From owner-freebsd-stable@FreeBSD.ORG Fri Dec 16 22:28:27 2011 Return-Path: Delivered-To: freebsd-stable@FreeBSD.org Received: from mx2.freebsd.org (mx2.freebsd.org [IPv6:2001:4f8:fff6::35]) by hub.freebsd.org (Postfix) with ESMTP id 7E26C1065670 for ; Fri, 16 Dec 2011 22:28:27 +0000 (UTC) (envelope-from dougb@FreeBSD.org) Received: from 172-17-198-245.globalsuite.net (hub.freebsd.org [IPv6:2001:4f8:fff6::36]) by mx2.freebsd.org (Postfix) with ESMTP id 254CA152490; Fri, 16 Dec 2011 22:27:42 +0000 (UTC) Message-ID: <4EEBC5DD.7080904@FreeBSD.org> Date: Fri, 16 Dec 2011 14:27:41 -0800 From: Doug Barton Organization: http://SupersetSolutions.com/ User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:8.0) Gecko/20111110 Thunderbird/8.0 MIME-Version: 1.0 To: Michel Talon References: <1350C7A0-BE58-4C34-804A-A6A3C1C61761@lpthe.jussieu.fr> <4EEBBD5E.50603@FreeBSD.org> <91A8A86F-4D83-4C6F-8E27-B74204C6ACF9@lpthe.jussieu.fr> In-Reply-To: <91A8A86F-4D83-4C6F-8E27-B74204C6ACF9@lpthe.jussieu.fr> X-Enigmail-Version: undefined OpenPGP: id=1A1ABC84 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: freebsd-stable@FreeBSD.org Subject: Re: switching schedulers (Re: SCHED_ULE should not be the default) X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 16 Dec 2011 22:28:27 -0000 On 12/16/2011 14:16, Michel Talon wrote: > Of course, you are perfectly right., and i had misunderstood Adrian's > post. Happens to the best of us. :) > But if the problem is only to change scheduler by rebooting, i think > it is no more expensive to compile a kernel with the other scheduler. > Or is it that people never compile kernels nowadays? That's part of it. For my money the other 2 big problems are first that we'd like to make it as easy on the 'make release' and installer processes as possible. I imagine (although I would not object to being proven wrong) that 1 kernel with knobs is easier to manage and less resource intensive than 2 kernels that differ only by this 1 feature. The other big problem is freebsd-update. While I assume that logic could be built into the system to handle this issue, if the guts can be built into the kernel itself why not do that instead? Of lesser, but not insignificant consideration is the possibility that at some point we'll have more than 2 scheduler options. Doug -- [^L] Breadth of IT experience, and depth of knowledge in the DNS. Yours for the right price. :) http://SupersetSolutions.com/