One other thing I stumbled upon:
7.1 "There are no ordering restrictions for completions to the host."

Does that mean if, for example, command A and B were executed in order A,B 
they do not have to complete in this order on the CQ?

Thanks,
Jonas

  On Fri, 23 Mar 2018 12:59:54 +0100
  "Jonas Pfefferle" <pepperjo(a)japf.ch> wrote:
> 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
>>>
>>>
>>> _______________________________________________
>>> SPDK mailing list
>>> SPDK(a)lists.01.org
>>> https://lists.01.org/mailman/listinfo/spdk
>>>
>> -- 
>> 
>> Regards,
>> Andrey
> 
> 
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