On Mar 3, 2006, at 1:47 PM, Stefan Richter wrote:
Steve Byan wrote:
On Mar 2, 2006, at 11:21 AM, Vladislav Bolkhovitin wrote:
Apparently, hardware SCSI targets don't suffer from queuing
overflow
[...]
No, they just have big queues.
Depending on the the transport protocol, the problem of queue depth
at the target may not even exist in the first place. This is the
case with SBP-2 where the queue of command blocks resides at the
initiator.
Yes, and that's a clever optimization in SBP-2 to support resource-
poor targets. Thanks for reminding us of it.
Too bad SATA drives didn't take advantage of the SATA first-party DMA
to implement SBP-2. The definition of the tag field for native
command queuing adopted by T13 essentially makes it infeasible to
revisit this decision.
Regards,
-Steve
--
Steve Byan <smb@xxxxxxxxxxx>
Software Architect
Egenera, Inc.
165 Forest Street
Marlboro, MA 01752
(508) 858-3125
-
: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
