Re: [Xenomai] Differents switch mode from differents Xenomai skin

[Huy Cong Vu <huy-cong.vu@wandercraft.eu>]

----- Mail original -----
> De: "Gilles Chanteperdrix" <gilles.chanteperdrix@xenomai.org>
> À: "Huy Cong Vu" <huy-cong.vu@wandercraft.eu>
> Cc: xenomai@xenomai.org
> Envoyé: Mercredi 24 Décembre 2014 01:29:12
> Objet: Re: [Xenomai] Differents switch mode from differents Xenomai skin

> On Tue, Dec 23, 2014 at 05:58:42PM +0100, Huy Cong Vu wrote:
>> 
>> 
>> ----- Mail original -----
>> > De: "Gilles Chanteperdrix" <gilles.chanteperdrix@xenomai.org>
>> > À: "Huy Cong Vu" <huy-cong.vu@wandercraft.eu>
>> > Cc: xenomai@xenomai.org
>> > Envoyé: Mardi 23 Décembre 2014 17:46:59
>> > Objet: Re: [Xenomai] Differents switch mode from differents Xenomai skin
>> 
>> > On Tue, Dec 23, 2014 at 05:43:41PM +0100, Huy Cong Vu wrote:
>> >> 
>> >> 
>> >> ----- Mail original -----
>> >> > De: "Gilles Chanteperdrix" <gilles.chanteperdrix@xenomai.org>
>> >> > À: "Huy Cong Vu" <huy-cong.vu@wandercraft.eu>
>> >> > Cc: xenomai@xenomai.org
>> >> > Envoyé: Mardi 23 Décembre 2014 17:35:35
>> >> > Objet: Re: [Xenomai] Differents switch mode from differents Xenomai skin
>> >> 
>> >> > On Tue, Dec 23, 2014 at 05:23:07PM +0100, Huy Cong Vu wrote:
>> >> >> void mini( void *ptr )
>> >> >> {
>> >> >> 
>> >> >> 
>> >> >> 	uint8_t b;
>> >> >> 	int ret1;
>> >> >> 	int idx;
>> >> >> 
>> >> >> 	pthread_set_mode_np(0, PTHREAD_WARNSW);
>> >> >>    printf("Starting posix test\n");
>> >> >> 
>> >> >> 	ec_port = malloc(sizeof(ecx_portt*));
>> >> >> 
>> >> >> 	if (setup_nic(ec_port,"rteth0") > 0) {
>> >> >> 		   idx = getindex (ec_port);
>> >> >>    		/* setup datagram */
>> >> >> 			b = 0x0000;
>> >> >>    		setupdatagram (ec_port, &(ec_port->txbuf[idx]),0x0009, idx, 0x0000, 0x0103,
>> >> >>    		sizeof(b), &b );
>> >> >>    		/* send data and wait for answer */
>> >> >>    		wkc = srconfirm (ec_port, idx, EC_TIMEOUTRET3);
>> >> >> 	}
>> >> >> 	
>> >> >> }
>> >> > 
>> >> > Typically, as I already explained, what you do here is wrong: you
>> >> > should not arm the PTHREAD_WARNSW bit before call such as malloc or
>> >> > the calls in setup_nic, which switch to secondary mode.
>> >> 
>> >> Ok, should I call it laterly? It is just for detect mode switch
>> >> reason in fact
>> > 
>> > How to use PTHREAD_WARNSW is thoroughly documented, see:
>> > https://xenomai.org/2014/06/finding-spurious-relaxes/
>> > 
>> 
>> So perhaps I was misunderstanding this statement?
>> Then, you need to enable the warn_upon_switch capability on a per-thread basis.
>> For instance, a POSIX-based application would run this code from the thread to
>> monitor for spurious relaxes:
>> 
>>     /* Ask Xenomai to warn us upon switches to secondary mode. */
>>     pthread_set_mode_np(0, PTHREAD_WARNSW);
>> 
>> Does that means that I must put the line into the thread with function calls
>> that cause mode switch?
>> I thought it means that I have to put the line in the threads of my program (in
>> my case mini() ).
> 
> Enabling this bit, causes every switch to secondary mode of the
> thread where you enabled it to send a signal to that thread. I do
> not understand what is so hard to understand about this.

Ok, so I guess I didn't understand this wrongly at least.  

Suppose that I remove PTHREAD_WARNSW bit, here what I got in output: 
SOEM (Simple Open EtherCAT Master)
Simple test
Starting posix test
Mode switch (reason bad functions call while holding mutex, or other unknown issue), aborting. Backtrace:
./posix_minimal[0x401bf6]
/lib/x86_64-linux-gnu/libpthread.so.0(+0xfcb0)[0x7f94ef972cb0]
/usr/xenomai/lib/libpthread_rt.so.1(__wrap_send+0xd5)[0x7f94efd8f9f5]
./posix_minimal[0x4017dc]
./posix_minimal[0x4016ed]
./posix_minimal[0x4011cd]
/usr/xenomai/lib/libpthread_rt.so.1(+0x5b45)[0x7f94efd8cb45]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x7e9a)[0x7f94ef96ae9a]
/lib/x86_64-linux-gnu/libc.so.6(clone+0x6d)[0x7f94ef28d3fd]
Temps UCT limite expiré (core dumped)

It is the same output as when PTHREAD_WARNSW is active. Could you give me some hints why?

> 
> --
> 					    Gilles.

-- 
Huy Cong
Wandercraft SAS