From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758429AbZHRKWY (ORCPT ); Tue, 18 Aug 2009 06:22:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750880AbZHRKWY (ORCPT ); Tue, 18 Aug 2009 06:22:24 -0400 Received: from metis.ext.pengutronix.de ([92.198.50.35]:52316 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750743AbZHRKWX (ORCPT ); Tue, 18 Aug 2009 06:22:23 -0400 Date: Tue, 18 Aug 2009 12:21:36 +0200 From: Robert Schwebel To: Marco Stornelli Cc: Johannes Stezenbach , Denys Vlasenko , linux-kernel@vger.kernel.org, linux-embedded@vger.kernel.org, Arjan van de Ven , Tim Bird , kernel@pengutronix.de Subject: Re: New fast(?)-boot results on ARM Message-ID: <20090818102136.GN29655@pengutronix.de> References: <20090814170228.GM13320@pengutronix.de> <1158166a0908141304y70300ab3p899b0d4609efded9@mail.gmail.com> <20090814204305.GA31727@pengutronix.de> <20090815103532.GA5596@sig21.net> <4A8A7D38.5020201@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <4A8A7D38.5020201@gmail.com> X-Sent-From: Pengutronix Entwicklungszentrum Nord - Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Impressum: Pengutronix - Linux Solutions for Science and Industry Handelsregister: Amtsgericht Hildesheim, HRA 2686 Peiner Strasse 6-8, 31137 Hildesheim, Germany Phone: +49-5121-206917-0 | Fax: +49-5121-206917-5555 Inhaber: Dipl.-Ing. Robert Schwebel X-Message-Flag: See Message Headers for Impressum X-Uptime: 12:13:13 up 12 days, 21:32, 53 users, load average: 6.51, 6.04, 4.11 User-Agent: Mutt/1.5.18 (2008-05-17) X-SA-Exim-Connect-IP: 2001:6f8:1178:2:215:17ff:fe12:23b0 X-SA-Exim-Mail-From: rsc@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Marco, On Tue, Aug 18, 2009 at 12:06:48PM +0200, Marco Stornelli wrote: > Yeah, I agree, do you really need udevd, device file creation at every > start-up in /dev? Usually static devices nodes and mdev for hotplug are > enough or at least you could use a simple script to create only once > time the devices file (mdev -s). About the fs, do you really need a > rootfs with ubifs? I mean, you could "split" your fs. You could use a > read-only fs (SquashFS for example) for your root-fs, ubifs for > permanent storage data (mounted under /data for example) and a ram fs > for volatile data. Well, we try to find out what is possible with a fast booting Linux system which *still* is as "vanilla" as possible. All the "boot-in-one-second" systems out there are highly squeezed, which is surely good if you have a scenario with high production volumes. You can do the optimization in the last steps then and it doesn't really matter how much time you spend with testing to come from a system that works for a developer to a production system. For most of our use cases here at Pengutronix, we see that: - Customers want in-system upgradability on a per-packet base; so the flash filesystems should be normally r/o, but may be remounted r/w. - Development systems should be close to production systems, in order to be able to have more "early testing"; so things like printk-ripout or special non-mainline patches/tweaks should be avoided as far as possible. - In general we want to have our systems close to what the mainline does; Automation & Embedded is only a small market, and anything which is *not* specific to these markets but mainline is good. So let's see what we'll reach while trying what people have suggested. Thanks, rsc -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |