Date: Tue, 19 Jan 1999 23:31:50 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: Matthew Jacob <mjacob@feral.com> Cc: "Kenneth D. Merry" <ken@plutotech.com>, cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG Subject: Re: cvs commit: src/sys/cam cam_xpt.c Message-ID: <199901200731.XAA00578@apollo.backplane.com> References: <Pine.LNX.4.04.9901192309200.22955-100000@feral-gw>
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:Yes, that's true. Sorry- I wasn't thinking clearly. It is just that
:retrofitting for breakage is a losing game.
:
:It might make more sense to limit tags to something lower *unless* there's
:a quirks that says this drive can take a lot. By and large I'd really
:wonder that > 8 per spindle makes any sense at all.
:
Oh yah, it definitely makes sense. I dunno about reversing the state
of the quirk, but there are major performance benefits to being able
to queue a large number of commands to a drive on a heavily loaded
system.
Not only that, but a SCSI unit might not address just a single HD. A
RADI SCSI unit, for example, might fan-out to many drives and limiting
the tags to 8 would have a severe effect on performance.
-Matt
Matthew Dillon
<dillon@backplane.com>
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