From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753986Ab3A2KRL (ORCPT ); Tue, 29 Jan 2013 05:17:11 -0500 Received: from caramon.arm.linux.org.uk ([78.32.30.218]:57428 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750913Ab3A2KRJ (ORCPT ); Tue, 29 Jan 2013 05:17:09 -0500 Date: Tue, 29 Jan 2013 10:15:49 +0000 From: Russell King - ARM Linux To: Andrew Morton Cc: Kyungsik Lee , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Michal Marek , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, x86@kernel.org, Nitin Gupta , Richard Purdie , Josh Triplett , Joe Millenbach , Albin Tonnerre , hyojun.im@lge.com, chan.jeong@lge.com, gunho.lee@lge.com, minchan.kim@lge.com, namhyung.kim@lge.com, raphael.andy.lee@gmail.com, CE Linux Developers List Subject: Re: [RFC PATCH 0/4] Add support for LZ4-compressed kernels Message-ID: <20130129101549.GP23505@n2100.arm.linux.org.uk> References: <1359179447-31118-1-git-send-email-kyungsik.lee@lge.com> <20130128142510.68092e10.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130128142510.68092e10.akpm@linux-foundation.org> User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 28, 2013 at 02:25:10PM -0800, Andrew Morton wrote: > What's this "with enabled unaligned memory access" thing? You mean "if > the arch supports CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS"? If so, > that's only x86, which isn't really in the target market for this > patch, yes? > > It's a lot of code for a 50ms boot-time improvement. Does anyone have > any opinions on whether or not the benefits are worth the cost? Well... when I saw this my immediate reaction was "oh no, yet another decompressor for the kernel". We have five of these things already. Do we really need a sixth? My feeling is that we should have: - one decompressor which is the fastest - one decompressor for the highest compression ratio - one popular decompressor (eg conventional gzip) And if we have a replacement one for one of these, then it should do exactly that: replace it. I realise that various architectures will behave differently, so we should really be looking at numbers across several arches. Otherwise, where do we stop adding new ones? After we have 6 of these (which is after this one). After 12? After the 20th?