From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4F7AA9E8.5020900@domain.hid> Date: Tue, 03 Apr 2012 09:42:32 +0200 From: Philippe Gerum MIME-Version: 1.0 References: <4F7AA402.3040803@domain.hid> <4F7AA45B.4030908@domain.hid> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-help] Is it compulsory to apply the PREEMPT_RT patch (to Linux) when running Xenomai on the top of it? List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anisha Kaul Cc: xenomai@xenomai.org On 04/03/2012 09:37 AM, Anisha Kaul wrote: > On 3 April 2012 12:48, Philippe Gerum wrote: >>> No. >> >> I mean: this is not implied, and you don't need _RT (actually, to have it, >> you would need a specific interrupt pipeline patch). > > Thanks for replying. > > I read that this patch allows nearly all of the kernel to be > preempted, with the exception of a few very small regions of code > ("raw_spinlock critical regions"), can you please point out a few > cases in which actually we "should" apply this patch? > > Xenomai already gives a hard real time, so why would we need this > patch? Any hints please? > > This is a different approach to a same problem: - _RT attempts to make the whole regular kernel real-time aware. - Xenomai 2.x provides a co-kernel for exclusively handling real-time processing. There are pros and cons in the two approaches, this is basically why Xenomai 3 will allow both. > -Anisha > -- Philippe.