[Xenomai] Performance monitoring question

[Xenomai] Performance monitoring question

[Mathew Benson]

I'm using the native skin.  I understand there are things you can do to cause a user space task to fall back to the normal Linux scheduler.  How do I know if this has happened?  Will RT functions like semaphores fail with an incorrect mode failure?  Can I register a callback to be notified?

I'm asking because I added code to my project fully expecting it to kick it back to normal scheduler or cause timers to fail, but nothing.  Everything still seems to be working just fine.  Specifically, I'm making ioctl calls to access a webcam.  So what can I do to verify that my tasks really are running on the rt scheduler?

Sent from my Packard Bell 386

Re: [Xenomai] Performance monitoring question

[Gilles Chanteperdrix]

On Sun, Nov 30, 2014 at 10:39:56PM -0600, Mathew Benson wrote:
> I'm using the native skin. I understand there are things you can
> do to cause a user space task to fall back to the normal Linux
> scheduler. How do I know if this has happened? Will RT functions
> like semaphores fail with an incorrect mode failure?

No, Xenomai automatically switches user-space tasks to primary or
secondary mode when needed.

> Can I register a callback to be notified?
> 
> I'm asking because I added code to my project fully expecting it
> to kick it back to normal scheduler or cause timers to fail, but
> nothing. Everything still seems to be working just fine.
> Specifically, I'm making ioctl calls to access a webcam. So what
> can I do to verify that my tasks really are running on the rt
> scheduler?

See:
http://xenomai.org/2014/06/finding-spurious-relaxes/

-- 
					    Gilles.

Re: [Xenomai] Performance monitoring question

[Mathew Benson]

Perfect.  Thanks.

Sent from my Packard Bell 386

On Dec 1, 2014, at 1:31 AM, Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org> wrote:

> On Sun, Nov 30, 2014 at 10:39:56PM -0600, Mathew Benson wrote:
>> I'm using the native skin. I understand there are things you can
>> do to cause a user space task to fall back to the normal Linux
>> scheduler. How do I know if this has happened? Will RT functions
>> like semaphores fail with an incorrect mode failure?
> 
> No, Xenomai automatically switches user-space tasks to primary or
> secondary mode when needed.
> 
>> Can I register a callback to be notified?
>> 
>> I'm asking because I added code to my project fully expecting it
>> to kick it back to normal scheduler or cause timers to fail, but
>> nothing. Everything still seems to be working just fine.
>> Specifically, I'm making ioctl calls to access a webcam. So what
>> can I do to verify that my tasks really are running on the rt
>> scheduler?
> 
> See:
> http://xenomai.org/2014/06/finding-spurious-relaxes/
> 
> -- 
>                        Gilles.