From owner-freebsd-hackers@FreeBSD.ORG Tue Apr 9 05:05:35 2013 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id 26E379B for ; Tue, 9 Apr 2013 05:05:35 +0000 (UTC) (envelope-from adrian.chadd@gmail.com) Received: from mail-we0-x236.google.com (mail-we0-x236.google.com [IPv6:2a00:1450:400c:c03::236]) by mx1.freebsd.org (Postfix) with ESMTP id B39FD9B for ; Tue, 9 Apr 2013 05:05:34 +0000 (UTC) Received: by mail-we0-f182.google.com with SMTP id k14so5135097wer.13 for ; Mon, 08 Apr 2013 22:05:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:x-received:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; bh=NvkdZtWLPOBfKiKxn+w6o3rrZtWDdyRrtFgVDofKsQ8=; b=Qkd9FTjhEwC8/kKtlfYLBSyoLqR+A5sURmYc/I07WaEacpuN4gIUF3lQD79JK+qbX7 unD3Kv1k5lcSwwcrA9D3wpVmSbhoVcDGP4OAP6QVimw4yWO4MLtkLBPpDOIgGoXCdxuZ MsRIXyD7Q246sBy7Jd/a7JZXIhlpYw8XOEjiEi5kBXjJQpYtWdQYLK3gZPmKfs4y3kcF VSwK5sYQ0bqK+M5sppARhyRCtXybdXOyHEfnU+DouUDT/JXwJpZEjFv3Y+9VAF4/Afo0 2vbb0ts6Z+poj8SZbSbOcqYTX5vefb3B/EN8Ei8oigiSXTXU55FogIRmdineZfpogR9U BX0Q== MIME-Version: 1.0 X-Received: by 10.194.143.50 with SMTP id sb18mr5886412wjb.44.1365483933844; Mon, 08 Apr 2013 22:05:33 -0700 (PDT) Sender: adrian.chadd@gmail.com Received: by 10.217.121.136 with HTTP; Mon, 8 Apr 2013 22:05:33 -0700 (PDT) In-Reply-To: References: <20130408224423.GA64696@stack.nl> <5163622F.60604@mu.org> Date: Mon, 8 Apr 2013 22:05:33 -0700 X-Google-Sender-Auth: G5ZJvtF3QDZYawU3C3_PEnuI1Nw Message-ID: Subject: Re: GSOC 2013 project " Kernel Size Reduction for Embedded System " From: Adrian Chadd To: Kevin Day Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: freebsd-hackers@freebsd.org, Alfred Perlstein , Amit Rawat , Jilles Tjoelker X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 09 Apr 2013 05:05:35 -0000 On 8 April 2013 19:28, Kevin Day wrote: > Ages ago we had to make things work in 16 or 32MB of total system memory = on i386. > > For the most part, disabling every compiled-in option/driver we didn't ne= ed was 90% of the effort. Which options/drivers is going to be totally appl= ication dependent, so that really can't be done for you. > > As for the rest, there isn't any large low hanging fruit that can get cul= led from the kernel easily. The base kernel isn't modular enough to trim ou= t individual syscalls or anything, and doing so wouldn't have made a huge d= ent. > > There are a lot of ways FreeBSD could be more embedded friendly (being ab= le turn on/off parts of userland depending on licenses is a huge one), but = producing a trimmed kernel isn't something I'd rank very highly. If buildin= g a kernel with everything modularized as possible isn't small enough, Free= BSD probably isn't going to work for you for other reasons. The MIPS kernels I'm producing are pretty bare. There's not a lot of options to disable at this point.. :( Adrian