Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933057Ab2HPRwk (ORCPT ); Thu, 16 Aug 2012 13:52:40 -0400 Received: from one.firstfloor.org ([213.235.205.2]:56330 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756713Ab2HPRwi (ORCPT ); Thu, 16 Aug 2012 13:52:38 -0400 Date: Thu, 16 Aug 2012 19:52:34 +0200 From: Andi Kleen To: Roman Mamedov Cc: Johannes Stezenbach , "Markus F.X.J. Oberhumer" , linux-kernel@vger.kernel.org, Andi Kleen , chris.mason@fusionio.com, linux-btrfs@vger.kernel.org, Nitin Gupta , Richard Purdie , richard -rw- weinberger , linux-arm-kernel@lists.infradead.org Subject: Re: [GIT PULL] Update LZO compression Message-ID: <20120816175234.GL11413@one.firstfloor.org> References: <50299142.2030504@oberhumer.com> <20120814123937.GA14756@sig21.net> <502B8FE3.7080501@oberhumer.com> <20120815144539.GA8300@sig21.net> <502C92C3.7090701@oberhumer.com> <20120816150647.GA22010@sig21.net> <20120816232549.4d14a6aa@natsu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120816232549.4d14a6aa@natsu> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1162 Lines: 27 > I have locked the Allwinner A10 CPU in my Mele A2000 to 60 MHz using cpufreq-set, > and ran your test. rnd.lzo is a 9 MB file from /dev/urandom compressed with lzo. > There doesn't seem to be a significant difference between all three variants. I found that in compression benchmarks it depends a lot on the data compressed. urandom (which should be essentially incompressible) will be handled by different code paths in the compressor than other more compressible data. It becomes a complicated memcpy then. But then there are IO benchmarks which also only do zeroes, which also gives an unrealistic picture. Usually it's best to use some corpus with different data types, from very compressible to less so; and look at the aggregate. For my snappy work I usually had at least large executables (medium) and some pdfs (already compressed; low) and then uncompressed source code tars (high compression) -Andi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/