From owner-freebsd-arch@FreeBSD.ORG Tue Jan 1 10:59:50 2008 Return-Path: Delivered-To: freebsd-arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 4E98416A418 for ; Tue, 1 Jan 2008 10:59:50 +0000 (UTC) (envelope-from kris@FreeBSD.org) Received: from weak.local (freefall.freebsd.org [IPv6:2001:4f8:fff6::28]) by mx1.freebsd.org (Postfix) with ESMTP id A2AC113C447; Tue, 1 Jan 2008 10:59:39 +0000 (UTC) (envelope-from kris@FreeBSD.org) Message-ID: <477A1D16.2090605@FreeBSD.org> Date: Tue, 01 Jan 2008 11:59:34 +0100 From: Kris Kennaway User-Agent: Thunderbird 2.0.0.9 (Macintosh/20071031) MIME-Version: 1.0 To: Karsten Behrmann References: <200712271704.44796.jhb@FreeBSD.org> <4774DBB2.5060707@FreeBSD.org> <20080101033620.4050569c@Karsten.Behrmanns.Kasten> In-Reply-To: <20080101033620.4050569c@Karsten.Behrmanns.Kasten> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-arch@freebsd.org Subject: Re: kernel features MIB X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 01 Jan 2008 10:59:50 -0000 Karsten Behrmann wrote: > On Fri, 28 Dec 2007 12:19:14 +0100, Kris Kennaway wrote: >> John Baldwin wrote: >>> One of the things we have at work is a kern.features sysctl MIB that contains >>> nodes to indicate if a named feature is present. For example, on i386 we >>> have kern.features.pae and we auto enable -DPAE for kernel modules if the >>> currently running kernel is using PAE using that sysctl. >>> [...] >>> Any objections to the idea? >> I have wanted something like this for a long time. In ports land they >> often need to know this kind of thing, e.g. is compat4x support enabled >> in the kernel, etc. > > Hmm. But will everyone be running a kernel and system that the stuff they > build will later run on? (when upgrading, or when building > kernel and tools to be installed via NFS and pals) > > Mind, it could be a good heuristic for the common cases, and directly > useful for some libraries, but I'm thinking that we may need some easily- > accessible override knobs. I could be wrong, though. It would just be used to display informational messages about the need to recompile the kernel, etc. Kris