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Disable tagged queueing for the IBM DCAS drives. These drives have poor

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write performance when tagged queueing is enabled.

Although the PR was submitted for the 4 gig version of this drive, the
assumption is that the 2 gig version has the same problem.  Therefore
tagged queueing is disabled for both.

Also, update the comment for the Western Digital Enterprise drives to note
that the best performance for those drives is achieved when tagged queueing
is disabled and write caching is enabled.

PR:		kern/10398
Submitted by:	Hideaki Okada <hokada@isl.melco.co.jp>
This commit is contained in:
Kenneth D. Merry 1999-03-14 05:15:38 +00:00
parent 5b76055cb5
commit ca3b51e9ed
1 changed files with 30 additions and 1 deletions
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31
sys/cam/cam_xpt.c
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@ -26,7 +26,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: cam_xpt.c,v 1.47 1999/03/07 22:48:50 ken Exp $
* $Id: cam_xpt.c,v 1.48 1999/03/11 10:48:02 jkh Exp $
*/
#include <sys/param.h>
#include <sys/systm.h>
@ -335,6 +335,31 @@ static struct xpt_quirk_entry xpt_quirk_table[] =
{ T_DIRECT, SIP_MEDIA_FIXED, seagate, "ST39140*", "*"},
/*quirks*/0, /*mintags*/2, /*maxtags*/2
},
{
/*
* Slow when tagged queueing is enabled. Write performance
* steadily drops off with more and more concurrent
* transactions. Best sequential write performance with
* tagged queueing turned off and write caching turned on.
*
* PR: kern/10398
* Submitted by: Hideaki Okada <hokada@isl.melco.co.jp>
* Drive: DCAS-34330 w/ "S65A" firmware.
*
* The drive with the problem had the "S65A" firmware
* revision, and has also been reported (by Stephen J.
* Roznowski <sjr@home.net>) for a drive with the "S61A"
* firmware revision.
*
* Although no one has reported problems with the 2 gig
* version of the DCAS drive, the assumption is that it
* has the same problems as the 4 gig version. Therefore
* this quirk entries disables tagged queueing for all
* DCAS drives.
*/
{ T_DIRECT, SIP_MEDIA_FIXED, "IBM", "DCAS*", "*" },
/*quirks*/0, /*mintags*/0, /*maxtags*/0
},
{
/* Broken tagged queuing drive */
{ T_DIRECT, SIP_MEDIA_REMOVABLE, "iomega", "jaz*", "*" },
@ -360,6 +385,8 @@ static struct xpt_quirk_entry xpt_quirk_table[] =
* Slow when tagged queueing is enabled. (1.5MB/sec versus
* 8MB/sec.)
* Submitted by: Andrew Gallatin <gallatin@cs.duke.edu>
* Best performance with these drives is achieved with
* tagged queueing turned off, and write caching turned on.
*/
{ T_DIRECT, SIP_MEDIA_FIXED, west_digital, "WDE*", "*" },
/*quirks*/0, /*mintags*/0, /*maxtags*/0
@ -369,6 +396,8 @@ static struct xpt_quirk_entry xpt_quirk_table[] =
* Slow when tagged queueing is enabled. (1.5MB/sec versus
* 8MB/sec.)
* Submitted by: Andrew Gallatin <gallatin@cs.duke.edu>
* Best performance with these drives is achieved with
* tagged queueing turned off, and write caching turned on.
*/
{ T_DIRECT, SIP_MEDIA_FIXED, west_digital, "ENTERPRISE", "*" },
/*quirks*/0, /*mintags*/0, /*maxtags*/0