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, 4 Jan 2010 08:03:04 -0800 (PST) Message-ID: References: <7vtyv4cpna.fsf@alter.siamese.dyndns.org> <87ljgfgbl0.fsf@catnip.gol.com> <877hrzga16.fsf@catnip.gol.com> <7v3a2mzzg4.fsf@alter.siamese.dyndns.org> <20100104053125.GA5083@coredump.intra.peff.net> <7vbphaquwl.fsf@alter.siamese.dyndns.org> <20100104064408.GA7785@coredump.intra.peff.net> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Jeff King , Junio C Hamano , Nguyen Thai Ngoc Duy , git@vger.kernel.org To: Miles Bader X-From: git-owner@vger.kernel.org Mon Jan 04 17:03:26 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 1NRpOp-0003Lh-2Y for gcvg-git-2@lo.gmane.org; Mon, 04 Jan 2010 17:03:19 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753498Ab0ADQDR (ORCPT ); Mon, 4 Jan 2010 11:03:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753464Ab0ADQDQ (ORCPT ); Mon, 4 Jan 2010 11:03:16 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:53091 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753463Ab0ADQDP (ORCPT ); Mon, 4 Jan 2010 11:03:15 -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 o04G34xu004873 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 4 Jan 2010 08:03:05 -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 o04G34UM003425; Mon, 4 Jan 2010 08:03:04 -0800 X-X-Sender: torvalds@localhost.localdomain In-Reply-To: User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) X-Spam-Status: No, hits=-5.447 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 Tue, 5 Jan 2010, Miles Bader wrote: > On Tue, Jan 5, 2010 at 12:54 AM, Linus Torvalds > wrote: > > And "perf record" followed by "perf report" on the internal one shows > > that it's not even regexec() - we use strstr() for the trivial case: > > Does strstr use e.g. boyer-moore? I imagine grep does... It doesn't matter. Since we do the line-by-line thing, the input is always so short that DFA vs NFA vs BM vs other-clever-search doesn't matter. There is no scaling - the grep buffer tends to be too small for the algorithm to matter. And the reason we do things line-by-line is that we need to then output things line-per-line. Linus