lsr: ls with io_uring

Re:lsr: ls with io_uring by maplant on Friday July 18, 2025 @10:31AM (#44605037)

This seems more interesting as demonstration of the amortized performance increase you'd expect from using io_uring, or as a tutorial for using it. I don't understand why I'd switch from using something like eza. If I'm listing 10,000 files the difference is between 40ms and 20ms. I absolutely would not notice that for a single invocation of the command.

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Re:lsr: ls with io_uring by rockorager on Friday July 18, 2025 @11:57AM (#44606229)

Yeah, I wrote this as a fun little experiment to learn more io_uring usage. The practical savings of using this are tiny, maybe 5 seconds over your entire life. That wasn't the point haha

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Re:lsr: ls with io_uring by JuettnerDistrib on Friday July 18, 2025 @12:20PM (#44606524)

I'd be curious to know if this helps on supercomputers, which are notorious for frequently hanging for a few seconds on an ls -l.

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Re:lsr: ls with io_uring by mrlongroots on Friday July 18, 2025 @02:37PM (#44608279)

It could, but important to keep in mind that the filesystem architecture there is also very different with a parallel filesystem with disaggregated data and metadata.

When you run `ls -l` you could potentially be enumerating a directory with one file per rank, or worse, one file per particle or something. You could try making the read fast, but I also think that it makes no sense to have that many files: you can do things to reduce the number of files on disk. Also many are trying to push for distributed object stores instead of parallel filesystems... fun space.

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Re:lsr: ls with io_uring by maplant on Friday July 18, 2025 @12:35PM (#44606697)

It's a very cool experiment. Just wanted to perhaps steer the conversation towards those things rather than whether or not this was a good ls replacement because like you say that feels like it was missing the point

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Re:lsr: ls with io_uring by 0x000xca0xfe on Friday July 18, 2025 @11:08AM (#44605508)

Well I have a directory with a couple million JSON files and ls/du take minutes.

Most of the coreutils are not fast enough to actually utilize modern SSDs.

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Re:lsr: ls with io_uring by otterley on Friday July 18, 2025 @11:31AM (#44605839)

What’s the filesystem type? Ext4 suffers terrible lookup performance with large directories, while xfs absolutely flies.

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Re:lsr: ls with io_uring by 0x000xca0xfe on Friday July 18, 2025 @11:45AM (#44606046)

Yup, default ext4 and most files are <4KB, so it's extra bad.

Thanks for the comment, didn't know that!

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