[PATCH 0/4] iopoll support for io_uring/nvme passthrough

[Kanchan Joshi]

On Fri, Aug 05, 2022 at 11:04:22AM -0600, Jens Axboe wrote:
>On 8/5/22 9:42 AM, Kanchan Joshi wrote:
>> Hi,
>>
>> Series enables async polling on io_uring command, and nvme passthrough
>> (for io-commands) is wired up to leverage that.
>>
>> 512b randread performance (KIOP) below:
>>
>> QD_batch    block    passthru    passthru-poll   block-poll
>> 1_1          80        81          158            157
>> 8_2         406       470          680            700
>> 16_4        620       656          931            920
>> 128_32      879       1056        1120            1132
>
>Curious on why passthru is slower than block-poll? Are we missing
>something here?
passthru-poll vs block-poll you mean?
passthru does not have bio-cache, while block path is running with that.
Maybe completion-batching is also playing some role, not too sure about that
at the moment.