From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Daniel Berlin" Subject: Re: Git and GCC Date: Fri, 7 Dec 2007 18:33:26 -0500 Message-ID: <4aca3dc20712071533k3189d25dp901c5941e5326ead@mail.gmail.com> References: <20071206.193121.40404287.davem@davemloft.net> <20071207063848.GA13101@coredump.intra.peff.net> <9e4733910712062310s30153afibc44a5550fd9ea99@mail.gmail.com> <20071207.045329.204650714.davem@davemloft.net> <4759AC8E.3070102@develer.com> <1197069298.6118.1.camel@ozzu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: "Jakub Narebski" , "Linus Torvalds" , "David Miller" , jonsmirl@gmail.com, peff@peff.net, nico@cam.org, harvey.harrison@gmail.com, ismail@pardus.org.tr, gcc@gcc.gnu.org, git@vger.kernel.org To: "Giovanni Bajo" X-From: git-owner@vger.kernel.org Sat Dec 08 00:33:51 2007 Return-path: Envelope-to: gcvg-git-2@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by lo.gmane.org with esmtp (Exim 4.50) id 1J0mha-00025u-E2 for gcvg-git-2@gmane.org; Sat, 08 Dec 2007 00:33:50 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751659AbXLGXd2 (ORCPT ); Fri, 7 Dec 2007 18:33:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751544AbXLGXd2 (ORCPT ); Fri, 7 Dec 2007 18:33:28 -0500 Received: from rv-out-0910.google.com ([209.85.198.184]:40260 "EHLO rv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751307AbXLGXd1 (ORCPT ); Fri, 7 Dec 2007 18:33:27 -0500 Received: by rv-out-0910.google.com with SMTP id k20so863522rvb for ; Fri, 07 Dec 2007 15:33:26 -0800 (PST) Received: by 10.142.100.1 with SMTP id x1mr2492118wfb.1197070406100; Fri, 07 Dec 2007 15:33:26 -0800 (PST) Received: by 10.142.199.2 with HTTP; Fri, 7 Dec 2007 15:33:26 -0800 (PST) In-Reply-To: <1197069298.6118.1.camel@ozzu> Content-Disposition: inline Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: On 12/7/07, Giovanni Bajo wrote: > On Fri, 2007-12-07 at 14:14 -0800, Jakub Narebski wrote: > > > > >> Is SHA a significant portion of the compute during these repacks? > > > >> I should run oprofile... > > > > SHA1 is almost totally insignificant on x86. It hardly shows up. But > > > > we have a good optimized version there. > > > > zlib tends to be a lot more noticeable (especially the > > > > *uncompression*: it may be faster than compression, but it's done _so_ > > > > much more that it totally dominates). > > > > > > Have you considered alternatives, like: > > > http://www.oberhumer.com/opensource/ucl/ > > > > > > As compared to LZO, the UCL algorithms achieve a better compression > > ratio but *decompression* is a little bit slower. See below for some > > rough timings. > > > > > > It is uncompression speed that is more important, because it is used > > much more often. > > I know, but the point is not what is the fastestest, but if it's fast > enough to get off the profiles. I think UCL is fast enough since it's > still times faster than zlib. Anyway, LZO is GPL too, so why not > considering it too. They are good libraries. At worst, you could also use fastlz (www.fastlz.org), which is faster than all of these by a factor of 4 (and compression wise, is actually sometimes better, sometimes worse, than LZO).