From owner-freebsd-arm@freebsd.org Sun Mar 4 19:55:14 2018 Return-Path: Delivered-To: freebsd-arm@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 2F145F2D8C4 for ; Sun, 4 Mar 2018 19:55:14 +0000 (UTC) (envelope-from marklmi26-fbsd@yahoo.com) Received: from sonic311-14.consmr.mail.bf2.yahoo.com (sonic311-14.consmr.mail.bf2.yahoo.com [74.6.131.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id BBEEE6CF85 for ; Sun, 4 Mar 2018 19:55:13 +0000 (UTC) (envelope-from marklmi26-fbsd@yahoo.com) X-YMail-OSG: 98TUnA0VM1lhVDp02cZGYBQ6TAzHRg8KXGENjl8vBqnJQBGGGi.xmke026xRKUC CkfnKp.1amx_MqqdBjKWAgjh.4r0UTMMgRpWOQe6Y1MTKaAtcgrUaH6qXYUX9ggZWBj9v0qvouh. eeqRbsLFQ96_retrfeTWfx_I1y8KGv8TtSq3i3WcQNExPHa1e04IIJoLG_FF9.bGo8FazZmhGXJQ NBEXmlbuwAns736O8HwvCOKQ8WUH7ay2izDRJIKfiwXNxkflEwIh1stJ0l58bjJcos2sUOdFvMRp .teNxXXUzx6fdOxLwGJANYUXG8MbX_EtiUxodluKuvNG3Q5jshMR7fEllyolba4ANSu1yDccEMfF XWkEf85IJJDypR1bijqBrmNIBvChwMcPRpGOGRuWsRZDNx3LPnRJMQ3Ffjz5ere7PDdCYvdC7Xmd N.3sCm.G_B3BBJ53yR2DqGhAUwLsGsLuOFC0WpM_tSTgUcr6_49i6YAlbiWcLNRIUgSLZ Received: from sonic.gate.mail.ne1.yahoo.com by sonic311.consmr.mail.bf2.yahoo.com with HTTP; Sun, 4 Mar 2018 19:55:07 +0000 Received: from smtp104.rhel.mail.bf1.yahoo.com (EHLO [192.168.1.25]) ([98.139.230.215]) by smtp404.mail.bf1.yahoo.com (JAMES SMTP Server ) with ESMTPA ID 1245dd2daae98c5d26e08a06f08c696d; Sun, 04 Mar 2018 19:55:07 +0000 (UTC) From: Mark Millard Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (Mac OS X Mail 11.2 \(3445.5.20\)) Subject: Re: Is maximum swap usage tunable? Date: Sun, 4 Mar 2018 11:55:05 -0800 References: <1EB91943-C141-4EA6-AD63-A629525E206E@yahoo.com> To: bob prohaska , Freebsd-arm In-Reply-To: <1EB91943-C141-4EA6-AD63-A629525E206E@yahoo.com> Message-Id: X-Mailer: Apple Mail (2.3445.5.20) X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 04 Mar 2018 19:55:14 -0000 On 2018-Mar-4, at 11:51 AM, Mark Millard wrote: > bob prohaska fbsd at www.zefox.net write on > Sun Mar 4 18:28:36 UTC 2018: > >> The worst-case events were >> dT: 10.002s w: 10.000s >> L(q) ops/s r/s kBps ms/r w/s kBps ms/w %busy Name >> . . . >> 0 1 0 13 5.6 1 28 5674 88.3 da0b >> . . . > > I'll note that (1000s/ms)*(ms/w) != 1/(w/s) here > (and frequently). (ms/r and r/s are similarly related.) I was interrupted and screwed up the calculation text without noticing: (s/(1000ms))*(ms/w) != 1/(w/s) > It appears that ms/w counts time with the write > waiting in a queue to be executed or some such but > w/s is strictly the observed rate of writes happening, > independent of how long each waited. (The columns need > not refer to the exact same time frame either as far > as I can tell.) > > [Someone may know the actual details of what ms/w > and ms/r spans. The above includes guess work.] > > Also: 5674 ms/w is over 5 seconds "per write" (probably > a "mean" form of average, but possibly only one write > covered). I doubt that we can be sure of much about the > stages involved in that large figure if "time waiting > in the queue" and later stages of the processing all > contribute. === Mark Millard marklmi at yahoo.com ( markmi at dsl-only.net is going away in 2018-Feb, late) === Mark Millard marklmi at yahoo.com ( markmi at dsl-only.net is going away in 2018-Feb, late)