[PATCH rfc 0/6] convert nvme pci to use irq-poll service

[Keith Busch]

On Wed, Oct 05, 2016 at 12:42:08PM +0300, Sagi Grimberg wrote:
> I ran some tests with this and it seemed to work pretty well with
> my low-end nvme devices. One phenomenon I've encountered was that
> for single core long queue-depth'ed randread workload I saw around
> ~8-10% iops decrease. However when running multi-core IO I didn't
> see any noticeable performance degradation. non-polling Canonical
> randread latency doesn't seem to be affected as well. And also
> polling mode IO is not affected as expected.
> 
> So in addition for review and feedback, this is a call for testing
> and benchmarking as this touches the critical data path.

Hi Sagi,

Just reconfirming your findings with another data point, I ran this on
controllers with 3D Xpoint media, and single depth 4k random read latency
increased almost 7%. I'll try see if there's anything else we can do to
bring that in.