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Date:      Mon, 22 Feb 1999 09:22:32 -0500 (EST)
From:      Andrew Gallatin <gallatin@cs.duke.edu>
To:        Ruslan Ermilov <ru@ucb.crimea.ua>
Cc:        "Kenneth D. Merry" <ken@plutotech.com>, stable@FreeBSD.ORG, allenc@verinet.com
Subject:   Re: Tagged queueing
Message-ID:  <14033.25751.508511.815083@grasshopper.cs.duke.edu>
In-Reply-To: <19990222140147.A2015@ucb.crimea.ua>
References:  <19990219233927.A4953@ucb.crimea.ua> <199902201930.MAA13801@panzer.plutotech.com> <19990222140147.A2015@ucb.crimea.ua>

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Ruslan Ermilov writes:
 > On Sat, Feb 20, 1999 at 12:30:43PM -0700, Kenneth D. Merry wrote:
 > >
 > > The AHC_TAGENABLE option is no longer necessary.  Tagged queueing is
 > > enabled by default.
 > > 
 > > The reason your drive does not have tagged queueing enabled is because it is
 > > a Western Digital Enterprise drive:
 > > da0 at ahc0 bus 0 target 0 lun 0
 > > da0: <WDIGTL ENTERPRISE 1.80> Fixed Direct Access SCSI-2 device 
 > > da0: 40.000MB/s transfers (20.000MHz, offset 8, 16bit)
 > > da0: 4157MB (8515173 512 byte sectors: 64H 32S/T 4157C)
 > > 
 > > Andrew Gallatin reported that his western digital enterprise drives only
 > > get 1.5MB/sec throughput with tagged queueing turned on, and 8MB/sec
 > > throughput with tagged queueing turned off.  Therefore, we have a quirk
 > > entry in the transport layer that disables tagged queueing for those
 > > drives.
 > Reported?  What's the number of his problem report?

I talked to him via private email shortly after CAM went into -current.

I have two WDE's:

da0 at ahc0 bus 0 target 0 lun 0
da0: <WDIGTL WDE4360-1807A3 1.80> Fixed Direct Access SCSI-2 device 
da0: 40.0MB/s transfers (20.0MHz, offset 8, 16bit)
da0: 4095MB (8388314 512 byte sectors: 255H 63S/T 522C)


da1 at ahc0 bus 0 target 1 lun 0
da1: <WDIGTL ENTERPRISE 1.91> Fixed Direct Access SCSI-2 device 
da1: 40.0MB/s transfers (20.0MHz, offset 8, 16bit)
da1: 4157MB (8515173 512 byte sectors: 255H 63S/T 530C)

Both show piss-poor performance with TQ enabled.  Note that they are
'different' than yours at least in that my drive with 4157MB has
revision 1.91 of the firmware.  Perhaps that has something do do with
it...  Anyway,  with TQ disabled, WCE on both drives I see decent
performance: 

<9:12am>grasshopper/gallatin:tmp>df /var/tmp
Filesystem   512-blocks     Used    Avail Capacity  Mounted on
/dev/da0s1e      575486   453702    75746    86%    /var
<9:12am>grasshopper/gallatin:tmp>dd if=/dev/zero of=/var/tmp/test bs=64k count=1000
1000+0 records in
1000+0 records out
65536000 bytes transferred in 8.440735 secs (7764253 bytes/sec)

<9:13am>grasshopper/gallatin:tmp>df /freebsd/tmp/
Filesystem   512-blocks     Used    Avail Capacity  Mounted on
/dev/da1s1c     8252330  4384130  3208014    58%    /freebsd
<9:13am>grasshopper/gallatin:tmp>dd if=/dev/zero of=/freebsd/tmp/test bs=64k count=1000
1000+0 records in
1000+0 records out
65536000 bytes transferred in 7.876551 secs (8320393 bytes/sec)

<9:15am>grasshopper/gallatin:tmp>uname -a
FreeBSD grasshopper.cs.duke.edu 4.0-CURRENT FreeBSD 4.0-CURRENT #0: Sun Jan 24 16:17:20 EST 1999     gallatin@grasshopper.cs.duke.edu:/freebsd/src/sys/compile/GRASSHOPPER  i386

I'm sorry, but I've got a bit too much state laying around to be able
reboot to turn on tagged queuing to verify my drives performance with
TQ enabled still stinks...

Drew

------------------------------------------------------------------------------
Andrew Gallatin, Sr Systems Programmer	http://www.cs.duke.edu/~gallatin
Duke University				Email: gallatin@cs.duke.edu
Department of Computer Science		Phone: (919) 660-6590




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