From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Nieder Subject: Re: Why is "git tag --contains" so slow? Date: Thu, 14 Oct 2010 13:59:45 -0500 Message-ID: <20101014185945.GA14634@burratino> References: <20100701121711.GF1333@thunk.org> <20100701150331.GA12851@sigill.intra.peff.net> <20100701153842.GA15466@sigill.intra.peff.net> <20100702192612.GM1333@thunk.org> <20100703080618.GA10483@sigill.intra.peff.net> <20100704005543.GB6384@thunk.org> <20100705122723.GB21146@sigill.intra.peff.net> <20100705123923.GC21146@sigill.intra.peff.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: tytso@mit.edu, Avery Pennarun , git@vger.kernel.org To: Jeff King X-From: git-owner@vger.kernel.org Thu Oct 14 21:03:23 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 4.69) (envelope-from ) id 1P6T5H-0005pC-Dv for gcvg-git-2@lo.gmane.org; Thu, 14 Oct 2010 21:03:23 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755466Ab0JNTDR (ORCPT ); Thu, 14 Oct 2010 15:03:17 -0400 Received: from mail-ew0-f46.google.com ([209.85.215.46]:51319 "EHLO mail-ew0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754930Ab0JNTDQ (ORCPT ); Thu, 14 Oct 2010 15:03:16 -0400 Received: by ewy20 with SMTP id 20so3830363ewy.19 for ; Thu, 14 Oct 2010 12:03:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:date:from:to:cc:subject :message-id:references:mime-version:content-type:content-disposition :in-reply-to:user-agent; bh=IqOGlLDwAvtH4vV07jUSLn3/totfV2k1JAKcSDAUDgs=; b=v8MimAyvVNdasRT964hIDhGj6Hc4fyzgA/Gl+T21v4DxeooFDo2lYqElv7DLVY8nz9 JeZVVGRI0BuzaE0/isu1bH7SLmZJd4Z8jUjLqXptHoadkvFNpGMIQ01K7DmO+WrYA82K I3fGEYrvpxkzJgmtgj33UuzYL3AAhqzBwCkTw= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=Wa4ykTMFpMQpE3e0X2LHFLjlJmJdEYl5trQE1wk57s5/F7qg72bMn3xK3RH3DDH8yw bGorA3Wmk5m16THa8n++4U7r5utEe0eYxTAB2mnbD66j6QsYvZNiK8Y06urg0SCzF/eh vBvwb1uVm4qRisi9C9iQXdA1D3v4nlT4wktR8= Received: by 10.213.22.66 with SMTP id m2mr2347378ebb.56.1287082994838; Thu, 14 Oct 2010 12:03:14 -0700 (PDT) Received: from burratino (adsl-68-255-106-176.dsl.chcgil.ameritech.net [68.255.106.176]) by mx.google.com with ESMTPS id v56sm1513104eeh.14.2010.10.14.12.03.12 (version=SSLv3 cipher=RC4-MD5); Thu, 14 Oct 2010 12:03:13 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20100705123923.GC21146@sigill.intra.peff.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: Jeff King wrote: > This patch doesn't implement auto-detection of skew, but is the program > I used to calculate, and would provide the basis for such > auto-detection. It would be interesting to see average skew numbers for > popular repositories. You can run it as "git skew --all". Fun. The story this tells me is that most repositories would benefit more from special-casing a few commits than from a "[core] clockskew" setting. Caveat: the repos mentioned below are not canonical at all. They are just some repos I happened to have around, some tracking multiple upstreams. project # skewed maximum skew notes ------- -------- ------------ ----- gtk+ 13 13 hrs worst example seems to be tz related systemd 3 1 hr all three come from a single 65min jump. Same committer before+after. dpkg 2 76 days automatic import from manually written changelog glibc 2 31 months (tag) commits imported to wrong branches by "git cvsimport", I think git 4 7 minutes all four come from a single merge commit, parents have same committer as the merge. probably clock drift corrected with something like ntp. guilt 22 96 minutes from the known (fixed) bug, I assume linux-2.6 1226 99 days probably the old guilt bug (e.g., in ext4, blackfin trees) sed 0