rio VS glommio

Also, not to be too bad about a reputation fallacy, but I found the author to be flippant and disrespectful when good-faith unsoundness was pointed out in his crates: https://github.com/spacejam/rio/issues/30

In my previous post on linear types I spent quite a bit of time motivating linear types. For example the ergonomic rio io_uring library could be made sound if it could guarantee destructors are run. Or performing FFI with async C++ could be made more efficient if it could rely directly on destructors rather than having to involve an intermediate runtime for each call.

It's like cargo should have a way to mark a dependency as unsafe. That way, you could have a safe mmap crate as an unsafe dependency. Or something like rio which is deliberately unsound (but is fine if you abide by its rules through the entirety of the program)

for completeness there is also rio, but:

rio still has known soundness issues– its Completion futures block the thread when dropped (!!!), and can allow for use-after-free bugs if leaked. See https://github.com/spacejam/rio/issues/30 for details.

Here are some posts about the design. https://without.boats/blog/io-uring/ https://github.com/spacejam/rio/issues/30 https://github.com/axboe/liburing/issues/109

The author of sled[1], an embedded database in Rust which has a number of promising features, has also written parts of rio[2], an underlying pure Rust io_uring library, which is intended to become the core write path for sled. rio has support for files but also has a demo for TCP (on Linux 5.5 and later) and O_DIRECT.

I tested rio recently as I had a Brilliant but Bad Idea™ involving file access and was pleasantly surprised by the API, as I have been with sled's.

I'm excited for the experimentation in the Rust ecosystem and for such low level crates to handle the complex io_uring tasks (relatively) safely!

[1]: https://github.com/spacejam/sled

[2]: https://github.com/spacejam/rio

I used glommio as the async executor (instead of something like tokio), and it is wonderful. For people wondering whether it's "good enough" or to use C++ and seastar (as I have thought about a lot before starting this project), take the leap of faith, it's fast - both in terms of run time and to code.

My understanding is you always need a runtime, somethings needs to drive the async flow. But there are others on the market, just not without the.. market domination... of tokio.

https://github.com/smol-rs/smol looks promising simply for being minimal

https://github.com/bytedance/monoio looks potentially easier to work with than tokio

https://github.com/DataDog/glommio is built around linux io_uring and seems somewhat promising for performance reasons.

I haven't played with any of these yet, because Tokio is unfortunately the path of least resistance. And a bit viral in how it's infected tings.

I think you missed one which is based on io_uring [1].

In my benchmarks with a slightly tweaked version it was 2x faster than Nginx and and 30x faster than Python's SimpleHttpServer.

[1] https://github.com/DataDog/glommio/blob/master/examples/hype...

b) It's proven now e.g Seastar, Glommio that the fastest way to run a multi-threaded application is to have one instance with one thread pinned per CPU core. Then to have fibers/lightweight threads on top handling all of the asynchronous code. Your approach of lots of instances is the slowest so there will be a ton of unnecessary thread context-switching.

I assume Tokio itself, see e.g monoio or glommio, but also Seastar for C++.

https://github.com/DataDog/glommio Rust thread per core library.

> Few of us have really figured out io_uring. But that doesn't mean it is slower.

seastar.io is a high level framework that I believe has "figured out" io_uring, with additional caveats the framework imposes (which is honestly freeing).

Additionally the rust equivalent: https://github.com/DataDog/glommio

This use case is perfect for https://github.com/DataDog/glommio which is a thread-per-core runtime that is appropriate for latency sensitive code.

It's worth mentioning: Under "Async Executors", for "io_uring" there is only "Glommio"

I recently found out that ByteDance has a competitor library which supposedly has better performance:

https://github.com/bytedance/monoio

https://github.com/DataDog/glommio/issues/554

FYI, Datadog has a Rust library for scheduling things to run thread-per-core with io_uring

It'd be really useful for DB use cases:

https://github.com/DataDog/glommio