What is io_uring?
An attempt at concise explanation of what io_uring is.
io_uring is a new Linux kernel interface for making system calls.
Traditionally, syscalls are submitted to the kernel individually and
synchronously: a syscall CPU instruction transfers control from the
application to the kernel; control returns to the application only when the
syscall is completed. In contrast, io_uring is a batched and asynchronous
interface. The application submits several syscalls by writing their codes &
arguments to a lock-free shared-memory ring buffer. The kernel reads the
syscalls from this shared memory and executes them at its own pace. To
communicate results back to the application, the kernel writes the results to a
second lock-free shared-memory ring buffer, where they become available to the
application asynchronously.
You might want to use io_uring if:
- you need extra performance unlocked by amortizing userspace/kernelspace context switching across entire batches of syscalls,
- you want a unified asynchronous interface to the entire system.
You might want to avoid io_uring if:
- you need to write portable software,
- you want to use only old, proven features,
- and in particular you want to use features with a good security track record.