, then the semaphore count should be '-n'
*/
sched_lock(); /* Needs to be atomic */
ret = sem_getvalue(&g_sem, &count);
nwaiting = nhighpri_waiting();
sched_unlock();
if (ret < 0)
{
printf("lowpri_thread-%d: ERROR sem_getvalue failed: %d\n", threadno, errno);
}
printf("lowpri_thread-%d: Sem count: %d, No. highpri thread: %d\n", threadno, count, nwaiting);
/* The middle priority task is running, let go of the semaphore */
if (g_middlestate == RUNNING && nwaiting == -count)
{
/* Good.. the middle priority task is still running and the counts are okay. */
retval = NULL;
}
else
{
/* If the sem count is positive, then there all of the higher priority threads
* should have already completed.
*/
printf("lowpri_thread-%d: %s the middle priority task has already exitted!\n",
threadno, count >= 0 ? "SUCCESS" : "ERROR" );
printf(" g_middlestate: %d sem count=%d\n", (int)g_middlestate, count);
for (i = 0; i < NHIGHPRI_THREADS; i++)
{
printf(" g_highstate[%d]: %d\n", i, (int)g_highstate[i]);
}
}
}
ret = pthread_getschedparam(pthread_self(), &policy, &sparam);
sem_enumholders(&g_sem);
sem_post(&g_sem);
if (ret != 0)
{
printf("lowpri_thread-%d: ERROR pthread_getschedparam failed: %d\n", threadno, ret);
}
else
{
if (nwaiting > 0)
{
expected = g_highpri;
}
else
{
expected = g_lowpri;
}
printf("lowpri_thread-%d: %s priority before sem_post: %d\n",
threadno,
sparam.sched_priority != expected ? "ERROR" : "SUCCESS",
sparam.sched_priority);
if (sparam.sched_priority != expected)
{
printf(" ERROR should have been %d\n", expected);
}
}
ret = pthread_getschedparam(pthread_self(), &policy, &sparam);
if (ret != 0)
{
printf("lowpri_thread-%d: ERROR pthread_getschedparam failed: %d\n", threadno, ret);
}
else
{
printf("lowpri_thread-%d: %s final priority: %d\n",
threadno,
sparam.sched_priority != g_lowpri ? "ERROR" : "SUCCESS",
sparam.sched_priority);
if (sparam.sched_priority != g_lowpri)
{
printf(" ERROR should have been %d\n", g_lowpri);
}
}
sem_enumholders(&g_sem);
printf("lowpri_thread-%d: Okay... I'm done!\n", threadno);
FFLUSH();
g_lowstate[threadno-1] = 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[NLOWPRI_THREADS];
pthread_t medpri;
pthread_t highpri[NHIGHPRI_THREADS];
pthread_addr_t result;
pthread_attr_t attr;
struct sched_param sparam;
int my_pri;
int status;
int i;
printf("priority_inheritance: Started\n");
g_middlestate = NOTSTARTED;
for (i = 0; i < NHIGHPRI_THREADS; i++) g_highstate[i] = NOTSTARTED;
for (i = 0; i < NLOWPRI_THREADS; i++) g_lowstate[i] = NOTSTARTED;
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, NLOWPRI_THREADS);
dump_nfreeholders("priority_inheritance:");
/* Start the low priority threads */
for (i = 0; i < NLOWPRI_THREADS; i++)
{
int threadno = i+1;
printf("priority_inheritance: Starting lowpri_thread-%d (of %d) at %d\n",
threadno, NLOWPRI_THREADS, 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-%d priority to %d\n",
threadno, sparam.sched_priority);
}
status = pthread_create(&lowpri[i], &attr, lowpri_thread, (void*)threadno);
if (status != 0)
{
printf("priority_inheritance: pthread_create failed, status=%d\n", status);
}
}
printf("priority_inheritance: Waiting...\n");
sleep(2);
dump_nfreeholders("priority_inheritance:");
/* Start the medium priority thread */
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();
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);
dump_nfreeholders("priority_inheritance:");
/* Start the high priority threads */
for (i = 0; i < NHIGHPRI_THREADS; i++)
{
int threadno = i+1;
printf("priority_inheritance: Starting highpri_thread-%d (of %d) at %d\n",
threadno, NHIGHPRI_THREADS, 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 - i;
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-%d priority to %d\n",
threadno, sparam.sched_priority);
}
FFLUSH();
status = pthread_create(&highpri[i], &attr, highpri_thread, (void*)threadno);
if (status != 0)
{
printf("priority_inheritance: pthread_create failed, status=%d\n", status);
}
}
dump_nfreeholders("priority_inheritance:");
FFLUSH();
/* Wait for all thread instances to complete */
for (i = 0; i < NHIGHPRI_THREADS; i++)
{
printf("priority_inheritance: Waiting for highpri_thread-%d to complete\n", i+1);
FFLUSH();
(void)pthread_join(highpri[i], &result);
dump_nfreeholders("priority_inheritance:");
}
printf("priority_inheritance: Waiting for medpri_thread to complete\n");
FFLUSH();
(void)pthread_join(medpri, &result);
dump_nfreeholders("priority_inheritance:");
for (i = 0; i < NLOWPRI_THREADS; i++)
{
printf("priority_inheritance: Waiting for lowpri_thread-%d to complete\n", i+1);
FFLUSH();
(void)pthread_join(lowpri[i], &result);
dump_nfreeholders("priority_inheritance:");
}
printf("priority_inheritance: Finished\n");
sem_destroy(&g_sem);
dump_nfreeholders("priority_inheritance:");
FFLUSH();
#endif /* CONFIG_PRIORITY_INHERITANCE && !CONFIG_DISABLE_SIGNALS && !CONFIG_DISABLE_PTHREAD */
}
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