From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4BF1D6F0.2030305@domain.hid> Date: Tue, 18 May 2010 01:53:20 +0200 From: Gilles Chanteperdrix MIME-Version: 1.0 References: <2319761F7FA0D1479BA77EC2E0A8E7BCE3D6E7@domain.hid><245373446233674495BCA5CA2FC1EB17378D01593B@RCexchangeSVR1.ruggedcom.local> <4BED2910.6020105@domain.hid> <181804936ABC2349BE503168465576460EBD6239@domain.hid> <4BF17464.5090100@domain.hid> <181804936ABC2349BE503168465576460EBD62C8@domain.hid> <4BF1794A.6050207@domain.hid> <181804936ABC2349BE503168465576460EBD6778@domain.hid> In-Reply-To: <181804936ABC2349BE503168465576460EBD6778@domain.hid> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-help] Question about getting system time List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Steve Deiters Cc: Jan Kiszka , Andreas Glatz , "Mauerer, Wolfgang" , xenomai@xenomai.org Steve Deiters wrote: > Even more of a problem is how I am supposed to know which calls are > similar to this. I would expect I could call any Linux service without > causing a deadlock/livelock situation, although in a nondeterministic > manner. If I understood your explanation correctly, this is hanging > whenever the Xenomai task tries to spin on the same lock as the kernel. > However, I don't see how this is not a problem in general for acquiring > any spinlock from a Xenomai task. I would expect once you introduce a > priority based scheduler any spinlock becomes unsafe. The set of services which you can call from a real-time thread without loosing determinism are those found in the Xenomai posix skin documentation: http://www.xenomai.org/documentation/xenomai-2.5/html/api/group__posix.html Other than that, any service emitting a syscall causes a switch to secondary mode. What remains are services not emitting syscalls, and for these ones, all bets are off. -- Gilles.