From owner-freebsd-current@freebsd.org Sun Jun 4 05:33:04 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 0C209AFB4A8 for ; Sun, 4 Jun 2017 05:33:04 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: from mail-it0-x22f.google.com (mail-it0-x22f.google.com [IPv6:2607:f8b0:4001:c0b::22f]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id C64DF6604F for ; Sun, 4 Jun 2017 05:33:03 +0000 (UTC) (envelope-from wlosh@bsdimp.com) Received: by mail-it0-x22f.google.com with SMTP id m47so37703819iti.1 for ; Sat, 03 Jun 2017 22:33:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bsdimp-com.20150623.gappssmtp.com; s=20150623; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:to:cc; bh=lw7Sf7kStioLZapnkl+guNduk/1AW3T86bCsawK2Z9k=; b=rWNBY1OFgu8VqeYca9l4vy3x4cyfj1MDPoIels6kYPX3mr+tvxZJJ72hdswdgkhPn9 UK9T3p3wi+8iH2XhEsXTqHoQ0ORAz/j5jX2hqYhq9/6gbHk2c+i/XFTa0yXxqKxo4zvS aljx1Si3FQDbSh/HIywgtevVsmoOY64elvbe45KrdIRpawCOfeXrMHsRL9DBHCuF1tJi OItKwNuW/WlfVa7Zn8gEIq+rZEgXWaa6f8YHkpMRUPZv0pE8GIy/ydb+xcQDzuMfGKRC QUeUcfc73XhjatjCmORD0iU32wiXqUixQrpjpGzVcvDq1JQDhU4VSH/DEZsKzHx5ewhA PZ3w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:to:cc; bh=lw7Sf7kStioLZapnkl+guNduk/1AW3T86bCsawK2Z9k=; b=Z5CeJJNLF4VRbcstfkEhn+nv6UwA+aIOEX3yKOgFzemdub4mMkUdCOlj1j2w388ftq t+UMJ/etWz/7f75YfJGSN38eIbeBuKWCMeTuxgsL18hJJ7kzIpZPyygbJPy3A8lcmiC1 sJ96tIXHyD1XdyY7RkRKswmYpEObxeWV9GqAtQUBb+5pX2AO0CCQp/FIH7QfAAJPT4pR vXiZB6tfVfIMNp/JFJx5EVtSGfM4NGxaKwx+65yXpmcweUW/TB5rIbKlu9WsBK8RslZt utkKpnLb9g8QzYNXEipumRkTlo5fVQeiTziZS9PsKHOxBV9Jt8YrBz8mlljy9drmImlk iFBQ== X-Gm-Message-State: AODbwcAdPgFciGnWbb5df3S4Xteu7XWFFgSBapaTnP9Tt5Nxiu8SeWHU PYRzrtHxg+sC7u4ovem/3PpY+FsS6sC3 X-Received: by 10.36.105.13 with SMTP id e13mr6175673itc.64.1496554383197; Sat, 03 Jun 2017 22:33:03 -0700 (PDT) MIME-Version: 1.0 Sender: wlosh@bsdimp.com Received: by 10.79.192.69 with HTTP; Sat, 3 Jun 2017 22:33:02 -0700 (PDT) X-Originating-IP: [2603:300b:6:5100:f916:f485:1733:1e28] In-Reply-To: <0100015c6fc1167c-6e139920-60d9-4ce3-9f59-15520276aebb-000000@email.amazonses.com> References: <0100015c6fc1167c-6e139920-60d9-4ce3-9f59-15520276aebb-000000@email.amazonses.com> From: Warner Losh Date: Sat, 3 Jun 2017 23:33:02 -0600 X-Google-Sender-Auth: ywZBp4ty4EJC6It94DhpWFyeWDc Message-ID: Subject: Re: Time to increase MAXPHYS? To: Colin Percival Cc: "freebsd-current@freebsd.org" Content-Type: text/plain; charset="UTF-8" X-Content-Filtered-By: Mailman/MimeDel 2.1.23 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 05:33:04 -0000 On Sat, Jun 3, 2017 at 2:59 PM, 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). > MAXPHYS is the largest I/O transaction you can push through the system. It doesn't matter that the I/O is physical or not. The name is a relic from a time that NFS didn't exist. Warner