feat(utils): introduce utils crate with compio utilities

[numinnex]

monoio has an utility module, one of the methods that it exposes is bind_to_cpu_set. It's a simple wrapper around nix crate with sched feature flag, that allows to pin thread to cpu cores.

This PR creates a compio-utils module, that exposes bind_to_cpu_set method (the code is identical to what monoio does).

If you don't feel like creating such module and would rather that not be part of compio feel free to close this PR, it's not a blocker for us rather a convenience.

[Berrysoft]

Well, it seems that this functionality is independent to compio.

[numinnex]

It is independent, but it's very common with thread per core runtimes to pin threads to individual cores. Both monoio and glommio have that utility method, that's why I thought maybe as part of API compatibility it would be nice to expose it directly and in the future use the utils crate for some extra stuff.

Right now, we have to take an external dependency in order to do that, where compio internally uses nix already, so it's just matter of proxying it.

[Berrysoft]

I mean, as it is independent to runtime, it doesn't have to be in compio. It's OK just to be an independent crate. Furthermore, it seems that there already has been one: https://crates.io/crates/core_affinity

[numinnex]

I mean, as it is independent to runtime, it doesn't have to be in compio. It's OK just to be an independent crate. Furthermore, it seems that there already has been one: https://crates.io/crates/core_affinity

Yeah core_affinity is what we are using right now as a replacement for monoio::utils::bind_to_cpu_set.

As I've said it's not a must have, but rather a convenience for us. Maybe the Dispatcher could use it as well and provide an flag in it's builder that allows to pin threads.

[Berrysoft]

Yes, you mentioned dispatcher - I would prefer a PR for compio-dispatcher, adding functionality to pin cpu core for each worker thread.

[numinnex]

So, just a builder flag in the dispatcher, No compio-utils and re-exporting it via compio for users ?

[Berrysoft]

Acceptable:

• Builder flag for compio-runtime.
• Builder flag for compio-dispatcher.

Not recommended:

• A crate with compio-* name but does nothing with compio.

[numinnex]

Closing as #445 reworks the whole feature according to feedback from this PR.