Re: [Xenomai-help] RT_QUEUE problem in Sender/Receiver order

[Michel He <michel.he@domain.hid>]

Re,

    In order to describe it (by thousand words as the proverbe said),  
I attach the following example.
You notice that in the line 85 :
rv = rt_task_send(&test_task3_ptr,&mcb_send,&mcb_reply,task_period_ns);

whenever you change &test_task3_ptr to &test_task2_ptr, the message is  
NOT delivered at all. Only task3 can receive good msg. (not task2)

thank you


/*
  * tasksend.c
  *
  *  Created on: 7 avr. 2010
  *      Author: hemichel
  */

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <sys/time.h>
#include <sys/io.h>
#include <sys/mman.h>
#include <native/task.h>
#include <native/queue.h>
#include <native/intr.h>

#define STACK_SIZE 8192
#define STD_PRIO 1


#define MAXRECVTASK 0
#define ANYSRC 0
#define MAX_MESSAGE_LENGTH 4
#define QUEUE_LIM 512
#define PROBECODE 0xa

RT_TASK test_task_ptr,test_task2_ptr,test_task3_ptr;

//tache maintenant la liste recvhostlist
RT_TASK *recvTask[MAXRECVTASK];
unsigned int nrecvhost=0;

int int_count = 0;
int end = 0;

//delay reception 0.1 s
#define PEER_RATE_NS 100000000

//cycle de la tache d'emission
//                     --s-ms-us-ns
RTIME task_period_ns =   1000000000llu;



void testtask(void *cookie) {
	RT_TASK_MCB mcb_send, mcb_reply;
	int flowid, i, rv;
	unsigned char datasend[16];
	unsigned char datareply[16];

	int count = 0;
	int ret;
	unsigned long overrun;
	ret = rt_task_set_periodic(NULL, TM_NOW, rt_timer_ns2ticks(task_period_ns));
	if (ret) {
		rt_printf("error while set periodic, code %d\n",ret);
		return;
	}

	mcb_send.opcode = 0x03;
	datasend[0]='a';
	mcb_send.data = datasend;
	mcb_send.size = sizeof(datasend);

	mcb_reply.size = sizeof(datareply);
	mcb_reply.data = datareply;

	while(!end){

		if (ret) {
			rt_printf("error while rt_task_set_mode, code %d\n",ret);
			return;
		}
		ret = rt_task_wait_period(&overrun);
		if (ret) {
			rt_printf("error while rt_task_wait_period, code %d\n",ret);
			return;
		}
		count++;
		rt_printf("message from testtask: count=%d\n", count);

		rv = rt_task_send(&test_task3_ptr,&mcb_send,&mcb_reply,task_period_ns);
		if (rv < 0) rt_printf("rt_task_send error\n");
		else rt_printf("get mcb_reply=%d\n",mcb_reply.data[0]);
		fflush(NULL);
	}
}


void testtask2(void *cookie) {
	RT_TASK_MCB mcb_rcv, mcb_reply;
	int flowid, i, rv;
	unsigned char datareply[16];
	unsigned int taskmsg;
	int count = 0;
	int ret;
	unsigned long overrun;
	ret = rt_task_set_periodic(NULL, TM_NOW, rt_timer_ns2ticks(task_period_ns));
	if (ret) {
		rt_printf("error while set periodic, code %d\n",ret);
		return;
	}

	while(!end){

		ret = rt_task_wait_period(&overrun);
		if (ret) {
			rt_printf("error while rt_task_wait_period, code %d\n",ret);
			return;
		}

		mcb_rcv.data = (caddr_t)&datareply;
		mcb_rcv.size = sizeof(datareply);

		flowid = rt_task_receive(&mcb_rcv,PEER_RATE_NS);
		rt_printf("%s flowid=%d opcode=%d\n",\
				__FUNCTION__, flowid, mcb_rcv.opcode);
		if(flowid >= 0)
		{
				//this is my answer
				mcb_reply.opcode = 1;
				mcb_reply.size = 1;
				mcb_reply.data = datareply;
				datareply[0]=100;
				rt_task_reply(flowid, &mcb_reply);
				rt_printf("task2 replied to Sender\n");
		}
		else
		{
			rt_printf("err task2 : flowid neg\n");
		}

		fflush(NULL);
	}
}


void testtask3(void *cookie) {
	RT_TASK_MCB mcb_rcv, mcb_reply;
	int flowid, i, rv;
	unsigned char datareply[16];
	unsigned int taskmsg;

	int count = 0;
	int ret;
	unsigned long overrun;
	ret = rt_task_set_periodic(NULL, TM_NOW, rt_timer_ns2ticks(task_period_ns));
	if (ret) {
		rt_printf("error while set periodic, code %d\n",ret);
		return;
	}

	while(!end){

		ret = rt_task_wait_period(&overrun);
		if (ret) {
			rt_printf("error while rt_task_wait_period, code %d\n",ret);
			return;
		}

		mcb_rcv.data = (caddr_t)&datareply;
		mcb_rcv.size = sizeof(datareply);

		flowid = rt_task_receive(&mcb_rcv,PEER_RATE_NS);
		rt_printf("%s flowid=%d opcode=%d\n",\
				__FUNCTION__, flowid, mcb_rcv.opcode);
		if(flowid >= 0)
		{
				//this is my answer
				mcb_reply.opcode = 1;
				mcb_reply.size = 1;
				mcb_reply.data = datareply;
				datareply[0]=100;
				rt_task_reply(flowid, &mcb_reply);
				rt_printf("task3 replied to Sender\n");
		}
		else
		{
			rt_printf("err task3 : flowid neg\n");
		}

		fflush(NULL);
	}
}


// signal-handler, to ensure clean exit on Ctrl-C
void clean_exit(int dummy) {
	rt_printf("cleanup\n");
	end = 1;
	rt_task_delete(&test_task_ptr);
	rt_printf("end\n");
}

int main(int argc, char *argv[]) {
	int err, ret;
	int itask;


	// install signal handler
	signal(SIGTERM, clean_exit);
	signal(SIGINT, clean_exit);

	mlockall(MCL_CURRENT | MCL_FUTURE);

	/* Perform auto-init of rt_print buffers if the task doesn't do so */
	rt_print_auto_init(1);

	//Initialisation de Dispatch Sender
	for (itask=0; itask < nrecvhost; itask++)
	{
		recvTask[itask]=NULL;
	}

	err = rt_task_spawn(&test_task_ptr, "Timer", STACK_SIZE, STD_PRIO, 0,  
&testtask, NULL);
	recvTask[nrecvhost]=&test_task_ptr;
	nrecvhost++;
	if (err) {
		rt_printf("error rt_task_spawn\n");
		return 0;
	}

	nrecvhost=0;
	rt_printf("Fin Initialisation de la tache Emetteur\n");

	err = rt_task_spawn(&test_task2_ptr, "Timer2", STACK_SIZE, STD_PRIO,  
0, &testtask2, NULL);
	recvTask[nrecvhost]=&test_task2_ptr;
	nrecvhost++;
	if (err) {
		rt_printf("error rt_task_spawn\n");
		return 0;
	}


	err = rt_task_spawn(&test_task3_ptr, "Timer3", STACK_SIZE, STD_PRIO,  
0, &testtask3, NULL);
	recvTask[nrecvhost]=&test_task3_ptr;
	nrecvhost++;
	if (err) {
		rt_printf("error rt_task_spawn\n");
		return 0;
	}



	// wait for signal & return of signal handler
	pause();
	fflush(NULL);
	return 0;
}


Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org> a écrit :

> Michel He wrote:
>> hello everyone,
>>
>>     I find out a problem (it seems already mentionned before but I
>> can't find the link to the forum and the post). It deals with the
>> message passing, eg. when we change the order of task execution,
>> something can get wrong. Notice that codes below, if we launch the
>> exection of Recep2,Recep3,Sender, Recep2 won't get the right message.
>> But if we change the order to : Sender,Recep2,Recep3, everything is
>> back to OK. So any explanation ?
>
> A piece of self-contained code, compiling and demonstrating a bug when
> running is worth a thousand words.
>
>
> --
> 					    Gilles.
>