From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Torvalds Subject: Re: [PATCH] grep: do not do external grep on skip-worktree entries Date: Mon, 11 Jan 2010 11:29:01 -0800 (PST) Message-ID: References: <7vtyv4cpna.fsf@alter.siamese.dyndns.org> <7v3a2mzzg4.fsf@alter.siamese.dyndns.org> <20100104053125.GA5083@coredump.intra.peff.net> <7vbphaquwl.fsf@alter.siamese.dyndns.org> <20100104064408.GA7785@coredump.intra.peff.net> <7vvdf9402f.fsf@alter.siamese.dyndns.org> <4c8ef71001111119p253170f8q37bcd3708d894a62@mail.gmail.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Junio C Hamano , Miles Bader , Jeff King , Nguyen Thai Ngoc Duy , git@vger.kernel.org To: Fredrik Kuivinen X-From: git-owner@vger.kernel.org Mon Jan 11 20:29:26 2010 Return-path: Envelope-to: gcvg-git-2@lo.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by lo.gmane.org with esmtp (Exim 4.50) id 1NUPx7-0007Jt-SL for gcvg-git-2@lo.gmane.org; Mon, 11 Jan 2010 20:29:26 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753951Ab0AKT3W (ORCPT ); Mon, 11 Jan 2010 14:29:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753946Ab0AKT3W (ORCPT ); Mon, 11 Jan 2010 14:29:22 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:38113 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753578Ab0AKT3V (ORCPT ); Mon, 11 Jan 2010 14:29:21 -0500 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 o0BJT18j010476 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 11 Jan 2010 11:29:03 -0800 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 o0BJT1Va022848; Mon, 11 Jan 2010 11:29:01 -0800 X-X-Sender: torvalds@localhost.localdomain In-Reply-To: <4c8ef71001111119p253170f8q37bcd3708d894a62@mail.gmail.com> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) X-Spam-Status: No, hits=-5.449 required=5 tests=AWL,BAYES_00,OSDL_HEADER_SUBJECT_BRACKETED,PATCH_SUBJECT_OSDL 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 Mon, 11 Jan 2010, Fredrik Kuivinen wrote: > > Any ideas on how this can be explained? Could it be a bad 'strstr()' implementation? Try a complex pattern ("qwerty.*as" finds the same line), and see if that too is slower than before. If that is faster than it used to be (with --no-ext-grep, of course), then it's strstr() that is badly implemented. For me, on x86-64 (Fedora-12), strstr() seems to do pretty well. But it's easy to do a stupid implementation of strstr that does a 'strlen()' first, for example, and thus always traverses all data _twice_ etc. Depending on cache sizes etc, that can end up killing performance (or not mattering much at all..) Linus