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> In practice, things are a bit more complicated. In fact, I don’t know of any async/await embedding on top of io_uring in any language yet, because it doesn’t

> In practice, things are a bit more complicated. In fact, I don’t know of any async/await embedding on top of io_uring in any language yet, because it doesn’t quite match this model. But generally, that’s the idea. Glommio and monoio are async runtimes in rust on top of io_uring and Tokio has an optional io_uring backend. Does that not count? This is such a well researched article that this kind of statement makes me think I’m missing something - surprising the author would get this wrong.

koakuma-chan 1y ago
As far as I know those libraries only implement basic things. They don't use registered buffers, registered file descriptors, etc, and don't implement advanced features like chained operations.
- ozgrakkurt 1y ago
  They are async libraries built on io-uring though. Other mainstream async libraries also don’t go as deep as possible on epoll or other things either afaik
Yoric 1y ago
(author here) I didn't mention tokio's io_uring because, as far as I understand, it is unmaintained. I vaguely recall a conversation in which someone (a contributor?) was claiming that it was not possible to implement most of the features of tokio on io_uring due to conflicting models. [source needed], obviously. I will admit the very existence of glommio or monoio had entirely slipped my mind. I'll probably need to add a few paragraphs about thread-per-core runtimes. Thanks!
- yencabulator 1y ago
  > due to conflicting models The big one is this, and this will wreck a lot of pre-io_uring APIs: Historically, you pass in a buffer to read(2). There is one buffer per pending read. (And this is a scalability limitation.) With io_uring, you have a pool of buffers and a read completes by grabbing a buffer from the pool and putting the data there. io_uring highest-performance API is fundamentally at odds with the historical read API that was inherited from POSIX to just about every stdlib.
lukeh 1y ago
I wrote one for Swift a few years ago, not sure if anyone else is using it but I am! https://github.com/PADL/IORingSwift https://github.com/PADL/IORingSwift
gpderetta 1y ago
boost.asio as well seems [1] to have io_uring support, including registered buffers. It was experimental in 1.21; lots of fixes since, don't know if it is currently considered stable. Asio supports async/await, stackful coroutines and plain old manual continuation passing. [1] https://think-async.com/Asio/asio-1.36.0/doc/asio/history.html#asio.history.asio_1_21_0 https://think-async.com/Asio/asio-1.36.0/doc/asio/history.ht...

koakuma-chan 1y ago

As far as I know those libraries only implement basic things. They don't use registered buffers, registered file descriptors, etc, and don't implement advanced features like chained operations.

ozgrakkurt 1y ago
They are async libraries built on io-uring though. Other mainstream async libraries also don’t go as deep as possible on epoll or other things either afaik

Yoric 1y ago

(author here) I didn't mention tokio's io_uring because, as far as I understand, it is unmaintained. I vaguely recall a conversation in which someone (a contributor?) was claiming that it was not possible to implement most of the features of tokio on io_uring due to conflicting models. [source needed], obviously. I will admit the very existence of glommio or monoio had entirely slipped my mind. I'll probably need to add a few paragraphs about thread-per-core runtimes. Thanks!

yencabulator 1y ago
> due to conflicting models The big one is this, and this will wreck a lot of pre-io_uring APIs: Historically, you pass in a buffer to read(2). There is one buffer per pending read. (And this is a scalability limitation.) With io_uring, you have a pool of buffers and a read completes by grabbing a buffer from the pool and putting the data there. io_uring highest-performance API is fundamentally at odds with the historical read API that was inherited from POSIX to just about every stdlib.

lukeh 1y ago

I wrote one for Swift a few years ago, not sure if anyone else is using it but I am! https://github.com/PADL/IORingSwift https://github.com/PADL/IORingSwift

gpderetta 1y ago

boost.asio as well seems [1] to have io_uring support, including registered buffers. It was experimental in 1.21; lots of fixes since, don't know if it is currently considered stable. Asio supports async/await, stackful coroutines and plain old manual continuation passing. [1] https://think-async.com/Asio/asio-1.36.0/doc/asio/history.html#asio.history.asio_1_21_0 https://think-async.com/Asio/asio-1.36.0/doc/asio/history.ht...