From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Beller Subject: Re: [PATCH] lookup_object: split up displacement penalty for hash collisions Date: Fri, 16 Aug 2013 11:41:07 +0200 Message-ID: <520DF3B3.3050900@googlemail.com> References: <1376595306-6335-1-git-send-email-stefanbeller@googlemail.com> <87haeqdop3.fsf@linux-k42r.v.cablecom.net> <8761v6dm0r.fsf@linux-k42r.v.cablecom.net> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig6158060FDC53289F9DE48818" Cc: git@vger.kernel.org, peff@peff.net To: Thomas Rast X-From: git-owner@vger.kernel.org Fri Aug 16 11:41:33 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 1VAGXF-0006Sv-8h for gcvg-git-2@plane.gmane.org; Fri, 16 Aug 2013 11:41:33 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755111Ab3HPJlY (ORCPT ); Fri, 16 Aug 2013 05:41:24 -0400 Received: from mail-ea0-f169.google.com ([209.85.215.169]:65039 "EHLO mail-ea0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755100Ab3HPJlT (ORCPT ); Fri, 16 Aug 2013 05:41:19 -0400 Received: by mail-ea0-f169.google.com with SMTP id z7so900159eaf.28 for ; Fri, 16 Aug 2013 02:41:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type; bh=Xj7xmMLGw38jyhRTbBTMTzcGKQEGmH+qtqTLB5hvo8s=; b=HcTpwRO7QARYUa/4DD6CqUi6ifyAzE8UVVrlCFqqfabF5lAnwgU7ksfMBRNQAR0lFR l5VO2lAbeTk1SFzniW/SO6+SuFM/Zg8tWLcUxfocLwPpJAEIIySPsact10LnX5gh30Pn qr5mErh5HRDl1QNUcLszobl/OVBBirEm8p8d7Bfkle/UKb2gQA1/JJFcQlImHJb8HM5v 1mCzUTBsjdA0Lee5Zx/L9KOa5jMjs1AGH1mY4p0A8o4vY7KywPBlXQMdm0ih4Jdv5la3 c0KgpxlFo2GS6A/JcTedhBUUhwrm69nM8SXFvrY68xT4hDXUTkhuIrQrRpE5rQ986EZF keuA== X-Received: by 10.15.24.129 with SMTP id j1mr1077921eeu.17.1376646078002; Fri, 16 Aug 2013 02:41:18 -0700 (PDT) Received: from [192.168.1.3] (ip-109-91-109-128.unitymediagroup.de. [109.91.109.128]) by mx.google.com with ESMTPSA id k3sm1317128een.16.1969.12.31.16.00.00 (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Fri, 16 Aug 2013 02:41:17 -0700 (PDT) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130803 Thunderbird/17.0.8 In-Reply-To: <8761v6dm0r.fsf@linux-k42r.v.cablecom.net> X-Enigmail-Version: 1.4.6 Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig6158060FDC53289F9DE48818 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 08/16/2013 11:26 AM, Thomas Rast wrote: > Thomas Rast writes: >=20 >> Stefan Beller writes: >> >>> However please do check if this patch brings the promised performance= >>> on your own, as you're likely using different hardware and another >>> software setup. Feel free to share your performance differences. >> >> I get this on an i7-M620 laptop from t/perf/p0001-rev-list.sh: >> >> Test HEAD next = =20 >> --------------------------------------------------------------------= ----------- >> 0001.1: rev-list --all 6.29(6.03+0.22) 6.33(6.06+0.2= 4) +0.6% =20 >> 0001.2: rev-list --all --objects 53.22(52.48+0.54) 54.90(54.15+0= =2E55) +3.2%* >> --------------------------------------------------------------------= ----------- >> Significance hints: '.' 0.1 '*' 0.05 '**' 0.01 '***' 0.001 > [...] >> I trust the laptop numbers less because it has far more thermal (and >> thus throttling) issues, but the runs do show a significant difference= , >> though less than you claimed. >=20 > Well, as I feared... another run on the same laptop: >=20 > Test HEAD next = =20 > -----------------------------------------------------------------------= ------- > 0001.1: rev-list --all 6.41(6.14+0.24) 6.36(6.10+0.23) = -0.9%*=20 > 0001.2: rev-list --all --objects 54.60(53.84+0.55) 54.23(53.50+0.53= ) -0.7% > -----------------------------------------------------------------------= ------- > Significance hints: '.' 0.1 '*' 0.05 '**' 0.01 '***' 0.001 >=20 I did some more tests as well, and I seem to have just been lucky with the results initially posted. Now I got a negative impact as well on one test, so that patch is not worth for includsion. Thanks, Stefan --------------enig6158060FDC53289F9DE48818 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) Comment: Using GnuPG with undefined - http://www.enigmail.net/ iQIcBAEBAgAGBQJSDfO7AAoJEJQCPTzLflhqehcP/A8S21uWxgbWhzAI0R8E5t3k FZKVCi7vA0STjWCSaQC+h1WbhvTAWunzUNzl8cxO/GyI//siPPbGe4hpPS0NI0Q9 q+CSOvTgTgRA/I4fWkhQpvA2mviZms+GfPbVDh1uxjb1zJ8UgSmUuyl3uGUdbKiU 8BR8vQ1Vqfm3xv0DELNmU4jZzWJajnzLzRNNqa2iIjbhaJYvHwYn8y8OwW+p/Bbb az4wiBzMsDjfGcmg2gLc00i3o394g5VRDjyrdnfaCd+3iIzdzRK2zbL5YTnv5xvL wYoJWMuw3VEECQfYv0UUXIjYJX/awJlaW612aKE3imdPjRBz7YlMhItp/ziIdu4a qtf5FfCkh4a7xXvxLkiTGGiLXKA2J1hcUIQLYGA2Le60xuqyT+Y/CeHlSGbIj1rq rrzPqFkhl5/upkBICJGkrOCOko/lrbroMGfu/bdrbUXL2zUxtlhF6C2EYgpamYC3 8cgMOvs84brnFN8EOf0+V0F5KZnJrQLPw2CjUOnqu6cIKJbgaIMwu/PX5Vr2PfxO rvEP1bL3WjlTP/iZ5stBCp56KH2jff6q+4+LwY43bWRUJfX9W4jliDyJnccmOWsr hKjJ0w2TZc3WeJRl+2yS3mU6cPPRt/JSWPdQo3u9e/DJD8D5zo5W8ppU8ReJWNLn pXtLNYrTaRQFpp0E36xm =G4S+ -----END PGP SIGNATURE----- --------------enig6158060FDC53289F9DE48818--