[RFC PATCH 0/3] nvme sq associations

[Christoph Hellwig]

On Sat, Sep 25, 2021 at 06:31:58PM +1000, Benjamin Herrenschmidt wrote:
> On Sat, 2021-09-25 at 12:02 +0900, Keith Busch wrote:
> > 
> > Different submission queue groups per NVM Set sounds right for this
> > feature, but I'm not sure it makes sense for these to have their own
> > completion queues: completions from different sets would try to
> > schedule on the same CPU. I think it should be more efficient to
> > break the 1:1
> > SQ:CQ pairing, and instead have all the SQs with the same CPU
> > affinity share a single CQ so that completions from different
> > namespaces could be handled in a single interrupt.
> 
> Can this be an incremental improvement ?

Honestly I'd rather not merge this whole patchset at all.  It is a
completly frinde feature for a totally misdesigned part of the NVMe
spec.  Until actual controller in the hands of prosumers support
anything like that I'm very reluctant to bloat the driver fast path for
it.