[PATCH V2 0/2] nvme: replace linked list with xarray for ns tracking

[Chaitanya Kulkarni]

On 7/1/20 6:21 AM, Keith Busch wrote:
> On Wed, Jul 01, 2020 at 07:36:09AM +0200, Christoph Hellwig wrote:
>> On Tue, Jun 30, 2020 at 07:25:15PM -0700, Chaitanya Kulkarni wrote:
>>> Hi,
>>>
>>> This is a small patch-series which replaces ctrl->namespaces with
>>> xarray for host-core and target-core. We can see following
>>> performance improvement when running fio with 32 parallel jobs where
>>> first 16 namespaces and last 16 namespaces are used for I/O. See [1] for
>>> detailed performance numbers.
>> Why would that make any difference given that we don't look up namespaces
>> in the I/O path?
> Not in host side. Target does a lookup on each IO through:
> 
>    nvmet_req_init()
>      nvmet_parse_io_cmrd()
>        nvmet_find_namespaces()
> 
> And this detail should be mentioned in the test setup for the cover
> letter, or in patch 2.
> 
Yes I've missed that I'll add these details in V3.