AnSpake / osiris

A simple server/client using io_uring in order to play with it

Osiris

Disclaimer

This is a ongoing project. Benchmarking results are not out yet.
This project uses latest master of https://github.com/axboe/liburing/commits/master as of Feb 13, 2021, commits 5671af3 YOU NEED TO BE ON LINUX KERNEL 5.11 OR LATER.

io_uring benchmarking

This repository contains:

• epoll server with Level and Edge trigger modes
• io_uring server with interrupt, poll and kernel polling modes
• benchmarking results (faio)

io_uring additionnal informations

• Kernel polling mode will only cost 2 context switches for the server (and additionnal context switches to wake up the kernel thread)
• Kernel polling mode only works with "registered file descriptor" unless you use the IORING_FEAT_SQPOLL_NONFIXED
• Interrupt and polling modes can use the flag IORING_FEAT_FAST_POLL to gain more performance (https://github.com/axboe/liburing/blob/master/man/io_uring_setup.2#L255)
• This io_uring server uses automatic buffer selection (https://lwn.net/Articles/815491/)
• IORING_FEAT_SINGLE_MMAP enable the SQ and CQ rings to be mapped in one mmap call, the SQEs must still be allocated separately. This brings the necessary mmap calls down from 3 to 2.

TODO

• Test w/ io_uring kernel polling mode without IORING_FEAT_SQPOLL_NONFIXED
• Test w/ io_uring without automatic buffer selection

Authors

Amandine Nassiri [e-mail]
https://github.com/AnSpake/osiris