From owner-freebsd-current@freebsd.org Sun Apr 1 15:23:23 2018 Return-Path: Delivered-To: freebsd-current@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 64B6DF5470C for ; Sun, 1 Apr 2018 15:23:23 +0000 (UTC) (envelope-from se@freebsd.org) Received: from mailout05.t-online.de (mailout05.t-online.de [194.25.134.82]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mailout00.t-online.de", Issuer "TeleSec ServerPass DE-2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id E5C9370E25 for ; Sun, 1 Apr 2018 15:23:22 +0000 (UTC) (envelope-from se@freebsd.org) Received: from fwd23.aul.t-online.de (fwd23.aul.t-online.de [172.20.26.128]) by mailout05.t-online.de (Postfix) with SMTP id 03AB742171B0 for ; Sun, 1 Apr 2018 17:18:08 +0200 (CEST) Received: from Stefans-MBP-7.fritz.box (ZG32sYZEwhad9JPWy8eNPc5mbXFzgg8tzDq13YedibP6ER4LarYRTek7Lr5GOW0gX0@[84.154.109.148]) by fwd23.t-online.de with (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384 encrypted) esmtp id 1f2ek9-1PWmBc0; Sun, 1 Apr 2018 17:18:05 +0200 To: FreeBSD Current From: Stefan Esser Subject: Extremely low disk throughput under high compute load Openpgp: preference=signencrypt Autocrypt: addr=se@freebsd.org; keydata= xsBNBFVxiRIBCADOLNOZBsqlplHUQ3tG782FNtVT33rQli9EjNt2fhFERHIo4NxHlWBpHLnU b0s4L/eItx7au0i7Gegv01A9LUMwOnAc9EFAm4EW3Wmoa6MYrcP7xDClohg/Y69f7SNpEs3x YATBy+L6NzWZbJjZXD4vqPgZSDuMcLU7BEdJf0f+6h1BJPnGuwHpsSdnnMrZeIM8xQ8PPUVQ L0GZkVojHgNUngJH6e21qDrud0BkdiBcij0M3TCP4GQrJ/YMdurfc8mhueLpwGR2U1W8TYB7 4UY+NLw0McThOCLCxXflIeF/Y7jSB0zxzvb/H3LWkodUTkV57yX9IbUAGA5RKRg9zsUtABEB AAHNLlN0ZWZhbiBFw59lciAoVC1PbmxpbmUpIDxzdC5lc3NlckB0LW9ubGluZS5kZT7CwH8E EwEIACkFAlhtTvQCGwMFCQWjmoAHCwkIBwMCAQYVCAIJCgsEFgIDAQIeAQIXgAAKCRBH67Xv Wv31RAn0B/9skuajrZxjtCiaOFeJw9l8qEOSNF6PKMN2i/wosqNK57yRQ9AS18x4+mJKXQtc mwyejjQTO9wasBcniKMYyUiie3p7iGuFR4kSqi4xG7dXKjMkYvArWH5DxeWBrVf94yPDexEV FnEG9t1sIXjL17iFR8ng5Kkya5yGWWmikmPdtZChj9OUq4NKHKR7/HGM2dxP3I7BheOwY9PF 4mhqVN2Hu1ZpbzzJo68N8GGBmpQNmahnTsLQ97lsirbnPWyMviWcbzfBCocI9IlepwTCqzlN FMctBpLYjpgBwHZVGXKucU+eQ/FAm+6NWatcs7fpGr7dN99S8gVxnCFX1Lzp/T1YzsBNBFVx iRIBCACxI/aglzGVbnI6XHd0MTP05VK/fJub4hHdc+LQpz1MkVnCAhFbY9oecTB/togdKtfi loavjbFrb0nJhJnx57K+3SdSuu+znaQ4SlWiZOtXnkbpRWNUeMm+gtTDMSvloGAfr76RtFHs kdDOLgXsHD70bKuMhlBxUCrSwGzHaD00q8iQPhJZ5itb3WPqz3B4IjiDAWTO2obD1wtAvSuH uUj/XJRsiKDKW3x13cfavkad81bZW4cpNwUv8XHLv/vaZPSAly+hkY7NrDZydMMXVNQ7AJQu fWuTJ0q7sImRcEZ5EIa98esJPey4O7C0vY405wjeyxpVZkpqThDMurqtQFn1ABEBAAHCwGUE GAEKAA8FAlVxiRICGwwFCQWjmoAACgkQR+u171r99UQEHAf/ZxNbMxwX1v/hXc2ytE6yCAil piZzOffT1VtS3ET66iQRe5VVKL1RXHoIkDRXP7ihm3WF7ZKy9yA9BafMmFxsbXR3+2f+oND6 nRFqQHpiVB/QsVFiRssXeJ2f0WuPYqhpJMFpKTTW/wUWhsDbytFAKXLLfesKdUlpcrwpPnJo KqtVbWAtQ2/o3y+icYOUYzUig+CHl/0pEPr7cUhdDWqZfVdRGVIk6oy00zNYYUmlkkVoU7MB V5D7ZwcBPtjs254P3ecG42szSiEo2cvY9vnMTCIL37tX0M5fE/rHub/uKfG2+JdYSlPJUlva RS1+ODuLoy1pzRd907hl8a7eaVLQWA== Message-ID: Date: Sun, 1 Apr 2018 17:18:04 +0200 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: 7bit X-ID: ZG32sYZEwhad9JPWy8eNPc5mbXFzgg8tzDq13YedibP6ER4LarYRTek7Lr5GOW0gX0 X-TOI-MSGID: e2b012b9-9b2d-4f36-9b00-0c8868fa04d4 X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.25 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, 01 Apr 2018 15:23:23 -0000 My i7-2600K based system with 24 GB RAM was in the midst of a buildworld -j8 (starting from a clean state) which caused a load average of 12 for more than 1 hour, when I decided to move a directory structure holding some 10 GB to its own ZFS file system. File sizes varied, but were mostly in the range 0f 500KB. I had just thrown away /usr/obj, but /usr/src was cached in ARC and thus there was nearly no disk activity caused by the buildworld. The copying proceeded at a rate of at most 10 MB/s, but most of the time less than 100 KB/s were transferred. The "cp" process had a PRIO of 20 and thus a much better priority than the compute bound compiler processes, but it got just 0.2% to 0.5% of 1 CPU core. Apparently, the copy process was scheduled at such a low rate, that it only managed to issue a few controller writes per second. The system is healthy and does not show any problems or anomalies under normal use (e.g., file copies are fast, without the high compute load). This was with SCHED_ULE on a -CURRENT without WITNESS or malloc debugging. Is this a regression in -CURRENT? Regards, STefan