From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Tue, 4 Dec 2001 20:38:40 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Tue, 4 Dec 2001 20:38:30 -0500 Received: from ziggy.one-eyed-alien.net ([64.169.228.100]:12296 "EHLO ziggy.one-eyed-alien.net") by vger.kernel.org with ESMTP id ; Tue, 4 Dec 2001 20:38:25 -0500 Date: Tue, 4 Dec 2001 17:38:19 -0800 From: Matthew Dharm To: Jeremy Puhlman Cc: "H. Peter Anvin" , Ingo Oeser , linux-kernel@vger.kernel.org Subject: Re: [PATCH] Endianness-aware mkcramfs Message-ID: <20011204173819.C29968@one-eyed-alien.net> Mail-Followup-To: Jeremy Puhlman , "H. Peter Anvin" , Ingo Oeser , linux-kernel@vger.kernel.org In-Reply-To: <3C0BD8FD.F9F94BE0@mvista.com> <3C0CB59B.EEA251AB@lightning.ch> <9uj5fb$1fm$1@cesium.transmeta.com> <20011205013630.C717@nightmaster.csn.tu-chemnitz.de> <3C0D6CB6.7000905@zytor.com> <20011204164941.A29968@one-eyed-alien.net> <20011204170235.M25671@mvista.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-md5; protocol="application/pgp-signature"; boundary="9Ek0hoCL9XbhcSqy" Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20011204170235.M25671@mvista.com>; from jpuhlman@mvista.com on Tue, Dec 04, 2001 at 05:02:35PM -0800 Organization: One Eyed Alien Networks X-Copyright: (C) 2001 Matthew Dharm, all rights reserved. Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --9Ek0hoCL9XbhcSqy Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Dec 04, 2001 at 05:02:35PM -0800, Jeremy Puhlman wrote: > On Tue, Dec 04, 2001 at 04:49:41PM -0800, Matthew Dharm wrote: > > There is another argument for supporting both endiannesses.... > >=20 > > Consider an embedded system which can be run in either endianness. Sou= nds > > silly? MIPS processors can run big or little endian, and many people > > routinely switch between them. > Yes but typically this also includes a step of reflashing firmware or > swaping of firmware...So it would not be unrealistic to swap out the > filesystem as well... Not necessarily. Consider a configuration where the kernel comes in over a network, but each board contains board-specific configuration data in flash. Reflashing isn't likely. And yes, people do that. I have a day job in the single-board-computer industry. > Since in a deployment situation you will always be sticking with one endi= anness=20 > it makes sense that you would want the most speed for your buck...Since f= lash=20 > filesystems are slow to begin with also adding in the decompression > hit you get from cramfs...it would seem to me that adding in le<->be > would just add to its speed reduction....That would seem to be a good > place to trim the fat so to speak... The speed reduction is going to be minimal. Implement it via macros, like it's done everywhere else. If the endianness is one way, the macros get optimized away. If it's the other way, then they convert into an inlined byte swap. Yes, there can be a small performance hit, but it's absolutely tiny. Matt --=20 Matthew Dharm Home: mdharm-usb@one-eyed-alien.= net=20 Maintainer, Linux USB Mass Storage Driver It was a new hope. -- Dust Puppy User Friendly, 12/25/1998 --9Ek0hoCL9XbhcSqy Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE8DXqLz64nssGU+ykRAsXxAKDFHmur8zchKcUbG8czkhZyw8yFQgCbBqhZ 8/t/uFaW3MFqjmmBsC72aPo= =2ula -----END PGP SIGNATURE----- --9Ek0hoCL9XbhcSqy--