From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Torvalds Subject: Re: Performance issue of 'git branch' Date: Sat, 25 Jul 2009 21:49:41 -0700 (PDT) Message-ID: References: <20090723195548.GA28494@Pilar.aei.mpg.de> <20090724234648.GA4616@Pilar.aei.mpg.de> <20090725004122.GA28477@Pilar.aei.mpg.de> <20090725215739.d074e947.tihirvon@gmail.com> <20090725203130.GB1640@glandium.org> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Mike Hommey , Timo Hirvonen , git@vger.kernel.org, "Carlos R. Mafra" , Junio C Hamano To: Johannes Schindelin X-From: git-owner@vger.kernel.org Sun Jul 26 06:50:32 2009 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 1MUvgt-00015x-8i for gcvg-git-2@gmane.org; Sun, 26 Jul 2009 06:50:31 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751200AbZGZEuV (ORCPT ); Sun, 26 Jul 2009 00:50:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751130AbZGZEuU (ORCPT ); Sun, 26 Jul 2009 00:50:20 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:53017 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751014AbZGZEuU (ORCPT ); Sun, 26 Jul 2009 00:50:20 -0400 Received: from imap1.linux-foundation.org (imap1.linux-foundation.org [140.211.169.55]) by smtp1.linux-foundation.org (8.14.2/8.13.5/Debian-3ubuntu1.1) with ESMTP id n6Q4ngr8014409 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Sat, 25 Jul 2009 21:49:43 -0700 Received: from localhost (localhost [127.0.0.1]) by imap1.linux-foundation.org (8.13.5.20060308/8.13.5/Debian-3ubuntu1.1) with ESMTP id n6Q4nfPf004654; Sat, 25 Jul 2009 21:49:41 -0700 X-X-Sender: torvalds@localhost.localdomain In-Reply-To: User-Agent: Alpine 2.01 (LFD 1184 2008-12-16) X-Spam-Status: No, hits=-3.459 required=5 tests=AWL,BAYES_00 X-Spam-Checker-Version: SpamAssassin 3.2.4-osdl_revision__1.47__ X-MIMEDefang-Filter: lf$Revision: 1.188 $ X-Scanned-By: MIMEDefang 2.63 on 140.211.169.13 Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: On Sun, 26 Jul 2009, Johannes Schindelin wrote: > > > > It seems to come from libcrypto. I can get rid of it with NO_OPENSSL, and > > that cuts down on the number of system calls in my startup by 16 (getting > > rid of both libcrypto and libdl). I wonder if there is some way to get the > > optimized openssl sha1 routines _without_ that silly ldl thing. > > OpenSSL allows for so-called engines implementing certain algorithms. > These engines are dynamic libraries, loaded via dlopen(). Ah. Ok, that explains it. It's a bit sad, since the _only_ thing we load all of libcrypto for is the (fairly trivial) SHA1 code. But at the same time, last time I benchmarked the different SHA1 libraries, the openssl one was the fastest. I think it has tuned assembly language for most architectures. Our regular mozilla-based C code is perfectly fine, but it doesn't hold a candle to assembler tuning. Oh well. Linus