Command Deadlines: HP's Modest Proposal

George Penokie george.penokie at avagotech.com
Wed Sep 3 15:19:03 PDT 2014


Formatted message: <a href="http://www.t10.org/cgi-bin/ac.pl?t=r&f=r1409031_f.htm">HTML-formatted message</a>

:Paul,
One timeout per opcode per I_T_L nexus sounds like one heck of a lot of
timers to me.
Bye for now,
George Penokie
Avago Technologies
Attn: George Penokie
4109 Manor View Dr NW
Rochester , MN 55901
507-328-9017
george.penokie at avagotech.com
On Wed, Sep 3, 2014 at 4:30 PM, Paul Suhler <Paul.Suhler at hgst.com> wrote:
>  Hi, all.
>
>
>
> Curtis Ballard has made an interesting suggestion for a major change to
> last week’s T10/14-107r2:
>
>
>
> Instead of providing two sets of fifteen timeouts, one timeout would be
> provided per-opcode-per-I_T_L nexus.	That timeout would be used if a
> newly-allocated bit in the CDB’s Control byte were set.
>
>
>
> Advantage:
>
> No need to wait for the Command Priority attribute to be added to
> transport implementations and to driver stacks, which could take years.
>
>
>
> Disadvantage:
>
> In cases where an initiator wants to change the timeout for  a particular
> command (e.g., READ(16)) on a particular LU, it would have to send a MODE
> SELECT.
>
>
>
> Questions:
>
> 1)	  Does anyone feel that one timeout per opcode per I_T_L nexus is
> too much of a constraint?  HP doesn’t.
>
> 2)	  Does anyone object to using mode pages, with the requirement that
> the data length on MODE SELECT must match the data length on MODE SENSE?
> (The alternative is yet another command.)
>
>
>
> Thanks for your feedback,
>
>
>
> Paul
>
>
>
> *Paul A. Suhler, PhD*
>
> Research Staff Member
>
> HGST Research
> *paul.suhler at hgst.com <paul.suhler at hgst.com>*
> o: 949-476-1180 x275448
>
> m: 949-241-6443
>
> 3001 Daimler St.
> Santa Ana, CA 92705-5812
> www.hgst.com
>
>
>



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