From owner-freebsd-arm@freebsd.org Sun Mar 4 19:51:49 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 E0FD0F2D508 for ; Sun, 4 Mar 2018 19:51:49 +0000 (UTC) (envelope-from marklmi26-fbsd@yahoo.com) Received: from sonic315-14.consmr.mail.bf2.yahoo.com (sonic315-14.consmr.mail.bf2.yahoo.com [74.6.134.124]) (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 8EEE76CDC0 for ; Sun, 4 Mar 2018 19:51:49 +0000 (UTC) (envelope-from marklmi26-fbsd@yahoo.com) X-YMail-OSG: HMtfn1gVM1m7LxnKKmAfZk4jClMebx4T7soa4kUzvGzfFwwmp5opx8A6wWuQez3 gy4aRbyGqIzbFxr9iY5sK2kcij2vYYwEIC0lVD4toMwV4ENV9OwqhKNoHPSX12160RH3g6c8g5e1 iuNSQII7oNBNhUiwkUmUpCeD6l6U5OAUFVY0kDz0taoQeUg41g9pZJjttYCmYvpxHtagSE5h79dQ yll8n0kjCR8ILTL8uOyPNTqsac1DyqEQJsFw7vnALl1_KrN_K_.Jzy6zVN8G4XF.iY2U_vh29Z2P 2GQodRKdto_aOs4XKhVqMpuY2JCP063mCqUUFuFtL2Agif.ubsXSbdfH1gqWwRa15ttYaIA.J9M5 nsf0er2q3cw0IL4.oOUlb1AZxKmtWS313Q4SB7a_.omvTY4x7grrRqC3nPnJrD.pcJddEZapDmyc X6r4Qd89Q2NWBbrxpUWu98_o7ifJvRKT38my1fQJi6v9ODz3d6RF6tsR8cb__VvV7iVLI Received: from sonic.gate.mail.ne1.yahoo.com by sonic315.consmr.mail.bf2.yahoo.com with HTTP; Sun, 4 Mar 2018 19:51:43 +0000 Received: from smtpgate101.mail.bf1.yahoo.com (EHLO [192.168.1.25]) ([72.30.28.45]) by smtp414.mail.bf1.yahoo.com (JAMES SMTP Server ) with ESMTPA ID 2b50a3b4302e038f5dd8031ef3222bb2 for ; Sun, 04 Mar 2018 19:51:40 +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? Message-Id: <1EB91943-C141-4EA6-AD63-A629525E206E@yahoo.com> Date: Sun, 4 Mar 2018 11:51:39 -0800 To: Freebsd-arm 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 19:51:50 -0000 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.) 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)