io_uring By Example

This repository is a companion repo for the article series io_uring By Example on the Unixism blog.

It features a set of example programs that serve as an example to illustrate the usage of Linux's io_uring subsystem. The examples build one on top of the other, becoming progressively complex.

Here are what the examples do:

• 01_regular_cat: This is an example of a "cat" program equivalent that uses regular, synchronous I/O. This program is there to illustrate the difference between synchronous I/O and the asynchronous io_uring API.
• 02_cat_uring: This example builds a version of cat with the raw interface provided by io_uring. This is done so that the user understands how the io_uring interface works at a low-level.
• 03_cat_liburing: This example is functionally the same as the previous example, but uses the higher-level API provided by liburing.
• 04_cp_liburing: This example is an implementation of a copy command that uses multiple requests in io_uring's submission queue.
• 05_webserver_liburing: This is the final example in the series. This bulids a simple web server that is capable of serving static files. It illustrates the use of accept(), along with readv() and writev().

Please note that you will need at least Linux kernel version 5.5 and above to get all these examples to work. Support for the accept() operation in io_uring was added in kernel v5.5.

The example web server in action