From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Rast Subject: Re: [PATCH] Hold an 'unsigned long' chunk of the sha1 in obj_hash Date: Thu, 2 May 2013 10:52:04 +0200 Message-ID: <87vc71u5l7.fsf@linux-k42r.v.cablecom.net> References: <6c2b67a2f0b67ee796c7676e3febe4c61ab85d4a.1366912627.git.trast@inf.ethz.ch> <20130501204947.GA12789@sigill.intra.peff.net> Mime-Version: 1.0 Content-Type: text/plain Cc: , =?utf-8?B?Tmd1eeG7hW4gVGjDoWkgTmfhu41j?= Duy , Junio C Hamano To: Jeff King X-From: git-owner@vger.kernel.org Thu May 02 10:52:14 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 1UXpFO-0005OF-EG for gcvg-git-2@plane.gmane.org; Thu, 02 May 2013 10:52:14 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751443Ab3EBIwJ (ORCPT ); Thu, 2 May 2013 04:52:09 -0400 Received: from edge20.ethz.ch ([82.130.99.26]:53515 "EHLO edge20.ethz.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750822Ab3EBIwI (ORCPT ); Thu, 2 May 2013 04:52:08 -0400 Received: from CAS22.d.ethz.ch (172.31.51.112) by edge20.ethz.ch (82.130.99.26) with Microsoft SMTP Server (TLS) id 14.2.298.4; Thu, 2 May 2013 10:51:58 +0200 Received: from linux-k42r.v.cablecom.net.ethz.ch (129.132.153.233) by CAS22.d.ethz.ch (172.31.51.112) with Microsoft SMTP Server (TLS) id 14.2.298.4; Thu, 2 May 2013 10:52:03 +0200 In-Reply-To: <20130501204947.GA12789@sigill.intra.peff.net> (Jeff King's message of "Wed, 1 May 2013 16:49:47 -0400") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.2 (gnu/linux) X-Originating-IP: [129.132.153.233] Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: Jeff King writes: > It _might_ still be advantageous to do your patch on top, but I suspect > it will diminish the returns from your patch (since the point of it is > to probe less far down the chain on average). No, mine makes it slower again. Apparently the increased size is no longer worth it. You'll need a wide window to read this: Test next tr/hash-speedup jk/hash-speedup both-hash-speedup ---------------------------------------------------------------------------------------------------------------------------------------- 0001.1: rev-list --all 0.66(0.63+0.02) 0.66(0.63+0.03) -0.4% 0.66(0.63+0.03) -0.6% 0.66(0.62+0.03) -0.6% 0001.2: rev-list --all --objects 4.12(4.05+0.05) 3.81(3.74+0.06) -7.6%*** 3.50(3.43+0.05) -15.1%*** 3.56(3.49+0.05) -13.7%*** ---------------------------------------------------------------------------------------------------------------------------------------- Note that the scripts always generate the percentages and significance w.r.t. the first column. Comparing yours with both instead gives Test jk/hash-speedup both-hash-speedup --------------------------------------------------------------------------- 0001.1: rev-list --all 0.66(0.63+0.03) 0.66(0.62+0.03) +0.0% 0001.2: rev-list --all --objects 3.50(3.43+0.05) 3.56(3.49+0.05) +1.6%* --------------------------------------------------------------------------- which is still significant (in the statistical p=5% sense). For kicks I also ran some other tests, which generally show that the speedups are limited to this specific workload: Test next tr/hash-speedup jk/hash-speedup both-hash-speedup ------------------------------------------------------------------------------------------------------------------------------- 3201.1: branch --contains 0.76(0.74+0.02) 0.75(0.73+0.02) -1.0%* 0.77(0.74+0.02) +0.7% 0.76(0.73+0.02) -0.7% 4000.1: log -3000 (baseline) 0.12(0.09+0.02) 0.12(0.10+0.02) +3.2% 0.12(0.10+0.01) +0.0% 0.12(0.10+0.02) +3.2% 4000.2: log --raw -3000 (tree-only) 0.53(0.47+0.05) 0.52(0.46+0.05) -0.9% 0.53(0.46+0.06) +0.0% 0.52(0.45+0.06) -0.9% 4000.3: log -p -3000 (Myers) 2.39(2.23+0.14) 2.38(2.23+0.13) -0.4% 2.38(2.23+0.14) -0.4% 2.38(2.23+0.13) -0.5% 4000.4: log -p -3000 --histogram 2.43(2.28+0.13) 2.43(2.28+0.13) -0.0% 2.43(2.28+0.13) -0.1% 2.43(2.28+0.14) +0.1% 4000.5: log -p -3000 --patience 2.72(2.57+0.12) 2.74(2.59+0.12) +0.7% 2.72(2.57+0.13) +0.2% 2.74(2.59+0.13) +0.8%. ------------------------------------------------------------------------------------------------------------------------------- -- Thomas Rast trast@{inf,student}.ethz.ch