From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4B8D156F.7000604@domain.hid> Date: Tue, 02 Mar 2010 14:41:03 +0100 From: Daniele Nicolodi MIME-Version: 1.0 References: <4B8D0EEA.3090409@domain.hid> <4B8D10C5.9050108@domain.hid> In-Reply-To: <4B8D10C5.9050108@domain.hid> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-help] Which process synchronization primitive? List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gilles Chanteperdrix Cc: xenomai@xenomai.org 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