From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Torvalds Subject: Re: [RFC] git-split: Split the history of a git repository by subdirectories and ranges Date: Mon, 23 Oct 2006 14:06:49 -0700 (PDT) Message-ID: References: <451A30E4.50801@freedesktop.org> <7vlko5d3bx.fsf@assigned-by-dhcp.cox.net> <453C96C9.4010005@freedesktop.org> <453D17B5.6070203@freedesktop.org> <453D2B98.8010903@freedesktop.org> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Junio C Hamano , git@vger.kernel.org X-From: git-owner@vger.kernel.org Mon Oct 23 23:07:58 2006 Return-path: Envelope-to: gcvg-git@gmane.org Received: from vger.kernel.org ([209.132.176.167]) by ciao.gmane.org with esmtp (Exim 4.43) id 1Gc70h-0007Tc-UV for gcvg-git@gmane.org; Mon, 23 Oct 2006 23:07:04 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751999AbWJWVHB (ORCPT ); Mon, 23 Oct 2006 17:07:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752002AbWJWVHA (ORCPT ); Mon, 23 Oct 2006 17:07:00 -0400 Received: from smtp.osdl.org ([65.172.181.4]:39386 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1751999AbWJWVHA (ORCPT ); Mon, 23 Oct 2006 17:07:00 -0400 Received: from shell0.pdx.osdl.net (fw.osdl.org [65.172.181.6]) by smtp.osdl.org (8.12.8/8.12.8) with ESMTP id k9NL6oaX007044 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NO); Mon, 23 Oct 2006 14:06:51 -0700 Received: from localhost (shell0.pdx.osdl.net [10.9.0.31]) by shell0.pdx.osdl.net (8.13.1/8.11.6) with ESMTP id k9NL6n4p006362; Mon, 23 Oct 2006 14:06:50 -0700 To: Josh Triplett In-Reply-To: <453D2B98.8010903@freedesktop.org> X-Spam-Status: No, hits=-0.978 required=5 tests=AWL,OSDL_HEADER_SUBJECT_BRACKETED X-Spam-Checker-Version: SpamAssassin 2.63-osdl_revision__1.95__ X-MIMEDefang-Filter: osdl$Revision: 1.155 $ X-Scanned-By: MIMEDefang 2.36 Sender: git-owner@vger.kernel.org Precedence: bulk X-Mailing-List: git@vger.kernel.org Archived-At: On Mon, 23 Oct 2006, Josh Triplett wrote: > > Or have I misunderstood the case you have concerns about? Why would the > "nice" format incur additional cost? Try it. The default "extreme" simplification is a _hell_ of a lot faster than doing the full history. [torvalds@g5 linux]$ time git-rev-list --full-history --parents HEAD -- kernel/sched.c >/dev/null real 0m4.660s user 0m4.612s sys 0m0.044s [torvalds@g5 linux]$ time git-rev-list --parents HEAD -- kernel/sched.c >/dev/null real 0m1.684s user 0m1.680s sys 0m0.004s and the "nice" thing will be much slower still: just trying to figure out whether a commit is a parent of another commit is expensive. Doing so for _each_ merge is more expensive still. I think it's O(n^3), but what do I know.. Linus