Re: [RFC 00/13] uring-passthru for nvme

[Jens Axboe <axboe@kernel.dk>]

On 12/20/21 7:17 AM, Kanchan Joshi wrote:
> Here is a revamped series on uring-passthru which is on top of Jens
> "nvme-passthru-wip.2" branch.
> https://git.kernel.dk/cgit/linux-block/commit/?h=nvme-passthru-wip.2
> 
> This scales much better than before with the addition of following:
> - plugging
> - passthru polling (sync and async; sync part comes from a patch that
>   Keith did earlier)
> - bio-cache (this is regardless of irq/polling since we submit/complete in
>   task-contex anyway. Currently kicks in when fixed-buffer option is
> also passed, but that's primarily to keep the plumbing simple)
> 
> Also the feedback from Christoph (previous fixed-buffer series) is in
> which has streamlined the plumbing.
> 
> I look forward to further feedback/comments.
> 
> KIOPS(512b) on P5800x looked like this:
> 
> QD    uring    pt    uring-poll    pt-poll
> 8      538     589      831         902
> 64     967     1131     1351        1378
> 256    1043    1230     1376        1429

These are nice results! Can you share all the job files or fio
invocations for each of these? I guess it's just two variants, with QD
varied between them?

We really (REALLY) should turn the nvme-wip branch into something
coherent, but at least with this we have some idea of an end result and
something that is testable. This looks so much better from the
performance POV than the earlier versions, passthrough _should_ be
faster than non-pt.

-- 
Jens Axboe