Re: [Xenomai-help] Which process synchronization primitive?

[Daniele Nicolodi <daniele@domain.hid>]

Gilles Chanteperdrix wrote:
>> I think message queues can work well but I'm not sure they are the best
>> choice when I do not have to communicate any message. Would be
>> semaphores best suited to my needs?
> 
> You can use process-shared mutexes or semaphores.

There is somewhere a comparison of the overhead of the different
solutions? Do I need to do my own benchmarks? Is the API the only
difference?

> But there is something
> which must be said clearly: compiling or not with Xenomai support is all
> or nothing. Either you build all the applications with Xenomai posix
> support or none of them. There is no way you can synchronize a real-time
> thread with a non real-time thread without loosing determinism.

I understood this reading the documentation (and it is fairly
intuitive). I would like to use the posix skin to be able to compile my
application also on an host without xenomai support (and of course give
up the real time capability).

> And
> beware of the kind of priority inversions which would result from
> calling a Linux system call while holding a mutex shared with real-time
> processes, as explained here:
> 
> http://www.xenomai.org/index.php/Porting_POSIX_applications_to_Xenomai#Chasing_the_unwanted_mode_switches.

I was just reading this.

Thanks! Cheers,
-- 
Daniele