From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Schnell Subject: Re: AMP on an SMP system Date: Fri, 02 Aug 2013 18:00:02 +0200 Message-ID: <51FBD782.9070309@lumino.de> References: <51FB6EE1.3090708@lumino.de> <20130802114225.GR3880@pengutronix.de> <51FBA261.10301@lumino.de> <51FBC7FE.4000403@gmail.com> <51FBCF46.4080700@lumino.de> <51FBD223.9020809@gmail.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <51FBD223.9020809@gmail.com> Sender: linux-embedded-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Cc: linux-embedded@vger.kernel.org On 08/02/2013 05:37 PM, Marco Stornelli wrote: > > I don't know your hw so my consideration are really general. The hardware is not decided yet (it will be some A9 thingy). So for me "really general" is just fine. > ISRs in rt kernel doesn't exist or at least the only work is to wake > up the kernel thread for the management. I see. But how to determine the max latency for this ? > The thing you can do is to move the kernel thread for interrupt X > where you want to manage it, or you can set a specific scheduler > policy. For example you can set a SCHED_FIFO with a very high priority > for your "really low latency" tasks. RT kernel does the work for you > :) You can see here: http://lwn.net/Articles/146861/ This seems be rather easy to do. If this is "good enough" latency wise, it seems to be the way to go. -Michael