Re: [Xenomai-help] Preemptive scheduling

["Jack Whorn" <jackwhorn@domain.hid>]

Hi Philippe,

thank you for this suggestion!

You are right, I`m  still using version 2.3. This is due to some adjustments I have made in the Xenomai Sources which prevent me from simply overwriting the old files.

I have just locked at the source-code, the only occasion I use T_LOCK is in the rt_task_set_mode() call, used as the first argument (clear mask!). So there should not be a T_LOCK at all.

Nevertheless, if anybody could provide me with the appropriate positions in Xenomai`s source code, I might apply this bugfix manually and find out whether the problem is solved this way.

Thank you very much,

Jack


-------- Original-Nachricht --------
Datum: Tue, 03 Apr 2007 22:24:35 +0200
Von: Philippe Gerum <rpm@xenomai.org>
An: Jack Whorn <jackwhorn@domain.hid>
CC: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>, xenomai@xenomai.org
Betreff: Re: [Xenomai-help] Preemptive scheduling

> On Tue, 2007-04-03 at 22:05 +0200, Jack Whorn wrote:
> > Hi Gilles, Hi folks,
> > 
> > The data is stored by a thread that periodically issues a single call to
> > rt_task_set_mode(0, T_PRIMARY, NULL) followed by several file operation
> calls like fprintf() and finally a call to fflush(NULL) and sync().
> > 
> > The application is not a kernel module, so - as far as I see it - it is
> a user mode thread, and it actually has the highest priority in my system.
> > 
> > Does this help understanding the phenomenon?
> > 
> 
> This whole thing reminds me of an issue involving T_LOCK that existed
> for any version earlier than 2.3.1. The way the scheduler lock (i.e.
> T_LOCK) was managed at that time would cause unexpectable results (aka
> "utter mess") to happen whenever a scheduler lock holder thread switches
> to secondary mode, and thinking about it, this would surely cause a
> lockup due to a scheduling wreckage. This has been fixed on January 30,
> by allowing the currently running thread which holds the scheduler lock
> to sleep.
> 
> You may want to try 2.3.1 to check this.
> 
> -- 
> Philippe.
> 

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