Re: [PATCH v3 01/18] block: introduce duration-limits priority class

[Bart Van Assche <bvanassche@acm.org>]

On 1/24/23 11:27, Bart Van Assche wrote:
> Implementing duration limit support using the I/O priority mechanism 
> makes it impossible to configure the I/O priority for commands that have 
> a duration limit. Shouldn't the duration limit be independent of the I/O 
> priority? Am I perhaps missing something?

(replying to my own e-mail)

In SAM-6 I found the following: "The device server may use the duration 
expiration time to determine the order of processing commands with
the SIMPLE task attribute within the task set. A difference in duration 
expiration time between commands may override other scheduling 
considerations (e.g., different times to access different logical block 
addresses or vendor specific scheduling considerations). Processing of a 
collection of commands with different command duration limit settings 
should cause a command with an earlier duration expiration time to 
complete with status sooner than a command with a later duration 
expiration time."

Do I understand correctly that it is optional for a SCSI device to 
interpret the command duration as a priority and that this is not mandatory?

Thanks,

Bart.