Bonjour,

J'essaie d'ecrire un code qui comprend deux thread un master et un slave le master a un timer temps reel (2 ms) a chaque tic le slave peut avoir la parole. Pour cela j'ai préparé un environnement temps reel un noyau 3.6.11 avec un patch temps reel preempt RT et timers high resolution. L'environnement est testé en fait sans le slave thread j'arive a avoir une periode de 2ms +/- 30 ms ce qui est normal sauf qu'avec le slave la periode s"eleve a 2600 / 2700 ms donc il y'a un retard de 600 ms inexpliqué. Qui peut m'aider a regler ce probleme ? Je pense qu'il y manque quelques choses.
Code : Sélectionner tout - Visualiser dans une fenêtre à part
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#define _GNU_SOURCE
#include <pthread.h>
#include <stdio.h>
#include <sched.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <time.h>
#include <unistd.h>
#include <sys/types.h>
#include <semaphore.h>
#include <sys/syscall.h>
//////////////////////
#define sigev_notify_function	_sigev_un._sigev_thread._function
#define sigev_notify_attributes	_sigev_un._sigev_thread._attribute
#define sigev_notify_thread_id	_sigev_un._tid
//////////////////////
#define PERIOD_SIG SIGRTMIN
#define NBR_CYCLE 20
#define NBR_TRAME 1
#define PTU_NS 2000000           // 2ms
#define HIGHEST_PRIORITY 99
 
 
 
/////////////////// CREATION DES SEMAPHORES
sem_t sync_pass, slave_pass;
//////////////////Gobals
int master_ID;
int sync_sig=-1;
int nodes_nbr=1;
struct timeval last;
 
///////////////////Function qui retourne le TID
static pid_t mygettid(void)
{
	return syscall(SYS_gettid);
}
/////////////////// MASTER_FUNC
void * master_func()
{
 
	///
	struct timeval begin;
	struct timeval last;		
	long long int difference = 0;
	////
	int global_cycle = 0 ;
//////////Creer un timer de 2 ms 
	struct itimerspec ptu_period;
	timer_t ptu_timer;
	sigset_t mask;
	struct sigevent ptu_event = {
		.sigev_notify = SIGEV_THREAD_ID,
		.sigev_signo = PERIOD_SIG,
		.sigev_notify_thread_id = mygettid(),
	};
/* Bloque le signal PERIOD_SIG pour le thread appelant uniquement */
	if (sigemptyset(&mask) ||
	    sigaddset(&mask, PERIOD_SIG) ||
	    sigprocmask(SIG_BLOCK, &mask, NULL))
		pthread_exit((void *) 10);
	siginfo_t si;
	int sig;
	if (timer_create(CLOCK_REALTIME, &ptu_event, &ptu_timer))
	pthread_exit((void *) 11);
	ptu_period.it_value.tv_sec = 0;
	ptu_period.it_value.tv_nsec = PTU_NS;
	ptu_period.it_interval.tv_sec = 0;
	ptu_period.it_interval.tv_nsec = PTU_NS;
	if (timer_settime(ptu_timer, 0, &ptu_period, NULL))
		pthread_exit((void *) 12);
 
/////////////////////////////
	while(1)
 
	{
		if ((sig = sigwaitinfo(&mask, &si)) < 0)
			pthread_exit((void *) 13);
		if (sig != PERIOD_SIG)
			continue;
///////////////////////////// Tache a repeter chaque 2 ms
		gettimeofday(&begin, NULL);
			difference += 1000000 * (begin.tv_sec - last.tv_sec);
			difference += (begin.tv_usec - last.tv_usec);
		last=begin;
 
 
		sem_wait(&sync_pass);
		sync_sig++; 
		sync_sig %= NBR_CYCLE;
		if (sync_sig==0)
			{	
				global_cycle=global_cycle+1;
				fprintf(stdout,"New cycle = %d\n", global_cycle);
			}
 
		fprintf(stdout,"The Master is talking (%d) elapsed time (%6lld) \n",sync_sig,difference);
		difference = 0;
 
 
 
 
		sem_post(&sync_pass);
		sched_yield();
 
	}
	return(0);
}
///////////////////// SLAVE_FUNC 
void *slave_func(void *slave_data)
{	
	while(1)
	{
 
 
		sem_wait(&sync_pass);	
		sem_wait(&slave_pass);
 
		fprintf(stdout,"slave (%lu) is talking the current sync is (%d) \n",pthread_self(),sync_sig);
 
		sem_post(&slave_pass);
		sem_post(&sync_pass);
		pause();
 
	}
	return(0);
}
 
////////////////MAIN
int main ()
{
 
	int val,i,j;
	int err,priority;
	struct sched_param param_processus;
	struct sched_param param_master_thr , param_slave_thr ;
	pthread_attr_t master_attr , slave_attr;
	pthread_t master_thr, slave_thr[nodes_nbr];	
	/////////////////     AFFECTATION PRIORITE TEMPS REEL FIFO
	param_processus.sched_priority = HIGHEST_PRIORITY;
	if (sched_setscheduler(0, SCHED_FIFO, &param_processus) != 0)
	{
		perror("processus sched_setscheduler");
		exit(EXIT_FAILURE);
	}
 
	priority=sched_getscheduler(0);
	switch (priority)
	{  
		case SCHED_FIFO :
			fprintf(stdout,"FIFO PRIORITY IS : %d \n",param_processus.sched_priority);
			break;
		case SCHED_RR :
			fprintf(stdout,"ROUND ROBIN PRIORITY IS : %d \n",param_processus.sched_priority);
			break;
		default:
			fprintf(stdout,"OTHER PRIORITY USED \n");
			break;
	} 
 
	/////////////////     PREPARATION DES ATTRIBUTS DU MASTER_THREAD
	pthread_attr_init(&master_attr);
 
	if ((err=pthread_attr_setschedpolicy(&master_attr,SCHED_FIFO))!=0)
	{
		fprintf(stderr,"setschedpolicy master thread: %s\n",strerror(err));
		exit(EXIT_FAILURE);
	}
	if ((err=pthread_attr_setinheritsched(&master_attr,PTHREAD_EXPLICIT_SCHED))!=0)
	{
		fprintf(stderr,"setinheritshed master thread: %s\n",strerror(err));
		exit(EXIT_FAILURE);
	}
 
	param_master_thr.sched_priority = 99;
 
	if ((err=pthread_attr_setschedparam(&master_attr,&param_master_thr))!=0)
	{
		fprintf(stderr,"setschedparam master thread: %s\n",strerror(err));
		exit(EXIT_FAILURE);
	}
	/////////////////     PREPARATION DES ATTRIBUTS DU SLAVE_THREAD
	pthread_attr_init(&slave_attr);
 
	if ((err=pthread_attr_setschedpolicy(&slave_attr,SCHED_FIFO))!=0)
	{
		fprintf(stderr,"setschedpolicy slave thread: %s\n",strerror(err));
		exit(EXIT_FAILURE);
	}
	if ((err=pthread_attr_setinheritsched(&slave_attr,PTHREAD_EXPLICIT_SCHED))!=0)
	{
		fprintf(stderr,"setinheritshed slave thread: %s\n",strerror(err));
		exit(EXIT_FAILURE);
	}
 
	param_slave_thr.sched_priority = 50;
 
	if ((err=pthread_attr_setschedparam(&slave_attr,&param_slave_thr))!=0)
	{
		fprintf(stderr,"setschedparam slave thread: %s\n",strerror(err));
 
		exit(EXIT_FAILURE);
	}
//////////////////    INITIALISATION DES SEMAPHORES
	if (sem_init(&sync_pass,0,1)==-1)
	{
		perror("sync sem init");
		exit (EXIT_FAILURE);
	}
 
	if (sem_init(&slave_pass,0,nodes_nbr)==-1)
	{
		perror("slave sem init");
		exit (EXIT_FAILURE);
	}
 
///
	gettimeofday(&last, NULL);	
 
 /////////////////////   EXECUTION DES THREAD
 
	if((err=pthread_create(&master_thr,&master_attr,master_func,NULL)!=0))
	{
		fprintf(stderr,"can't create master thread %s \n",strerror(err));
		exit(EXIT_FAILURE);
	}
 
	for ( i=0;i<nodes_nbr;i++)
	{
		if((err=pthread_create(&slave_thr[i],&slave_attr,slave_func,NULL)!=0))
		{	
			fprintf(stderr,"can't create slave thread %s \n",strerror(err));
			exit(EXIT_FAILURE);
		}
	}
 
//
	/// ATTENTE DE TOUS LES THREAD
	pthread_join(master_thr, NULL);
	for ( i=0;i<nodes_nbr;i++)
	{
		pthread_join(slave_thr[i], NULL);	
	}
 
return (0);
 
}