From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4C1B8C04.3010900@domain.hid> Date: Fri, 18 Jun 2010 17:08:52 +0200 From: Gilles Chanteperdrix MIME-Version: 1.0 References: <4C1B7EB1.2040006@domain.hid> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-core] Fwd: problem in pthread_mutex_lock/unlock List-Id: Xenomai life and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Nero Fernandez Cc: xenomai@xenomai.org Nero Fernandez wrote: > > On Fri, Jun 18, 2010 at 7:42 PM, Gilles Chanteperdrix > > wrote: > > Nero Fernandez wrote: > > Hi, > > > > Please find an archive attached, containing : > > - a program for testing context-switch-latency using posix-APIs > > for native linux kernel and xenomai-posix-skin (userspace). > > - Makefile to build it using xenomai > > Your program is very long to tell fast. But it seems you are using the > mutex as if they were recursive. Xenomai posix skin mutexes used to be > recursive by default, but no longer are. > > Also note that your code does not check the return value of the posix > skin services, which is a really bad idea. > > -- > Gilles. > > > Thanks for the prompt response. > > Could you explain 'recursive usage of mutex' a little further? > Are the xenomai pthread-mutexes very different in behaviour than regular > posix mutexes? The posix specification does not define the default type of a mutex. So, in short, the behaviour of a "regular posix mutex" is unspecified. However, following the principle of least surprise, Xenomai chose, like Linux, to use the "normal" type by default. What is the type of a posix mutex is explained in many places, starting with Xenomai API documentation. So, no, I will not repeat it here. -- Gilles.