From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aaron Lehmann Subject: Re: Performance of various compressors Date: Fri, 22 Apr 2005 13:38:01 -0700 Message-ID: <20050422203801.GE7437@vitelus.com> References: <426734DE.3040606@timesys.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: git@vger.kernel.org X-From: git-owner@vger.kernel.org Fri Apr 22 22:34:15 2005 Return-path: Received: from vger.kernel.org ([12.107.209.244]) by ciao.gmane.org with esmtp (Exim 4.43) id 1DP4q9-0002Ya-Kv for gcvg-git@gmane.org; Fri, 22 Apr 2005 22:33:30 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262125AbVDVUiF (ORCPT ); Fri, 22 Apr 2005 16:38:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262126AbVDVUiE (ORCPT ); Fri, 22 Apr 2005 16:38:04 -0400 Received: from dsl081-060-252.sfo1.dsl.speakeasy.net ([64.81.60.252]:14812 "EHLO vitelus.com") by vger.kernel.org with ESMTP id S262125AbVDVUiC (ORCPT ); Fri, 22 Apr 2005 16:38:02 -0400 Received: from aaronl by vitelus.com with local (Exim 4.32) id 1DP4uX-0006bG-DM; Fri, 22 Apr 2005 13:38:01 -0700 To: Mike Taht Content-Disposition: inline In-Reply-To: <426734DE.3040606@timesys.com> User-Agent: Mutt/1.5.8i Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org On Wed, Apr 20, 2005 at 10:06:38PM -0700, Mike Taht wrote: > That doing the compression at a level of 3, rather than the max of 9, > cuts the cpu time required for a big git commit by over half, and that > that actually translates into a win on the I/O to disk. (these tests > were performed on a dual opteron 842) If (de)compression is slowing things down, you might want to check out lzo (http://www.oberhumer.com/opensource/lzo/). I tested it on the 2.6.11 kernel source and found that lzo -7 output is only 2% larger than gzip -3, but lzo decompression is almost 3 times faster. The downside is that lzo took 5 times longer to perform the compression at -7. Compression with lzo -3 is 3.5 times faster than gzip -3, but it produces a file that's 37% bigger. Unfortunately, lzo has no settings in between -3 and -7. I'd expect git to be more sensitive to decompression speeds, though. BTW, lzo decompression speed is not affected by the compression level.