From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.windriver.com (mail.windriver.com [147.11.1.11]) by mx1.pokylinux.org (Postfix) with ESMTP id E03F74C80050 for ; Mon, 6 Dec 2010 19:00:13 -0600 (CST) Received: from ALA-MAIL03.corp.ad.wrs.com (ala-mail03 [147.11.57.144]) by mail.windriver.com (8.14.3/8.14.3) with ESMTP id oB710D57013707; Mon, 6 Dec 2010 17:00:13 -0800 (PST) Received: from ala-mail06.corp.ad.wrs.com ([147.11.57.147]) by ALA-MAIL03.corp.ad.wrs.com with Microsoft SMTPSVC(6.0.3790.1830); Mon, 6 Dec 2010 17:00:12 -0800 Received: from bruce-ashfields-macbook.local ([128.224.143.25]) by ala-mail06.corp.ad.wrs.com with Microsoft SMTPSVC(6.0.3790.1830); Mon, 6 Dec 2010 17:00:12 -0800 Message-ID: <4CFD871A.10904@windriver.com> Date: Mon, 06 Dec 2010 20:00:10 -0500 From: Bruce Ashfield User-Agent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.2.13) Gecko/20101203 Thunderbird/3.1.7 MIME-Version: 1.0 To: Darren Hart References: <4CFD6C73.20006@linux.intel.com> In-Reply-To: <4CFD6C73.20006@linux.intel.com> X-OriginalArrivalTime: 07 Dec 2010 01:00:12.0821 (UTC) FILETIME=[1A49BC50:01CB95AA] Cc: poky@yoctoproject.org Subject: Re: PREEMPT_RT support X-BeenThere: poky@yoctoproject.org X-Mailman-Version: 2.1.13 Precedence: list List-Id: Poky build system developer discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 07 Dec 2010 01:00:14 -0000 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit On 10-12-06 6:06 PM, Darren Hart wrote: > I'm looking at how to best support PREEMPT_RT. We have a few things in > the works which prevent the ideal scenario (which is just a new recipe > using the preempt_rt branch in linux-yocto). > > 2.6.34 never had an -rt patch. The WR folks created one that builds and > is undergoing review from tglx - but that doesn't appear to be near the > top of his stack. 2.6.37 is still pending an -rt patch, also blocked on > -tglx. We'll be doing one at WR eventually, so it will exist in one form or another for version > 2.6.34. > > I'm thinking of creating a meta-rt layer which would provide a latest > -rt kernel and the rt-tests suite along with a non-graphical image > definition that facilitates latency detection and rt performance > measurement. poky-image-rt-test or something along those lines. > > Any objection to this approach? As we will eventually move these recipes > into the core poky recipes, I'd suggest we put this in an > "experimental/meta_rt" git repository. I'm worrying about this muddying the water with respect to the -rt branches in the linux-yocto repositories. In particular if we go *backward* from the 2.6.34 variant that we already have (remember, that -rt kernel has been heavily abused for 9 months now and is just as stable (probably more so for non-x86) as anything else you'll find). Why can't we continue to consolidate these into fewer kernels and recipes ? We can't share fixes and BSPs easily if everything is kept separate. We can obviously pair the tests/utilities along with the linux-yocto -rt branches, so I'd prefer that approach and continue to work on improving the base that we already have. Cheers, Bruce > > Thoughts? >