From owner-svn-src-all@FreeBSD.ORG Wed May 27 13:53:16 2015 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 19E6620C; Wed, 27 May 2015 13:53:16 +0000 (UTC) (envelope-from lidl@pix.net) Received: from hydra.pix.net (hydra.pix.net [IPv6:2001:470:e254::4]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mail.pix.net", Issuer "Pix.Com Technologies, LLC CA" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id B57B0A69; Wed, 27 May 2015 13:53:15 +0000 (UTC) (envelope-from lidl@pix.net) Received: from torb.pix.net (verizon.pix.net [71.178.232.3]) (authenticated bits=0) by hydra.pix.net (8.15.1/8.15.1) with ESMTPA id t4RDrDa2097549; Wed, 27 May 2015 09:53:13 -0400 (EDT) (envelope-from lidl@pix.net) X-Authentication-Warning: hydra.pix.net: Host verizon.pix.net [71.178.232.3] claimed to be torb.pix.net Message-ID: <5565CC49.1020800@pix.net> Date: Wed, 27 May 2015 09:53:13 -0400 From: Kurt Lidl User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Bruce Evans , Eitan Adler CC: 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 References: <201504050518.t355IFVJ001786@svn.freebsd.org> <20150405163305.A2515@besplex.bde.org> <20150406152653.K1066@besplex.bde.org> In-Reply-To: <20150406152653.K1066@besplex.bde.org> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 27 May 2015 13:53:16 -0000 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 -Kurt