From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jon Smirl" Subject: Re: Git and GCC Date: Fri, 7 Dec 2007 02:08:09 -0500 Message-ID: <9e4733910712062308t22258c6anb685b18a663e0a31@mail.gmail.com> References: <4aca3dc20712051947t5fbbb383ua1727c652eb25d7e@mail.gmail.com> <4aca3dc20712052032n521c344cla07a5df1f2c26cb8@mail.gmail.com> <20071205.204848.227521641.davem@davemloft.net> <4aca3dc20712052111o730f6fb6h7a329ee811a70f28@mail.gmail.com> <4aca3dc20712061004g43f5902cw79bf633917d3ade9@mail.gmail.com> <1196995353.22471.20.camel@brick> <9e4733910712062006l651571f3w7f76ce64c6650dff@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: "Harvey Harrison" , "Daniel Berlin" , "David Miller" , ismail@pardus.org.tr, gcc@gcc.gnu.org, git@vger.kernel.org To: "Linus Torvalds" X-From: git-owner@vger.kernel.org Fri Dec 07 08:08:34 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 1J0XK5-0005Sc-MT for gcvg-git-2@gmane.org; Fri, 07 Dec 2007 08:08:34 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750998AbXLGHIM (ORCPT ); Fri, 7 Dec 2007 02:08:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750759AbXLGHIM (ORCPT ); Fri, 7 Dec 2007 02:08:12 -0500 Received: from qb-out-0506.google.com ([72.14.204.225]:28302 "EHLO qb-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750925AbXLGHIK (ORCPT ); Fri, 7 Dec 2007 02:08:10 -0500 Received: by qb-out-0506.google.com with SMTP id e11so4514390qbe for ; Thu, 06 Dec 2007 23:08:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; bh=M9xABKCFrBngt2wfro1HCWOBn2jm2epU1EzzByrDtCY=; b=M4ev+aQUgjwzbNbwHfiyOSRgIbv53623h3e7zs1RUyxk1gtzHifvQwtVmWA+RTS/Jpu3TzMtY3oKsxqRbrXk7Aq39bbxqdONU0DRqNFQcw6tF/TZv+CooyG5o96ZoG5dBtBCBOy42AByzIT5Ouo3Sl+TK3/kBhKee7rWPDVrOQU= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=lVmweiak3rSUHA3H2IrOJlt5s50H82Iq6hqmhiSEEY83D1YUdu+HQPmPDd/B63sws8QgooNkyZtv0I2nU32XREuxtpvsRNs6I2R8AUdkz/rCjIzwsGzQPD/gna88v+xFf54YQr32X+j3oH13KMeLvDNFwLp3XJ1hdb7TIdvsUpA= Received: by 10.114.154.1 with SMTP id b1mr3191368wae.1197011289532; Thu, 06 Dec 2007 23:08:09 -0800 (PST) Received: by 10.114.208.17 with HTTP; Thu, 6 Dec 2007 23:08:09 -0800 (PST) In-Reply-To: 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, Linus Torvalds wrote: > > > On Thu, 6 Dec 2007, Jon Smirl wrote: > > > > > > time git blame -C gcc/regclass.c > /dev/null > > > > jonsmirl@terra:/video/gcc$ time git blame -C gcc/regclass.c > /dev/null > > > > real 1m21.967s > > user 1m21.329s > > Well, I was also hoping for a "compared to not-so-aggressive packing" > number on the same machine.. IOW, what I was wondering is whether there is > a visible performance downside to the deeper delta chains in the 300MB > pack vs the (less aggressive) 500MB pack. Same machine with a default pack jonsmirl@terra:/video/gcc/.git/objects/pack$ ls -l total 2145716 -r--r--r-- 1 jonsmirl jonsmirl 23667932 2007-12-07 02:03 pack-bd163555ea9240a7fdd07d2708a293872665f48b.idx -r--r--r-- 1 jonsmirl jonsmirl 2171385413 2007-12-07 02:03 pack-bd163555ea9240a7fdd07d2708a293872665f48b.pack jonsmirl@terra:/video/gcc/.git/objects/pack$ Delta lengths have virtually no impact. The bigger pack file causes more IO which offsets the increased delta processing time. One of my rules is smaller is almost always better. Smaller eliminates IO and helps with the CPU cache. It's like the kernel being optimized for size instead of speed ending up being faster. time git blame -C gcc/regclass.c > /dev/null real 1m19.289s user 1m17.853s sys 0m0.952s > > Linus > -- Jon Smirl jonsmirl@gmail.com