Re: [Xenomai-help] Problems with rt_task_create and rt_task_join

[Philippe Gerum <rpm@xenomai.org>]

On Fri, 2011-01-21 at 18:01 +0100, Michel Rinaldi wrote:
> Hi to all,
> 
> I'm running an application on a Linux system with kernel 2.6.35.7
> patched with Xenomai 2.5.5.2, Adeos ipipe patch 2.7-04.
> My application uses native skin and creates some realtime tasks, each
> with rt_task_shadow(), each other with rt_task_create().

Sorry, -ENOPARSE. rt_task_shadow() is usually invoked from the main
thread to make it a Xenomai thread, rt_task_create is normally used to
create more tasks. Who is doing what in your code exactly? How many
times is rt_task_shadow() invoked?

>  When I call for first time rt_task_create(), this function is very
> slow (700-800 ms) to execute, also if rt_task_shadow() calls come
> first. Subsequent calls of rt_task_create() are quick as expected. I
> read on manual that at first call rt_task_create() creates a signal
> handler for SIGWINCH signal: could be this operation that wastes time,
> maybe on waiting some resources from Linx kernel? 

No, can't be that long. Something looks wrong in your application init.

> Another problem that I've encountered is that if I call a
> rt_int_delete() and then a rt_task_join() on userspace task that
> handles destroyed IRQ,  rt_task_join() never returns (obviously this
> task was created with joinable flag). If I create this task without
> joinable flag and then I call rt_task_delete() instead rt_task_join()
> I obtain two different behaviours: sometimes rt_task_delete() returns
> but I still view task on /proc/xenomai/sched (with X status),
> sometimes system freezes on this call.

Make sure to test the return values of ALL Xenomai syscalls in your app,
particularly what rt_intr_wait() sends you back, and make sure to break
out from your work loop whenever it signals any error.

> Thanks to all in advance.
> Regards
> 
> Mauro Salvini
> 
> 
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-- 
Philippe.