enarx VS MIO

Do you mean a trusted execution environment, like Intel SGX? GPUs live outside the TEE, so, no, I think what you're asking for isn't possible. But for doing TEE stuff in Rust, see https://enarx.dev/ .

Keep in mind that I'm using "OS" here loosely; it's a bare-metal program that exposes a subset of Linux syscalls so that the interpreter (which itself is compiled for Linux) can run in the extremely strange context that we target. It's still early days so I won't spend too much time shilling it, but all the code is open source and lives under the umbrella of the Linux Foundation: https://enarx.dev/

What do you use to run Wasm on untrusted systems? Is it Enarx by chance?

Here's the project: https://enarx.dev/

There's not much to say about the company just yet, but I'll note that all of our code is open source and the main project itself that we develop and that does most of the magic lives under the Linux Foundation's Confidential Computing Consortium, it's called Enarx: https://enarx.dev/ . TL;DR: use fancy new CPU features to run workloads in the cloud where both the program itself and all the data it processes are hidden from the cloud provider.

This is my second blog of the Outreachy'22 internship. Before this Internship, I never had any strong development experience. This is the opportunity that enabled me to work across a really good technical Project i.e. "The Enarx Project".

The Enarx Project is the part of Confidential Computing Consortium from the Linux Foundation, the folks here are very collaborative and welcoming. As a fellow mentee, I'd like to thank the Community Manager- Nick Vidal sir. In addition to me, he provided the right guidance to all of us contributors and mentored us to the right path. There were many folks who were more proficient than me and were making up numerous commits, but I tried my level best and was focused to contribute as much as possible and ended up making the maximum number of contributions.

Was playing around with mio (https://github.com/tokio-rs/mio) (not that mio itself is very important here!) and was trying to implement a simple something that I've done in java before: a Reactor that you can register ReactorClients with that will get callback whenever there are events on the corresponding socket etc.

How does it compare to mio?

TcpStream gets its wake behavior by delegating to the fd wakers. The Unix wakers have a few implementations, for different platforms. On Linux and Android, epoll is used.

The real implementation details of the I/O event queue is done in mio as u/hniksic pointed out, but that's more comparable with libuv which is certainly a huge part of the Node runtime. mio and libuv have a lot of similarities (at least they used to).

My example was "twice by one developer", not "twice across all indexed repos."

A spot check shows that quite a few in your link are used specifically to ensure correct handling of Rust multi-level breaks work syntax, like https://github.com/rust-lang/rust-analyzer/blob/master/crate... , https://github.com/rust-lang/rustfmt/blob/master/tests/sourc... , https://github.com/rust-lang/rust/blob/master/src/tools/rust... , https://github.com/rust-lang/rust/blob/master/src/tools/rust... and likely more.

Another is a translation of BASIC code to Rust, using break as a form of goto. https://github.com/coding-horror/basic-computer-games/blob/e...

The example at https://github.com/tokio-rs/mio/blob/master/tests/tcp.rs is a nice one

    // Wait for our TCP stream to connect

In my program, I have about 6 different components that follow the pattern below. Basically, the components run a thread while polling on crossbeam channels, file descriptors or sockets. For polling, I am using Mio (https://github.com/tokio-rs/mio).

On the code side it's pretty much the same as C++. You have a module that defines an interface and per-platform implementations that are included depending on a "configuration conditional checks" #[cfg(target_os = "linux")] macro.

https://github.com/tokio-rs/mio/blob/c6b5f13adf67483d927b176...

Made possible by Wasi support for Mio https://github.com/tokio-rs/mio/pull/1576

Indeed! In practice it's done through the polling operation: instead of a separate poll for op1 and op2, the program essentially tells the OS "wake me when either op1 or op2 is ready" (through the epoll syscall on Linux). The mio crate implements this, and the example on the readme is basically the same loop, but written with this polling strategy in mind.