From owner-svn-src-head@FreeBSD.ORG Wed May 27 21:06:23 2015 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 5560FE0F; Wed, 27 May 2015 21:06:23 +0000 (UTC) (envelope-from jmg@gold.funkthat.com) Received: from gold.funkthat.com (gate2.funkthat.com [208.87.223.18]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "gold.funkthat.com", Issuer "gold.funkthat.com" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 085A17AC; Wed, 27 May 2015 21:06:22 +0000 (UTC) (envelope-from jmg@gold.funkthat.com) Received: from gold.funkthat.com (localhost [127.0.0.1]) by gold.funkthat.com (8.14.5/8.14.5) with ESMTP id t4RL6K9d072201 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 27 May 2015 14:06:20 -0700 (PDT) (envelope-from jmg@gold.funkthat.com) Received: (from jmg@localhost) by gold.funkthat.com (8.14.5/8.14.5/Submit) id t4RL6Klq072200; Wed, 27 May 2015 14:06:20 -0700 (PDT) (envelope-from jmg) Date: Wed, 27 May 2015 14:06:20 -0700 From: John-Mark Gurney To: Kurt Lidl Cc: Bruce Evans , Eitan Adler , Adrian Chadd , "src-committers@freebsd.org" , "svn-src-all@freebsd.org" , "svn-src-head@freebsd.org" Subject: Re: svn commit: r281103 - head/sys/amd64/amd64 Message-ID: <20150527210619.GA50817@funkthat.com> References: <201504050518.t355IFVJ001786@svn.freebsd.org> <20150405163305.A2515@besplex.bde.org> <20150406152653.K1066@besplex.bde.org> <5565CC49.1020800@pix.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5565CC49.1020800@pix.net> X-Operating-System: FreeBSD 9.1-PRERELEASE amd64 X-PGP-Fingerprint: 54BA 873B 6515 3F10 9E88 9322 9CB1 8F74 6D3F A396 X-Files: The truth is out there X-URL: http://resnet.uoregon.edu/~gurney_j/ X-Resume: http://resnet.uoregon.edu/~gurney_j/resume.html X-TipJar: bitcoin:13Qmb6AeTgQecazTWph4XasEsP7nGRbAPE X-to-the-FBI-CIA-and-NSA: HI! HOW YA DOIN? can i haz chizburger? User-Agent: Mutt/1.5.21 (2010-09-15) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.7 (gold.funkthat.com [127.0.0.1]); Wed, 27 May 2015 14:06:21 -0700 (PDT) X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 27 May 2015 21:06:23 -0000 Kurt Lidl wrote this message on Wed, May 27, 2015 at 09:53 -0400: > On 4/6/15 1:42 AM, Bruce Evans wrote: > > On Mon, 6 Apr 2015, Eitan Adler wrote: > > > >> + a few people interested in the diff > >> > >> On 5 April 2015 at 02:55, Bruce Evans wrote: > >>> On Sun, 5 Apr 2015, Eitan Adler wrote: > >> > >> I did not confirm the performance impact, but the submitter and others > >> indicated they saw a difference. > >> > >> Do you have specific data that shows that there was an improvement? > > > > Only micro-benchmark output that indicates little difference. This > > is probably very MD (depending on write combining hardware), so you > > might only see a difference on some systems. > > > > I also have micro-benchmark output for network packets/second that > > shows 10% differences for the change of adding 1 byte of padding > > in code that is never executed. This seems to be due to different > > cache misses. To eliminate differences from this (except ones > > caused by actually running different code), create a reference > > version by padding the functions or data to be changed so that > > the change doesn't affect the address of anything except the > > internals of the changed parts. > > > > I might try a makeworld run to see if changing the non-temporal > > accesses in pagecopy and pagezero to cached. > > > I ran a few (total of 12) buildworld runs after this discussion. > I finally got around to posting the results to the original bug. > > The data is here: > > https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=199151#c3 If you run ministat on the real results, there won't be a difference w/ 95% confidence... -- John-Mark Gurney Voice: +1 415 225 5579 "All that I will do, has been done, All that I have, has not."