Date: Wed, 20 Apr 2016 01:10:07 +0000 (UTC) From: Warren Block <wblock@FreeBSD.org> To: doc-committers@freebsd.org, svn-doc-all@freebsd.org, svn-doc-head@freebsd.org Subject: svn commit: r48679 - head/en_US.ISO8859-1/htdocs/news/status Message-ID: <201604200110.u3K1A7Ve022160@repo.freebsd.org>
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Author: wblock Date: Wed Apr 20 01:10:07 2016 New Revision: 48679 URL: https://svnweb.freebsd.org/changeset/doc/48679 Log: Add CAM I/O Scheduler report from Warner Losh <imp@bsdimp.com>. Modified: head/en_US.ISO8859-1/htdocs/news/status/report-2016-01-2016-03.xml Modified: head/en_US.ISO8859-1/htdocs/news/status/report-2016-01-2016-03.xml ============================================================================== --- head/en_US.ISO8859-1/htdocs/news/status/report-2016-01-2016-03.xml Tue Apr 19 18:25:50 2016 (r48678) +++ head/en_US.ISO8859-1/htdocs/news/status/report-2016-01-2016-03.xml Wed Apr 20 01:10:07 2016 (r48679) @@ -2523,4 +2523,47 @@ <a href="https://www.freebsdfoundation.org/blog/introducing-a-new-look-for-the-foundation/">new look</a>.</p> </body> </project> + + <project cat='kern'> + <title>CAM I/O Scheduler</title> + + <contact> + <person> + <name> + <given>Warner</given> + <common>Losh</common> + </name> + <email>wlosh@netflix.com</email> + </person> + </contact> + + <links> + <url href="https://people.freebsd.org/~imp/bsdcan2015/iosched-v3.pdf">I/O Scheduling in FreeBSD's CAM Subsystem (PDF)</url> + <url href="https://www.youtube.com/watch?v=3WqOLolj5EU">The BSDCan 2015 Talk</url> + </links> + + <body> + <p>An enhanced CAM I/O scheduler has been committed to the tree. + By default, this scheduler implements the old behavior. + However, a more adaptive scheduler can be enabled. The more + adaptive scheduler allows pacing of different types of I/O to + allow the workload-preferred I/O to experience maximum + performance. By measuring device response time at the lowest + levels, many artifacts of software queueing can be eliminated + and better performance can be achieved. In addition, Queued + Trims are now supported for SATA devices that support them. + Details about the new scheduler are available in the + <a href="https://people.freebsd.org/~imp/bsdcan2015/iosched-v3.pdf">I/O Scheduling in FreeBSD's CAM Subsystem article (PDF)</a> + or from + <a href="https://www.youtube.com/watch?v=3WqOLolj5EU">the BSDCan 2015 talk</a>.</p> + + <p>In essence, this I/O scheduler allows the user to choose + improved read performance by trading off some write + performance. Or, if SSDs cannot garbage collect fast enough + to keep up with writes, to improve write performance at the + cost of some read performance.</p> + </body> + + <sponsor>Netflix</sponsor> + </project> </report>
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