Stream: compiler development

Topic: somewhat off topic io-uring

Ayaz Hafiz (Jul 30 2023 at 03:15):

does anyone here have experience with io-uring?

I am trying to write a program that scans all files recursively in a directory and spits out some metadata about them, including a hash of their contents (here i am using blake3). I'm testing it on a pretty underpowered 2cpu machine with a 5.15 kernel.

I ended up writing a lot of versions but here are 3 that work okay (for a directory with 36K nested files):

• synchronous IO on a threadpool with rayon: 400ms
• async IO with io_uring with a threadpool, each thread sending one IO request to the kernel at a time: 450ms
• async IO with io_uring with a threadpool, each thread send multiple IO requests to the kernel at a time: 400-450ms

I'm really surprised the third version isn't so much better.. does anyone know if I'm doing something obviously wrong?

I am asking elsewhere too but linking here since I know this is something we care about and may want to reference later.

Last updated: Jul 06 2025 at 12:14 UTC