Date: Wed, 5 Jun 2013 06:30:44 -0700 From: "Justin T. Gibbs" <gibbs@scsiguy.com> To: Steven Hartland <smh@FreeBSD.org> Cc: "svn-src-stable@freebsd.org" <svn-src-stable@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org>, "svn-src-stable-9@freebsd.org" <svn-src-stable-9@freebsd.org> Subject: Re: svn commit: r251372 - in stable/9/sys/cam: ata scsi Message-ID: <4A91EB3F-56FD-4E94-9981-0422032C9240@scsiguy.com> In-Reply-To: <201306041047.r54AljAX050733@svn.freebsd.org> References: <201306041047.r54AljAX050733@svn.freebsd.org>
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On Jun 4, 2013, at 3:47, Steven Hartland <smh@FreeBSD.org> wrote: > Author: smh > Date: Tue Jun 4 10:47:44 2013 > New Revision: 251372 > URL: http://svnweb.freebsd.org/changeset/base/251372 >=20 > Log: > Enhanced BIO_DELETE support for CAM SCSI to add ATA_TRIM support. >=20 > Disable CAM BIO queue sorting for non-rotating media by default. Using the elevator makes perfect sense even for random access devices when o= perations can be merged. Even SSDs have fixed, per-command overheads and mer= ging writes may help prevent fragmentation. On drivers that support unmappe= d I/O, merging should be fairly cheap. It would be an interesting performance experiment. >=20 -- Justin=
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