Date: Thu, 17 Oct 1996 21:57:31 -0700 From: "Michael L. VanLoon -- HeadCandy.com" <michaelv@MindBender.serv.net> To: "Marc G. Fournier" <scrappy@ki.net> Cc: Michael Hancock <michaelh@cet.co.jp>, Jaye Mathisen <mrcpu@cdsnet.net>, current@freebsd.org Subject: Re: Iozone: local vs nfs drives Message-ID: <199610180457.VAA14497@MindBender.serv.net> In-Reply-To: Your message of Fri, 18 Oct 96 00:24:39 -0400. <Pine.NEB.3.95.961018002236.6698E-100000@quagmire.ki.net>
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>> >> Did you have tagged-command queuing enabled? According to my tests,
>> >> that will make a BIG difference, if you have decent drives.
>> > I don't know...I haven't enabled it manually, so I would assume
>> >not.
>> > How do I check/enable it? Any caveats I should worry about?
>> Put "options AHC_TAGENABLE" in your kernel config file, and rebuild
>> (this is on NetBSD, anyway, but it's the common code written by Justin
>> Gibbs).
> Okay...to me, AHC_ brings to mind the Adaptec code...I'm using
>one of the ASUS SC-100 PCI controllers for my drives, so just want to
>confirm that this will work similar here?
Ah yes. It must have been someone else that posted that he was using
an Adaptec 2940. I mis-threaded...
I know the NCR supports tagged-command-queuing, also, but since I
don't use one (except on some NT machines at work), I don't know what
you do to enable it. Joe Greco would know.
> And, you mention "the drive supporting tagged command queueing"...
>how does one determine that? What if some of my drives do, and some don't...
>will it get disabled altogether as a result, or...?
Some older SCSI drives don't support it. And some that claim they do,
don't support it "correctly". I have a Quantum TrailBlazer 850MB and
a Quantum LPS 540 that don't support it. My HP 1GB drives do. My
Seagate Barracudas and Hawks do, also, but I run NT on those.
The Adaptec driver tells you if you have a "tagged queuing device" on
each SCSI device:
ahc0: target 0 synchronous at 10.0MHz, offset = 0xf
ahc0: target 0 Tagged Queuing Device
sd0 at scsibus0 targ 0 lun 0: <HP, C3323-300, 5011> SCSI2 0/direct fixed
sd0: 1003MB, 2982 cyl, 7 head, 98 sec, 512 bytes/sec
ahc0: target 1 synchronous at 10.0MHz, offset = 0xf
ahc0: target 1 Tagged Queuing Device
sd1 at scsibus0 targ 1 lun 0: <HP, C3323-300, 5011> SCSI2 0/direct fixed
sd1: 1003MB, 2982 cyl, 7 head, 98 sec, 512 bytes/sec
ahc0: target 2 synchronous at 10.0MHz, offset = 0x8
sd2 at scsibus0 targ 2 lun 0: <QUANTUM, LPS540S, 590S> SCSI2 0/direct fixed
sd2: 516MB, 2740 cyl, 4 head, 96 sec, 512 bytes/sec
ahc0: target 5 synchronous at 4.0MHz, offset = 0xf
cd0 at scsibus0 targ 5 lun 0: <SONY, CD-ROM CDU-55S, 1.0t> SCSI2 5/cdrom removable
Once again, the NCR driver does this, as well, but you'll have to get
the specifics from somewhere else.
-----------------------------------------------------------------------------
Michael L. VanLoon michaelv@MindBender.serv.net
--< Free your mind and your machine -- NetBSD free un*x >--
NetBSD working ports: 386+PC, Mac 68k, Amiga, Atari 68k, HP300, Sun3,
Sun4/4c/4m, DEC MIPS, DEC Alpha, PC532, VAX, MVME68k, arm32...
NetBSD ports in progress: PICA, others...
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