From owner-freebsd-current@freebsd.org Sat Jun 3 20:59:11 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 C6068BF902F for ; Sat, 3 Jun 2017 20:59:11 +0000 (UTC) (envelope-from 0100015c6fc1167c-6e139920-60d9-4ce3-9f59-15520276aebb-000000@amazonses.com) Received: from a8-176.smtp-out.amazonses.com (a8-176.smtp-out.amazonses.com [54.240.8.176]) (using TLSv1 with cipher ECDHE-RSA-AES128-SHA (128/128 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 8DB257DDE8 for ; Sat, 3 Jun 2017 20:59:11 +0000 (UTC) (envelope-from 0100015c6fc1167c-6e139920-60d9-4ce3-9f59-15520276aebb-000000@amazonses.com) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/simple; s=ae7m2yrxjw65l2cqdpjxuucyrvy564tn; d=tarsnap.com; t=1496523544; h=To:From:Subject:Message-ID:Date:MIME-Version:Content-Type:Content-Transfer-Encoding; bh=57PAa8IQpoQIqei4+hrxx4ZD2VYRrrP4k7fYVbKUd2c=; b=MaPbaTOq95kuFdCZZCCG5L7DynIHcOKaHduHg2dXHuraS73wghRv1LBdIJcQXml3 DP17zNckmqzDdlWJ5YYfGshRjo1wk9d35Iuw3WPD+Kh/a8GH3pqrXATUHgZyBTujw+Y as3BNlENifza8Rlsv9fnnt5Ac7tyqJnv3LJ/1zEk= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/simple; s=224i4yxa5dv7c2xz3womw6peuasteono; d=amazonses.com; t=1496523544; h=To:From:Subject:Message-ID:Date:MIME-Version:Content-Type:Content-Transfer-Encoding:Feedback-ID; bh=57PAa8IQpoQIqei4+hrxx4ZD2VYRrrP4k7fYVbKUd2c=; b=QHB307M/WEDBZ/2E9GotrsBBt+fbiRDnJsVsqEJscVsS+Rmw2TNtLIrMUwTI3wDV 9oMe3/gmJVeeGBG4QhSCjXqv84+JzOxfOrKrP1JNXKSTFX8ZxtuVjAOSOcFwG+azvdR zviXejiD8tboW8ZUfZ6W8SJDEsntk3K/40TItzj4= To: "freebsd-current@freebsd.org" From: Colin Percival Subject: Time to increase MAXPHYS? Message-ID: <0100015c6fc1167c-6e139920-60d9-4ce3-9f59-15520276aebb-000000@email.amazonses.com> Date: Sat, 3 Jun 2017 20:59:04 +0000 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-SES-Outgoing: 2017.06.03-54.240.8.176 Feedback-ID: 1.us-east-1.Lv9FVjaNvvR5llaqfLoOVbo2VxOELl7cjN0AOyXnPlk=:AmazonSES X-Mailman-Approved-At: Sun, 04 Jun 2017 00:29:32 +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: Sat, 03 Jun 2017 20:59:11 -0000 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). -- Colin Percival Security Officer Emeritus, FreeBSD | The power to serve Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid