From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?B?QWxleCBCZW5uw6ll?= Subject: Re: Poor performance of git describe in big repos Date: Thu, 30 May 2013 14:09:42 +0100 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: git@vger.kernel.org To: Ramkumar Ramachandra X-From: git-owner@vger.kernel.org Thu May 30 15:09:51 2013 Return-path: Envelope-to: gcvg-git-2@plane.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Ui2bz-0003eG-IL for gcvg-git-2@plane.gmane.org; Thu, 30 May 2013 15:09:47 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754518Ab3E3NJo convert rfc822-to-quoted-printable (ORCPT ); Thu, 30 May 2013 09:09:44 -0400 Received: from mail-ob0-f176.google.com ([209.85.214.176]:61360 "EHLO mail-ob0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751624Ab3E3NJm convert rfc822-to-8bit (ORCPT ); Thu, 30 May 2013 09:09:42 -0400 Received: by mail-ob0-f176.google.com with SMTP id v19so477178obq.7 for ; Thu, 30 May 2013 06:09:42 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding:x-gm-message-state; bh=Nd9raqlLEqSWJMhq9+3sW21dPVTgsndPyaB6IkPD/g0=; b=EHZWEMngq44XDP6AjZRgsnMrjdN4RImgTPOtJzqwfw4I4ryjjFjSytZsV5TNLYiEZO KGiMER5VQ3uo045EsUFr8xjhpkIWjDWwLbCEc+cPRPonioeBmVeqyysUh6zDTD/sGx4F PoQRlpx/6dl7MN0Ii3zwwi2xo6QDSiRcLvt95roZDDsoVtNVkw48CTNQxfilGVfnq/1L 6Xyj+FaRBlHHy3mLwHZ4Oac4uO6CRLUXUVtxkVLH3bSepnJp975ElFZ1ZVDTz+Zd6/zN lIYW1xKWhcjS8FpViDmlx8Vo7tNnkI3aOUsdeBjmHAuzRB7uRkKnAQ1EUlZu01F87yeg HO5A== X-Received: by 10.182.38.201 with SMTP id i9mr3973079obk.55.1369919382233; Thu, 30 May 2013 06:09:42 -0700 (PDT) Received: by 10.76.98.137 with HTTP; Thu, 30 May 2013 06:09:42 -0700 (PDT) In-Reply-To: X-Google-Sender-Auth: CaMlNpsQJIGYpILfPrhWbESy1FY X-Gm-Message-State: ALoCoQkSmTrfg+aZFlSWxkkBKSZ0MsNUys8qqEGLdmXD4qEOc+CmWm07NKPBWNWdkHbvPntxj3CT Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: It looks like it's a file caching effect combined with my repo being more pathalogical in size and contents. Note run 1 (cold) vs run 2 on the linux file tree: 13:52 ajb@sloy/x86_64 [linux.git] >time git describe --debug --long --tags HEAD~10000 searching to describe HEAD~10000 annotated 57 v2.6.34-rc2 annotated 1688 v2.6.34-rc1 annotated 7932 v2.6.33 annotated 8157 v2.6.33-rc8 annotated 8381 v2.6.33-rc7 annotated 8637 v2.6.33-rc6 annotated 8964 v2.6.33-rc5 annotated 9493 v2.6.33-rc4 annotated 9912 v2.6.33-rc3 annotated 10202 v2.6.33-rc2 traversed 10547 commits more than 10 tags found; listed 10 most recent gave up search at 55639353a0035052d9ea6cfe4dde0ac7fcbb2c9f v2.6.34-rc2-57-gef5da59 real 0m7.332s user 0m0.308s sys 0m0.244s 14:03 ajb@sloy/x86_64 [linux.git] >time git describe --debug --long --tags HEAD~10000 searching to describe HEAD~10000 annotated 57 v2.6.34-rc2 annotated 1688 v2.6.34-rc1 annotated 7932 v2.6.33 annotated 8157 v2.6.33-rc8 annotated 8381 v2.6.33-rc7 annotated 8637 v2.6.33-rc6 annotated 8964 v2.6.33-rc5 annotated 9493 v2.6.33-rc4 annotated 9912 v2.6.33-rc3 annotated 10202 v2.6.33-rc2 traversed 10547 commits more than 10 tags found; listed 10 most recent gave up search at 55639353a0035052d9ea6cfe4dde0ac7fcbb2c9f v2.6.34-rc2-57-gef5da59 real 0m0.298s user 0m0.244s sys 0m0.036s Although the perf profile looks subtly different. =46irst through the linux tree: 22.35% git libz.so.1.2.3.4 [.] inflate 18.56% git libz.so.1.2.3.4 [.] inflate_fast 17.48% git libz.so.1.2.3.4 [.] inflate_table 7.84% git git [.] hashcmp 3.93% git git [.] get_sha1_hex 3.46% git libz.so.1.2.3.4 [.] adler32 And through my "special" repo: 41.58% git libcrypto.so.1.0.0 [.] sha1_block_data_order_ssse3 33.62% git libz.so.1.2.3.4 [.] inflate_fast 10.39% git libz.so.1.2.3.4 [.] adler32 2.03% git [kernel.kallsyms] [k] clear_page_c I'm not sure why libcrypto features so highly in the results -- Alex. On 30 May 2013 12:33, Ramkumar Ramachandra wrote: > Alex Benn=C3=A9e wrote: >>>time /usr/bin/git --no-pager >> traversed 223 commits >> >> real 0m4.817s >> user 0m4.320s >> sys 0m0.464s > > I'm quite clueless about why it is taking this long: I think it's IO > because there's nothing to compute? I really can't trace anything > unless you can reproduce it on a public repository. On linux.git wit= h > my rotating hard disk: > > $ time git describe --debug --long --tags HEAD~10000 > searching to describe HEAD~10000 > annotated 5445 v2.6.33 > annotated 5660 v2.6.33-rc8 > annotated 5884 v2.6.33-rc7 > annotated 6140 v2.6.33-rc6 > annotated 6467 v2.6.33-rc5 > annotated 6999 v2.6.33-rc4 > annotated 7430 v2.6.33-rc3 > annotated 7746 v2.6.33-rc2 > annotated 8212 v2.6.33-rc1 > annotated 13854 v2.6.32 > traversed 18895 commits > more than 10 tags found; listed 10 most recent > gave up search at 648f4e3e50c4793d9dbf9a09afa193631f76fa26 > v2.6.33-5445-ge7c84ee > > real 0m0.509s > user 0m0.470s > sys 0m0.037s > > 18k+ commits traversed in half a second here, so I really don't know > what is going on. --=20 Alex, homepage: http://www.bennee.com/~alex/