On 01/11/2017 09:36 PM, Stephen Bates wrote:

quoted

quoted

I'd like to attend LSF/MM and would like to discuss polling for block
drivers.

Currently there is blk-iopoll but it is neither as widely used as NAPI
in the networking field and accoring to Sagi's findings in [1]
performance with polling is not on par with IRQ usage.

On LSF/MM I'd like to whether it is desirable to have NAPI like polling
in more block drivers and how to overcome the currently seen performance
issues.

It would be an interesting topic to discuss, as it is a shame that
blk-iopoll isn't used more widely.

--
Jens Axboe

I'd also be interested in this topic. Given that iopoll only really makes
sense for low-latency, low queue depth environments (i.e. down below
10-20us) I'd like to discuss which drivers we think will need/want to be
upgraded (aside from NVMe ;-)).

I'd also be interested in discussing how best to enable and disable
polling. In the past some of us have pushed for a "big hammer" to turn
polling on for a given device or HW queue [1]. I'd like to discuss this
again as well as looking at other methods above and beyond the preadv2
system call and the HIPRI flag.

This is a separate topic. The initial proposal is for polling for
interrupt mitigation, you are talking about polling in the context of
polling for completion of an IO.

We can definitely talk about this form of polling as well, but it should
be a separate topic and probably proposed independently.

-- 
Jens Axboe