[PATCH 2/2] nvme: extend show-topology command to add support for multipath

[Nilay Shroff]

Hi Daniel,

A gentle ping about this patchset... Do you have any further recommendation as I suggested below?

Thanks,
--Nilay

On 7/10/25 7:16 PM, Nilay Shroff wrote:
> 
> 
> On 7/9/25 2:58 PM, Daniel Wagner wrote:
>> Hi Nilay,
>>
>> On Fri, Jul 04, 2025 at 07:19:54PM +0530, Nilay Shroff wrote:
>>> $ nvme show-topology -r multipath
>>>
>>> nvme-subsys2 - NQN=nvmet_subsystem
>>>                hostnqn=nqn.2014-08.org.nvmexpress:uuid:12b49f6e-0276-4746-b10c-56815b7e6dc2
>>>                iopolicy=numa
>>>
>>>           _ _ _<head-node>
>>>          /              _ _ _ <ana-state>
>>>         /              /      _ _ _ <numa-node-list>
>>>        /              /      /  _ _ _<queue-depth>
>>>       |              /      /  /
>>>  +- nvme2n1 (ns 1)  /      /  /
>>>  \                 |      |  |
>>>   +- nvme2c2n1 optimized 1,2 0 nvme2 tcp traddr=127.0.0.2,trsvcid=4460,src_addr=127.0.0.1 live
>>>   +- nvme2c3n1 optimized 3,4 0 nvme3 tcp traddr=127.0.0.3,trsvcid=4460,src_addr=127.0.0.1 live
>>>
>>> Please note that the headers shown above (e.g., <numa-node-list>,
>>> <ana-state>, <hed-node>, and <queue-depth>) are included for clarity
>>> only and are not part of the actual output.
>>
>> I do like the annotation what the numbers mean. Could you also add those
>> annotation to the output?
>>
> 
> Yes, I agree that the annotations explaining the numbers are helpful. 
> However, if there are multiple subsystems on a host, including such
> annotations inline might make the output look cluttered.
> 
> Instead, I propose using the following tabular format, which is more 
> readable and scalable. We can display this enhanced format only when
> the user specifies a --verbose option. Without the --verbose flag, we
> can continue using the current tree-style format.
> 
> Example verbose output:
> 
> $ nvme show-topology --verbose -r multipath
> 
> nvme-subsys2 - NQN=nvmet_subsystem
>                hostnqn=nqn.2014-08.org.nvmexpress:uuid:12b49f6e-0276-4746-b10c-56815b7e6dc2
>                iopolicy=numa
>                model=Linux
>                serial=d5dc1170f62100d47204
>                firmware=6.16.0-r
>                type=nvm
> 
> <head-node> <namespace>   <path>    <ana-state>  <numa-list>  <queue-depth>   <ctrl>  <state>  <transport>    <address>                  
>     |          |             |           |           |            |              |       |          |             |
> nvme2n1        1          nvme2c2n1   optimized     1,2           0            nvme2   live        tcp        traddr=127.0.0.2,trsvcid=4460,src_addr=127.0.0.1 
> nvme2n1        1          nvme2c3n1   optimized     3,4           0            nvme3   live        tcp        traddr=127.0.0.3,trsvcid=4460,src_addr=127.0.0.1
> 
> What do you think?
> 
> Thanks,
> --Nilay
>