Re: [PATCH V3 4/8] blk-mq: introduce BLK_MQ_F_HOST_TAGS

Christoph Hellwig
2018-03-08T07:52:52Z

On Tue, Feb 27, 2018 at 06:07:46PM +0800, Ming Lei wrote:
> This patch can support to partition host-wide tags to multiple hw queues,
> so each hw queue related data structures(tags, hctx) can be accessed in
> NUMA locality way, for example, the hw queue can be per NUMA node.
>
> It is observed IOPS can be improved much in this way on null_blk test.

null_blk isn't too interesting, so some real hardware number would
be very useful here.

Also the documentation should be a lot less sparse. When are we going
to set this flag? What help are we going to give driver authors to
guide chosing the option?