From owner-freebsd-current@freebsd.org Sun Jun 4 02:35:37 2017 Return-Path: Delivered-To: freebsd-current@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 0C7FEAF89C7 for ; Sun, 4 Jun 2017 02:35:37 +0000 (UTC) (envelope-from julian@elischer.org) Received: from vps1.elischer.org (vps1.elischer.org [204.109.63.16]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "vps1.elischer.org", Issuer "CA Cert Signing Authority" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id D091513E3 for ; Sun, 4 Jun 2017 02:35:36 +0000 (UTC) (envelope-from julian@elischer.org) Received: from Julian-MBP3.local (106-68-195-68.dyn.iinet.net.au [106.68.195.68]) (authenticated bits=0) by vps1.elischer.org (8.15.2/8.15.2) with ESMTPSA id v542ZUsF062285 (version=TLSv1.2 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Sat, 3 Jun 2017 19:35:33 -0700 (PDT) (envelope-from julian@elischer.org) Subject: Re: Time to increase MAXPHYS? To: Colin Percival , "freebsd-current@freebsd.org" References: <0100015c6fc1167c-6e139920-60d9-4ce3-9f59-15520276aebb-000000@email.amazonses.com> From: Julian Elischer Message-ID: <972dbd34-b5b3-c363-721e-c6e48806e2cd@elischer.org> Date: Sun, 4 Jun 2017 10:35:24 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.1.1 MIME-Version: 1.0 In-Reply-To: <0100015c6fc1167c-6e139920-60d9-4ce3-9f59-15520276aebb-000000@email.amazonses.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-Mailman-Approved-At: Sun, 04 Jun 2017 03:50:38 +0000 X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 04 Jun 2017 02:35:37 -0000 On 4/6/17 4:59 am, Colin Percival wrote: > On January 24, 1998, in what was later renumbered to SVN r32724, dyson@ > wrote: >> Add better support for larger I/O clusters, including larger physical >> I/O. The support is not mature yet, and some of the underlying implementation >> needs help. However, support does exist for IDE devices now. > and increased MAXPHYS from 64 kB to 128 kB. Is it time to increase it again, > or do we need to wait at least two decades between changes? > > This is hurting performance on some systems; in particular, EC2 "io1" disks > are optimized for 256 kB I/Os, EC2 "st1" (throughput optimized spinning rust) > disks are optimized for 1 MB I/Os, and Amazon's NFS service (EFS) recommends > using a maximum I/O size of 1 MB (and despite NFS not being *physical* I/O it > seems to still be limited by MAXPHYS). > We increase it in freebsd 8 and 10.3 on our systems, Only good results. sys/sys/param.h:#define MAXPHYS (1024 * 1024) /* max raw I/O transfer size */