Thanks!

  On Fri, 23 Mar 2018 11:25:26 +0000
  Andrey Kuzmin <andrey.v.kuzmin(a)gmail.com> wrote:
> On Fri, Mar 23, 2018, 12:04 Jonas Pfefferle <pepperjo(a)japf.ch> 
>wrote:
> 
>> Hi @all,
>>
>> Can anyone clarify this for me:
>> NVMe spec 6.3 Command Ordering Requirements
>> "For all commands which are not part of a fused operation (refer to 
>>section
>> 4.10), or for which the write size is greater than AWUN, each 
>>command is
>> processed as an independent entity without reference to other 
>>commands
>> submitted to the same I/O Submission Queue or to commands submitted 
>>to
>> other
>> I/O Submission Queues"
>>
>> So writes <= AWUN size are atomic but there is no ordering between 
>>the
>> commands, e.g. write command A issued before write command B to the 
>>same
>> LBA
>> can be executed in order AB or BA, the only thing guaranteed is that 
>>they
>> are executed atomically? And there is no way to enforce ordering 
>>except on
>> the host side?
>>
> 
> Right, that's exactly what the spec says in that same paragraph you 
>quote
> above: "If there are ordering requirements between these commands, 
>host
> software or the associated application is required to enforce that 
>ordering
> above the level of the controller. " (1.3a, P. 179).
> 
> Regards,
> Andrey
> 
> 
>> Regards,
>> Jonas
>>
>>
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> -- 
> 
> Regards,
> Andrey