Re: [Xenomai-core] [RFC] shadow threads with prio 0 / SCHED_NORMAL

[Philippe Gerum <rpm@xenomai.org>]

Gilles Chanteperdrix wrote:
> Philippe Gerum wrote:
>  > What I suggested was to let people create normal threads using 
>  > pthread_create (likely conforming to the SCHED_OTHER policy), then use 
>  > the redirected pthread_setschedparam syscall (i.e. always applied to the 
>  > current thread) to promote them as Xenomai shadows, but leave them in 
>  > their original scheduling class. The same goes for rt_task_shadow. This 
>  > would be explicit actions that would not leave much room for "surprises".
> 
> If I understand correctly, you mean that one should not be able to
> create real-time threads with pthread_create. My question was about what
> to do of explicit scheduling parameters passed to pthread_create through
> thread creation attributes.

Nope, this is obviously not what I meant... :o>

This is how one would create hybrids, without changing anything else to
the current interface:

     pthread_attr_init(&attr);
     ...
     pthread_attr_setschedpolicy(&attr,SCHED_OTHER);
     ...
     pthread_create(...,&attr,&foo,NULL);

and,

void *foo (void *cookie)
{
	/* The following call maps a shadow thread to "current", but 
       	    currently only accepts SCHED_FIFO, and would be changed to 
                            	    allow SCHED_OTHER/NORMAL. */
	pthread_setschedparam(...,SCHED_OTHER,...);
	/* OR, for the native API */
	rt_task_shadow(...,pri=0,...);
}

-- 

Philippe.