From owner-freebsd-arm@freebsd.org Sat Sep 15 07:11:56 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 316AB109EAE7 for ; Sat, 15 Sep 2018 07:11:56 +0000 (UTC) (envelope-from marklmi@yahoo.com) Received: from sonic305-20.consmr.mail.ne1.yahoo.com (sonic305-20.consmr.mail.ne1.yahoo.com [66.163.185.146]) (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 B934882462 for ; Sat, 15 Sep 2018 07:11:55 +0000 (UTC) (envelope-from marklmi@yahoo.com) X-YMail-OSG: el9r4LgVM1kWQ_MPq6bxXKSfYmViTlJJvEm_qapiL4mEM8kydPRQiF_ZVsaO3Re LMdthfGa228BY7fRKeXSmjEUF0aWQWDcT2OzmGyIYSgqguzgAAAQUf4Gpfy0mDdMXmzOmcxoTHvw egRWy4v4BgVo2znVZi1zgnxbJkXgJrbVUNZk_kg7kRtAX3v87v1YAFTwZhTZbTPCz1ZyEhwi388j Hy1x4g8qP5nALC1hc6q7ApzNlt5j1VxMT9GLcGzh3Uf9gNlU8moI5DEkw.AmKz368uavoUKe3gFG 1o_mNOHUzM1g7r71obhoP2.CFgbgdpcJW98owmVC6cx9bzddLKnzHXrTyjX92ZXPox1R2Q2Cl0se lmVVlOUvOyF0mr4EAtrDaRn2FYz5a52hdx5tpDy51G2lX.uhQS67MOTr0KwsU2bu02QEjQKpgrJl GSK2uA59xybKK5sp.pmnTpjO3YRmlOHgbPDt7my_lirU47xqUd9zS2Ft5ost3_ZK7ab2PUEHFMNi Q1SY422vkwhzmIxAEmCDr8ynOphkINyXam_nziIBVGr4YIgNhC8P03Jkh3E64zH3t2n30MZr6uYa oQUVQs_yf.9swoW1vd.MucFIUBGu8mnA.BpCna.8QkJW1CVpkaM1quk9Je.6_xo990rtFafj0ytz 2FMyZTk_OvOb4OYZblaMLs895Y973VuxKALM4OVXX06dYAz87tWJdZQgyEd4xDeYsVtCyEvFeI5r 5h3WuaAUgMQPlHoXW.7evi7q2RW8vsy3M86f_QRtyuVaNU9jX.iOHU5E35fJn2Z8dl_k9Uf2SMns JOrCJzpdGSiUaEAtnGJ.EKQyl51UkyJDwuFPbFuty31xcvMchpFfz1Jg1sJHAVMPoeNxxNITSkF2 9VRMEB.4g3XPI4obWxtsNHXMhvEGAUDX0_MJuGLpqVMoWDwlRdGY0hDeSu_Vv2nkSLbSTN7TY3eZ zzdEf4UWbcdL7oVGYnN2DkCsK1kaiBnK2DVtXw.NvKbxnIXJFQxYfoMwBeDjP3i8JNZzz1UMEaR2 3Y_W_bd.5IUD5 Received: from sonic.gate.mail.ne1.yahoo.com by sonic305.consmr.mail.ne1.yahoo.com with HTTP; Sat, 15 Sep 2018 07:11:54 +0000 Received: from ip70-189-131-151.lv.lv.cox.net (EHLO [192.168.0.105]) ([70.189.131.151]) by smtp401.mail.ne1.yahoo.com (Oath Hermes SMTP Server) with ESMTPA ID 607b1e7c1fa3793bcacf7adff1a3cf55; Sat, 15 Sep 2018 07:11:50 +0000 (UTC) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 11.5 \(3445.9.1\)) Subject: Re: RPI3 swap experiments (r338342 with vm.pageout_oom_seq="1024" and 6 GB swap) From: Mark Millard In-Reply-To: <8fd79c5e-4998-274a-6457-ac2a6bf939bb@sentry.org> Date: Sat, 15 Sep 2018 00:11:48 -0700 Cc: freebsd-arm@freebsd.org Content-Transfer-Encoding: quoted-printable Message-Id: References: <20180815013612.GB51051@www.zefox.net> <20180815225504.GB59074@www.zefox.net> <20180901230233.GA42895@www.zefox.net> <20180906003829.GC818@www.zefox.net> <20180906051520.GB3482@www.zefox.net> <059D2FED-6E7C-4FEF-8807-8D4A0D0B3E26@yahoo.com> <20180906155858.GA5980@www.zefox.net> <075BD4BB-CAFB-4C9B-809A-10901522D1ED@yahoo.com> <20180915050842.GA65045@www.zefox.net> <8fd79c5e-4998-274a-6457-ac2a6bf939bb@sentry.org> To: Trev X-Mailer: Apple Mail (2.3445.9.1) X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.27 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 15 Sep 2018 07:11:56 -0000 On 2018-Sep-14, at 11:18 PM, Trev wrote: > bob prohaska wrote on 15/09/2018 15:08: >> There were many spurious "indefinite wait" and [...] warnings on the = console, [Bob did not say if he had Mark Johnston's reporting patches in place or not.] > Those warnings are not actually spurious, rather indicative of = significant i/o delays: >=20 > https://www.freebsd.org/doc/en/books/faq/troubleshoot.html#idp59131080 >=20 > What does the error swap_pager: indefinite wait buffer: mean? >=20 > This means that a process is trying to page memory to disk, and the = page attempt has hung trying to access the disk for more than 20 = seconds. It might be caused by bad blocks on the disk drive, disk = wiring, cables, or any other disk I/O-related hardware. If the drive = itself is bad, disk errors will appear in /var/log/messages and in the = output of dmesg. Otherwise, check the cables and connections. =46rom what I can see from: http://www.zefox.net/~fbsd/rpi3/swaptests/r338572/1.8gbsd/swapscript.log no I/O errors were reported. ("swap_pager: indefinite wait buffer:" messages do show.) microsd card slots do not have cables or cable-connections involved generally: what would be analogous would be far harder to do anything about. =46rom what I've seen the I/O for the paging (mixed with the other I/O activity) can potentially queue enough data to be paged out that, under normal operation, the microsd card would take more than 20 seconds to write it all out. Say, 10 MiBytes/sec * 20 sec =3D 200 MiByte, to give ball park figures that likely are on the large side as I understand. (Paging is not sequential and reads/writes are mixed.) So if the time waiting in the queue of pending I/O is counted in that 20 seconds for the data in question, that alone might lead to message for the data that is far from the front of the queue when it is first added, no errors involved. But, that is an "if": I do not know just what starts the 20 second measurement. It looks like the distinct swap_pager messages for the ultra plus only example were: $ grep swap_pager: ~/Downloads/swapscript_rpi3_ultra_plus.log | sort | = uniq Sep 11 07:12:52 www kernel: swap_pager: indefinite wait buffer: bufobj: = 0, blkno: 88445, size: 4096 Sep 11 07:13:01 www kernel: swap_pager: indefinite wait buffer: bufobj: = 0, blkno: 464452, size: 12288 Sep 11 07:13:56 www kernel: swap_pager: indefinite wait buffer: bufobj: = 0, blkno: 11922, size: 4096 Sep 11 11:34:08 www kernel: swap_pager: indefinite wait buffer: bufobj: = 0, blkno: 295286, size: 8192 Sep 11 11:34:08 www kernel: swap_pager: indefinite wait buffer: bufobj: = 0, blkno: 371269, size: 4096 Sep 11 12:48:23 www kernel: swap_pager: indefinite wait buffer: bufobj: = 0, blkno: 408974, size: 4096 Sep 11 13:09:07 www kernel: swap_pager: indefinite wait buffer: bufobj: = 0, blkno: 293166, size: 8192 Sep 11 13:10:19 www kernel: swap_pager: indefinite wait buffer: bufobj: = 0, blkno: 226334, size: 8192 =3D=3D=3D Mark Millard marklmi at yahoo.com ( dsl-only.net went away in early 2018-Mar)