IoUring: Add IoUringChannelOption.IOSQE_ASYNC

[normanmaurer]

Motivation:

Sometimes it might be benefitial to use IOSQE_ASYNC when submitting stuff to the ring.

Modifications:

Add IoUringChannelOption.IOSQE_ASYNC to enable it per Channel

Result:

More flexibility when using io_uring

[normanmaurer]

/cc @dreamlike-ocean

[chrisvest]

Sometimes it might be benefitial to use IOSQE_ASYNC when submitting stuff to the ring.

Is it beneficial on a channel level or only certain types of operations?

It effectively doubles the test matrix, so I just want to be sure it's worth it.

[dreamlike-ocean]

There are really too many flags that can be configured in the io_uring_sqe.
I think it would be nice to have a custom post or pre-processor for IoUringOps that can be provided for users to use.

[normanmaurer]

There are really too many flags that can be configured in the io_uring_sqe.

I think it would be nice to have a custom post or pre-processor for IoUringOps that can be provided for users to use.

I think this is overkill for now and might mess up things easily by the user

[normanmaurer]

Sometimes it might be benefitial to use IOSQE_ASYNC when submitting stuff to the ring.

Is it beneficial on a channel level or only certain types of operations?

It effectively doubles the test matrix, so I just want to be sure it's worth it.

I think it's mostly for read / accept / recv. So maybe we should only apply it for these ? Just wanted to keep it simple

[normanmaurer]

@franz1981 @chrisvest WDYT ?

[normanmaurer]

@chrisvest related to this #14650 which allows to configure the number of workers for unbounded work (which is what we want)