From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff King Subject: Re: Branches & directories Date: Mon, 3 Oct 2011 03:34:56 -0400 Message-ID: <20111003073456.GA10054@sigill.intra.peff.net> References: <4E889813.8070205@gmail.com> <20111003030723.GA24523@sigill.intra.peff.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: Hilco Wijbenga , Robin Rosenberg , Kyle Moffett , Michael Witten , Junio C Hamano , Evan Shelhamer , Git Mailing List To: Matthieu Moy X-From: git-owner@vger.kernel.org Mon Oct 03 09:35:04 2011 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 4.69) (envelope-from ) id 1RAd3I-0000T7-8P for gcvg-git-2@lo.gmane.org; Mon, 03 Oct 2011 09:35:04 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750991Ab1JCHfA (ORCPT ); Mon, 3 Oct 2011 03:35:00 -0400 Received: from 99-108-226-0.lightspeed.iplsin.sbcglobal.net ([99.108.226.0]:51450 "EHLO peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750775Ab1JCHe6 (ORCPT ); Mon, 3 Oct 2011 03:34:58 -0400 Received: (qmail 24541 invoked by uid 107); 3 Oct 2011 07:40:03 -0000 Received: from sigill.intra.peff.net (HELO sigill.intra.peff.net) (10.0.0.7) (smtp-auth username relayok, mechanism cram-md5) by peff.net (qpsmtpd/0.84) with ESMTPA; Mon, 03 Oct 2011 03:40:03 -0400 Received: by sigill.intra.peff.net (sSMTP sendmail emulation); Mon, 03 Oct 2011 03:34:56 -0400 Content-Disposition: inline In-Reply-To: Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: On Mon, Oct 03, 2011 at 09:32:07AM +0200, Matthieu Moy wrote: > Hilco Wijbenga writes: > > > Yes, I meant it literally. And, no, Git could not possibly know so it > > would have to be optional behaviour. But it's probably a lot of work > > for (for most people) little gain. > > Not only little gain, but also important risk: users of this feature > would be likely to spend hours debugging something just because some > files weren't recompiled at the right time. > > If you want to optimize the number of files compiled by "make", then > ccache is your friend. This one is safe. Yes. Despite my previous message showing what _could_ be done, I do think it's crazy. You should just use ccache. Speaking of which; does anybody know of a git-aware ccache-like tool? We already have a nice index of the sha1 of each file in the repository (along with a stat cache showing us whether it's up-to-date or not). Something like ccache could avoid even looking in the C files at all if it relied on git's index. I don't know how much speedup it would yield in practice, though. -Peff