Re: [LSF/MM TOPIC][LSF/MM ATTEND] NAPI polling for block drivers

Andrey Kuzmin
2017-01-18T14:36:48Z

On Wed, Jan 18, 2017 at 5:27 PM, Sagi Grimberg <sagi@grimberg.me> wrote:
>
>> So what you say is you saw a consomed == 1 [1] most of the time?
>>
>> [1] from
>> http://git.infradead.org/nvme.git/commitdiff/eed5a9d925c59e43980047059fde29e3aa0b7836
>
>
> Exactly. By processing 1 completion per interrupt it makes perfect sense
> why this performs poorly, it's not worth paying the soft-irq schedule
> for only a single completion.

Your report provided this stats with one-completion dominance for the
single-threaded case. Does it also hold if you run multiple fio
threads per core?

Regards,
Andrey

>
> What I'm curious is how consistent is this with different devices (wish
> I had some...)
>
>
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