From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from LGEMRELSE1Q.lge.com ([156.147.1.111]:56581 "EHLO LGEMRELSE1Q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755827Ab3B0NYB (ORCPT ); Wed, 27 Feb 2013 08:24:01 -0500 Date: Wed, 27 Feb 2013 22:23:58 +0900 From: Kyungsik Lee Subject: Re: [RFC PATCH v2 0/4] Add support for LZ4-compressed kernel Message-ID: <20130227132358.GA25071@Corona> References: <1361859870-15751-1-git-send-email-kyungsik.lee@lge.com> <512D1C12.4080109@oberhumer.com> <20130227073646.GA22333@Corona> <20130227095139.GX17833@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130227095139.GX17833@n2100.arm.linux.org.uk> Sender: linux-kbuild-owner@vger.kernel.org List-ID: To: Russell King - ARM Linux , "Markus F.X.J. Oberhumer" , Andrew Morton Cc: 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, celinux-dev@lists.celinuxforum.org, Nicolas Pitre , Nitin Gupta , Richard Purdie , Josh Triplett , Joe Millenbach , David Sterba , Richard Cochran , Albin Tonnerre , Egon Alter , hyojun.im@lge.com, chan.jeong@lge.com, raphael.andy.lee@gmail.com On Wed, Feb 27, 2013 at 09:51:39AM +0000, Russell King - ARM Linux wrote: > On Wed, Feb 27, 2013 at 04:36:47PM +0900, Kyungsik Lee wrote: > > Compiler: Linaro ARM gcc 4.6.2 > > 2. ARMv7, 1.7GHz based board > > Kernel: linux 3.7 > > Uncompressed Kernel Size: 14MB > > Compressed Size Decompression Speed > > LZO 6.0MB 34.1MB/s Old > > ---------------------------------------- > > 6.0MB 34.7MB/s New > > 6.0MB 52.2MB/s(UA) > > ============================================= > > LZ4 6.5MB 86.7MB/s > > UA: Unaligned memory Access support > > That is pretty conclusive - it shows an 8% increase in image size vs a > 66% increase in decompression speed. It will take a _lot_ to offset > that increase in decompression speed. > > So, what I think is that yes, we should accept LZ4 and drop LZO from > the kernel - the "fast but may not be small" compression title has > clearly been taken by LZ4. I have read the comments regarding how many compressors the kernel should support and understand that it can not support all the compressors available. However, I don't think that LZO can be replaced by LZ4 in all the cases. The benchmark above shows only about improved decompression speed. Thanks, Kyungsik